eChapters

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.

Animal protein has a great importance in human health by providing essential amino acids. It is supplied by the milk, meat, fish, eggs etc. Specifically meat has a prime position in the human’s diet particularly for those who are non- vegetarians. As per Indian Council of Medical Research (ICMR) recommendations a normal human being requires 60 gram protein in a day with the net protein utilization (NPU) of 65. In ideal cases 30 to 50 percent of daily protein intake should be from animal sources to get optimal range of amino acids. In present scenario human beings all over the globe are getting 29 gram of protein while developing countries have 15 g per day availability and developed nations are getting 60 grams protein per day per head. However, in India availability of protein is only 10 grams/day/head.

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.