eChapters

Life forms are composed of one of two basic cell types : Eukaryotic or Prokaryotic. Generally, eukaryotic cells are larger and more complex than the prokaryotic cells and possess a membrane-enclosed nucleus; eukaryotic means ‘true nucleus’ (eu=true; karyon = nucleus). All plants, animals, fungi, protozoa and algae are composed of eukaryotic cells. Only the microorganisms classes as bacteria and the archaea are prokaryotic cells. Prokaryotic cells have no nuclear membrane and therefore lack a true nucleus. The latin prefix pro means ‘early’ and in this instance suggests the somewhat primitive nuclear structure found in bacterial cells. Eukaryotic microorganism are sometimes simply referred to as eukaryotes, and the prokaryotic microbes as prokaryotes.

The term growth as applied to higher organisms such as animals commonly is concerned with increase in protoplasmic mass and does apply to reproduction or to increase in number. In microbiology the term refers to increase in the number of organisms. Bacteria increase in number by a process of simple binary fission. Each cell increase in size and redivide into two similar cells. Each of the divide cells may in turn divide to become two cells. Each division produces what is termed as new generation of cells, theoretically there are 2,4,8,16,32,64,128,256 cells in the 2,3,4,5,6,7,8,& 9th generation, this is known as logarithmic growth – the population doubles with each successive generation. Under favourable conditions, bacteria produce generation within 15min. Under unfavourable conditions 24 hours of more may be needed for each generation. Generation time for E.coli is 17 to 20 minutes.

The sources of contamination of milk on the farm can broadly be categorized as

    a)    Interior of the Udder
    b)    Exterior of the Udder.
The interior reflects the health of the animal, while the exterior depends on the farm condition, equipment, persons, water etc.

a) Interior of the Udder
The animal by itself is one of the most significant contributors of microorganism in milk. The bacteria in the udder usually enter from the teat opening and get distributed internally by their own growth and physical movement. In the normal healthy udder, the types encountered in milk are most predominantly Micrococci, followed by Streptococci, Corynebacterium and others. Most of the bacteria are excreted in fore milk.

The Concept of ‘Clean Milk’ Production

Although milk is nature’s most ideal and perfect single food both for the newborn and the mature human beings, the possibility of it being a source of biological and chemical hazards cannot be excluded. In view of the immense dietary importance of milk, the need for production of safe, clean and wholesome milk is emphasized. The term ‘clean milk’ does not mean milk in which all visible dirt is absent or milk from which it has been removed; rather it does denote raw milk from healthy animals, that has been produced and handled under hygienic conditions; that contains only small number of harmless bacteria and that possesses a good keeping quality without being treated by heat. In other words, the unhygienic production of milk may lead to inferior keeping quality as a result of rapid microbial multiplication under favourable storage conditions apart from serving as a potential health hazard. These microorganisms cause the milk to sour quickly, putrefy and develop undesirable flavours, colour defects, ropiness and bitterness. On the other hand, the pathogenic microorganisms, which may gain entry through various sources, may cause many diseases to the consumers.

In India, the collection, transport and distribution of raw milk involves a number of agencies and persons at rural and urban level – village producers, milk collectors, halwais (Sweet-makers), milk vendors, dairies, producer-retailers and wholesale or retail markets.

1. Collection

Usually, the milk collectors approach the small village producers to collect milk and the same is sold directly or indirectly (through agents) to a dairy (milk procurement centres) or halwais or city milk vendors or consumers. The producer – retailers themselves, in some cases, supply the milk to the above said parties. The production of milk in small, scattered holdings in village causes problems during its collection. It involves visits to many villages, some of which are not easily accessible for the purpose.

Starters are selected strains of micro-organisms deliberately added to milk during conversion into cheese, dahi, yoghurt and other fermented dairy products to bring about specific changes in the appearance, body, texture and flavour characteristics of the desired final products.

Functions of Starters

The primary function of almost all starter culture is to develop acid in the product. The secondary effects of acid production include coagulation, expulsion of moisture, texture formation and initiation of flavour production. In addition to these, the starters also help in imparting pleasant acid taste, conferring protection against potential pathogens and providing a longer shelf life to the product. These bacteria convert 1% of lactose in milk approximately to lactic acid with very little by-products such as acetic acid, ethanol, CO2 and normally with no substances causing taints and hence leading to a clean and wholesome milk souring.

Milk fermentation is process by which a change is produced in milk through the activity of microorganism. As milk leaves the udder it serves as a medium for the growth of many species and accordingly undergoes a series of changes, the processes producing these changes constitute the milk fermentation.

Fermentation of organic compounds, especially in the lack of oxygen leads to the rapid break-down of ‘biopolymers’ to produce ‘anaerobic food chains’.

Bacteriophage is the term applied to bacterial viruses. Bacteriophage having the ability to lyse certain sensitive living cells. Phages are small particles, which can only be seen in the electron microscope after the application of suitable staining techniques. All phages have a head and most have a tail. The head may be isometric or prelate with a hexagonal outline.

There are two types of phages virulent and temperate which enter a different relationship with the host, the lytic and lysogenic cycles respectively.

The significance of milk in human nutrition is now well established as it is considered as the best, ideal and complete food for all age groups. However, in spite of being so, milk can also serve as a potential vehicle for transmission of some diseases under certain circumstances. Moreover, by virtue of possessing almost all the essential nutritional factors, milk can also serve as an excellent culture and protective medium for certain microorganisms, which may include potential pathogens capable of causing serious health problems to the consumers. In this way, milk may serve not only as a vehicle of transmission of disease causing organisms, but it can also allow these pathogens to grow, multiply and produce certain toxic metabolites, thereby making itself an extremely vulnerable commodity from public health point of view.

According to International Dairy Federation(IDF),1980, Mastitis also called as ‘mammitis’ is defined as an inflammation of the udder, almost always of microbial origin and is the outcome of a local or a general infection. The common symptoms are related to inflammation, viz., swollen, hot, red, and painful udders. Mastitis can be classified based on symptoms or on the causative organism.

A) Forms of mastitis based on symptoms

    1.    Acute or clinical
    2.    Sub-acute or subclinical
    3.    Chronic.

Tuberculosis

Tuberculosis has been recognized as one of the most important infectious diseases in the world because of its high global impact and its chronic debilitating character, particularly in the poor section of society. Milk-borne tuberculosis is directly or indirectly related to the consumption of raw milk from infected dairy herds.

Normally raw milk contains different levels of inhibitory substances, which restrict the normal development of bacteria and some times may even kill them. The degree of inhibitory activity varies considerably in milks of different species, viz, cow, buffalo, human. Maximum activity present in human milk, variations occur in the milks of individual animals and some times even at different milking or from different quarters of the udder of the same animal.
There are two groups of antimicrobial substances present in milk:
    1.    Inherent or naturally occurring substances in milk. 
    2.    Non- inherent compounds secreted into milk from other sources.

Dairy equipment and utensils with which milk and milk products come into contact are the main sources of contamination in the products. By the use of effective equipment cleaning and sterilization methods on routine basis, milk of high bacteriological quality can be consistently produced. In composite milk plant, a variety of equipment and utensils are used. The use of stainless steel for the fabrication of dairy utensils and equipment provide highly polished and hard smooth surface that can be cleaned readily, apart from showing resistance to corrosive action of detergents and bactericidal solutions. Utmost care is taken to avoid dents and scratches, which could be the possible focal points of subsequent contamination. To overcome all these problems aluminium and stainless steel vessels and equipment present an ideal situation.

Introduction

Numerous characteristics of food determine its acceptability to consumers and to regulatory officials. Before accepting a food for consumption, it must be attractively presented, must have desirable odour and flavour characteristics and other qualities and must be free from potential pathogens or their toxic products. The ultimate nutritive qualities, flavour and appearance have been preserved and no harmful organisms or substances are present to affect the consumer adversely. If the quality of the product is good, its keeping quality is also likely to be substantial. Conversely, there are more chances of spoilage of an inferior quality food product during storage.

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.

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.

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

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

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

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

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

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

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
 
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

Recently, the reduction of post harvest food losses around the globe is a critical issue for ensuring future food security. Drying techniques is important option to prevent losses and preserve food for long time. The solar thermal energy required to remove moisture from the food during the drying process can be optimized by designing suitable solar dryers. Moreover, the application of solar energy in drying of agricultural products has tremendous potential, since it can easily provide the low temperature heating required for drying and helps in reduction of CO2 emissions. Hence, the present chapter deals with descriptions of different types of solar dryers used to dry various types of agricultural food products and design of solar dryers. Also, the heat and mass transfer parameters with respect to various process variables to estimate the performance of the food dryer system were analyzed. The advantages of solar dryers in terms of net CO2 emissions mitigation potential and the quality attributes of dried food products are also discussed. It is suggested that properly designed solar dryers having low operational cost compared to electrically heated dryers may prove to be an energy saving device for drying of agricultural products. However, the techno-economical and environmental aspects of various efficient solar dryers are needed to be further studied for applications in various irregular shaped food products.

Abstract

The primary commercial energy sources such as coal, oil and natural gas poses an enormous challenge to our development goals including environmental degradation, as India is not well endowed with these exhaustible natural resources. Further, these conventional sources are also not available in right quantity and producing environmental pollution manifold in land, air and water. There are number of unit operations in food processing and value addition consuming bulk of conventional energy sources where renewable energy sources can easily be integrated for energy conservation and environment protection. There is significant potential for application of Renewable Energy Sources in different unit operation of food processing including drying of food products for energy conservation and for reducing hydrocarbon emissions.

Abstract
 
Drying is one of the most popular methods used for preserving products and extending their shelf lives by reducing moisture content to a low level to prevent microbial spoilage and moisture-mediated deteriorative reactions. As an efficient technology with high heat and mass transfer rates, impingement drying has been commonly used in various industrial drying such as tissue paper, textiles, photographic films, coated paper, nonwovens, carpets, lumber etc. In the past two decades, air impingement technology has got more and more attention in the field of food and agricultural products processing.

Abstract

There are several empirical models to describe deep bed drying dividing the domain into many thin layers. Empirical equations are seen as a resource that only serves to describe the thin layer drying kinetics of an agricultural product. Normally an empirical model is used to determine drying rate. The validity of following thin-layer drying models are accounted by coefficient of correlation (R2), standard error of estimated (SEE), root mean square error (RMSE). The properties of dried foods vary substantially depending upon the type of product, moisture content, drying type and ultimately drying conditions. To take care all above variables, a promising approach is to use Artificial Neural Network (ANN). In process control, the main objectives are food safety, high quality and yield at minimal costs. To obtain high quality products, on-line control techniques are required. Most food processes are highly nonlinear, with time varying dynamics, which complicates food automation. However, the recent developments in artificial intelligence based advanced control tools such as ANN to food processing have opened up novel possibilities for processing industries.

Abstract

Food dehydration is an oldest method to increase the shelf life of food by reducing the water activity. A dried food product provides advantages of increased shelf life and reduced cost due to decreased weight as well as transportation. However, there is a decrease in product quality due to inadequate control on drying process parameters such as drying temperature and moisture removal together with change in thermo-physical properties of food. Computational modeling and simulations can provide a unique insight on the drying parameters that influences the product quality, and optimize the process conditions which are difficult by experimental analysis. Moreover, the computational techniques are advantageous over experimental optimization methods by minimizing the time and cost. This chapter reviews different computational modeling techniques such as, finite element modeling, finite volume and finite difference methods for modeling of food dehydration process. Also, this chapter describes the application of modeling techniques for determining the influence of shrinkage and porosity during dehydration.

Abstract

It is well known that drying is an important unit operation in food processing industries, essentially used to extend the shelf life but also in making innovative processed products such as snacks with desired functionalities. Although drying of food products is carried out traditionally using several methods, the quality and energy aspects have been major focus of food drying research in the last decade or two. This is achieved by modifying and/or optimizing the existing drying systems, improving pre and post processing of the product, combination of more than one dryer type or developing altogether a new drying technique. There several dryer types which can give extremely good product quality, however, cost-effectiveness can be a major issue. It is necessary to balance both good product quality and minimum energy usage in order to sustain highly competitive market. This lecture will provide an overview of conventional drying methods used for foods, followed by some advances in these conventional methods and a discussion on some new drying techniques developed in recent years that are either commercialized or have potential of industrial use.

Abstract

Drying is an age old practice of food preservation. Removal of moisture from the food materials is usually carried out at atmospheric pressure and elevated temperature. In the presence of oxygen, drying can cause oxidation of some compounds leading to quality deterioration. Drying at higher temperature adds to the losses and can be responsible for enzymatic and non enzymatic browning, loss of aroma, nutrients, antioxidants, pigments etc. On the other hand, drying under sub atmospheric pressure helps in retaining the themosensitive compounds present in natural foods as drying can be accomplished in oxygen free environment. Under vacuum, evaporation of moisture can be possible at lower temperatures.

Abstract

Refractance Window (RW) drying is a relatively new drying technology. This method is carried out by spreading a thin film of food slurry on a conveyor belt made up of a transparent polyester material. The slurry is thermally heated as it moves along the conveyor belt, resulting in rapid drying of the product. RW drying is similar to Drum Drying, but conducted at lower temperatures (95–97^ºC) and without direct contact with the heat source. RW drying offers low operating costs with excellent retention of color, flavor and nutrients.

Abstract

Fruit leather is a concentrated source of nutrient, energy and minerals processed from fruits in the form of sheet or leather. It is eaten as a desert or snack since ancient time. Fruit leathers have a greater benefit than fresh fruits if equilibrium ingredients are established and seasonal surplus of fruits are utilized and contributed to minimize post-harvest losses. The process of making fruit leathers involve making fruit puree and adding additives and preservatives for the purpose of enhancing taste and shelf-life. Drying, the key unit operation in making fruit leathers, is the most energy intensive and time consuming step in the process, modern drying techniques can be implemented to overcome the limitations. By novel means of processing technologies or enrichment could lead fruit leather to introduce high quality food product in the market. Continuous research and development can lead to a new era of production and development of fruit processing and overcome the obstacles during processing. In addition study on chemical and biochemical hazards involved in overall process will guide to ensure product safety. Market research tools e.g. quality function deployment method and other market analysis methods could be applied to understand the product trend, demand, consumer expectations and the scopes of improvement.

Abstract

Medicinal herbs are economically and nutritionally important plants, which are rich in health-promoting compounds. Herbs are the backbone of both the traditional Chinese and Indian medicine, which has long history as part of their culture. Ensuring the quality of herbs is a crucial step for integrating the traditional medicine into science-based modern medicine. Drying is an essential technique in preservation of herbs as it affects directly the quality attributes of the dried products, whereas many producers lose much profit due to poor drying techniques. So, employing a suitable drying technology and selection of appropriate drying conditions are very important for producing high quality herb products. The aim of this article is to summarize the advances in drying technologies of medicinal plants, describe the current status and identify future research opportunities. The current work provides more data and information for selecting optimum technology for herb drying and would trigger innovative drying technologies to enhance drying kinetics and quality of herb drying.

Abstract

Food proteins are among the commonly used ingredients by food manufacturers to produce different products with desired characteristics. Due to several nutritional and functional properties, proteins have different functions in various food products in addition to their role in metabolic system of the human body. Dilute or concentrated solutions of pure proteins or unprocessed food products which are rich in protein are very sensitive to deterioration or degradation by microorganisms and thus have short shelf life at ambient temperatures due to their highly moist structure and high protein content. Drying is one of the best methods that can guarantee preservation, a longer shelf life, chemical or thermal stabilization and resistance against other stresses. A full understanding of stresses encountered during drying is needed to choose an appropriate drying process and to optimize this process for maximum product quality. A number of methods have been used by various researchers to dry protein-containing foods. Among these methods, freeze drying and spray drying are the most common techniques. Sun drying, convective hot air drying, vacuum drying, heat pump drying, radio frequency drying as well as combined or hybrid drying methods with two or more of the drying methods have also been developed.

Abstract

Application of solar energy for drying of agricultural food products is one of the most attractive and cost-effective drying techniques. However, the intermittent nature of the solar energy is one of the major shortcomings of the solar drying system that can be alleviated by storing excess energy during the peak time and using it in off sun hours or when the direct availability of solar energy is inadequate. The use of sensible and latent heat storage systems in solar dryer is an effective way of storing thermal energy for drying purpose. This chapter will present information on different thermal energy storage (TES) materials, their advantages and disadvantages. The information available in the literature regarding the studies conducted on TES assisted solar drying systems is also covered in this chapter. In addition, some of the models that have been used by different researchers to test the performance of different TES materials are also reviewed.

Abstract

Drying remained at the centre stage since the initiation of the food processing due to its promise to preserve agricultural products economically and add functionality to a food product unlike other thermal as well as non-thermal food processing operations. However, many existing drying techniques have their own limitations like nutrient loss, damage of the organoleptic quality, high cost etc. Therefore, research for better drying technologies is going on. Supercritical drying (SCD) is one such technology which utilizes higher dissolving power of super critical fluids (SCFs) to dry food products. The current chapter illustrates the mechanism of SCD as well as current state-of-art and promise of the drying technology. Also, some modelling approach of SCD has been included in the discussion to facilitate new designs and optimization of SCD for various food products.

Abstract
 
Spray drying is used as one of the best alternatives for extracting essential constituents of fruit and vegetables. Spray drying of fruits and vegetable juice/purees, which is an excellent source of bio-functional properties into a solid phase helps to enhance their stability and controlled release in different food matrices. Spray drying along with different carrying agents helps to retain essential active compounds in fruits and vegetables. Spray drying is generally carried in three steps viz. atomization of liquid feed by suitable atomizer; drying of droplets with the help of hot air and motion of droplets. Carrier agents like maltodextrin, wax starch, Gum Arabic and microcrystalline cellulose are added to the feed to increase glass transition temperature. Chapter presents the effects of different operating parameters of spray drying as well as effects of carrier agents on the physicochemical and functional properties of spray dried fruit and vegetables powders.

Abstract

Dietary antioxidants can be found naturally in various fruits, vegetables and food products.Typically, antioxidant phytochemicals commonly found in food products are Vitamin C, Vitamin E, carotenoids, polyphenols, melanoidins and indoles. The main characteristic of an antioxidant is its ability to scavenge free radicals and form stable end product which inhibit the chain oxidative mechanisms that lead to degenerative diseases which are harmful to human health. Drying is widely used in food processing to minimize food wastage and to extend food shelf-life. Pretreatment, drying methods and storage conditions are some of the processing parameters affecting the quality of dried products. Selection of processing conditions and storage environment are therefore critical in maximizing the retention of food antioxidants. This chapter aims to compile and summarize studies carried out for antioxidants namely antioxidant contents in dried food products, effect of processing parameters and quantification methods in the analyses of antioxidants.

Abstract

Water, the most important component of common foods, is considered to be desirable as well as undesirable in the different food systems. Water-solid interaction in food systems controls various biological, biochemical and biophysical reactions affecting their acceptability. The retention or release of water from solid has been quantified in the terms of sorption isotherm. Sorption isotherm techniques have been used to characterize and identify the type of water-solid interaction in different food products. Sorption isotherm provides various information useful in designing and optimization of drying, storage, packaging, predicting quality and shelf life of the product.

Abstract

Most dryers operate at low thermal efficiency. The development of models and control systems offers an opportunity to improve dryer operation and efficiency. Dryer control is very important and with deeper understanding of the drying concept, new “smart” dryers can be made more reliable and more cost-effective than classical dryers. This chapter will provide an overview of necessity of control and safety measure in food drying system, and terminology related with drying control system. Different control strategy includes conventional and advanced techniques implemented in drying operation are reviewed  here and simple outline of intelligence control system in drying technology are briefly described in succeeding section. Various hazards in drying process and risk and safety management will also be discussed.

Abstract

Packaging plays an important role in the food processing Industry. It makes food more convenient as well as gives the food greater safety assurance from microorganisms, biological and chemical changes such that the packed foods can have longer shelf life. In order to meet the huge demand of processed food with longer shelf life, various methods of preservation and packaging are being used in the food processing industry. Drying and dehydration is one of the method which helps preservation of a perishable commodity against deterioration or spoilage.

Abstract

By loosely inspiring the actions of neurons in the human brain, artificial neural networks (ANNs) are widely accepted as a powerful nonlinear adaptive approach to tackle complex, dynamic, highly nonlinear, and ill-defined problems in an increasing number of fields of food industry.They have been used extensively in food drying to solve problems of nonlinear function approximation, pattern recognition, data description, optimization, simulation, pattern recognition, control, data sorting, clustering, and noise reduction, due to their massively parallel structure and capability to learn from examples. In this chapter, after providing a brief description of ANN technology and its principles as well as the structure of the most commonly employed ANNs in this context, an example is given to explain how the ANN technique is used for modeling and controlling food drying process. Generally, modeling, prediction, and optimization of heat and mass transfer, thermodynamic performance indicators, and quality parameters as well as physico-chemical attributes of dried foods are the most popular subjects to attract researchers’ attention to apply the ANNs in food drying industry.

Abstract

Inspired by the human eye to brain assessment process, computer vision technology has demonstrated its potential for monitoring and controlling of several operations in food industry. Computer vision technology is, therefore, applied extensively in food drying process for monitoring nutritional value and sensorial characteristics because of its promising characteristics such as reliable objectivity and repeatability. In this chapter, after providing a brief explanation of the computer vision technology and its prerequisites and principles, an example is given to elucidate how this technology is used for monitoring the visual attributes of foodstuffs during drying process. Overall, monitoring the visual properties of food products like size, shape, color, and texture in off-line mode are the most popular issues to fascinate researchers’ attention to apply the computer vision technology in food drying. Nevertheless, industrial applications of the computer vision technology for real-time monitoring and control of food drying facilities as final goals of its introduction in food drying industry seem to be limited. For future studies, it is suggested to apply this unique technology along with advanced soft computing methodologies for in-line monitoring and control of food drying process in order to achieve high quality dried products. Finally, outlooks and potential employment of this technology in food drying domain are discussed as well.

It is difficult to ascertain which came first, food or human being. It is the same situation as chicken and egg where we lack evidence to indicate which came first on earth.

It does not matter which came first but we know for sure that human being needs food and he or she needs everyday and throughout his or her life. In other words, a human being cannot survive without food indicating permanent unbreakable bondage between food and human being. It supports the basics of human civilization-food, agriculture and humanity.

1.    I deem it a singular honour to deliver Dr. Sen Memorial Lecture. Dr. Sen, who was both an administrator and a visionary, was instrumental for:

SYNOPSIS

Food is an essential element without which human being cannot survive. We need it for our maintenance and growth everyday and through the longevity of our life. As we understand food, it is a bunch of essential elements which is essentially needed for the engine of human body to run non-stop. The understanding of food is much required by masses who consume it every day. The present paper attempts to describe the knowledge on food, feeling on food by consumers, prevailing food, hunger and malnutrition, healthy food and studies required on consumable foods.

SYNOPSIS

We lag in nutritional awareness. The therapeutic values of plant foods, such as vegetables, fruits, grains, legumes, nuts, seeds, herbs, spices and other foods like dairy products, fluids and meats are to be brought to light. The values of important nutrients, may lead to the basis for nutritional education lacking at present. There is need to bring awareness and add to the knowledge of the younger generation. A food is something that provides nutrients. Nutrients are substances that provide: energy for activity, growth, and all functions of the body such as breathing, digesting food, and keeping warm; materials for the growth and repair of the body, and for keeping the immune system healthy.

SYNOPSIS

The availability of food is of paramount importance without which it is hard for human beings to survive. The recognized way of making food available is to produce but it is also equally important that food produced is utilized well without loss of edible food materials. The paper discusses on unused food, under- utilized food within and across countries, and puts emphasis on utilization and handling of food. In perspective, the paper highlights the steps to be taken up to save and utilize the food already produced.

SYNOPSIS

In all probability the ancient farmer’s market originated on the streets of villages and later on, on the streets of towns. The street food survived through decades and centuries and now it has assumed its new role in fulfilling the readymade food demand of the working people of mega cities. The street food has now more relevance to the growing urban population. With the lapse of time and migration people to the cities, the business and activities of street food got expanded in qualitative and quantitative terms worldwide.