eChapters

Abstract
 
Grains are usually harvested above 20% (wb) moisture level and they are prone to microbial attack at high moisture level. In order to avoid both qualitative and quantitative losses that arise from microbial growth, grains are usually dried to safe moisture level. The safe storage moisture content may vary from 8-16% (wb), depending upon the grain and climate type. Therefore, drying is a necessary step in preventing these losses. Drying also reduces the bulk weight of the materials, thus easing transportation and storage. Drying can occur in thin layer or in deep bed. Different drying theories are proposed to characterize these drying processes. Theoretical as well empirical drying equations have been developed.

Abstract

The objective of this chapter is to provide an overview of heat pump dryer (HPD) and recent developments in its applications for drying of agricultural and food products. The basics of heat pump dryer, classification, operating principle, configuration and control system have been presented for better understanding. Many researchers have concluded that HPDs use energy more efficiently than electrical dryers. The heat pump dryer is best suited for drying high value commodities such as fruits, vegetables, spices, condiments, herbs, medicinal and aromatic plants at near ambient temperature for producing better quality dehydrated product.

Abstract

Drying is a very important unit operation in food processing. Being an energy intensive unit operation, drying process demands improvement to make it energy efficient. Beside this operating conditions used in drying affect product quality substantially; however, traditional dryers do not allow enough flexibility to meet quality requirements for several products. This has resulted in development of number of new drying techniques, to cope with both energy efficiency and product quality.

Abstract

In recent years microwave processing have attained increasing recognition in food industries particularly in drying and dehydration. During microwave processing, electromagnetic energy is supplied directly to the food material for volumetric heating. This provides rapid temperature rise throughout the material with reduced thermal gradients. This unique heating mechanism reduces processing time and saves energy. In-spite of advantages of microwave heating it leads to overheating in food material and formation of cold and hot spots if applied improperly during drying. To overcome these challenges different microwave assisted hybrid drying technologies have been developed by many researchers. These techniques are microwave assisted hot air drying, microwave assisted osmotic dehydration, microwave assisted vacuum drying, microwave- infrared assisted hot air drying, microwave assisted rotary drying. This chapter comprises the fundamentals of microwave and provides comprehensive update of microwave assisted hybrid drying processes for food and agricultural materials.

Abstract

Hot air circulation is the most common industrial method of drying foods which has its own inherited disadvantages. Microwave drying can be an alternative method for removing moisture from foods and there has been a surge of interest in the application of microwave to process the foods, in past few years. The reason being that there is worldwide energy crisis and the growing acceptance and familiarity with domestic microwave ovens. It is well known that conventional means of heat processing irreversibly alter the flavor, colour, and texture of many foods. From the point of flavor alone, it is desirable to improve our present methods of processing foods. Some improvements have been made in this direction with a number of food products by use of high-temperature short- time processing.

Abstract

Spray drying is one of the most preferred methods of converting food and pharmaceutical solutions into powder form. Very high product throughput, hygienic and highly automated process and relatively benign thermal and dehydration stress on products associated with this process has made it ubiquitous in powder manufacture. Compared to freeze drying, spray drying is significantly less expensive both in terms of operation and capital costs. In this chapter, key features of spray drying such as underlying operational principle, types of spray nozzles used, the flow pattern of droplets/particles and drying medium within the drying chamber, the particle formation process of individual droplet are discussed in considerable detail. The modelling aspect of a single droplet subjected to spray drying environment has also been included. Finally, the most commonly considered characteristics of spray dried powders including morphology, crystalline/amorphous nature and solubility are highlighted and discussed.  The content presented in this chapter will be very useful for practising engineers, technologists, researchers as well as postgraduate and undergraduate students.

Abstract

Osmotic dehydration is gaining popularity due to several energy and product quality related advantages it offers. It has huge potential as a complementary process step prior to operations such as air-drying, microwave drying, freezing, frying etc, if not an alternative one, in the food process chain. It can be easily integrated with other processing steps in order to improve the overall efficiency of a given food process. Application of additional driving force either prior to or during osmotic dehydration can enhance the mass transfer rates in the osmotic dehydration. Role of mathematical modelling both in osmotic dehydration and rehydration have been discussed. Current limitations for the adaptation of osmotic dehydration in the food processing industry and possible solutions are also discussed in detail.

Abstract

Classification of the hundreds of possible dryers is essential to the logical selection of appropriate dryer for a given application. Diverse criteria for classification as well as selection of dryers are presented and discussed briefly. The advantages and limitations of different dryer types must be taken into consideration. Initial capital cost is often the key deciding criterion in industrial dryer selection. This is not a good strategy as the user must pay for the operating costs over a long period of life of the dryer. In general several different dryer types are suitable for a given product. Careful selection is essential for cost-effective operation of the dryer.

Abstract
 
Food products can have moisture content as high as 90% which needs to be lowered to acceptable limits to prevent microbial growth and deteriorative reactions. Drying is one of the most common and cost effective techniques for removal of excess moisture from the food by application of heat. In addition to its role of extending the product shelf life and providing stability, drying also helps to produce variety of products from agricultural, horticultural and industrial products. But to obtain the desired quality product, adequate drying is essential which depends on type of dryer and drying technique employed which further requires proper understanding of drying process. Despite being important unit operation in food processing industry, appropriate scientific knowledge of the drying process is still limited. So, the fundamental principles and associated terminologies with drying has been discussed in detail in this chapter to have thorough understanding of the drying process. In addition, different models and calculation procedures for drying of different types of commodities has also been reviewed.

Since time immemorial, women have played and continued to play a key role in conservation of basic life support system, such as, land, water, flora and fauna. Women power at present constitutes nearly half of the global population and account one third of the total work force. They contribute more than half of duties and responsibilities but are not given proper rights. In India till now rural women continue to struggle with dual responsibilities of economic production and domestic labour, and most are confronted by poverty, illiteracy, high health risks, inadequate access to productive resources, and lack of credit/market access. The empowerment and autonomy of women and the improvement of women’s social, political, legal and economic status is essential for sustainable rural development

Both women and men play critical roles in agriculture throughout the world, producing, processing and providing the food we eat. Rural women in particular are responsible for half of the world’s food production and produce between 60 and 80 percent of the food in most developing countries. Yet, despite their contribution to global food security, women farmers are frequently underestimated and overlooked in development strategies.

Rural women are the main producers of the world’s staple crops – rice, wheat, maize – which provide up to 120 percent of the rural poor’s food intake. Women sow, weed, apply fertilizer and pesticides, harvest and thresh the crops. In the livestock sector, women feed and milk animals, while raising poultry and small animals such as sheep, goat, etc. Also, once the harvest is in, rural women provide most of the labour for post-harvest activities, taking responsibility for storage, handling, processing and marketing.

1. Feminization of Agriculture

Almost all active women in rural India can be considered as ‘farmers’, in some sense – working as agricultural labourer, unpaid workers in the family farm enterprise, or combination of the two. Moreover, several farm activities traditionally carried out by men are also being undertaken by women as men are pulled away into higher paying employment. Thus rural India is witnessing a process which could be described as ‘feminization of agriculture’. The significantly high and growing population of female headed households has also highlighted women’s contribution to agriculture.

The interventions for women empowerment was perhaps started intensively since fourth plan period. Subsequently many more initiatives are taken for the total all round development of women in this country.

A. 4^TH FIVE YEAR PLAN (1969-1974)

Farmers Training and Education Programme

It was for the first time in the 4^th Five Year Plan that an effort was made by Ministry of Agriculture to address the training and extension needs of women farmers with new and improved technology through “Farmers Training and Education Programme”, in which a network of 150 Farmers Training Centers were established to close the visible gap between the recommended package of practices and the farm women’s knowledge and skills about them. In this programme, a linkage of the supply of production inputs with improved technical training, supported by Farm Radio Broadcast and Functional Literacy was provided. The unique feature of this programme was that for the first time, a cognizance of women’s participation in agriculture was taken. The experience of the programme had shown that the states which gave due importance to this programme, especially in terms of curriculum planning and syllabus formulation (based on true status and needs of women farmers), achieved very good results. It was, this programme, which focused many issues that had to be categorically considered while planning and implementing agriculture support programmes for women farmers.

Women are the backbone of rural economy. They play a significant role in domestic and socio-economic life of the society. National development is not possible without developing this important and substantial segment of any society. To achieve anything, women are obliged to surmount host of obstacles. The difficulty in gaining access to land, credit and agricultural inputs hampers their potential as producers who feed the world. Barriers of tradition and discrimination have limited their access towards technology, training and education. Moreover, the extension approaches and strategies usually followed for transfer of technology to women are not keeping match with their specific needs and problems. The World Food Summit convened by FAO in 1996 drew up a plan of action to address the major impediments to universal food security. It also called for the full and equal participation of both the genders so as to ensure gender equality and empowerment of women.

Introduction

The economic choice of any process is the criterion for efficient utilization of the by-product that is produced along side of main product. During manufacture of major dairy products, the dairy industry also ends up in producing different by-products. Various by-products of dairy industry are skim milk, butter milk , whey and ghee residue. Dairy industry is particularly confronted with the problem of economic utilization of whey and ghee residue. The techno-economical problems associated with utilization of these by-products, is now receiving considerable attention. More efficient, cost effective and sophisticated technologies have opened up new vistas for manufacture of number of derived by-products. Further more the market for dairy by-products, as an ingredients in other consumer food products like snacks, ready meals and microwavable food products, has been growing.

Introduction

In the recent past there has been a great deal of questioning regarding role of milk fat in cholesterol metabolism and other body functions. The enormous wave against cholesterol containing foods has damaged the image and market growth of fat rich dairy products. This trend is due to presence of saturated fats and cholesterol that are known to increase the incidence of coronary heart diseases one of the common cause of heart attack. The educated and urban society is more health conscious about the presence of cholesterol in their diets. This has led to the greater demand of cholesterol free foods. Ghee being a saturated fat and containing little amount of cholesterol, is suspected to contribute towards coronary heart diseases. However, critically surveyed scientific literature indicates that there is no evidence of any association of milk fat with increased risk of coronary heart diseases. Age old and proven Ayurvedic system of medicine has proved the usage of ghee to induce several beneficial effects on human health and used extensively for therapeutic purpose like in treatment of skin allergy, respiratory diseases, curative for ulcers and eye diseases. This suggest that ghee is a valuable form of dietary fat.

Introduction
Ghee is the pure clarified butter fat prepared chiefly from cream and/or desi butter (Makhan) to which no colouring matter is added.  Ghee manufacture has great significance and relevance to Indian masses and the dairy industry. Ghee is a very popular product since ancient time and has greater demand during festival and other ceremonial functions where use of ghee in food has been considered to delicacy due to its pleasing flavour and aroma. There are sufficient recorded evidence to prove that the manufacture of ghee originated from India and has been used extensively for religious and dietary purposes since Vedic times. Presently about 28% of total milk production is utilized for manufacture of about 1 million tones of ghee per annum. It is the traditional product with an established market. Cow ghee is golden yellow in colour, and is attributed unique therapeutic value.  The colour of buffalo ghee is greenish yellow due to presence of pigments called billirubin and billiverdin. Ghee is characterized by its pleasant, cooked and rich flavour. The preferred texture is of larger uniform size from grains having non-greasy consistency.

Introduction

The demand for butter as table spread has declined due to high cost, poor spreadability at low temperature, high saturated fat and cholesterol content, changing life style and increased demand for healthy products. Today food industry is actively involved in new product development, this includes new formulations and imitation of foods being designed to compete with or replace existing products based on their superiority in convenience, cost and quality. The wide acceptance of bread in regular diet among urban consumers (75 percent of all household) reflects around 8 percent rate of growth in bread consumption. With this increase, the requirement of a suitable spread to complement has also increased. Table spreads include a variety of spreadable semi-solid products such as fat spreads, cheese spread, peanut butter etc. Butter has also been blended with vegetable oils/fat to produce a product that retains dairy qualities of butter with enhanced spreadability.

Butter is one of the leading milk product in developed countries of the world. It serves as a balance wheel of dairy industry. Surplus milk is generally converted into butter to be used during the times of scarcity. It is an article of commerce and a sign if wealth. Butter is a fat concentrate, which is obtained by churning cream, gathering the fat into a compact mass and then working it for proper distribution of moisture and salt. The art of butter making has a long history. The manufacture of butter was confined to colder regions where gravity creaming was successful. The milk was allowed to stand undisturbed for 10-12 hours until layer of cream collects at the top.

Introduction
Makkhan (Makhan) is an indigenous(desi) butter obtained by hand churning of dahi using wooden beater (mathani). It is traditional unsalted butter characterized by its delectable and rich flavour. It is white in colour with slightly greenish tinge and has typical soft body and a smooth grainy texture with pleasant aroma. This product has been extensively used for dietary and religious practices since vedic times. The entire quantity produced forms an intermediate product for preparation of ghee (clarified butter fat). Nearly 30% of the total milk production goes for desi butter manufacture. The average yield of the product is very low ranging from 5.5-7.0% for every 100 kg milk used for the purpose. The chemical composition of the product is variable depending upon the method of manufacture. It is difficult to achieve the uniform standard of 20% moisture in the final product due to limitations in the technique adopted for its manufacture. The non fatty solids and lactic acid are derived from the method of preparation and preservation. Higher non fatty solids in makhan indicates use of self soured milk, while a high lactic acid content indicates prolonged storage and in sanitary conditions of manufacture.