eChapters

Abstract

Vitamin D or “sunshine vitamin” is an essential fat soluble vitamin required for healthy bones. It is responsible for enhancing intestinal absorption of calcium and phosphate. Its deficiency leads to osteoporosis and osteomalacia in adults and rickets and other bone deformities in children. Vitamin D deficiency is being reported to be quite common these days due to modernization accompanied with changes in lifestyle and environmental pollution which limit sun exposure for several individuals. Inadequate sun exposure results in reduced vitamin D synthesis and ultimately poor vitamin D status necessitating compensation through dietary intake. Dietary vitamin D intake is very low in India because of low consumption of vitamin D rich foods, absence of fortification and little use of supplements. It is becoming a major public health problem, needing immediate attention. Fortification of milk and milk products is the safe and effective approach to deal with widespread vitamin D deficiency as milk is consumed and liked equally by all age groups. This paper highlights the importance, sources, recommended allowances and other relevant issues related to vitamin D fortification and its health effects.

Homogenization is now a widely used industrial process in dairy production, essential for stabilizing milk and other liquid dairy products. Its main purpose is to prevent fat from separating out of the milk, ensuring a smooth, consistent, and uniform product. Milk is a complex emulsion comprising water, fat, proteins, carbohydrates, minerals, and vitamins. Among these constituents, fat plays a critical role in determining the texture, flavor, and overall sensory quality of milk and dairy products. In its natural state, milk fat exists in the form of globules of varying sizes, surrounded by a thin membrane that stabilizes them in the aqueous phase. These fat globules typically range in size from 2 to 10 μm and have a lower density than the surrounding water-based phase of milk. This difference in density causes the fat globules to rise and form a cream layer when milk is left undisturbed, leading to an uneven texture and separation during storage.
Homogenization is a mechanical process applied to milk to modify fat globules by forcing the milk under high pressure through a tiny orifice. This reduces the average size of the fat globules while increasing their number and surface area. Practically, this greatly minimizes the tendency of fat globules to rise and form a cream layer. The enhanced stability of homogenized milk is due to three key factors: the reduction in the average diameter of fat globules, as described by Stokes’ Law, which slows their upward movement; the uniformity in size distribution, which ensures globules rise at similar speeds, preventing clustering; and the increased density of fat globules caused by the adsorption of a protein membrane, bringing their density closer to that of the surrounding liquid. Additionally, heat pasteurization complements homogenization by breaking down the cryo-globulin complex, which otherwise promotes clustering and cream formation.
The smaller and uniformly dispersed fat globules create a smoother, creamier texture and enhance the mouthfeel. This process also contributes to the visual appeal of milk, making it appear whiter and more uniform. Homogenization is, therefore, an essential step in modern dairy processing, ensuring the stability, quality, and consistency of milk and other dairy products, while addressing the challenges posed by the inherent properties of milk fat and its lower density.

India

Milk legislation and regulations are designed to prevent fraud and adulteration. But they now cover many factors that affect sanitation and public health. Milk generally is classified into grades according to the care with which it is produced.

Milk lipids or milk fats exist as an emulsion of small spherical droplets called milk fat globules. These globules are very small in size but very large in number. The diameter of the milk fat globules ranges between 0.1 and 22 µm and the number varies between 1.5 and 3.0 billion globules/mL. The average size of milk fat globules ranges from 2 to 5 µm. The average fat globule size in cow and buffalo milk are 3.4 and 4.5 µm, respectively. The surface of the milk fat globules is coated with an adsorbed layer of material known as the milk fat globule membrane (MFGM). MFGM contains phospholipids and proteins in a complex form. MFGM has two main functions (a) fat globule stabilization and (b) preservation of the fat globule’s identity.

General Composition

Triacylglycerols (triglycerides) represent 97–98% of the total lipids in the milk of most species. The diglycerides probably represent incompletely synthesized lipids in most cases. Although phospholipids represent less than 1% of total lipids, they play an important role in being present mainly in the MFGM and other membranous material in milk. The principal phospholipids are phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin. Trace amounts of other polar lipids, including ceramides, cerebrosides, and gangliosides, are also present. Phospholipids represent a considerable percentage of the total lipid of buttermilk and skim milk reflecting the presence of proportionately larger amounts of membrane material in these products.

The primary objective of dairy plant hygiene is to ensure the consistent daily turn-out of safe and clean products which comply with pure-food and public health laws. A secondary and commercially important aim is to preserve the keeping quality of dairy products and so enhance consumer confidence in them. An integral part of a dairy is the quality control laboratory. Continuous testing is necessary for many purposes, including equipment hygiene. Bacteriological standards of dairy products can be maintained only if the raw product is of good bacteriological quality and is protected against contamination from the equipment with which it comes in contact during all stages of processing. 
Many factors may influence the maintenance of dairy equipment in a hygienic condition; the most important are the dairy buildings, the materials and construction of the equipment, personnel, water supply, cleaning procedures, and laboratory control. It is quite impossible to place these points in order of importance, efficient control of dairy plant hygiene being dependent on proper attention to all factors.

10.1 Introduction

Milk is a unique substance in that it is both consumed, as fluid milk with minimal processing and it is the raw material used to manufacture a wide variety of products. From the nutrition point of view, milk is an almost ideal food and considered to be perfect food. The human body needs more than thirty distinct materials in its food supply. No single food stuff supplies all of them but milk supplies nearly all. Since milk by its nature is perishable and an ideal product for bacterial growth, so it must be carefully handled, both during production and while processing. This chapter focuses on the technological (processing) aspects of the transformation of milk into its various consumer products, including beverages, fermented products, concentrated and dried products, butter and ice cream.

Milk production in India is a subsidiary activity of agriculture in contrast to the organized dairy sector in the western countries. Farmers and landless labour maintain one to five milch animals. As a result, small quantities of milk are produced in a scattered manner. Due to this reason, milk procurement models from western countries, such as bulk cooling and bulk transportation are not applicable under Indian conditions. Collection of small amounts of milk is scattered over long distances and, therefore, poses a formidable challenge in maintaining the quality attributes and keeping costs down.

3.1. Rural Milk Collection

A systematic approach to rural milk collection suitable for the tropical climate and techno-economic conditions prevailing in India has been developed, based on the indigenous experience gained over the past few decades. In the first phase, extensive surveys are undertaken in the milkshed areas, where the milk plant is to be established. The second phase involves ‘route planning’ taking into account, availability of quantities of milk, access to roads for plying vehicles and distance from the site of dairy plant. Then zones are identified, representing equal costs of collection and transportation. In the third phase, planning is done for locating the primary collection centres as well as chilling centres, where, milk can be cooled to 4ºC before transporting to the milk plant. Milk may be collected from individual producers either by the contractor or by forming village level cooperative societies.

Bovine milk contains an average of 3.5% protein. The concentration of protein changes significantly during lactation. The first few days of lactation exhibit the main change in protein concentration. The main changes occur in whey protein fraction.

Distribution of Protein in Milk

80% casein and 20% whey protein (β lactoglobulin- 10%, α- lactalbumin- 5%, serum albumin, and immunoglobulin- 5%).

Fractionation of Milk Proteins Fractionation of milk protein is mainly done by acidification at pH 4.6 around 30 °C.

Almost 80% of the bovine milk protein precipitates at pH4.6, and this fraction yielded by precipitation is called casein.

The remaining soluble part of the protein is referred to as whey protein/serum protein/ non- casein protein. Wide variation is observed in the casein- whey protein ratio in different types of milk(protein synthesis is independent of animal diet)

Significant Difference Between Casein and Whey Protein

1. Casein precipitates at pH 4.6 but does not precipitate whey protein at that pH. This property of milk protein is commercially exploited for the preparation of industrial casein and certain varieties of cheese.

2. Chymosin or other proteolytic enzymes produce specific changes in casein resulting in coagulation in the presence of calcium. Whey protein does not undergo this type of coagulation.

3. Casein is very stable to high temperatures. They can withstand heating up to 140 °C for 20 minutes but whey protein is relatively heat labile. They are completely denatured by heating at 90 °C for 10 min.

4. Casein is a phosphoprotein containing an average of 0.85% phosphorous while whey protein does not contain any phosphorous. The phosphate of casein is an important contributor to remarkably high heat stability and calcium- induced coagulation of rennet- altered casein.

5. Casein contains very low sulfur (0.8%) whereas whey protein is relatively rich in sulfur (1%). The principle casein contains only methionine but whey protein contains a significant amount of cystine, cysteine, and methionine. These sulfur- containing amino acids are responsible for many changes in milk on heating.

6. Casein is synthesized only in the mammary gland and no other sources in nature. Some of the whey proteins β lactoglobulin, and α- lactalbumin are synthesized in the mammary gland but bovine serum albumin and immunoglobulin are not synthesized in the mammary gland but derived from blood.

7. The whey protein is dispersed in solution and has a simple quaternary structure. Casein has a complex quaternary structure and exists in milk as large colloidal aggregates.

The salts of the milk include those constituents that are present as ions or in equilibrium with ions. The main salts of milk are phosphates, citrates, chlorides, sulfates, carbonates, and bicarbonates of sodium, potassium, calcium, and magnesium. Approximately 20 other elements are found in milk in trace quantities including copper, iron, lead, boron, manganese, zinc, iodine, etc. These ions are more or less associated with themselves and with proteins. Some metals act as catalysts in the oxidation of milk fat leading to oxidative rancidity and certain metals like Ca, P, Mg, Mo, Co, Fe, etc. are components of metalloproteins such as lactoferrin, lactoperoxidase, xanthine oxidase, and parts of phospholipids.

Distribution of Salts Between Casein Micelles and Serum

The phosphorus is present as orthophosphate, but part of it is bound to organic components like serine and threonine residues of casein, molecules of hexoses and glycerol, phospholipids, etc. Phosphorus is also found in the hydroxyapatite structure of the colloidal calcium phosphate in the micellar structure of casein. The sulfur content of milk is about 0.36 g/kg, but most of it is in the amino acid residues methionine and cysteine of the proteins. About 10% is present as inorganic sulfate.

Physical Equilibria Among Salts

Milk contains several elements but all of them are not entirely in a soluble state. Some minerals exist in colloidal and ionic states at the normal pH of milk. The compounds that are in soluble condition play an important role in keeping various milk constituents in stable condition. A balance exists between the components that are in a soluble state and those which are in colloidal state.

INTRODUCTION

Fruits and vegetables are historically important constituents of human diet and the growing awareness of consumers about the beneficial effects of these commodities could result in enhancement of global trade involving fresh and processed fruits and vegetables. Emergence of postharvest handling of fresh fruits and vegetables facilitated global trade of these commodities. The developed countries started realizing the export potential of these commodities by development of adequate value addition in terms of pretreatments, shelf life extension and packaging besides grading and other associated packing house operations. However, the trade concerning fresh fruits and vegetables could never come out completely from problems related to pesticidal residues, spoilage, bulkiness of the commodities involving transportation of inedible portions and excessive packaging costs arising out of bulkiness. The other problems associated with fresh produce include mandatory requirement of specific storage temperatures with refrigeration as the primary means of regulation of metabolic rate.

Tamarind (Tamarindus Indica)

Introduction

The fruit of tamarind a pod 5 to 15 cm long, 3 to 10 seeds surrounded with edible pulp which is principal souring agent for sauces, chutney, in beverages and in general cooking. Pulp is carminative, laxative, given as infusion in biliousness and febrile conditions. It is also used in dyring and tanning and for polishing and cleaning metal ware. The tartaric acid is extracted from unripe fruits. The polysaccharide (jellose) is extracted from seeds, which is used as a sizing material in the cotton and jute industries. Besides, polyose obtained from the seed is good substitute for fruit pectin in the preparation of jam, jelly or marmalade. The bark and leaves are used for tanning. Tamarind balls are prepared after taking out seeds from the fruit. Tamarind paste and tamarind juice concentrate are the other commercial products.

The fruits, flattish, bean-like, irregulary curved and bulged pods, are born in great abundance along the new branches and usually vary from 2 to 7 in long and from 3/4 to 1 1/4 in (2-3.2 cm) in diameter. Exceptionally large tamarinds have been found on individual trees. The pods may be cinnamon-brown or grayish-brown externally and, at first, are tender-skinned with green, highly acid flesh and soft, whitish, under-developed seeds. As they mature, the pods fill out somewhat and the juicy, acidulous pulp turns brown or reddish-brown.

The quality of ice cream depends on the balanced interaction of its major and minor constituents. This chapter examines ice cream mix as a multiphase system and explains the chemistry and functionality of its principal components. Milk fat, milk solids-not-fat, proteins, lactose, sugars, stabilizers, emulsifiers, water, and other constituents are considered in relation to body, texture, flavour, viscosity, freezing behaviour, and stability. The chapter also discusses minor milk constituents and the ways in which individual components interact rather than functioning independently. Understanding these relationships helps manufacturers identify formulation-related defects and optimize composition for desired sensory, processing, nutritional, and storage characteristics.

The selection and management of ingredients are fundamental to producing consistent, safe, and high-quality ice cream. This chapter provides an overview of the principal ingredients used in ice cream mixes and explains their selection criteria, approximate composition, functionality, storage requirements, and handling practices. It considers dairy ingredients, sweeteners, stabilizers, emulsifiers, flavours, colours, inclusions, and other formulation components. Ingredient quality directly influences processing performance, sensory properties, shelf life, and product cost. The chapter also highlights incoming-material quality checks and common ingredient-related defects. By understanding ingredient functionality and quality specifications, manufacturers can improve formulation accuracy, process consistency, product performance, and overall manufacturing efficiency.

1. Introduction

Mixing is a fundamental and widely practiced operation in many fields, such as chemical, pharmaceutical, and food processing industries. The mixture’s primary aim is to increase the homogeneity of the material in bulk (Uhl and Gray, 1986; Patterson et al., 2004). Mixing means the random distribution of two or more ingredients throughout a system, which differs from the term’ agitation,’ which is defined as establishing a particular flow pattern with the liquid, especially in a circulatory motion within a container. Mixing is a necessary step in the context of food processing operations. 

For Indian foods

Food processing industries are the fastest growing in India. India is the largest producer of milk, bananas, mangoes, guavas, papaya, ginger and okra. It is the second largest producer of wheat, rice, fruits, vegetables, tea, sugarcane and cashew nut. It is the third largest producer of cereals, coconut, lettuce, chicory, nutmeg, mace, cardamom and pepper at the global level (Highlights of Agriculture Census, 2010-11, http://pib.nic.in/newsite/PrintRelease.aspx?relid=132799). Most part of the income is spent on foods. It is important to establish and nurture mutually beneficial relationships with global food processing, food retail and related supply chain organizations. This will in turn help in the realization of significant business growth opportunities in India, through newer technologies, innovations and ways of value additions. The geographical location of India helps in the export of items to other countries. It is connected to Europe, Middle East and Africa from the western coast and to Japan, Singapore, Thailand, Malaysia, Korea, Australia and New Zealand from the eastern coast. Food processing is a priority sector for the Indian Government, especially in recent times with “Make in India” initiative.The country is considered as one of the most favourable markets because of the easy and affordable credit and other fiscal incentives. The total consumption of food and beverages in India is US$ 369 billion which is expected to increase to US$1.142 trillion and the output in the food processing sector might increase to US$ 958 billion by 2025. This offers a vast market opportunity by the Indian food processing, food retail, transport, logistics and related infrastructure sectors to players in the food processing value chain. The market for plant and machinery in the food processing sector is estimated in the year 2024-25 to be USD 51.41 billion as compared to the current value of USD 17.3 billion (2016-17).

Abstract

Tremendous hike inworld population has increased thrust on the limited resources which has considerably affected the viability of the food. The emerging challenge for policy makers and food scientists is to put forward viable solutions. Utilization of underutilized crops/plants that act as good sources of starch could be explored in a better way for the sustenance of the limited sources like food crops/plants. The demand for starch and the foods containing starch has been increasing continually. Since, the starch in its native form has certain limitations in its functional properties to be used for different applications. Therefore, it becomes important to explore certain technologies which could be used for modification of starch. Among different technologies gamma irradiation ensures food safety while inducing physicochemical changes of the components. Although, the chemical modifications have been used widely so far but the concerns related to the chemical residues left are diminishing their demand. Hence, the physical processes particularly the gamma irradiation process has emerged as an efficient alternative with some benefits over other process like eco-friendly, economical, reliable and safe for altering the physico-chemical and biological characteristics of the product. Gamma Irradiation of starch has been successfully employed for the achievement of some desired physico-chemical, biological and functional properties of the foods and other related items. In this chapter, valuable impact of gamma irradiation on the physico-chemical, biological and functional properties of starch has been summarized.

13.1 Biopolymer-Based Coatings with Antimicrobial Properties 13.1.1 Understanding Biopolymer-Based Coatings Biopolymer-based coatings are a game-changer in food packaging, offering natural, sustainable solutions for food safety. These coatings, derived from renewable sources, like polysaccharides (e.g., chitosan, starch, cellulose), proteins (casein, gelatin), and lipids (wax, shellac), have proven to be biodegradable and consumer-friendly alternatives to synthetic polymers. 13.1.2 Antimicrobial Properties and How They Work • Antimicrobial coatings are crucial in slowing down spoilage and extending the shelf life of perishable foods. They work by disrupting cell membranes, inhibiting cell processes, and creating oxidative stress in microbes. This is achieved through natural antimicrobials like essential oils (e.g., oregano, thyme, clove), plant extracts, and organic acids; inorganic agents like silver nanoparticles, zinc oxide, and titanium dioxide; and microbial-derived substances like nisin, lysozyme, and bacteriocins (Yu, Z et al ., 2022)

Studies have shown that modified atmosphere packaging (MAP), and controlled atmosphere storage have the ability to delay quality losses and thus extend shelf life of fresh or minimally processed or fresh-cut produce (Church 1994; Gil et al. 1996a, b; Lee et al. 1995). Modified atmosphere packaging of fruits can result in reduction of respiratory activity, delay in softening and ripening and a reduced incidence of various physiological disorders and pathogenic infestations (Artés 1993).

A. Morphological Examination of Bacterial Samples
Introduction
Bacteria are most widely distributed, the simplest in morphology, the smallest in size and difficult to identify. They are prokaryotic and a few are photosynthetic. Most bacteria are only 0.5 to 2.0 μm in diameter. Bacteria are generally rod, spherical or curved shaped. Rod shaped bacteria may vary considerably in length, have square round or pointed ends and may be motile or non-motile. The spherical or coccus shaped bacteria may occur single, in pairs in tetrads, in chains or in regular masses. The helical and curved shaped bacteria exist as slender spirochetes, spirillum and bent rods (vibrios). In this exercise the ubiquitousness of these organisms will be demonstrated in the air and water, on body and in mouth etc.
Materials
1. Petri plates containing nutrient agar
2. Sterile cotton swabs
3. Sterile water blank
4. Tube of nutrient broth
5. Materials for simple staining

Bacteria are morphologically different. This characteristic is helpful in the identification of bacteria. Routine study of bacterial morphology should include examination of stained preparations. Motility should be examined by hanging drop preparation. According to the requirement, certain cell structures may be stained. Stained preparations should be made preferably from fresh agar slant cultures. Smears of Streptococcus should be made from a liquid culture. Morphology of bacteria may be described under the following terms:

1.Shape: Spherical, coccobacillary, short or long rods, filamentous, comma- shaped, curved or spiral forms.

2.Size: Spherical are measured in diameter and rod-shaped in length and breadth. Measurement is expressed in microns (µ).

3.Sides: Straight, concave, bulging, parallel or irregular.

4.Ends: Round, pointed, truncate or concave.

5.Axis: Straight or curved.

6.Arrangement: Singly, in twos, in groups of four or eight, in grape-like bunches, in long chains, or scattered irregularly, may be in bundles, angular arrangements or in Chinese letters.

7.Pleomorphism: Bacteria may differ from their typical shape. Some of the older cultures may depart greatly from their typical forms, and may show spindles, clubs, and filaments, swollen and branching forms. Variation may be both in shape and size.

8.Capsule: May or may not be present. When present, size should be noted. This requires special staining.