eChapters

1. INTRODUCTION

Fruits and vegetables represent highly perishable items of agricultural produce, mainly because of their high water content in the fresh form. Fruits and vegetables vary greatly in their protective covering, peel or rind, and also in shape, size, colour, texture and flavour. Their care starts from the field of harvest, including pre- harvest care to reduce postharvest infections and maintain quality. Because of the high rate of perishability in fresh form, fruits and vegetables are preserved by processing into several forms and choices, depending on the specific commodity to ensure reduction in mass, render storage stability for extension in storage life for both domestic and foreign trade over variable distance and time.

Food preservation can be defined as the science which deals with methods of prevention of decay or spoilage of food, thus allowing it to be stored in a fit condition for future use. In this chapter, food preservation and have been discussed in abroad way.

Thus, sugar serves as a preservative in jam and jelly, whereas salt is the major preservative for pickle. RTS (Ready-to-Serve) beverage under acidic conditions in pasteurized form can be stored at room temperature for approximately three months while dehydrated products with 5% residual moisture with suitable packages, depending on the low hygroscopicity can find storage life upto 12 months. Intermediate moisture product with 25% residual moisture is becoming popular to consume mango or papaya strips directly in ready-to-eat form. Storage quality of such forms assumes greater importance. The use of synthetic preservatives is highly questioned in the modern days. However, low concentrations of potassium meta-bisulfite and sodium benzoate are still in use. Formation of benzene under acidic conditions for example in products like RTS beverage by the use of sodium benzoate is said to be dangerous, as benzene is known to be carcinogenic. This takes us to a subject of food safety including hygiene and HACCP. Good manufacturing practices are practically the most useful form of product preparation to expect safety.

Preservation of foods including meat and aquatic foods is a creation of conditions for the food articles in such a way to stop or greatly slow down the activities of micro-organisms, chemical and enzymatic reactions and physical forces to prevent the meat and aquatic foods from spoilage while maintaining its nutritional value and sensory attributes.

Significance of Meat Preservation

1. Meat and aquatic foods are perishable food items and are very prone to spoilage and rancidity development due to high nutrients, moisture and neutral pH.
2. Once meat and aquatic foods is exposed to microbial contamination, chemical and enzymatic reactions then it will be very difficult to attain asepsis.
3. To enhance the keeping quality of meat and aquatic foods so that it will be available for further processing.
4. It protects meat and aquatic foods from shrinkage, sweeting and other physical forces.
5. To protect human health by providing the wholesome meat and aquatic foods to the consumers.
6. By this way we can minimize utilization of energy in processing of meat and aquatic foods.

Fermentation

The decomposition of carbohydrates by microorganisms and enzymes is known as fermentation. During fermentation process of food organic acids and alcohol etc are produced which act as preservatives and also provide fine flavor and aroma that increase the value of raw materials. Most fermented foods contain a complex mixture of carbohydrates, proteins and fats etc. Fermentation occurs when microorganisms consume susceptible organic substances as a part of their own metabolic processes. Natural fermentation is probably oldest form of food preservation.

Introduction
Preservation by using common salt, spices and vinegar is a common method for the preparation of pickles, sauce and chutneys. Salt is mostly used as a preservative in pickles in combination with acid. Sodium chloride is used in brines and curing solutions or is applied directly to the food. The quantity of salt necessary to inhibit growth or harm the cells varies with the type of microorganisms. However, the minimum concentration of salt to act as a preservative is about 12%. Salt (sodium chloride) exerts its preservative action
by performing the following functions:
? Causing high osmotic pressure resulting in plasmolysis of the microbial cells.
? Dehydrating food by tying up the moisture thus making it unavailabl for the growth of microorganisms.
? Salt lowers the water activity and thus has adverse effects on microorganisms.
? Affecting the solubility of oxygen in the food and thus inhibiting the growth of aerobic microorganisms.
? Salt ionizes to yield chlorine ions, which is harmful to microorganisms.
? Chlorine in sodium chloride is a good oxidizing agent & is, therefore, toxic to microorganisms.
 

Preservation of food (fruits and vegetables) in common salt sand vinegar is called pickling. It is one of the most ancient method of preservation of fruits and vegetables. Pickling is the result of fermentation by Lactic acid forming bacteria which are found in large number on the surface of fruits and vegetables. They can grow in acidic medium and in the presence of 8-10 percent salt solution. The growth of majority of undesirable bacteria is inhibited. Lactic acid most active at 30 °C temperature. This temperature should be maintained during the process of pickling.

Preparation of pickles

Pickles are prepared with salt, vinegar and oil or combination of these ingredients. Spices are also used for pickle preparation.

Preserves (Murabbas) are prepared from whole fruits and vegetables or their segments by addition of sugar followed by evaporation to a point where microbial spoilage cannot occur. The final soluble solids concentration is reached to about 70 per cent. The finished product can be stored with or without hermetic sealing and refrigeration.

Introduction
Food preservation refers to an art or science which deals with the process of prevention of decay, deterioration or spoilage of food commodity to allow it to be stored in a safe condition for future use. All foods gradually undergo deterioration or spoilage from the time immediately they are harvested or manufactured. Some commodities spoil rapidly, while others can keep longer but for limited periods. The basic purposes of food preservation are:
1. Extension of shelf life of foods thus increasing the supply
2. Ensuring the availability of seasonal foods throughout the year
3. Adding variety to the diet
4. Saving time by reducing preparation time and energy
5. Stabilizing farm prices and prices of food
6. Improving the nutritional qualities The food spoilage can be caused due to growth and activity of micro-organisms, insects or rodents, action of enzymes, chemical reactions and physical changes that takes place during processing, drying, or freezing etc. Classification of Food Depending upon the type of spoilage and level of perishability, the foods are classified into three broad categories:

Preservation means just protect the foods against the spoilage, but scientifically it may be defined as a science which deals with the process for prevention of decay or spoilage of the food is called preservation.

In other words, just controlling the physical, chemical or microbial changes in the foods is called preservation.

Physical Changes: Colour, flavour, texture and taste etc.

Chemical Changes: Carbohydrate, fats, proteins, vitamins and minerals.

Microbial Changes: Mould, yeasts and bacteria

Concept: Reduction of seed moisture content to the acceptable levels for enhancement of storability and longevity is known as seed drying.

The moisture content of seed is negatively related to its storability. As the moisture content of seed increases, its storability decreases. Adequate drying of seed prolongs viability for reasonably long periods without cold storage. The process of drying begins with physiological maturity till storage/packaging of seeds to avoid deterioration. The seed is hygroscopic in nature therefore it adjusts its moisture content in equilibrium to the existing environment.

Seed Drying

Seed drying is the process in which an environment with low humidity is created to remove moisture from the seed up to the desired level without any damage to its viability and physical appearance. This seed is stored at low moisture content under the low relative humidity to enhance its longevity. The initiation of seed moisture content and the desired level are what dictate the amount of the drying process, and these elements are determined by the following

• Type of seed: This will consider the longevity behaviour, seed content, and seed structure (i.e., how well the species stores energy).

Objective

Vegetable seed separation requires specialized training. A little carelessness during the seed extraction process can seriously harm the plant’s viability and vigor in addition to its outward look. Inadequate extraction methods can also result in in-situ germination. The seed can be separated by the following methods.

1. Manual Method

(a) Maceration e.g., watermelon,

(b) Crushing e.g., brinjal,

(c) Scraping e.g., cucumber

(d) Separated e.g., muskmelon,

(e) Scooping e.g., pumpkins and

(f) Extraction e.g., squashes.

Objectives of Seed Grading

Minimization of heterogeneity to the lowest level and enhancement of the homogeneity to the highest level in the seed lots received by the processing unit.

Principle

Separation of seed lots based on differences in the physical properties of the seeds.

Post harvest activities include threshing/ seed extraction, drying, pre-cleaning and conditioning, cleaning, fine-cleaning or grading, seed treatment, weighing and bagging/ packaging, sealing and labelling, storing, and transportation for marketing. Except for transportation and marketing, all these activities collectively known as seed processing. However, for most of the crop, threshing or seed extraction, basic cleaning even drying is done in the farm itself and in the processing unit, the threshed seed is received.

The objective of the seed processing is to prepare the harvested seed in such a way that seed of highest purity and quality would be available for marketing, also for planting. The cleaning and the grading are the foremost activity of the seed processing. The seed, which is received in the processing unit, contains many undesirable particles, which as such cannot be used for marketing, hence cleaning and grading become necessary.

The fruits and vegetables are highly perishable in nature. The losses in harvested fruits and vegetables start immediately after harvesting and the resulting spoilage caused by biochemical changes (enzymatic) and activity of microorganisms such as bacteria, moulds and yeast. The losses caused by the microorganism in fruits and vegetables products can be prevented by controlling or destroying these organisms in order to preserve fruits and vegetables by processing and preservation means. The processing and preservation is one of the most important activities among various types of activities of Horticultural Science.

Processing: The processing can be defined as an activity, which is performed to maintain or improve the quality or to change the form or characteristics of the product. Processing operations are undertaken to add value to horticultural produce after their production. The main purpose of processing is to minimize the qualitative and quantitative deterioration of produce after harvest.

Preservation: Preservation can be defined as the science which deals with the methods of prevention of decay or spoilage of produce and allow it to be stored in a fit condition for future use.

Fruits and vegetables can be preserved for short and long term. For short term preservation can be achieved by proper handling of produce and low temperature storage. Long term preservation can be achieved by canning, drying and dehydration, fermentation and by using chemical preservatives.

Concept: Seed blending is the process of merging two or more types of the same species, for as Kentucky bluegrass cultivars Merion, Baron, and Park. Contrarily, seed mixing refers to the blending of two or more species, however every species may have more than one variation represented, such as Jamestown and Cascade chewing fescue combined with Merion and Fylking Kentucky bluegrass. Seed is typically distributed in blends, primarily Kentucky bluegrass blends, for sod growing purposes. For home lawns, parks, and other utility areas where upkeep levels would not be adequate to maintain pure Kentucky bluegrass turf, mixes of different grasses are typically employed. Naturally, when it comes to pure seed quality, no blend of grass seeds is superior to the individual ingredients. Every time a new blend needs to be made; extreme caution must be taken to ensure that the mixing equipment can be completely cleaned to prevent any contamination from unwanted species—bent grasses are perhaps the most challenging to deal with.

Objective of Seed Storage

The primary goal of seed programs, which include storage, is to maintain the high standards of the seed from harvest until the crop is sown in the following or future seasons. Additionally, seeds are kept in storage for longer periods of time for a variety of reasons, including protection against crop failures during emergencies or natural disasters, maintaining active genetic stocks for breeding, germplasm preservation for long-term use, stock preservation for the domestic and international seed trade in response to market demands, and parental line seed preservation for the transnational seed industry during one or more growing seasons. The seeds of most major agricultural species can be classified as either orthodox or desiccation tolerant. A drop in storage temperature and relative humidity, commonly referred to as seed moisture content, shortens their shelf life. Seeds deteriorate even in dry storage because of alterations caused by pests and pathogens as well as physiological deterioration. This is accurate, even though the amount of time seeds takes to germinate and stay viable varies according to the makeup of the different plant species. A good seed program handles the seed with care, regulates the store’s temperature and relative humidity (or seed moisture in the case of hermetically sealed containers), and adheres to good sanitation practices to preserve the high planting value of the seed in terms of purity, germination, vigour, and seed health.

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.

Introduction

Food is the most vital prerequisite for sustenance of human life and provides adequate nutrients for the metabolism. Recently several hypothesis supports that, beyond meeting nutritional needs, they play beneficial roles in improving health, and minimize the risk of illnesses (Roberfroid, 2000a). In this way, a novel term “functional food” was introduced and plays an outstanding role in improving the overall conditions of the human body (e.g. pre- and probiotics), lessening the threat of some ailments (e.g. cholesterol-lowering products), and also as therapeutics for several diseases (Roberfroid, 2000a, Roberfroid, 2000b, Mollet and Rowland, 2002).

Recently throughout the world, an extensive array of functional foods were developed which includes prebiotics, probiotics, synbiotics, foods supplemented with anthocyanins, phytosterols, isoflavones, antioxidants, and fat, sugar and salt-reduced foods. Amongst them, probiotic functional food has exerted beneficial effects on the health and is comprised of both probiotic dairy foods and probiotic non-dairy foods. The demand for dairy probiotic foods are increasing as it attributes to the beneficial health effects on the host by improving the survival of gastrointestinal microflora, production of bioactive compounds and prevention of lactose intolerance. Consequently, production of these foods is a significant research importance for both food manufacturing units and research institutes.

Probiotics are the important ingredients for foods with a “healthy” image. It could be combined with other beneficial ingredients or simply used to supplement the natural functional qualities of whole foods. The amalgamation of probiotic bacteria with nutrient rich foods, like dairy products, will have the additional value of improving consumer nutrition.

Abstract

Nutraceuticals have potential to be used as food supplement, preventive medicine and the growing evidence points in the direction that certain foods fight and or prevent against diseases. The development of next generation nutraceutical “super foods” or products consist of value-addition in the traditional natural diets.The word Nutraceuticals combine ‘nutrition’ and ‘pharmaceuticals’ to mean that they can be used as preventive drugs or food supplements. The increase in knowledge about the immune response unveils the fact that besides immunological disorders and infections the outcome of many other diseases like diabetes, hypercholesterolemia, rheumatoid arthritis, etc. can be modified by modulating Immune response. Hence, the efficient immunomodulators can be employed to prevent or cure the diseases as immunotherapeutic agents. The most acceptable alternative therapeutic agents are the edible sources. Hence the researchers shifted towards formation of nutraceuticals or foods acting as medicine, a concept which was given by Hippocrates long back.

Introduction

The term probiotic is derived from Greek and means ‘for life’ as opposed to antibiotics which means ‘against life’. The history of probiotics began with the consumption of fermented foods which was first observed in ancient Greeks and Romans [1]. The term, probiotic, as is used today was first used by Parker in 1974. Parker defined ‘probiotic’ as substances and organisms which contribute to intestinal microbial balance. In 1989, the term was modified further by Fuller. Thus, probiotic is a live microbial supplement which affects the host’s health positively by improving its intestinal microbial balance. This definition was broadened to include mono or mixed culture of live microorganisms which benefits animals or man by improving the properties of the indigenous microflora [2]. Some authors have interpreted probiotics as microbial cell preparations or components of microbial cells that have a beneficial effect on the health and well-being of the host.

Introduction

During the first 50 years of the 20th century, scientific focus was on the identification of essential elements and their role in the prevention of various dietary deficiency diseases. This emphasis on nutrient deficiencies or “undernutrition” shifted dramatically, however, during the 1970s when diseases linked to excess and “overnutrition” became a major public health concern. “Let food be thy medicine and medicine be thy food”, the age old quote by Hippocrates is the ideology of today’s health conscious population. Eli Metchnikoff, the Russian Nobel prize winner was the first one to recognize the beneficial role of selected bacteria on gastrointestinal tract of humans. Subsequently the “Theory of Longevity” by Metchnikoff was correlated with prolonged youth and a healthy old age, observed largely in Balkan peasants of those times, who used cultured milks in their diet (Kaufmann, 2008). Since then, the quest continues for understanding the role of wide range of food components and nutrients in enhancing health or preventing chronic diseases. The research in this field has resulted in a plethora of new labels for pro-, pre- and synbiotics.

Abstract

The gut microbiota, microbe population living in the human large intestine is generally associated with various metabolic functions and it influences health and well-being. Taking into account the major role gut microbiota play in the normal functioning of the body and the different functions it accomplishes, experts nowadays consider it as an “organ”. However, it is an “acquired” organ, as babies are born sterile; that is, intestine colonisation starts right after birth and evolves as we grow. Each of us has a unique microbiota, as the fingerprints, it always fullfils the same physiological functions and they have a direct impact on our health. Gut microbiota consists of a complex of microorganism species that live in the digestive tracts of animals and is the largest reservoir of microorganisms mutual to humans. Gut microorganisms benefit the host by gleaning the energy from thefermentation of undigested carbohydrates and the subsequent absorption of short-chain fatty acids. The most important of these fatty acids are butyrates, metabolised by the colonic epithelium; propionates by the liver; and acetates by the muscle tissue. The human body carries about 100 trillion microorganisms in its intestines, a number ten times greater than the total number of human cells in the body Guarner and Malagelada, 2003). Gut microbiota, particularly the probiotics, have beneficial effects on gastroenteritis resistance, blood lipids, antitumor properties, lactose tolerance and gastrointestinal immunity. Probiotics have role in reducing the risk of rotavirus-induced diarrhea and colon cancer. The survivability of any probiotic bacteria till a longer time in the gut can be enhanced by the supplementation of prebiotics. Prebiotics are non-digestible food ingredients that benefit the host by selectively stimulating the growth or activity of one or a limited number of bacteria in the colon. There are so many prebiotics which stimulate the growth and survivability of probiotic bacteria such as fructo-oligosaccharide (FOS), inulin, galacto-oligosaccharide (GOS), polydextrose (PDX), acacia gum (GUM), lactulose (LOS), lactitol etc. Many research studies have been done on above mentioned prebiotics. Mostly inulin-type fructans have been used as functional food ingredients. The prebiotics are known for reduction of disease risk such as constipation relief, suppression of diarrhea and reduction of the risks of osteoporosis, atherosclerotic cardiovascular disease associated with dyslipidemia and insulin resistance, obesity and possibly type-2 diabetes. Probiotics are beneficial microbes that confer a realistic health benefit on the host, which in combination with prebiotics, (indigestible dietary fibre/carbohydrate), also confer a health benefit on the host via products resulting from anaerobic fermentation. The combination of probiotics and prebiotics in a synbiotic might improve the survival of the bacteria crossing the upper part of the gastrointestinal tract, thereby enhancing their effects in the large bowel and immune-modulatory ability.