eChapters

Abstract

India has become not only self sufficient in food grains but has also emerged as net exporter of wheat and rice. Acute famines in India have practically been eliminated, thanks to increased food availability at the national level, improved early warning systems and expanding infrastructure for more rapid transport of food grains and other products to needy areas. However, the existing post management system, strategies and policies don’t seem to match new challenges. Despite government intervention in pricing and procurement of food grains, primarily wheat and paddy, India continues to suffer heavily on account of losses and wastages incurred during the post harvest stages, which are more manmade than natural. Some losses have already occurred before the arrival of food grains in the regulated and wholesale markets and continue till food grains reach their destination. What contribute to continuing losses and wastages are improper post harvest handling, government policies and their implementation, which even stifle growth and modernisation of grain markets and processors.

Abstract

Garden peas of two cultivars (Pb-87 and Pb-88) were procured. Pods were shelled manually, grains were blanched and dehydrated. Other lot of peas of both the varieties was allowed to mature on the plant till the plant foliage dried up, harvested, pods were dried in shade for few days, shelled manually and grains were further dried in shade. Grits were prepared by grinding rice and pea (dhal) in a laboratory grinder to pass through 20 mesh sieve. Blends were prepared by mixing rice and pea grits in the ratio of 100:0, 85:15 and 70:30. The blends were subjected to extrusion cooking using Brabender single screw extruder. The extruder die pressure, specific energy consumption (SEC), expansion ratio, density, water absorption index (WAI), water solubility index (WSI) and organoleptic characteristics were studied. Addition of pea grits resulted in a decrease in die pressure in all the blends. Addition of pea grits showed a significant effect on SEC. A decrease in expansion with increase in the level of pea grits in blend was observed. The extrudates having lower expansion showed higher density values and vice versa. Effect of replacement of rice grits with pea grits on WAI was found to be significant. Level of pea grits significantly affected the WSI. Incorporation of pea grits in the rice grits significantly affected the sensory characteristics. Replacement of rice grits with mechanically dried pea grits resulted in deterioration of acceptability score, but addition of field dried pea grits improved the same.

Abstract

Paddy seeds of variety PR - 116 were obtained from the PAU seed farm. These seeds were cleaned with commonly used seed processing equipment. Samples were divided into 2 parts. One part was kept as such for taking the observations of feed (control) and the remaining part was passed through specific gravity separator for its refinement. The various fractions obtained were recovery, middlings, and rejections. These graded fractions as well as the feed were packed in 5-kg cloth bags and stored under ambient conditions. Different quality parameters viz. moisture content, physical purity, thousand grain weight, percent germination, root/shoot length, vigour index and speed of germination were recorded at 30 days interval. The physical purity, thousand grain weight, percent germination, root length, shoot length and vigour index were found to be higher in recovery and minimum for rejections while moisture content was highest for rejection as compared to all other fractions. Germination, root/ shoot length, vigour index and speed of germination increased with the duration of storage while moisture content, thousand-grain weight and physical purity followed a reversed trend. Compared to feed, the recovery had higher quality attributes after 4 months of storage viz. moisture content decreased by 0.3%; physical purity increased by 0.67%; thousand grain weight increased by 2.97 gm/ thousand grain, germination increased by 8%; vigour index increased by 481.1 points; speed of germination increased by 3.2 seedlings per day. The grading resulted in improvement in overall quality of sunflower seed.

Abstract

30 lines were selected from 864 germplasm lines for good biscuit making attributes on the basis of low protein content (<10.5%) and low sedimentation value (<40cc). These lines were further screened by actual baking test and alkaline water retention capacity (AWRC) test keeping the standard prescribed for biscuit making qualities viz., low protein content, low sedimentation value, low AWRC and larger diameter with larger spread ratio of biscuit. AWRC had significant negative correlation with biscuit spread ratio. Positive significant correlation was found between biscuit spread ratio and biscuit diameter. On the basis of above findings, it may be recommended that low protein content, low sedimentation value, low AWRC may be used as criteria for better biscuit making i.e. increase biscuit spread ratio and biscuit diameter. So wheat-breeding programme has opened up new opportunities for the end use quality product and wheat based food industry. Hence there is an urgent need for qualitative analysis of desired traits in wheat towards enhanced value addition and thereby an attempted has been made to identify suitable genotypes possessing good biscuit making attributes

Abstract

The control of micronutrient deficiency is a realizable goal, notwithstanding the magnitude of the task, challenges and constraints that need to be resolved. Since wheat products particularly maida and atta form the major raw material in widely consumed food items like chapati, bread and biscuit. Fortification of flour as followed in many other countries could be an important strategy to help realize this goal. The technology of flour fortification is effective and cost affordable. Effective flour fortification program would require collaboration between scientific community, governmental and non-governmental agencies, and industry and consumer groups.

Abstract

The constant improvement in automation of bakery industry has placed higher demands on wheat. As a consequence bakery industry requires wheat possessing specific quality attributes. In view of this, there is need to produce good quality wheat not only for good chapattis but also for better bakery products viz., bread, biscuit, noodles, pasta products. New technologies are emerging which could be exploited for determining the Indian wheats for their suitability for various value added products. In the current investigation, 50 genotypes possessing low protein content (<10.5%) selected from a vast amount of breeding material were analysed for their biscuit making attributes. These lines were screened by actual baking test and alkaline water retention capacity (AWRC) test keeping the standard prescribed for biscuit making qualities viz., low protein content, low sedimentation value, low AWRC and larger diameter with larger spread factor of biscuit. Further with the help of Stable Micro Systems TA.HDi Texture Analyser the biscuits were analysed for hardness and crispness. Correlation coefficient among 8 quality traits suggested highly significant and positive correlation between sedimentation value and AWRC, biscuit diameter and spread factor, and biscuit hardness and fracturability, and significant negative correlation between biscuit diameter and its thickness. On the basis of findings, genotypes identified for biscuit making qualities may be used as donor for developing varieties suitable for biscuit making.

Abstract

Pulses being nutritionally vital, is an important constituent of diet for a very large number of peoples. A part from being a relatively cheaper source of dietary protein, it is also an important source of calories, certain essential amino acid, minerals and vitamins. Post harvest scenario of pulse shows that 75 per cent of production was milled in pulses with as dehusked split i.e. dal. Traditionally green gram and black gram dal is dehulled manually after soaking in water. Present investigation was carried out to develop the wet type dehuller and study was carried out on water absorption characteristics of green gram and black gram. The result reveals that the dehulling efficiency of abrasion type mechanism was about 95 per cent and 92 per cent in case of shearing type mechanism. It has been observed that rate of water absorption was initially high and then gradually decreases i.e. 0.54 to 0.18 and 0.48 to 0.18 for black and green gram, respectively. 

Abstract

Consumers are now more conscious about quality and source of their foods. Attempts made to determine the quality of food materials are numerous, but most of them are destructive in nature. In recent years, nondestructive methods of quality evaluation have gained momentum and a considerable attempts have been made to develop them. This paper describes application of these non-emerging technologies: magnetic resonance imaging, x-ray computer tomography, near infrared spectroscopy and a few other important techniques for determination of different quality attributes with special emphasis on grain, and discusses their pros and cons for practical exploitation.

Abstract

Wheat gluten consists mainly of gliadin and glutenin polypeptides. During mixing gliadin and glutenin proteins interact to form a unique viscoelastic gluten network, which is envisaged as being necessary for holding the gases and for producing a light porous crumb textured bread. Recent work has confirmed that the elastic properties of gluten are due to the glutenin fraction, whilst the viscous properties are attributed to the gliadin fraction. Equal amount of these two major protein components of wheat gluten is required for achieving the desired bread quality, but variation in the composition and physical properties of the glutenin polypeptides appear to be largely responsible for the differences in the gluten viscoelasticity and breadmaking potential among wheat cultivars. Recently, associations of gliadin polypeptides with breadmaking quality have also been reported. Using improved protein separation and purification techniques, physical methods and genetic engineering, we are beginning to understand the structure-functional relationship of wheat gluten proteins, but much remains to be explored in the years to come. 

Abstract

Determination of quality of wheat is very important because quality requirement of an individual product vary from one another. Flour quality can be defined as the ability of the flour to produce a uniformly good end product. Flour quality factors can be divided into two basic groups: those that are inherent in the wheat as a result of the genetic make up and the changes brought about by growing conditions; secondly those factors that might be altered during the process of converting wheat into flour Wheat flour constituents play an important role in determining the quality of flour. The flour quality for baking could be assessed by measuring the physical, chemical and rheological characteristics.

Abstract

Adulteration refers to a process by which the quality or the nature of the given substance is reduced by the addition of foreign or an inferior substance, removal of vital component, packing and storage under harmful conditions, insect infestation, poisonous material, undesirable chemicals and unintentional contaminants. All these change in food whether intentional or unintentional are covered under food adulteration. In cereal grains adulteration results by incidental contamination during the period of growth, harvesting, processing, transport, and distribution and results in various health hazard, sand, marble chips, earth and filth are also adulterants in grains. Pest and pesticides residues are also hazardous.

Abstract

Majority of basic research in our country has foundations in Universities and various Institutions linked to them. This paves way for discovering wilder varieties of the present known cereals and other food crops. Such findings help in bioprospecting the required gene/genetic material for the improvement of the existing crops. As per the Biodiversity Act of 2002, it is the responsibility of these institutions to document the same. But, as research scientists are geared to meet the challenges? Being used to socialistic system from the days of Independence where knowledge generated was open to everyone or closed and kept under the mountains of files, the TRIPS agreement has come as a shock. But the true impact of it was realized in 1999-2000, when the patent amendments were taken up. The private institution/ companies went into the act immediately.  We in the University neither were slow to react nor were we prepared to take the shock.  In this paper some of the problems pertaining to IPR and scenario of Indian Universities and Institutions in this regard were highlighted.

Abstract

Mycotoxins are naturally occurring chemicals produced by fungi growing on grain, feed or food. The fungi that produce mycotoxins in grains commonly include Fusarium, Aspergillus and Penicillium species. The toxins can accumulate in maturing corns, cereals, soybeans, sorghum, peanuts and other food and feed crops in the field and in grain during transportation. The toxins may occur in storage under conditions favorable for the growth of the toxin producing fungi. Diseases in animals and human beings resulting from the consumption of mycotoxins are called Mycotoxicoses. These fungal metabolites are detrimental to the health of both animals and human. Toxicity ranges from acute death to chronic diseases, cancer and reproductive malfunction. Mycotoxin contamination of food and feed grains is a serious economic problem for grain producers and processors because grain contamination impacts market 

Abstract

There are enormous food processing industries comprising of grains and oilseeds milling, fruits and vegetables processing, spice grinding and other food processing units in India. Also, there are many seed processing companies in the country, which are engaged in the processing and production of good quality seeds of different crops besides National Seeds Corporation and State Seed Corporations. All industries are using different type of machinery and equipment like cleaner, grader, expeller, milling machines, polishers, dehusking machines, size reduction equipment, different type of grinders, separators, treatment machinery, mixers, pulverizes etc. Besides this equipment, material-handling equipment like conveyor (belt, chain or screw type), elevators, holding bins and other handling equipment are also frequently used in the processing plants. To meet the above requirement many firms are also involved in the manufacturing of these equipment and machinery. Since, most of the seed processing equipment, dhal milling plants, material handling equipment are manufactured by the unorganized sector and hence equipment and machinery fabricated by them are not of very good quality. However, Bureau of Indian Standards has formulated the codes of manufacturing for these equipment and machinery. Seed processing equipment manufactured in India are generally copy of imported processing equipment. The manufacturers do not use materials of good quality. Framework of the machines is very poor. These machines are not also tested for their efficiency, 

Abstract

Wheat is unique among cereals because of its ability to form viscoelastic dough. Variety of products such as leavened and unleavened breads, pasta, cookies, and breakfast cereals are prepared using wheat. The viscoelastic property of dough is mainly due to the presence of gluten proteins viz., gliadins and glutenins. Variations among these proteins play a significant role in determining the quality of wheat. Although considerable studies have been carried out on quantity and quality of protein and their relation to bread quality, very little work has been reported on their relation with quality of Indian traditional products like chapati and tandoori roti. Results indicate that ratio between gliadins and glutenins are important in determining the chapati quality. It has been found that varieties having 5+10 HMW glutenin subunits with IBL/ IRS chromosomes are more suitable for the preparation of chapati and roti. This article is focused on the relation between protein and its subunit composition and the quality of chapatti and roti quality.

Abstract
 
The definition of quality is described from a very simpler one “fitness for purpose or use” to a comprehensive “the totality of features and characteristics of a product or service that bear on its ability to satisfy stated or implied needs”. The concept of total quality management in food industry is adopted recently and it is the “integrated organization approach in delighting customer (both external and internal) by meeting their expectations on a continuous basis through everyone involved with the organization working on continuous improvement in all products/processes along with proper problem solving methodology”. TQM is concerned with the integration of all the efforts in organization towards quality improvement, quality development and quality maintenance to meet full customer satisfaction at economic levels. TQM enhances the work culture and employee’s satisfaction through participation and involvement and consequently the image of the organization.

Today it has been understood that yeasts have great potentials as novel probiotics (Nayak, 2011). They have been found to be safe for human consumption in traditional fermented foods (Jakobsen and Narvhus 1996). Yeasts have a great physiological importance inside the gastrointestinal (GI) tract (Czerucka et al., 2007; Gatesoupe, 2007). Jespersen (2003) has mentioned the role of consuming fermented foods and the health benefits attributed with it.Yeasts are known for prevention of table olive (Arroyo lopez et al., 2012). Bonatsau et al. (2015) have shown multi-functional property of yeast as starters.

In spite of the problems with dosage and viability of probiotic strains, a lot more work is required for industry standardization and safety issues. However, it is noted that probiotics have considerable potential against many pathogenic and other diseases. A wide range of clinical trials are still needed to standardize and optimize the conditions. Ongoing basic research will continue to identify and characterize existing strains of probiotics, identifying strain-specific outcomes, determine optimal doses needed for certain results and assess their stability through processing and digestion.

What new research is needed, what trials and how will the ultimate consumer and Industry benefit?
 
In Brazil, the sales of functional foods amounts to US $ 500 million per year representing about 1% of the total sale of the Brazilian food processing industry. According to a report the interests are mainly for dairy products, nutraceuticals and soy-based products. ABIA forecasts a substantial growth of 4.5-5% for this segment of the market (Stanton et al., 2001). In order to exert the health benefits beyond inherent basic nutrition, it is necessary that the activity of the probiotic culture should be maintained at very high levels during the shelf life of the product.

Probiotics are measured in colony forming units (cfu). CFUs are generally measured in the millions or billions per serving. Probiotics are most commonly beneficial bacteria, but can also be friendly fungal or other organisms, that are typically freeze dried to stabilize them in an inert state during storage and production. Then their continued stability and viability, as measured by CFU counts when cultured, is dependent on limiting their exposure to stimulating environmental conditions such as temperature and moisture. Besides refrigeration, this protection can be done by packaging in glass or by adding freshness packets that helps to absorb and reduce moisture in the package.

Antibiotic Resistance and Gene transfer
 
It is important that probiotic strains should be assessed for their phenotypical antibiotic resistance and potential to transfer resistance gene as otherwise they cannot be used in food (BgVV, 2000; Vankerckhoven et al., 2008). It is vital to do research on characterization of acquired resistance mechanisms and transferability of resistance genes and on methods for determining transferability.

Probiotic Fermented food products
 
An individual requires adequate nutrients like proteins, carbohydrates, vitamins, and minerals to maintain diet. There has been an explosion of the consumer interest in the role of enhancing the health by some specific foods or physiologically active food components, so called functional foods (Hasler, 1998). The concept of functional foods evolved in the year 1990 in Japan.

The lack of mechanistic understanding of probiotic activity is a major drawback for the prediction of safety of probiotic intervention. The complex gut-associated microbial ecosystem and nutritionally related factors are the most important environmental triggers for the development and modification of chronic degenerative diseases including immune and metabolic pathologies. In fact, the interaction between the gut microbial ecosystem and the host is considered to be a critical factor in overall health or disease. Whether probiotics will exert protective, harmful, immune-stimulating or immune-suppressing effects on a host is dependent on the interaction between the microbial signals, the genetic make-up of the host and the effects by the environment. Many studies have revealed that certain probiotic bacteria stimulate immune cell proliferation and activity as evidenced by the production of cytokines and antibodies, thereby enhancing the effectiveness of the immune response against pathogens. Ng et al. (2009)

4a. Intestinal Disorders
 
History of health claims
 
According to Bottazzi (1983) it was in 76 BC that the Roman historian Plinius recommended the use of fermented milk for treating gastroenteritis. Metchnikoff claimed that the intake of fermented milk containing Lactobacilli reduces the toxin producing bacteria, thereby increasing the longetivity of the host (Metchnikoff, 1908). Tissier (1905) showed that there was an increase in the Bifidobacteria in breast fed-infants, thus claiming that the administration of Bifidobacteria to infants suffering from diarrhea was very beneficial as they supersede the putrefactive bacteria that causes the disease. Intestinal beneficial microfloras are responsible to resist the disease (Bohnhoff et al., 1954).

LAB constitutes a group of gram positive bacteria. They are nonsporulating, nonrespiring but aerotolerant cocci or rods, which produce lactic acid as one of the main fermentation products of carbohydrates, they do not have cytochromes. They belong to the phylum Firmicuttes, class Bacilli and order Lactobacillaceae. The group includes several genera such as Lactobacillus, Lactococcus, Bifidobacterium, Pediococcus, Enterobacter, Corynebacterium, Streptococcus, Leuconostoc etc.

There are potential beneficial medicinal uses of probiotics for which research is limited and only preliminary results are available. Recent research on the molecular biology and genomics of Lactobacillus has focused on the interaction with the immune system, anti-cancer potential, and potential as a biotherapeutic agent in case of antibiotic-associated diarrhoea, traveller‘s diarrhoea, pediatric diarrhoea, inflammatory bowel diseases and irritable bowel syndrome (Ljungh et al., 2009). Studies of some probiotics tested in vitro on human epithelial cell lines have shown that they could block the adhesion of shiga toxin producing E. coli (Sherman et al., 2005). These are claimed to be health promoting and/ or disease preventing beyond the basic function of supplying nutrients. Probiotic foods are emerging as an important category of food supplements. Earlier workers have shown the inhibition of diarrhea caused by E.coli using probiotic lactic acid bacteria and yeast (Yan and Polk, 2006). Ratledge et al. (2002) have studied the biochemistry and molecular biology of lipid accumulation in oleaginous microorganisms.

Newer technologies involve fermentation by specific strains of lactic acid bacteria which bring specific fermentation under controlled conditions to a specific fermented product with enhanced organoleptic, nutritional and therapeutic qualities. Today health is of primary concern. It is important to have nutritionally balanced food with good bacteria. For this, probiotic foods top the list. The functional food concept was initially developed in Japan in 1990‘s as there were many side effects of allopathic medicines. A regulatory system has been initiated by the ministry of health and welfare to approve certain foods to improve health. These are now recognized as Foods for specialized health use (FOSHU). According to American dietic association (ADA) these foods are potential healthful food or food ingredients that may provide health benefits beyond the traditional nutrients. Probiotics are beneficial microorganisms. Probiotic foods as yogurt and sauerkraut are very well known. Fermentation increases the nutrient content and taste with the shelf life.

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.

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

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

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

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

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
 
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

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

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

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

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

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

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

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

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

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

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
 
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

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

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
 
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.

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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.