Abstract

Introduction: The problem statement of this research revolves around the problem faced by Toffo Co, which is the major trade of Tofoo in the UK. This organisation is dealing with high demand; thus, to increase production as well as the quality of tofoo, this research focus on identifying the most suitable particle size to gain the highest yield.

Aim: This research aims to identify the impact of soy milk slurry particle size on soya milk yield for manufacturing tofu at the Tofoo Company limited.

Objectives: Objectives of this research are to investigate the relationship between particle size and yield of soymilk production and suggest a method to ensure the selection of suitable particle size of soy milk slurry to gain the highest yield.

Methodology: Variation in soaking and grinding time has been considered for measuring yield from different sets of soybeans samples. While ensuring yield and identifying the particle size  Y= (W₁ * 100)/W₀ this formula has been considered.

Results: In results through statistical analysis, the indifferent grinding time and particle size was measured, and yield percentage was measured. The particle size and yield percentage has been measured by considering the formula of Y= (W₁ * 100)/W_0. Where Y represents Extract yield (g / 100g), W₁ Extract (g), and W₀ Initial dried soybean (g). The Most suitable particle size achieved was 136.6um. The experiment has been considered by 6 different grinding times in seconds. These grinding times range from 40 seconds to 300 seconds.  As per the changes in time yield percentage has also changed as per observation. During 40 second the yield was 48.73 percent and in 60 seconds the yield percentage was 53.4 percentage. During the grinding time of 120 seconds 56.2 percentage yield was achieved and in case of 180 second yield of 60.7 percent has been achieved. The highest yield was achieved at 300 second which was 74.3 percent. This signifies that as per increase in grinding time yield percentage has increased. As there has been direct relationship between particle size and yield percentage thus in the highest percentage particle size of 136.6 um has been witnessed. Thus, based on the results it becomes evident that along with increase in grinding time increase in yield and decrease in particle size has been witnessed thus there is strong relationship between reduced size of soybean particles and increase in yield.

Conclusion and recommendation: In conclusion, it can be identified that wet grinding techniques are most suitable, and 136.6um particle size results in the highest yield. A strict measure for following grinding time and wet grinding techniques has been suggested.

ACKNOWLEDGEMENTS

I want to thank all my supervisors and peers and also all my family members. I would also like to thank all individuals who enlightened me in my journey and helped me to think critically. I confirm that this dissertation is my work, and no part of it has been previously published elsewhere or submitted as part of any other module.

Thank you

Table of contents

1.0 INTRODUCTION. 8

1.1 Statement of the Problem.. 9

1.2 Aim.. 9

1.3 Objectives 9

1.4 Research questions 10

1.5 Purpose of study. 10

2.0 LITERATURE REVIEW.. 11

2.1 Introduction. 11

2.1 History of the Tofoo Company Limited. 11

2.1.1 TOFOO COMPANY LIMITED Financial Statements 13

2.2 Grinding Process 14

2.3 Grinding Process and Moisture. 16

2.4 Methods of grinding food materials 17

2.4.1 Dry and semi-dry/wet grinding process 17

2.4.2 Wet grinding. 18

2.5 Distribution of particles by shape and size. 19

2.6 Grinding process and specification of soy milk production. 20

2.2.1 Production of soy milk. 21

2.2.2 Production of Tofoo. 23

2.4 Particle size /Size Reduction. 24

3. Gap in literature. 24

3.0 METHODOLOGY. 25

3.1 Introduction. 25

3.2 Research method and material refer to a paper 25

3.2.1 Materials 25

3.2.2 Methods 25

3.2.2.1 Soybean Hydration. 25

3.2.2.2 Grinding techniques of soymilk. 26

3.2.2.3 Particle size method with the wet method. 26

3.3 Data collection process 27

3.4 Data analysis process 27

3.5 Limitation of method. 28

4.0 RESULTS. 29

4.2 Introduction. 29

4.2 Findings and analysis 29

5.1 Relationship between the particle size and yield in the soymilk production of Tofoo Co. 42

5.2Method for identifying the suitable particle size for getting high-quality soy milk in The Tofoo Co. 44

5.3 Suitable timing and particle size for extracting high-quality soy milk from soybeans in The Tofoo Co. 45

5.4 Difference between wet grinding and dry grinding in the process of soymilk extraction. 46

6.0 CONCLUSION AND RECOMMENDATIONS. 47

5.1 Conclusion. 47

5.2 Linking with objectives 47

5.3 Recommendations 48

5.4 Limitation of research. 49

5.5 Future scope of research. 49

REFERENCES. 50

APPENDIX. 56

List of figures

Figure 1: Pictorial representation of stages of processing of soy milk at The Tofoo Company Limited. 14

Figure 2: Flow Chart for Soymilk Production. 21

Figure 3: Soymilk production process step by step. 22

Figure 4: Image of hydrated (soaked) Soybeans 26

Figure 5: Pictorial representation of the Grinded sample. 26

Figure 6: Average yield soy milk extract of soybeans by grinding time. 29

Figure 7: Average particle size of soybeans by grinding time. 30

Figure 8: Different sample sizes and grinding times with parameters 32

Figure 9: Graphical representation of volume density with size class for sample A. 33

Figure 10: Graphical representation of volume density with size class for sample B. 33

Figure 11: Graphical representation of volume density with size class for sample C. 34

Figure 12: Graphical representation of volume density with size class for sample D. 35

Figure 13: Graphical representation of volume density with size class for sample E. 36

Figure 14: Graphical representation of volume density with size class for sample F. 37

1.0 INTRODUCTION

Tofu is a super healthy plant-based protein. It’s made from soybean curd, which sounds a bit weird but is amazing. It’s one of the most complete and versatile protein foods in the world. Tofu has a subtle flavour, making it a taste chameleon – taking on the flavour of any dish it goes in. Tofoo Company Limited is a functional company that merged on May 24, 1999, with a registered office in Malton, North Yorkshire. Tofoo Company Limited has been operating for 23 years. There are currently 4 directors in operation, according to the latest confirmation statement submitted on 24 May 2022. In 2015, husband and wife David Knibbs and Lydia Smith bought a small artisan tofu business in Malton, North Yorkshire, which had been run by Ron, a Vegan and absolute student of making the best tofu from a traditional Japanese recipe. Their vision was to launch an exciting new tofu brand using this fantastic product to show that the world should love tofu. They wanted to create a fun, exciting brand that could be stocked within UK supermarkets and made high-quality handmade tofu accessible to all. In September 2016, The Tofoo Co. was born. At Tofoo Co., Tofoo is made to a traditional Japanese recipe using only 3 ingredients: water, soya beans, and nigari as a binder which is only available within the UK. We source all our beans from Canada & Italy from reputable growers who do not incorporate pesticides and chemical fertilizers and who do not use genetically modified organisms. We are always looking for sources closer to home, but we will only ever buy great-tasting, salute-worthy, sustainable beans.

Soy milk is a creamy liquid made from soybeans that resemble cow’s milk in mien and firmness. It is highly nourishing and contains many proteins, vitamins, fats, minerals, and carbohydrates. It is because of the high plant-based protein and the relatively low cost compared to the animal-based protein that soy milk plays an important role in the diet of people that consume it (Deepika et al., 2017).

The major procedure involved in producing soy milk is wet or liquid grinding. Strategies have been developed to improve protein utilization by controlling factors such as the ratio of bean-to-water balance and grinding processes with varying degrees of success. Although the soaking of soybeans is an important step in the process, it has not received enough attention (Vishwanathan et al., 2011).

Grinding or size reduction is an important unit function that changes particle size and shape, increases compact mass, improves flow structures, increases porosity, and produces new space. However, the physical properties and flow of organisms depend largely on particle size and distribution (Thirupathihalli and Balaraman, 2013).

Grinding is an energy-hungry process, and it is important to use energy as efficiently as possible. Electrical power is required to separate objects and to overcome the friction between moving parts of a machine. Almost all the energy in the grinding system is dissipated as heat, and only 0.06 – 1% of the input energy is used to reduce the object’s size (Ghorbani et al., 2010).

Even though the above reports have improved the understanding of the benefits of pre-immersion and the regulation of ground temperatures in processing soybeans, there are no studies on the parameters of grinding soybeans. The current study, therefore, aims to investigate the impact of varying key parameters of the grinding process in manufacturing soymilk, such as the ratio of water addition, and to understand the influence of the output of particle size on protein extractability and yield. The processing area and laboratory spaces at the National Centre of Excellence for Food Engineering (NCEFE) and City campus will be utilized in this project after the process and parameters have been defined through a visit to The Tofoo Co factory.

1.1 Statement of the Problem

Tofu is made from the coagulation of soy milk, and soy milk is made from soybeans and water. As The Tofoo Co is growing, it becomes increasingly important that we extract every drop of soy milk out of those beans, so we want this project to take a very close look at how The Tofoo Co is making their soy milk.

1.2 Aim

This research aims to identify the impact of soy milk slurry particle size on soya milk yield for manufacturing tofu at the Tofoo Company limited.

1.3 Objectives

• To investigate the relationship between particle size and yield of soymilk production
• To suggest the method to ensure the selection of suitable particle size of soy milk slurry to gain the highest yield

1.4 Research questions

• ?

1.5 Purpose of study

The research has been considered for the Tofoo Co limited, and it is one of the renowned Tofoo makers in the country. In the year 2020, this company achieved a turnover of £14.7 million, it is a significant 89% increase from the first year of trading, which was 2016 (The Press, 2021). It becomes significant that this organisation has enhanced its productivity as well as it has enhanced the quality of Tofoo. The purpose of this research is to further guide this company by providing the measures and parameters of particle size desired for gaining the highest yield of soymilk. Achieving a high yield from each batch of soymilk will provide scope for this company to reduce costs of operation as well as it will help to meet growing demand in the market. The reason behind selection of the research topic is to provide idea of optimum grinding time particle size of soyabean for enhancing production of soymilk and tofoo. Thus findings of the research and optimum time and particle size identified can help this  company to meet rapid increase in customer demand.

2.0 LITERATURE REVIEW

2.1 Introduction

The soy milk manufacturing process is influenced by various parameters, including time, the particle size of soy milk slurry, and temperature. Thus, to understand the interrelationship of the parameters along with the yield percentage of soymilk, it becomes necessary to understand the factors influencing yield percentage along with particle size and other quality measures influenced by the grinding process. This literature review includes a brief description of the grinding process with detail of the grinding process and moisture along with the methods of grinding food materials.

2.1 History of the Tofoo Company Limited

THE TOFOO LIMITED is a limited private company (Ltd.) based at 4 RYE CLOSE YORK ROAD BUSINESS PARK, United Kingdom, employing 101 people. The company started trading on 24 May 1999. The company’s registration number is 03775780, the main business line producing other food products n.e.c, and the company is listed as active. In 2015, husband and wife team David and Lydia decided to rip up the rulebook and stick their tongue out at the tofu establishment. Here’s how it all went down:

2015

• David and Lydia saw a gap in the tofu game. No one was giving that block of white stuff much love. So, they hatched a plan to take over the (tofu) world.
• First job was designing the brand.

2016

• David and Lydia begged, borrowed, and blagged enough cash to buy a small artisan tofu business in Malton, which was already making the best organic tofu, to a traditional Japanese recipe. Handy!
• After a year’s extensive research, brand building, and schmoozing buyers, Naked and Smoked Tofoo hits the supermarkets. First major listings – Tesco in 2000 outlets & Ocado!

2017

• Sainsbury, Waitrose, and Co-op fall in love with Tofoo – they’re only human.
• We join forces with Mob Kitchen to make some ridiculously tasty recipes – including tofu coated in crispy cornflour. Did somebody say game changer?

2018 EXPANSION

• Sainsbury, Waitrose, and Co-op fall in love with Tofoo – they’re only human.
• We join forces with Mob Kitchen to make some ridiculously tasty recipes – including tofu coated in crispy cornflour. Did somebody say game changer?

2019

• 10K followers on Instagram – hello, Tofooniacs.
• New ranges: Crispy Tofoo – Southern Fried Tofoo Bites and Wholemeal Tofoo Chunkies.
• Say hello to Tempeh… tofu’s chunkier brother.

2020

• January helps us smash the £1million mark in January. Tofu is here to stay.
• The Tofoo Sizzler range launches with a bang! All sizzle, no shizzle.
• Tofoo becomes the UK’s number 1 tofu brand.
• Our Cubed range of Tofoo and Tempeh launches.
• Tofoo gets its first listings in Morrison’s!

2021

• January helps us smash the £1million mark in January. Tofu is here to stay.
• The Tofoo Sizzler range launches with a bang! All sizzle, no shizzle.
• Tofoo becomes the UK’s number 1 tofu brand.
• Our Cubed range of Tofoo and Tempeh launches.
• Tofoo gets its first listings in Morrison’s

2.1.1 TOFOO COMPANY LIMITED Financial Statements

According to a recent financial report from TOFOO COMPANY LIMITED submitted for 2020-12-31, the company has a net worth of £708,227.00, total assets of £7M, and while Working-Capital is £402,196.00. Compared to last year, the company reported a 99.98% increase in revenue, equivalent to -708093. At the same time, Total Assets increased by 37.95%, or -2690615.

Figure 1: Pictorial representation of stages of processing of soy milk at The Tofoo Company Limited

2.2 Grinding Process

The grinding process, a single operation to reduce the size of a material, plays an important role in many aspects of the food industry. Many food processes often require size reduction, which is achieved by applying different forces to create particles of specific sizes and shapes. Size reduction, directly related to chemical and microbiological stability and convenience, is one of the most drastic and energy-intensive processes in the food industry. In the food industry, powders are considered both final and intermediate products between unit operations (Murrieta-Pazos et al., 2012). The grinding process involves various operations using equipment such as meat grinders, grinders, cutters, mills, crushers, shredders, disintegrators, and homogenizers (Djantou et al., 2007). Grinding requires the destruction or rupture of materials through mechanisms such as compression, impact, abrasion or shear, and cutting (Barbosa-Cánovas et al., 2005). Solid food materials are broken down into small particles by size reduction mechanisms. The powders are then produced by grinding.

Many parameters involved in the grinding process and related to the material, such as the grinding method and equipment, grinding time, and the strength and moisture content of the material, affect the characteristics of the powder. The amount of moisture in food materials before grinding is a particularly important factor because it helps determine the physical properties of the materials and the properties of the powder (Ngamnikom and Songsermpong, 2011). Many researchers have investigated the effectiveness of the milling process on grains and other food materials with different moisture contents (Lee et al., 2013). Several studies have shown that particle properties depend on the structure of food materials, which may be different at different levels of moisture content (Lee and Yoon, 2015). In addition, their fraction of large particles is lower for those with lower humidity content than for those with high moisture levels, and vice versa (Moon and Yoon, 2017). The fact that coarser particles usually have less sphericity is closely related to the internal friction between the particles. In particular, the flow properties of the powder are significantly affected by the irregular shapes of the large particles (Lee and Yoon, 2015). Thus, powders from food materials with different moisture content levels may exhibit different powder properties concerning particle shape, particle size distribution, and flow ability—that is, the ability of the powder to flow. Grinding is an energy-intensive process in which a solid substance is broken down. Energy consumption to reduce the size of many types of agricultural and food materials increases as the screen opening size changes from coarser to finer and as the moisture content or hardness of the material increases (Rozalli et al., 2015). The need for energy consumption during grinding increases as the moisture level in the material increases. This is due to the higher moisture content, which makes the process of deformation and cutting of the material more intense (Lee and Yoo, 2014). Therefore, crushing energy needs to be analyzed to reduce inefficient energy consumption. Several models, such as Fitzpatrick et al. (2004), explain energy consumption in the grinding process of food and agricultural materials. The properties of powders play a major role in processing or handling processes such as preparation and mixing, storage in silos and bins, pressing and packaging, and transportation (Opalin’ski et al., 2012). The cohesiveness of powders is related to moisture content due to liquid bridges between particles that cause spontaneous aggregation of particles. The powder must exhibit properties that allow it to flow easily, similar to a liquid, so that the materials can be worked with without major limitations such as cohesion, friction, and interparticle bonding. Designing effective powder handling processes requires measuring the flow properties of the powder. Flowability includes particle properties (such as size and shape) during grinding, grinding energy consumption and model, and powder flowability depending on moisture content. Typically, the flow properties of powders are determined by a shear test based on the Jenike shear cell test (Fitzpatrick et al., 2004). Recently, many new methods have been published to optimize powder flow patterns in machining processes, such as discrete element modeling (DEM), rheological measurements, and computer-aided image analysis (Fu et al., 2012).

2.3 Grinding Process and Moisture

Grinding is carried out by exerting a mechanical impact on the material, followed by its rupture, and the energy required by this process depends on the friability of the material. During the grinding process, the initial moisture content affects the mechanical properties of the material, such as strength, stiffness, elasticity, and ductility (Djantou et al., 2011). Grinding time and energy consumption is determined by the mechanical properties of the food materials, as well as the appearance and characteristics of the final milled product (Balasubramanian et al., 2013). Generally, the efficiency of the food grinding process increases as the moisture content of the material decreases because the material with less moisture is more fragile (Dabbour et al., 2015). The increase in ductility or malleability of materials containing a large amount of moisture is responsible for the increase in energy consumption during grinding. Therefore, dry or wet milling methods, in which initial moisture content is adjusted before milling, are used in commercial milling processes to investigate the effect of moisture content on milling efficiency (Lee et al., 2013). These grinding processes using different machines affect the composition, particle size distribution, and quality of the final product of food materials. In addition, simulations of the grinding process have been studied and reported in the literature. These modeling studies addressed the so-called dynamic principle, which uses first-order reaction kinetics based on the kinetic behaviour of particle size reduction as well as grinding characteristics to predict, optimize, and analyze the grinding process.

2.4 Methods of grinding food materials

Grinding methods and machines are the main operational factors that control the properties of the powder with a certain initial moisture content of food materials. Three methods are used to prepare food powder by adjusting the moisture content: dry milling, semi-dry/wet milling, and wet milling (Chiang and Yeh, 2002). Dry grinding is done without water and with low grinding energy consumption. On the other hand, wet grinding uses excess water, which is directly related to powder loss, high water consumption, high energy consumption, and wastewater treatment. Powder properties such as structure, viscosity, and particle size can be controlled by implementing a semi-dry/wet milling process because intermediate properties can be found (Lee et al., 2013). Grinding operations using three grinding methods and different grinding machines lead to different grinding results, viz. particle size, composition, functional properties, and product quality using powder. On the other hand, the inherent structure of the food materials, the applied grinding power, and the grinding technology also contribute to the grinding properties, but this will not be covered in this bibliographic study regarding moisture content.

2.4.1 Dry and semi-dry/wet grinding process

Dry and semi-dry/wet grinding are conventional methods that do not add excess water during grinding, generate no wastewater, and therefore use less energy during grinding. A sample for dry grinding is usually used as is or dried, while semi-dry/wet grinding involves a pre-soaking and drying process. Generally, these are the three methods used in most grinding processes for food materials. Grinding machines used in the dry grinding process include pin mills, hammer mills, disc mills, roller mills, etc. Dry grinding machines are also used in the semi-dry/wet grinding process. Dry and semi-dry/wet grinding methods were used to study the effect of moisture content on the grinding of cereals, legumes, fruits, and spices (Dabbour et al., 2015). However, the dry milling method has some disadvantages due to the generation of heat that damages the physical and functional qualities of the resulting powders, such as nutritional components and aroma (Murthy et al., 2007). Dry milling of rice using a roller mill, hammer mill, and pin mill was investigated in a study by Ngamnikom and Songsermpong (2011). The maximum temperature of the samples after dry grinding increased to 46.5 ◦C, and after wet and sublimated grinding – to 39.5 ◦C and 25.2 ◦C, respectively. The pin mill and the hammer mill generate more heat than the roller mill; however, damage to starch content was highest in dry milling processes, and there were no significant differences in damaged starch content among grinders. In the semi-dry/wet milling process, the powder properties were average compared to the dry and wet powders in terms of the amount of damaged starch, viscosity, particle size, etc. the grinding method produces a powder of better physical and functional quality. Semi-dry/wet-milled rice powder had quality characteristics of whiteness and damaged starch content that improved as moisture content increased (Tong et al., 2015). However, it had a lower grinding efficiency than the dry grinding method (Tong et al., 2016).

2.4.2 Wet grinding

Wet milling is a common food powder preparation process that involves five sequential processes: hydration (also known as soaking), adding additional water during grinding, filtering, drying, and sieving. Wet grinding is generally done after complete hydration, which allows the food materials to soften. Generally, the moisture content of the soaking curve reaches equilibrium Ngamnik and Songsermpong (2011). Wet grinding is advantageous for the quality indicators of the final product. Rice powder showed the highest whiteness and the lowest damaged starch content in a study (Tong et al., 2015). Better rice starch quality after wet milling was also observed in the research of Leewatchararongjaroen and Anuntagool (2016). Pre-soaking of soybeans has been observed to be beneficial in reducing the size and separating the fiber from other components generated during the milling process, in addition to reducing milling time and energy (Djantou et al., 2011). The disadvantage of this process is that it requires a lot of equipment and human resources. Given the costs associated with product loss, an alternative method is needed for high water consumption, high energy consumption, and wastewater treatment Ngamnik and Songsermpong (2011). In addition, this method causes changes in both chemical and physical properties Ngamnikom and Songsermpong, (2011). For example, unpleasant flavors are formed during the wet grinding of soybeans, a process of pre-treatment of soy milk. Wet milling creates favorable conditions for the acceleration of chemical reactions, such as lipid oxidation, which occurs in water and air and is catalyzed by lipoxygenase. Therefore, operating costs, soaking time and material characteristics must be considered for this method.

2.5 Distribution of particles by shape and size

After grinding, the food powder particles have different sizes and shapes. In food processing, mixing and flow processes can be affected by particle sizes and shapes (Bayram and Öner, 2007). Therefore, in tasks related to food processing, such as the production and transportation of products, it is necessary to define and understand the characteristics of particles (Tong et al., 2015). In particular, the size of the particles determines the quality of food products. For example, the uniform dispersion of particles in food products showed an acceptable and desirable consistency. The grinding process, using shear or abrasion forces, plays an important role in producing fine food particles. According to Barbosa-Cánovas et al., (2005). Three main mechanisms of particle wear have been studied: cleavage, chipping, and erosion. These mechanisms are governed by the modes of failure, respectively, brittle, semi-brittle, and ductile. Medium-sized particles are produced by shattering, while smaller-sized particles are produced by erosion. Normally, soft materials undergo plastic failure. The initial moisture content of food materials can be closely related to these abrasion mechanisms. The shape and size distribution of the particles are closely related to the hardness of the material. After grinding, the particle shape of food materials with high moisture content becomes more irregular due to the brittle fracture characteristics. In dry and wet milling of rice, the shape of the particles after dry milling had sharp fracture angles, while the particles subjected to wet milling showed round and smooth surfaces (Ngamnikom and Songsermpong, 2011). For dry and semi-dry/wet milled powder, increasing the initial moisture content increased the average particle size and large particle fraction (Chiang and Yeh, 2002). If the moisture content is low, the food material becomes brittle and is broken down by force. However, an increase in the plasticity of the material is observed with an increase in humidity. In a study by Djantou et al. (2011), wheat kernels developed many cracks when the moisture content was less than 16%, while no cracks were observed when the moisture content was higher than 16%. Similar results were observed when grinding black soybeans and peas. On the other hand, the wet milling process produces the opposite results. On materials with equilibrium moisture, the softening effect of soaking in water resulted in smaller average particle sizes and smaller particle fractions. The smallest mean particle size after wet milling was observed for rice milling compared to particles obtained from dry and semi-dry/wet milling (Bayram and Öner, 2007).

2.6 Grinding process and specification of soy milk production

The grinding process of the soymilk is one of the key aspects for the final product to be of desired quality. As described by Zhang et al. (2018), the grinding process of the soymilk is the pivotal moments before the ingredients are soaked, producing the quality and the final product. One of the key aspects of the grinding process is size reduction, and it is one of the techniques that are used by most food manufacturing companies. As suggested by Choi et al. (2018), grinding allow converting soybeans to soy flour as based on soy flour quality, soy milk is prepared; thus, grinding play a vital role in soy milk processing. As per the views of Rodriguez et al. (2019), grinding equipment is available for grinding purposes, including mince, cutters, and grinders. As per solid food particles are concerned, they are being cut and reduced to smaller particles for the mechanisms of the grinding machinery to take over. That is the reason why to produce any of the fine particles of the food, some essential grinding parameters are needed to be considered and implemented fully. As described by Guan et al. (2020), the grinding parameters essential for the food industry to maintain are – the grinding method and machinery, grinding time, and the moisture of the particles involved can affect the powder particles. Soybeans were soaked overnight for 18 hours in warm drinking water to obtain a 1:3 bean: water ratio. When soaking soybeans at room temperature, a 0.5-1% solution of sodium bicarbonate is also used. Then strain the beans, rinse with drinking water, and blanch for 5 minutes in boiling water. Drain the blanched beans, peel them and grind them with drinking water in a blender. The resulting slurry is filtered through a muslin cloth, and the resulting extract (milk) is boiled for 15 minutes (Banerjee et al., 2019).

Soybeans

Sorting and Washing

Soaking (18 h)

Blanching (for 5min)

Draining

Dehulling

Grinding Milling

Diluting with water (1:3)

Sieving/Filtering

Boiling (for 15min)

Cooling

Soymilk

Figure 2: Flow Chart for Soymilk Production

(Source: Banerjee et al., 2019)

2.2.1 Production of soy milk

Soymilk can be explained as the aqueous extraction of sardines having a similar milk-like appearance. The traditional procedure of making soy milk is soaking the soya beans in water and grinding them with water. The resulting product is slurry boiled for 15 to 20 minutes after filtration and is considered to remove the insoluble residues such as soy pulp. As mentioned by Kristiningrum et al. (2021), soy milk has a distinct odour and taste due to the presence of lipoxygenase enzymes. This enzyme can be treated through a high temperature of 80 to 100^oC for 10 to 15 minutes to remove the odour and bean test. Then the soya milk is ready for consumption as per the traditional method. However, as per the improvement in technology and manufacturing facilities, soymilk is majorly produced in a manufacturing unit with the help of technology-guided apparatus. The tofoo card is made from soy milk, considered one of the most nutritious food ingredients, specifically in the Asian continent. The modern style soya milk-making procedure is also known as the reconstituted soy milk-making procedure. Majorly there are two types of reconstituted soymilk. The first has a slight bean-like flavour prepared by soaking and grinding the service with hot water. As stated by Hui et al. (2022) PH values in every stage of soymilk production need to be maintained for avoiding degraded quality of soymilk. People prefer soy products with a little bean-like flavour prefer this type of soymilk-based products. Another type of soya milk is considered white sand milk, and it has a dairy-like taste and is often unpasteurised. This type of white soya milk requires no refrigeration.

Figure 3: Soymilk production process step by step

(Source:  Hui et al., 2022)

There are mainly 11 step-by-step procedures for preparing the soymilk. However, before the first process can be started, it becomes necessary to access the raw materials. The raw materials for preparing the soya milk are very basic, which are soya beans and water. As soy milk has low acid content, thus it acts as a good source of bacteria. Thus, it becomes necessary to ensure an aseptic procedure while preparing the milk and it is necessary to be sealed away from the air to avoid any contamination. As suggested by Zhang et al. (2018) thermal storage mechanism influences the volatile profile in soymilk that impacts the flavour of soymilk. The first step is procuring the raw materials and, in this stage, the soybeans are directly stocked from farmers in case of industrial production. The second process associated with the production of soy milk is dehauling. In this process the soybeans are steamed and split in half this process loses the hull on the bean and then separated through a vacuum. The third stage of soya milk production is the invalidation of indigestible enzymes present in soybean. In this process, the soya beans are cooked to invalidate or counteract the enzymes that are considered to be indigestible to humans. The long hours of cooking lead to enzyme invalidation, and a specific high temperature and pressure must be maintained to ensure the invalidation process. The fourth stage is rough grinding, and in this stage, the cooked soybeans are grinded through a mill, and during the grinding process, water is added to prepare the slurry. The fifth stage is finally grinding, and in this stage, the cooked soya bean and slurry prepared to the good of grinding is further grinded to minimise the particle size for extracting more smooth slurry. The sixth stage is extracting, and in this stage, the centrifuge is used to extract the soya milk from soy fibre. The seven stages of blending and in the stage defined flavours, sugars, and vitamins are mixed with the soy milk to remove the flavour of raw milk or bean taste. The eighth stage is a septic sterilisation process, and in this step, the packaging process starts in which, in an airtight container, the raw milk or the soya milk is packaged. As mentioned by Waghmare et al. (2022), during the soymilk production process maintaining high-pressure and high-temperature treatment for a significant time after certain gaps lead to the successful completion aseptic sterilisation process. The sealed containers are then treated with high temperature and pressure for a short period for the sterilisation process. The ninth step is homogenising, and in this process, the mail is treated under high-pressure to prevent fat molecules from separating from the rest of the milk. The 10th step is cooling, and the hot milk is transferred to the cooling tank for the final stages.

At last, in the 11th stage, the cooked milk is stored in an air-sealed tank for packaging purposes. Thus it becomes evident that each step in the soymilk production process has significance and importance in maintaining the yield quality. It becomes necessary to maintain grinding times and pressure to achieve the particle size necessary for the highest yield and nutritional content in soymilk.

2.2.2 Production of Tofoo

Tofu making procedures start after the completion of the soymilk preparation process. Tofoo has solidified chunks of soymilk that can be made through both traditional and industrial processes. The process of tofu preparation can be differentiated into eight stages. These weight stages include the soaking process of beans and the processing of s soybeans. In the soaking process, similar to the soy milk preparation process, dry beans are soaked for a minimum of 12 to 14 hours, and as the beans soak in water, it becomes double in size. In the second stage, the soymilk extraction is completed, the slurry is prepared through the grinding machine, and the slurry is treated at a high temperature to neutralise enzymes for hindering digestion. In the third stage, the soymilk is further pressed with a roller press to separate the fibers from the main compound of the soymilk. This process is completed within 2 to 3 hours. The fourth stage is the solidification of the soymilk after the juice has been extracted from soybeans. As stated by Yang et al. (2020) salt bases coagulants in soy milk provide better self-life to tofoo prepared by ensuring aseptic properties. In this stage, coagulant such as calcium sulphate or magnesium chloride, also known as nigari, is added to the milk and these coagulants alter the PH balances resulting in the solidification of the tofoo. As mentioned by Guan et al. (2021) coagulation process alters the protein percentage yielded. Thus while coagulation and pasteurisation, it becomes necessary to maintain a high protein percentage. This step is completed in 20 minutes. The first stage is the pressing of the tofu and the bean curd is there pressed under high pressure for draining off the liquid to prepare blocks of pressed curds.   In the sixth stage, the tofu is cut, and in the 7th stage, the tofoo is packaged. The pasteurisation of tofoo occurs at this stage in which the tofu cubes are treated at 180oF, increasing the shelf life of the tofoo. The Tofoo Company follows all these stages to prepare high-quality tofu from soy milk.

2.4 Particle size /Size Reduction

Based on the particle size, the extractability of soy milk enhances. There are certain bio-reactive properties in soymilk that impair the colour and texture of Tofoo in this case; thus, the reduction in particle size leads to modification of the negative impact of bio-reactive compounds improving the gelatinous texture of tofu (Lan et al. 2021). Reduction in participle size enhances the micro-texture and improves the yield and superficial texture of tofu. The tofu cured is better bound if the particle size is reduced. Particle size reduction can be achieved by increasing the grinding time (Kim et al. 2019). Considering the benefits of particle size reduction, Tofoo Co limited can achieve better yield in soymilk and tofu production, which can benefit the company.

3. Gap in literature

The above literature review includes different grinding techniques and processes of tofu and soymilk production. The importance of particle size reduction to enhance yield quality has also been mentioned. However, this literature review lacks a detailed analysis of the particle size most suitable for achieving the highest yield for supporting Tofoo co to improve its production. This gap in literature will be met through results and discussion.

3.0 METHODOLOGY

3.1 Introduction

This chapter also includes the collection techniques of the data necessary for the research and the data analysis process that has been considered. The methodology certifies that the process that has been considered for the research and all the data that has been collected during the research is related and reliable so that by analysing that data, research findings can be drawn. The chapter also includes the limitation of the research methods and the research ethics.

3.2 Research method and material refer to a paper

3.2.1 Materials

The research materials are the key components for producing soymilk for the Tofu Company. Organic soybeans (Canadian origin) were gotten from The Tofoo Company Limited 4, Rye Close, Malton, North Yorkshire YO17 6YD and transported to the National Centre of Excellence for Food Engineering (NCEFE), Sheffield Hallam University, Sheffield, UK. The equipment used was supplied by the National Centre of Excellence for Food Engineering (NCEFE), Sheffield Hallam University, Sheffield, UK.

3.2.2 Methods

3.2.2.1 Soybean Hydration

As per the methods of the soybean are concerned, the first one is the hydration of the soybean. As mentioned by Mokarizadeh et al. (2021), hydration enhances the grinding process by softening the soybean. For the hydration process, 250 g soybeans were soaked separately in the water in a ratio of 1:5 for 16 hours in water at room temperature (16 ± 2 °C). Excess water was drained off before grinding.

Figure 4: Image of hydrated (soaked) Soybeans

3.2.2.2 Grinding techniques of soymilk

The grinding technique of the soybean is the key to all the essentiality of the grinding. As described by Li et al. (2020), the grinding technique is the key and an essential part of the process of the making of extraction of Soy milk. Here, the batch grinding technique has been considered, and hydrated soybeans are ground for 40, 60, 120, 180, 240, and 300 seconds by the use of the 220W laboratory blender with added 430 ml of water. All the wet samples are kept for further analysis.      

C

B

A

(a.) Grinded Slurry (b.) The extraction process of the sample using a muslin cloth (c.) Wet grinded sample

Figure 5: Pictorial representation of the Grinded sample

3.2.2.3 Particle size method with the wet method

After grinding at the defined grinding times, the wet samples were available for analysis. As described by Yu et al. (2021), the essentiality of the wet method is the key to the betterment of the process of Soy milk. The distribution of Soybean particles for the wet analysis is measured for laser diffraction. In this analysis, water is used for the dispersion of the sample materials from the inlet of the sample of cells. Almost 1g of the sample in the 10 ml of water has been used, but the dropping area of the sample is 400g. For assurance, the measurement has been repeated a minimum of three times.

3.3 Data collection process

Data has been collected based on measuring the extracted yield of soymilk based on the variation of soaking time and particle size of a soybean. The extracted yield is the key to the mixing and later grinding of the Soybeans. As mentioned by Li et al. (2019), the absorption of the water from the Soybean seed for the extraction yield is the key stage of the wet analysis. All the extracted samples are weighed and recorded as W₁. The initial weight of these Soybeans has been determined, and it has been recorded as W₀. The formula for the extracted yield calculation is

Y= (W₁ * 100)/W₀

Where Y represents Extract yield (g / 100g), W₁ Extract (g), and W₀ Initial dried soybean (g).   

The mathematical formula has been considered to evaluate the interrelation between particle size and yield percentage. As per the varying grinding time, each sample has been separated, and the differences between the initial weight and extract weight in each case have been determined.

3.4 Data analysis process

The statistical analysis process has been considered in this research to identify the interrelationship between particle size and the yield of soya milk. Statistical analysis is crucial for the experimental research process. As mentioned by Mareese et al. (2018), statistical data analysis provides the scope of graphical representation for better understanding. For the data analysis, the wet analysis is the process of analysis of variance. Different sample sizes are also being used for the analysis with the DMRT or the Duncan’s Multiple Test, and it has been used for the separation of the P_< 0.05 with the statistical package for the social sciences of version 16.0 windows.  

3.5 Limitation of method

This research has been completed in laboratory environment and practical in hand experiment has been considered. There is certain limitation of laboratory work in terms of lack of flexibility and repletion if any type of error occurs. In the current case similar limitation are applicable thus to avoid the limitation associated with of opportunity or petition same experience varying time span has been considered and literature review for gaining idea of optimum grinding time and particle size for highest yield has been gained. Based on the concept of literature revie the total experimental set up has been developed to avoid occurrence of biased findings.

4.0 RESULTS

4.2 Introduction

This chapter demonstrates the results, findings, and analysis for identifying the optimised parameters for the grinding element of the soymilk-making process of Tofoo Company limited. This chapter provides the process of average yield soy milk extract of soybeans by the grinding time and the average particle size of the soybeans by the same grinding time. There are multiple graphs and charts present along with this chapter for analysing the different parameters of the extraction of soy milk and the exact size of particles. The graphical representation also has been included in the findings and analysis section for a better understanding of the different experiments for extracting soy milk from the beans.

4.2 Findings and analysis

In the grinding process of soybeans to extract the soy milk of the best quality, the following formula has been used;

Y= (W1 * 100)/W0

Where Y represents Extract yield (g / 100g), W1 Extract (g), and W0 Initial dried soybean (g).

Figure 6: Average yield soy milk extract of soybeans by grinding time

The average yield of soy milk extract of soybean by the grinding time can be analysed from the formula. The above graphical representation mainly identifies different times below, such as 40 seconds or 60 seconds as well as 120 seconds, and the yield percentage shows 48.73% and 53.4% as well as 40%. The total amount of soya milk extraction is divided by different extract portion sizes and particle sizes. The formula mainly represents the extract yield and w1 extract as well as w0 initial dried soybean. From the first, it has been identified that if the grinding time is 40 seconds, the yield percentage will be 48.73. It is mainly calculated by understanding the exact portion size and initially dried soya bean and taking a hundred for making the dividation. However, during the test, 250 grams of soybean were taken, and after 16 hours, have been taken to soak the soybean to room temperature, and then the grinding started. Therefore it can be said that for all the milk extract preparation, the portion size and water soaking time are the same. After starting, the first soya milk was extracted by taking the grinding times of 40 seconds. Analysing it with the present formula is below;

Y= (W1 * 100)/W0

Y= (250*100)/400

It also has been identified that with the rapid change of grinding time, extraction of soya milk amount or quantity gets properly changed. Seven different grinding timings have been kept, which produce different yield percentages. First, the soya bean was a grind for 40 seconds, then the percent of yield came out to 43.73% for the same amount of soybean. When the soybean has been grinded for 60 seconds, the average yield of soya milk extractions have been increased from 48.73 to 53.4% and it is directly indicating that if the grinding time gets increased, then the extraction portion will also get increased to a certain extinct with the same volume with dried soybean. After that, the soya milk was grinded for 120 seconds, and the yield was 56.2%, which is only 3% more than the previous test results. From a brief analysis, the grinding time has been increased to 180 seconds, and it has been identified that the soya milk extraction was 60.7%. Furthermore, when the grinding time increased to 240 seconds, the amount increased to 72.2%, 12% more than the previous experiment.

Figure 7: Average particle size of soybeans by grinding time

This result is mainly showing the average particle size of the soya bean by the grinding Times when applying the formula of Y= (W1 * 100)/W0. From the very fast, the particle size has been categorised from 0 to 1000, and the grinding time also has been kept as before, which it belongs or varies from 40 seconds to 300 seconds. It has been identified that the average particle size varies from 100 to 300 based on the nature of grinding Times. Starting with 40 seconds grinding time of the soya beans the average particle size came with the valuation of 288 while the grinding time has been increased to a 60% reduction of particle size identified from 288 to 250.3. note another test was done with a grinding time of 120 seconds, and it has been identified that the particle size was further decreased to 201.3 while this particle size decrease ratio has been continued from 180 seconds to 300 seconds and the particle size reduced from 179.6 to 136.6. It also has been identified that the grinding time was increased from more than 300 seconds, but at this point, the particle size was increased to 907.6. During this test, a 220-watt laboratory blender was used, which also added 43 ml of arid water, and all the weight samples were kept for further analysis of these sample sizes. When combining the average yield soya milk extraction of soybeans by the grinding time with the average particle size of soya bean, it can be identified that in both cases, the 300 grinding times produced the maximum results; however, there are 7 different samples have been present by formatting on grinding time and soya milk extraction percentage on the parameter of 48.73 to 40.00. All these values are very much close to the standard deviation triplicate determination method, and it becomes very much important to properly identify the graphical representation in terms of properly identifying the parameters and the extractions of soya milk with the expected size of particles.

Figure 8: Different sample sizes and grinding times with parameters

From the first analysis, it can be identified that there is a sample size called A that has been kept for 40 seconds as a grinding time, and the soya milk extraction percentage was 48.73± 0.09. on the other hand at this particular sample size, the particle size was kept at 288± 11.76ⴏm. Furthermore, sample B mainly focuses on the 60 seconds of grinding time with a soya milk extraction of 53.40± 0.16 with the proper particle size of 250.3± 6.94ⴏm. The sample size C was made with a grinding time of 120 seconds, and the soya milk extractions were 56.20± 0.16% with a particle size of 201.3± 7.41ⴏm. The next sample size D has been taken with a grinding time of 180 seconds with the basic parameter of 60.70± 0.14% of soya milk extractions with a particle size of 179.6± 4.92ⴏm. After this, another sample size was taken under the sample name E with a grinding time of 240 seconds, and at that time, the soya milk extract percentage was 72.20± 0.16% with a particle size of 151.3± 1.25ⴏm. The sample size F has a grinding time of 200 seconds with a soya milk extract percentage of 74.53± 0.16% with a particle size of 136.6± 3.68ⴏm. Last but not least, another sample size has been kept under sample G with a grinding time of more than 300 seconds, and the basic parameters were the soya milk extraction percentage of 40.00± 0.00% while having the particle size of 907.6± 34.72ⴏm.

Figure 9: Graphical representation of volume density with size class for sample A

This test has been conducted by taking the size classes of 0.01 to 10000 with the volume density of 0% to 8%, and this graphical representation mainly analysing the particle size that is directly related to the sample on behalf of triplicate determination. From the results, it can be easily identified that during sample A which was ground for some time of 40 seconds, the multiple size classes are directly referring, and the particle size is directly indicated 288. At that particular time of 40 seconds, the total volume in the sample was 11.76. the test results are directly referring that when the science classes are bigger, the volume density also increases, and the graphical representation is analysed. The graph started from 1.0 and nearly ended very close to 80000, which was above the volume density of 6% to 8%.

Figure 10: Graphical representation of volume density with size class for sample B

From the above test results, the same volume density has been taken on the scale with the size class of 0.01 to 10000. This test was mainly done with sample B containing the proper period of 60 seconds with a size class of 250.3m. From the graphical representation, it can be identified that the volume density of the particle size was 6.94, while the size class started very fast from 1.0 and went beyond 3000.0.

Figure 11: Graphical representation of volume density with size class for sample C

From this graphical representation, it can be easily identified that there are slide changes that have been made as compared to the sample B graphical representation. This graph is for sample C, which also started from 1.0 and went beyond 3000; however, the timing period is only 120 seconds which twice sample b with a particle size of 201.3m. It also has been identified that the total volume of the sample size was 7.40m. it is visible that, like sample b, this graph is not meeting on 3000, which demonstrates that the end of the process was done by not touching the size classes and it was less than 3000.

Figure 12: Graphical representation of volume density with size class for sample D

This graphical representation mainly describes the sample size D, and the size of this graphical representation is slightly different from the previous graphical representation. After conducting the test results, it can be easily identified that the particle size in this representation was 179.6, with a total volume of 4.92. This test has been conducted with a grinding time of 187, and the graphical representation identifies that the volume tension was started before 1.0 and ended up in between the 3000 and 4000 size class.

Figure 13: Graphical representation of volume density with size class for sample E

This graphical representation is mainly done on sample E with the proper grinding time of 240 seconds. This graph representation is also very different from all the previous graphical representations. It started all ahead of the 1.0 size class and ended between 1000 to 2000 size classes. The 240 seconds grinding time mainly identifies that the volume density between 1.0 to 10.0 increased between zero percent to 2% while it went beyond 8% to 10% between 100 to 1000 size classes.

Figure 14: Graphical representation of volume density with size class for sample F

The sample F graphical representation is also different from the previous all, and during this test, a total of 300 seconds of grinding Times were taken. From the statistical results, it can be identified that it started from 1.0, and when the grinding size class reached 10.0, then the volume density was nearly 2%, but then between the size classes of 10 to 100, it was reduced by nearly 3% of its volume density. After that between 100 to 1000 the volume density increased by nearly 7.9% and the total particle size achieved was 136.6um with a total volume of 3.68m.

The analysis is currently showing in the form of tables and charts that the volume and particle size mainly refers to the production of soya milk. However, it is different if the grinding time is different than the production of soya milk, and its overall contamination will also get different. It has been identified that when the grinding time is very similar to 300 seconds, the particle size also gets lower, and this will produce a higher yield of milk that can be extracted from the soya beans. All these results were collected from the sample size that was directly collected from the company, and all the sample sizes had the lowest yield percentage rates; however, the particle size was very big. For the different grinding times, the amount of milk extractions also changed, and the table of average yield extractions is also showing that the extraction time of yield for the company was very much less. It is about 30 to 40% close to the particle size of 907.6. all these calculations have been produced by using the mean and standard deviation, and most of the time, all the calculations are near about 0.16 to 60.70. As per the views of Zhang (2018), it has been identified that 100 grams of soybean get soaked six times with a weighted of 600 ml cold water for near about 16 hours then the bean-to-water ratio will come to 1:10, and using the commercial blender can support the flow of soya milk extractions. It also has been identified that when the temperature of soya beans reaches 32 degree Celsius then the volume of soya milk will be decreased significantly. If the grinding time decreases, it will take fewer soya milk extractions. It is nearly 30% lower than 120 seconds of soya milk grinding.

Another thing is that the conversion size is directly related to the protein extractive and the formation of particles not only degrades into large particles when a small grinding time gets used (Zhang et al. 2021). It has been identified that when the grinding goes beyond the level for 30 seconds, the yield of solid Soybeans gets decreases in a significant way, and the blanching at 80 degrees Celsius for 1 minute could decrease the protein recovery and it could lead to the increase in soya milk to improve the recovery of solid during the grinding process incomplete hydration was also recognised that increases in 120 seconds to 160 seconds. An inter-relationship is present between the grinding time and particle size, and it refers to when the high proportion size does not allow the extraction of the high volume of soya milk. Still, the nutrition values and the graphical representation also have been soon the volume density increases and decreases with the size class increase or decrease. It is still beneficial to properly conduct some more tests in between 24200 seconds for generating major information regarding these volume changes.

From the test results, it has been identified that there are several hints present in the interpretation of the results and yield extraction of soya milk, and it has been identified that the increment in grinding time increases the chances of high protein recovery. It also leads to a significant improvement in protein content in soy milk, which leads to higher grinding time. As per the views of Varghese and Pare (2019), the particle size gives a direct influence on the final product as the size reduction ratio gets decreases if the grinding time gets increased. There is an inverse relationship present in the particle size; however, it also has been identified that if the grinding time gets increased from 40 seconds to 300 seconds, therefore, the marginal increase of particle size reduction gates visualised and as compared to the 300-second batch operation of laboratory blender the performance of the milk for optimising the best performance of the laboratory blender. The moisture content and the dry matter of soya milk and tofu are mainly determined by the grinding method used, and most of the time, the soya milk yield and solid, as well as the soya milk protein and whiteness index, directly refers to the ml gm per seed. As opined by Li et al. (2019), it also has been identified that the solid content and crude protein, as well as the fat content estimated by the standard procedure and the particle size analysis of soya milk, comes from the sample test, which is analysed for particle size distribution and average particle sizes. Most of the time, having an index ratio of 1.47, soya beans can be diluted by water to obtain 14% of obscuration. Most of the time, the absorption value can be set up to 0.0001, and the measurements must be carried out at 25 degree Celsius to obtain the best results. Under the hand, the texture profile of tofu can be easily determined by using the texture analyser in a microsystem equipped with 5 kg of soya beans, and the flat plate probe of 75 diameters 10 easily analyses the 50% of soybean sample with the 200 per second datagrams. From the sensory evaluation, it can be easily identified that the attributes of soya milk extractions from soybean are mainly colour and flavour as well as taste and texture. It is important to have proper clarity of soya milk with the interior appearance of tofu products. The Tofoo Co maintains the nutrient and anti-nutrient profile of the soya milk that differs from GCB temperature, and the moisture and protein, as well as fat content present inside soya milk and tofu, do not significantly get accepted by the grinding and processing temperatures. The further results also show that the slide variation on amounts of protein and fat can get changed inside the test sample due to the phenomena of the sprouting nature of soya beans. As suggested by Ahsan et al. (2021), these observations can be explained which consider the fact that a breakdown of reserve protein is present that accumulates in the form of amides such as glutamic acid and aspartic acid and nearly reduction of around 60% of soya milk within the grinding time can get decreased is the grinding time increased by 120 seconds. The use of extensive heat during the grinding process sometimes destroys the protein structure inside soya milk and it is important to have minimal heat intervention at 80 degree Celsius which will optimally reduce the 75% inhibitor. The level of phytic acid and soya milk is also different, as identified in the test results, and the psychic acid content can be confirmed with the increment of time. There are three to five-fold cereal grains present, which increases the phytase activities during the test results. It also can be identified from the characteristics of soya milk and tofu as the test samples range from 7.1 to 7.3 with a viscosity of 1.91 to 2.51, and if the timing increases in the process of soya bean grinding; therefore, the viscosity also gets decreased however there is a temperature involved that causing extractions results in significant higher viscosity. As coined by Gionfriddo et al. (2020), it can be further identified that the grinding temperature can lead to blanching, which can change the process for improving the quality of soya milk and tofu. The reduction of trypsin inhibitors retains 75% which is also recognised as a functional food. Soya milk has the extractability of protein, including smaller particle size and better colour profile, as well as good sensory scores. The tofu, made from soya milk and grinded for 120 seconds, will produce high-quality soya milk, and it will sprout as a pre-treatment resulting in saving energy and time as well as high quality of soya milk and tofu.

5.0 Discussion

5.1 Relationship between the particle size and yield in the soymilk production of Tofoo Co

It has been identified that particle size is very important during the grinding process, and it depends on the grinding time for extracting high quality and proper quantity of soya milk extractions. For example, if the particle size becomes very big, then the grinding time needs to be increased; otherwise, the extraction process will not be the best, and also it may reduce the quantity of soya milk production. The results also support that in different timing the extraction of soya milk quantity gets changed, and increments of 30 seconds can lead to the yield size changes and it also negatively impacts the better yield in terms of solubility with the water compared to the soaked soya beans for 8 to 10 hours. On the other hand, the grinding process needs at least 120 seconds to 240 seconds to give better yield results. In the experiment, all the soya beans were soaked for 8 to 10 hours before grinding. To properly produce the Soya pulps taking proper particle size is important as many moistures are present. Yield size is also very important and directly proportional to the temperature and the portion size during the grinding process of soya milk extractions. It has been identified that at 150 degrees Celsius, the maximum recovery occurs, and it will produce the highest quality of soya milk with the quantity and 90% of slurry milk gets extracted, and 90% of soya milk protein gets properly recovered for conducting the grinding process more than 120 seconds to 180 seconds. As coined by Ullah et al. (2019), during the analysis, it also has been identified that in optimum conditions, steam also gets retained and produces 8% residual and less grinding Browning. The process has been conducted under the laboratory requirements; however, during the traditional cooking method, 72% of slurry and 61% of soybean solids get produced which can recover 73% of protein. From the results, it has been identified that most of the soya milk extractions produced by the sample size F, which have been kept inside the grinding machine for nearly 300 seconds, the particle size in the grinding time have been kept in the sample size G. It is identifying that the Toffo company arranged the particle size in properly and the total size was 907 which is currently having a proper value of 34.72. The dividation of soya milk also included the small number of soybean batches in the machine and the amount of time guts increased from 40 seconds to 300 seconds; however, the mixture could not produce enough soya milk. It is also true that having an appropriate proportion size allows obtaining a high level of the yield of soya milk and if the high portion size gets implemented then the timing must be the same; otherwise, the soya pulps get increased, and the nutritional value will decrease (Lan et al. 2021). Keeping the appropriate particle size and yield gives a significant impact on drawing soya milk extractions which is very much important to give a positive impact on tofu strength. During the result, the higher seed protein content was kept in the lowest fuels, which suggests a negative relationship between the protein content of seeds and the tofu yield. Other factors include the milk yield and variety of soybean as well as the processing conditions like temperature and soybean to water ratio that needs to be constant. It also has been identified that the implication inside the Tofoo company is to develop a more sophisticated process as the varieties of soybean that can provide optimal milk yield deal with high levels of milk acceptability. During the sample, there are different types of varieties included, and the new highest milk yield that gives the lowest overall acceptability is because of the appropriate portion size and grinding time. As per the views of Pang et al. (2020), all the tests were conducted under the laboratory requirement. Therefore, the different processing techniques were not implemented, and only the simple grinding technology was used. It also deletes the filtration and hot extractions. Still, the results have been drawn perfectly, and there are no specific methods present that can recommend optimal milk processing from the varieties of soybean. From the results, it also has been identified that several compounds are present inside the soya milk extractions, which can cause flavours. Soya milk production will significantly decrease with the extension of hot water blanching and grinding time. It is very important to properly understand the relationship between the particle size and yield during soya milk production; however, by the sensory valuation, the texture and characteristics can get identified, and it will impact quality and nutrition as well as the flavour of. The results also showed that a particle size of 136 could produce 74.53% more soymilk, and the grinding time must be kept under 300 seconds. As stated by Zhang et al. (2021), it directly refers that keeping the particle size appropriate and maintaining it properly with the grinding time can help to extract high levels of soya milk yields and also it will help to keep the nutritional value of tofu in the future. If this relationship does not get balanced properly, then the production quality will get decreased, and the standardisation of food cannot be made. An unpleasant odour will also come out (Sun et al. 2022). From the other samples and particles size, it is identified that portion size can be changed, and it will be important also to change the grinding time to maximize the yield in the soya milk production; however, extractions and residuals need to be separated for checking more particles and producing thick soya milk so that it could not destroy the flavour of soya milk in the future. Therefore, it can be said that it is very much important to properly keep the particle size and yield in the soya milk production by the Tofoo to produce the highest quality of soya milk and also get it accepted under laboratory conditions.

5.2Method for identifying the suitable particle size for getting high-quality soy milk in The Tofoo Co

From the results, it becomes evident that particle size has a significant impact on the quality of soymilk and yield percentage. Thus the best method for identifying the suitable particle size is measuring the yield percentage per batch of soybean grinded each time. Based on the results, it can be identified that a high volume of yield was achieved at a particle size of 136.6um. Thus for earache batches, Tofoo Company Limited can consider the grinding time of 300 seconds for achieving particle size providing the highest yield. This meets the objectives of identifying the suitable method for achieving suitable particle size. In both dry and weight grinding, the soybeans are needed to be treated for 300 seconds as per the results obtained to achieve the desired yield. In this context, the findings by Li et al.(2019) water absorption percentage during soybean grinding directly influence the characteristics of soybean in terms of solubility and particle size. Thus it became evident that along with grinding, it becomes necessary to maintain absorption time for soybeans. Li et al.(2019)  also mentioned that excessive soaking in soybean could lead to bacterial growth; thus, it becomes necessary to maintain a minimum of 2 to 3 hours of seeking, which is optimum for achieving the minute particle size possible for gaining high yields. Apart from yield Tofoo Co is also needed to focus on protein percentage and yield quality. Thus along with particle size ensuring high yield is necessary to ensure the protein percentage is maintained. In this context, Edogawa et al. (2018) mentioned that during the dehulling process, the particles need to be fully dispersed. Thus the grinding time selected is needed to ensure all soybeans of the batches are properly dehulled.

Edogawa et al. (2018) also stated that the PH of soymilk has a significant impact on soy protein; thus, the PH values need to be measured after separating the soluble matters such as sugars and minerals. Fat concentration or oil percentage in soymilk is also needed to be discarded. Thus it has become evident that along with achieving the highest yield, Tofoo Co is needed to focus on its soymilk treatment measures to enhance the protein percentage along with enhanced yield. Guan et al. (2021) mentioned that soy protein is made of 40% of protein, 20% lipid and 25% carbohydrates and 5% crude fibre. High solubility protein signifies a high nutrient concentration of Tofoo.  Solubility is maintained through minimum particles; thus, retaining a minimum particle size can be beneficial for achieving high soluble protein amounts in tofoo. Thus a grinding time of 300 seconds for each batch of soybean will be beneficial for maintaining high yield and high protein content in each yield, thus enhancing the quality and quantity of Tofoo.

5.3 Suitable timing and particle size for extracting high-quality soy milk from soybeans in The Tofoo Co

Based on the results obtained, it can be identified that 300 seconds is the highest grinding time to gain the minimum particle size. Thus a grinding time of 300 seconds can be retained in this company to gain the highest yield and high protein percentage. As mentioned by Zhang et al. (2021), the solubility of the protein in soy milk is reflected through the degree of dispersion, aggression and denaturation of protein. Protein denaturation can occur if the soymilk is treated at a high temperature; thus, to retain the solubility and high protein content in tofu, the temperature must be managed in stages of pasteurisation the limit protein denaturation. Thus considering the need for high nutrition and high yield Tofoo Co can consider 300-second grinding time as prime time.

Further, through soaking and PH balance, this organisation can retain the requirement of high protein yield in this case. In this context, Myagmardorj et al. (2018) mentioned that observing the bacteria growth in soymilk is the most suitable measure for identifying the PH balance. Thus Tofoo Co can lead a series of tests to identify the soymilk samples as per time having bacterial growth to select the time for the highest protein percentage. However, a 300-second grinding time can also be considered suitable as this company will benefit from better solubility; thus, the quality of Toffo blocks will be high and as per the requirement of the consumers. This organisation can prioritise the time 300 grinding size to achieve the particle size of 136.6 um, which is suitable for the emulsification and high-quality tofoo preparation without impairing the nutrition content.

5.4 Difference between wet grinding and dry grinding in the process of soymilk extraction

Both wet and dry grinding can be utilised to achieve a minimum particle size standard to retain a high yield. However, for obtaining the results, wet grinding techniques have been used as soaking in water and adding water during grinding to help cope with the temperature that causes denaturing of protein and help in better disperse and solubility of protein and particles in the slurry prepared. During dry grinding, the soybeans collided with machinery apparatus leading to the powdery texture needed to be the mixed water to achieve the desired product in case of soymilk production. On the other hand, in the case of wet grinning there as the soybean is soaked for several houses and ground by adding water; thus, there is a recirculation process. This recirculation allows for ensuring the correct particle size by observing slurry by quality and texture. In the case of dry grinding, there can be several errors and trials which are not applicable in the case of wet grinding. As mentioned by Saini and Morya (2021), wet grinding leads to both physical and chemical changes in the slurry produced. Thus while wet grinding at low temperatures and the low PH balance is maintained to avoid the plant-based flavour and other textures that empire quality and texture of soymilk, during wet grinding, the fermentation process of tofoo preparation becomes the easier and smooth texture of tofoo can be achieved as per monitoring the desired texture of the soymilk. As Tofoo Co is focused on enhancing production along with the high quality of tofoo, wet grinding can be beneficial.

Further, there is also a need of identifying the benefits and limitations associated with dry grinding for the future scope of this company to flourish its business. As stated by Li et al. (2021) during dry grinding the dry portion of slurry remains high, which can impair protein solubility and the texture and quality of Tofoo. Dry grinding techniques also impair the activities of trypsin inhibitors due to a lack of solubility. Thus, there is a need to prioritise wet grinding over dry grinding. Dry or air grinding is less time-consuming than wet grinding as there is no need for packing and checking slurry quality. However, the product developed by dry grinding can lead to the discarding total batch not achieving the desired particle size and poor quality of slurry and mixing with water. Thus it becomes evident that it will be better for Tofoo Co to upgrade further its wet grinding technique for soymilk preparation to deal with issues associated with dry grinding and meet market demand.

6.0 CONCLUSION AND RECOMMENDATIONS

5.1 Conclusion

This research has focused on identifying the interrelations of the particle size and yield percentage of soy milk, considering the case of Tofoo Co Ltd. This research has been completed by considering six chapters starting from the introduction to ending in the recommendation and conclusion. The introduction includes the aim and objectives, and a detailed literature analysis is presented in the second chapter. The third methodology chapter and fourth is finings and the fifth is dicusssion. The last chapter is the conclusion and recommendation. Based on the findings, it can be identified that 136.6 um is the most suitable and minimum particle size achieved through wet grinding of soymilk. The time required to achieve this desired particle size is 300 seconds. In this particular size, a high yield has been achieved, and protein content is maintained in terms of PH balance. Thus it becomes evident that this grinding time and partial size is the most suitable for Tofoo Co.  Demand for Tofoo is rapidly increasing in the market and specifically for the Tofoo of this company. The soymilk is the basic competence of Tofoo. Thus, it becomes necessary to increase the extract and yield. Thus achieving a particle size of 136.6 um can allow this company to meet market demand.

5.2 Linking with objectives

To investigate the relationship between particle size and yield of soymilk production

This objective has focused on identifying the interrelationship of particles and the yield of soymilk. This objective has been met through extensive analysis of results and based on the results. It can be identified that smaller particle size leads to better yield and better quality of soymilk to retain tofoo quality. Based on the findings, it also becomes evident that consideration of 300 second grinding time leads to the desired particle size achievement, 136.6 um, which supports retaining the quality of soymilk. Based on the discussion, it can also be identified that wet grinding can be a suitable option for achieving the desired particle size. Thus this objective has been met, and Toffo Co can follow the results.

To suggest selecting the suitable particle size of soy milk slurry to gain the highest yield.

This objective has focused on identifying the most suitable method for achieving the suitable particle size. This objective has been completely met through discussion, and an explanation of both wet and dry grinding methods has been provided in the literature review. Based on discussion and analysis, it can be identified that wet grinding has several benefits, such as recirculation of slurry to achieve the desired particle size as well as achievement of desired protein content and quality soy milk. Thus as per the differences in time through wet grinding, the Tofoo Co can include variation in Tofoo interim texture; thus, wet grinding is best for the company.

5.3 Recommendations

Recommendation 1: Ensuring enough soaking time and following wet grinding

Soaking time ensures double the volume of and increases the weight of soybean. Thus soaking soybeans can ensure high yield as well as has a direct impact on solubility. As wet grinding ensures the opportunity for recirculation, thus, considering wet grinding as part of a major production process will be suitable (Li et al. 2021). Wet grinding reduces the scope of the solid part of the coarse grinding of soybeans, impairing the quality of soymilk and tofu. Thus considering the benefits of soaking the beans and the advantages of wet grinding Tofoo Co is needed to modify wet grinding techniques repeatedly to ensure enough yield to meet demand.

Recommendation 2: Ensuing a time of 300 seconds in the grinder to achieve the desired

Based on the results it can be identified that particle size has a significant impact on yield and the suitable particle size for Tofoo Co’s yield is 136.6 um as this particle size will provide enough yield to meet the current market demand. As particle size depends on grinding time, the consulate grinding time of 300 seconds in a wet grinder has been identified. Thus this company is needed to take strict measures during the soymilk production to ensure the desired time, as well as the automation process can be applied. There is also a need for a quality check of the slurry to achieve the desired quality of soymilk for the slurry prepared.

5.4 Limitation of research

This research has been completed in a laboratory environment using the production unit of Tofoo Co ltd. Though there is a presence of better presentation through statistical analysis, there are certain issues. Lack of flexibility and high potentiality of error are major areas of limitation, and once the result is taken as it is both time and cost-consuming to replicate the experience. Another limitation is associated with the research area as it only prioritises the yield, not the properties of soy milk, that influence quality. These gaps are needed to be met in future, and these gaps can be considered limitations in research.

5.5 Future scope of research

The future scope of research revolves around the requirement of including flexibility in the research process and identifying the impact of particle size on the quality of tofoo. Certain other factors influence the quality of Tofoo, which are not considered in this research. Thus its future focused on these factors can be made for better interaction and better development of findings as per the understanding of factors that influence the quality of tofu apart from yield.

APPENDIX

Table 1: Average yield soy milk extract of soy beans by grinding time

Grinding Time	Value (%)
	1	2	3	Mean	STD
A	48.80	48.60	48.80	48.73	± 0.09
B	53.60	53.20	53.40	53.40	± 0.16
C	56.00	56.20	56.40	56.20	± 0.16
D	60.80	60.80	60.50	60.70	± 0.14
E	72.00	72.20	72.40	72.20	± 0.16
F	74.40	74.40	74.80	74.53	± 0.19
G	40.00

KEY:

A = Soaked sample grinded at 40 seconds

B = Soaked sample grinded at 60 seconds

C = Soaked sample grinded at 120 seconds

D = Soaked sample grinded at 180 seconds

E = Soaked sample grinded at 240 seconds

F = Soaked sample grinded at 300 seconds

G = Sample gotten from Tofoo company

Table 2: Average particle size of soy beans by grinding time

Grinding Time	Value (ⴏm)
	1	2	3	Mean	STD
A	304	276	284	288	± 11.76
B	260	247	244	250.3	± 6.94
C	208	205	191	201.3	± 7.41
D	186	179	174	179.6	± 4.92
E	153	150	151	151.3	± 1.25
F	141	137	132	136.6	± 3.68
G	956	891	876	907.6	± 34.72

KEY:

A = Soaked sample grinded at 40 seconds

B = Soaked sample grinded at 60 seconds

C = Soaked sample grinded at 120 seconds

D = Soaked sample grinded at 180 seconds

E = Soaked sample grinded at 240 seconds

F = Soaked sample grinded at 300 seconds

G = Sample gotten from Tofoo company

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