eChapters

Introduction

Functional food is a natural or processed food that contains biologically active compounds like nutraceauticals and phytochemicals which have health benefit and thus, an important source in the prevention, management and treatment of chronic diseases. For centuries consumption of fruits and vegetables has been attributed to beneficial health effects. Research studies stated that approximately one-third of cancer risk in humans could be attributed to diet. Free radical formation of reactive oxygen species (ROS) and subsequent oxidative stress have been correlated to many human disorders including those of the kidney, eye, lung, liver, nervous system, heart and cardiovascular system. Therefore, foods in our diet that can aid in prevention of these diseases are of major interest to both the scientific community and the general public. Biologically active plant chemicals including traditional nutrients have a beneficial effect on human health. Onion and garlic have received considerable attention for their healthful, functional benefits.

Onion and garlic are the most important vegetable crops grown and consumed almost all over the country. Both the crops belong to the family Alliaceae and have gained the importance of a cash crop in recent years. Maharashtra, Gujarat, Uttar Pradesh, Karnataka, Tamil Nadu, Rajasthan, Andhra Pradesh and Odisha are the major onion growing states whereas Madhya Pradesh, Gujarat, Uttar Pradesh and Odisha are the major garlic growing states. India is a leading producer of onion supporting 20.2% of the world production. Onion is grown in kharif, late kharif and rabi seasons whereas, garlic is grown in rabi season only except in Nilgiri Hills where summer crop is also taken. Onion is normally produced from seeds except multiplier onions where production is taken up vegetatively from bulblets. Garlic is produced vegetatively by planting cloves. Both the crops are rich source of bioactive compounds and have outstanding nutritive value. The nutritive value (per 100g edible portion) of onion and garlic are as follows.

Introduction

Modern life style has taken the fitness out of the men. In ancient times, our life was labour oriented, whereas now we have lots of gadgetry to support our day to day living, thus making our life least labour oriented and we are now more susceptible to diseases diabetes, blood pressure and asthma were, until recently, associated with rich people only, however, these have now become common in urban and even rural areas irrespective of social status and age. The minimum physical exercise, coupled with carbohydrate and fat rich and fiber free diet and lots of tension in day to day life has given way to these diseases.

Since ages, plants have been mainstay medicinal support either in the form of herbal therapy (Like Ayurveda, Unani) or in the form of isolated active substances as being used in allopathic system of medicine. As per a WHO calculation, at least 80% population, in developing world, is dependent on direct use of medicinal plants.

Many of herbal therapies are very simple to use. It is therefore worthwhile to know about some of medicinal plants available commonly around us. The herbal preparations from these plants may not be dramatically effective to palliate disease, as allopathic medicines do, however, with judicious and regular use, we can avoid conversion of some of simple diseases into a major treatment problem.

It is fortunate that side effects of allopathic medicines have compelled us to reconsider the use of herbal remedies and physical exercise in the form of ‘Yoga’, aerobics or whatever you call it. The arid region of Northwest Rajasthan, although vegetated sparsely, is rich in medicinal plants. Some of the species, which are abound in the extreme arid ecosystem, have unique curative and therapeutic properties and some of them are getting a lot of mileage as nutraceuticals as well.

The importance of air in human life is well known as air is required for running different biological processes in human body. Unfortunately, the same life giving air or oxygen can cause harmful side effects like generation of oxidants or free radicals in our body. Reactive oxygen species, by product of respirative cycle of oxidative phosphorylation, are well known to interfere with cytoplasmic function and bio-molecules and for inflicting damages on cellular bio-molecules, which pre-disposes cells to several anomalies like mutagenic aberration, cell ageing, diseases, cancerous tumour growth and development of various lethal diseases such as cardio-vascular diseases, cancer, atherosclerosis etc. (Gorinstein and others 2001; Apak and others 2004). Free radicals disrupt the proper membrane function, denature proteins and inhibit enzyme function. Antioxidants, naturally present in food, play a vital role in trapping the radicals and; therefore, effective in reducing the risk of heart diseases, immune system decline, different inflammatory reactions etc. (Silici and others 2010).

Free radicals are unstable because they are missing an electron and they try to become stable by attaching to cell membranes in the body, snatching away electrons from them. This, in turn, sets free radicle molecules on an electron snatching spree and starts a chain reaction that ultimately leads to cell death. On the other hand, antioxidants (such as carotenoids, anthocyanins, ascorbic acid, flavonols, flavonoids, polyphenols etc.), present in our foods can prevent or slow down the oxidative damage by donating one of their own electrons, ending the electron-stealing reaction. Epidemiological evidences suggests that intake of antioxidants helps in scavenging free radicals, cause of a broad spectrum damages to biological system (Vertuani and others 2002). This has led consumers to look for a diet, derived from natural sources as well as rich in antioxidants as an strategy to counteract the cellular damages wreak by oxidative stress.

Introduction

The mankind in the past two centuries has witnessed several technology revolutions: industrial, agricultural, medical, info-tech, biotech etc. Nanotechnology is recent one in the series. Nanotechnology is the manipulation or self-assembly of individual atoms, molecules, or molecular clusters into structures to create materials and devices with new or vastly different properties. It uses techniques, processes and materials at the supramolecular level, approximately in a range between 1-100 nanometres (nm), in order to create new properties and to stimulate particular desired functionalities. For the food industry, nanotechnology applications include: release systems for pesticides or fertilizers in agriculture; antibacterial or easy-to-clean surfaces in food processing machines; food additives such as anti-caking in salt, powders and coffee creamers; anti-foaming agents for beer; natural colour additives for beverages; encapsulated nutraceuticals(antioxidants, vitamins) for dietary supplements; and, micelle systems for low-fat foods. It is predicted that in the foreseeable future nanotechnology will transform the entire food industry, changing the way food is produced, processed, packaged, transported, and consumed. The word “nano,” derived from the Greek “nano” signifying “dwarf,” is becoming increasingly too vast in terms of its huge potential in agriculture, health and the environment. In the agricultural sector, nanotech research and development is likely to facilitate next stage of development of genetically modified crops, farm and animal protection and production inputs, food processing, nutraceuticals etc. India is bestowed with a variety of crops, vegetables, fruits, flowers but food sector is handicapped due to inefficiencies in production, processing, storage and packaging. Most of the processing and packaging in industry and agriculture leaves behind a trail of environmental hazards, which if not tackled at this juncture, will add to long term ecological problems.

Introduction

From centuries, mankind is totally dependent on plants as a source of carbohydrates, proteins and fats for their food & shelter. In addition, plants are valuable source of a wide range of metabolites, which are used as pharmaceuticals, agrochemicals, flavors, fragrances, colors, biopesticides and food additives. In 1985, 3500 new chemical structures have been identified and 2600 derived from the higher plants. Worldwide, 121 clinically useful prescription drugs are derived from plants. Even today, 75% of the world’s population relies on plants for traditional medicine. In the US, where chemical synthesis dominates the pharmaceutical industry, 25% of the pharmaceuticals are based on plant-derived chemicals.

Biotechnology offers an opportunity to exploit the cell, tissue, organ or entire organism by growing them in-vitro and to genetically manipulate them to get desired compounds. Since the world population is increasing rapidly, there is extreme pressure on the available cultivable land to produce food and fulfill the needs. Therefore, for other uses such as production of pharmaceuticals and chemicals from plants, the available land should be used effectively. Chemical engineers are currently developing improved and appropriate bioreactors for the improvement of production systems by adopting techniques of growth and metabolite production coupled with downstream processing of the products. The improvements in molecular biological research have given a new dimension to in-vitro culture as well as for plant improvement, enhancing the yields of the product and resulting in multiple products or producing novel products from genetically engineered plants. Moreover, the need for safer drugs without side effects has led to the use of natural ingredients with proven safety. These factors have laid emphasis on the use of biotechnological methods to enhance the production of pharmaceuticals and food additives in quality and quantity.

Plant in vitro cultures are able to produce and accumulate many medicinally valuable secondary metabolites. Antioxidants are an important group of medicinal preventive compounds as well as being food additives inhibiting detrimental changes of easily oxidizable nutrients. Many different in vitro approaches have been used for increased biosynthesis and the accumulation of antioxidant compounds in plant cells. Antioxidants are capable of stabilizing, or deactivating, free radicals before they attack cells. Antioxidants are absolutely critical for maintaining optimal cellular and systemic health and well-being. Antioxidants are gaining a lot of importance as a panacea for a large number of life-style diseases like aging, cancer, diabetes, cardiovascular and other degenerative diseases etc. The present lecture summarizes the achievements of in vitro technology for the production of antioxidants compounds. The focus will be on the major chemical classes of antioxidants and on the approaches used to improve the in vitro methods for producing these compounds.

Introduction

Plants contain a variety of substances of nutraceuticals importance which are useful medicines, food additives, cosmetics and health supplements etc. However, low availability under in vivo condition, decreased plant resources, increases in labour cost and other problems in obtaining these high-value added substances from natural plants have pointed toward the use of in vitro techniques for production of the products. Because in vitro cultures are not affected as the production affected under in vivo conditios.This has led scientists and biotechnologists to consider plant cell, tissue and organ cultures as an alternative way to produce the corresponding secondary metabolites.Therefore, studies on the production of useful metabolite by in vitro techniques have been carried out on an increasing scale since the end of the 1950’s. The large scale cultivation of tobacco and various vegetable cells was examined in the late 1950’s and early 1960’s in the U.S., Canada, and Europe. At present, several firms are manufacturing a plant pigment, shikonin, and ginseng cell biomass on a commercial scale and several other products including anti-oxidant products.

Research efforts on in vitro derived extracts is well documented on each of these major product categories: flavors (onion and garlic, peppermint and spearmint, fruit flavors, chocolate aroma, seaweed flavors, vanilla, celery, coffee, spice, sweeteners, and so on); edible colors for foods and medicines (mainly betalains and anthocyanins): non-food pigments for cosmetics and textiles (shikonin, berberine, and various other products); several examples of fragrances and essential oils; and bioactive natural insecticides and phytoalexins useful in current integrated pest management programs. Of course, intensive activity has centered on production of natural drugs of chemoprotective compounds from plant cell culture. Some of the most prominent pharmaceutical products in this latter category include ajmalicine (a drug for circulatory problems) from Catharanthus roseus and taxol (a phytochemical effective in treatment of ovarian cancer) from Taxus species.

Introduction

Functional food or medicinal food is any healthy food claimed to have a health-promoting or disease-preventing property beyond the basic function of supplying nutrients. The general category of functional foods includes processed food or foods fortified with health-promoting additives, like “vitamin-enriched” products. Fermented foods with live cultures are considered as functional foods with probiotic benefits. Functional foods are an emerging field in food science due to their increasing popularity with health-conscious consumers. The term was first used in Japan in the 1980s where there is a government approval process for functional foods called Foods for Specified Health Use (FOSHU) (Benkouider, 2005).

Distinguishing functional foods from dietary supplements and natural or herbal medicine is especially difficult, and cultural perceptions on this vary. Further complications are the large number of terms often used interchangeably and in a confusing manner such as health foods, nutraceuticals, designer foods, pharmafoods, and so forth. Much of the basic fortification (such as iodization of table salt) is no longer considered “Functional food” but new specialized extracts and ingredients for functional food fortification have emerged, including dietary fibres, plant sterols and probiotics. There is growing research on the potential of biotechnology to develop functional foods for improved health effects of the staple foods in developing countries—for example, high-iron rice, high-vitamin A rice, improved oil content in oil crops, and improved protein.

Introduction

Fruits, vegetables and some non food crops are rich source of natural antioxidants, food colorants and other bioactive natural products. Nutraceuticals and natural food colorants exhibit anti-oxidant, anti-carcinogenic, anti-inflammatory, anti-bacterial and anti-proliferative properties. They tend to enhance ability of the body to fight, cure and prevent diseases. Natural anti-oxidants are particularly important because they scavenge harmful superoxide, hydroxy, and/or peroxide free radicals, and protect the body against a variety of cancers, heart and other life style related diseases. Vegetable like orange carrot, red carrot, black carrot, beet root, tomato, chilli, and fruits like pomegranate, cherries, berries, watermelon and jamun are rich source of natural antioxidants and food colorants. While tomato and red carrot are rich in lycopenes, and carotenes; black carrot is a major source of stable acylated anthocyanins. The dark red colour of beet root is associated with anthocyanin, betacyanin and betaxanthins. Similarly, the red colour of chilli is attributed to the carotenoid pigment capsanthin. Capsaicinoids in chilli are responsible for the hot flavour and anti-inflammatory properties. Antioxidant and other beneficial health effects of pomegranate, cherries, berries, etc. have been attributed to anthocyanins and related polyphenols. Jamun, an under-utilized tropical fruits is rich in anthocyanins and flavonoides. Like anthocyanins, flavonoides and carotenes, lycopene helps to prevent various types of cancer particularly the prostate cancer.

Microalgae represent a promising alternative to renewable source of feedstock for natural food colorants and nutraceuticals and functional food production. With over 40,000 identified species, microalgae are one of the most diverse groups of organisms on earth. They naturally produce large quantities of many biomaterials. Out of the diverse compounds produced by microalgae, the algal pigments such as phycobillins, carotenoids and xanthophylls have gained commercial importance owing to their unique and multiple applications as food and cosmetic colourants, antioxidants and several beneficial effects of nutraceutical and pharmaceutical value. Microalgal research over the years has geared up significantly from outdoor mass culture in algal ponds, refinement of the cultivation process and life cycle assessment, downstream processing of biomass (i.e., harvesting, dewatering, and drying), to extraction, to systems/process scale-up analysis and development of an economic feasibility model for commercialization of algal biomaterials with nutraceutical properties. Among the various microalgae, Spirulina and Haematococcus are the major source of naturally occurring biopigments which are gaining importance as natural pigments in food, drug and cosmetic industries as an alternative to currently used synthetic colour. Improvement in the cultivation methodologies and use of closed photobioreactors of different configurations, fermentation reactors, open reactors and tubular reactors have opened up new vistas for the development of microalgal biotechnology and bioprospecting. The main constraints in non-exploitation for mass cultivation of microalgae are their slow growth rate, low biomass yield and inadequate culture methodologies and these issues remain to be addressed.

Preservation methods are generally believed to be responsible for a depletion of naturally occurring antioxidants in food. Processed fruit and vegetables are expected to have a lower health protecting capacity than fresh ones. This is because, up to now, only selected and barely stable antioxidants of nutritional interest (e.g. ascorbic acid) have been commonly assessed as indicators of processing damage. On the basis of these supposed negative effects, in the past few years, the main tool for minimizing eventual processing damage was the strategy of ‘reconstitution’, achieved by the addition or the enrichment of the product with natural antioxidants.

It is well known that food processing can have many effects not all of which result in a loss of quality and health properties. Blanching also represents a useful tool in preventing enzymatic oxidations, which are the main cause of loss in naturally occurring antioxidants in raw material of plant origin. In fact, fruit and vegetables subjected to blanching retain most of their original antioxidant properties.

Lycopene appears to be a relatively stable compound during food processing but it has been reported that heating tomato pulp to produce paste, ketchup, juice and other products, can cause degradation of lycopene and other carotenoids. Other antioxidants naturally present in tomato, such as vitamin C, vitamin E, polyphenolic flavonoids and non-lycopene carotenoids, may play a role in preventing the degradation of lycopene. Thermal processes might break down cell walls and weaken the bonding forces between lycopene and the tissue matrix. Such disruptions in the cell wall fraction may enhance the release of phytochemicals from the matrix. This may make lycopene more accessible or more stable and thus increase the nutritional quality and antioxidant activity of product. An increase in carotenoids by thermal processing has also been attributed to enzymatic degradation which causes weakening in protein-carotenoid aggregates. Destruction of vitamin C is destroyed mainly due to oxidation reactions and the heat applied in the presence of air. The degree of loss of ascorbic acid is closely correlated to the drying temperature used for the production of the end product. The increase in the amounts of some phenolic substances having antioxidant activity was associated with two concomitant events: firstly, the thermally induced extraction of antioxidant molecules previously complexed or polymerized and secondly, the retention of active compounds caused by the inactivation of the enzymes involved in their catabolism.

Introduction

Microencapsulation is a process of entrapping solid particles, liquid droplets or gases in thin polymeric coatings. The outer film (wall) protects the encapsulated material (core) and allows for its controlled release. Application of this technique is wide spread in several industrial fields, including the manufacture of foods, pharmaceuticals, cosmetics and pesticides. Common food ingredients subjected to microencapsulation include probiotic bacteria, acidulates, flavours, colours, sweeteners, minerals and vitamins. A number of coating materials are employed in production of microcapsules, such as gums, starch, and starch derivatives, cellulosic materials, lipids, proteins and inorganic materials.

Actually the development of the formation of micro-encapsulates was partially inspired by the nature. Eggs, seeds, grains, nuts, fruits etc. are typical examples of the food encapsulation and natures own way of conserving and protecting natural products against its own deteriorating elements. Taking clue from this, man adopted this technology of protection of some of the foodstuffs as sauces, puddings etc. Microencapsulation can improve the convenience of food. The shell provides a barrier between reactive components (for instance, delaying the release of leavening agents for fluffier bread products or protecting oxygen-sensitive materials during processing and storage). Microcapsules can help fragile and sensitive materials survive processing and packaging conditions and stabilize the shelf-life of the active ingredient.Karel (1994) described various methods of encapsulation of food ingredients.Inaddition, microencapsulation can simplify the food manufacturing process by converting liquids to solid powder, decreasing production costs by allowing batch processing using low-cost, powder-handling equipment. To improve food safety, the technology can be used to indicate product tampering, thermal spoilage, and freeze-thaw cycles.

Introduction

“The World Packaging Organisation’s (WPO) slogan, “Better Quality of Life Through Better Packaging”, sumps up the important place that packaging occupies in a modern economy.

As the economics of many countries are increasing, the consumers have started using more processed food. As a matter of fact global food processing and packaging business has reached to multi trillion dollars. In today’s world of global markets and stiff competition in every product along with increasing consumer demand, it becomes imperative for companies to explore ways to improve their productivity in terms of maintaining safety, using sustainable packaging materials, implementing flexible and standardized technology, and adopting proven management. Towards this end, companies have been striving to improve the efficiencies of their operations through improvements in the processes. Reducing wastes and shortening lead times becomes all the more imperative in the food industry due to the perishable nature of the product. Moreover, recent advances in technology such as Radio Frequency Identification (RFID) and nano-materials afford companies greater opportunities to streamline the processing, packaging, and manufacturing schemes.

The term “nutraceutical” was coined from “nutrition” and “pharmaceutical” in 1989 by Stephen DeFelice, MD, founder and chairman of the Foundation for Innovation in Medicine (FIM), Cranford, NJ. According to DeFelice, nutraceutical can be defined as, “a food (or part of a food) that provides medical or health benefits, including the prevention and/or treatment of a disease”. In other words, nutraceuticals are chemical or natural feed ingredients which may enhance health by providing a physiological benefit by the provision of basic nutrients. Enzymes, prebiotics, probiotics, yeast and fungal extracts, predigested hydrolyzed carbohydrates and fats, phytogenic additives, acids etc are included in nutraceuticals. However, the term nutraceutical as commonly used in marketing has no regulatory definition.

Feed accounts for a major portion of farm expenses in livestock and poultry production. Thus, to obtain maximum profitability, it must be ensured that the feed should not only be well balanced nutritionally but economical too. Rising prices of feeds certainly have reduced the profitable nature of broiler farming. For better utilization of feed and to improve feed efficiency, antibiotics were used at sub-therapeutic levels in the animal ration.

Development of antibacterials progressed very quickly and as a result, certain new antibacterial substances were discovered and developed for use as growth promoting agents in livestock and poultry. The antibiotics act by reducing nutrient destruction in the intestine, increasing microbial synthesis of certain vitamins and amino acids, reducing the rate of passage of nutrients in the gastrointestinal tract and reducing the thickness of the intestinal wall. This thinner wall and reduced rate of passage have been suggested as factors favoring efficient absorption of nutrients. It is also reported that the antibiotics also inhibit the bacterial production of ammonia and other harmful nitrogenous compounds such as trimethylamine that reduce the growth of chickens.

The increasing use of antibiotics in livestock and poultr y led to development of antibiotic resistant micro organisms and antibiotic residues in livestock products besides other side effects. These caused alarm bells ringing all over the world and by the end of June, 1999 majority of antibiotics as growth promoters in monogastric diets had been banned within the EU. The ban on use of antibiotic at sub therapeutic level in Europe and the potential for a ban in the United States have made scientists to seriously think of alternatives to antibiotics. In fact, the use of probiotics for farm animals was already stimulated by the findings of the Schwann Committee in 1969 which recommended that antibiotics in animal feeds should be restricted. However, the concept of probiotics gained momentum in later part of the last century. In recent years, with the public disapproval of using antibiotics in livestock and poultry production due to their residual effects in their products, there has been a greater emphasis on the use of probiotics in poultry.

Prebiotic foods have been consumed for centuries, either as natural components of food, or as fermented food. However, interest in dietary use of prebiotics blossomed in the later 1800s and early 1900. Preliminary researches revealed that lactose had a profound effect on the pH of the caecal contents and intestine due to lactic acid fermentation resulting in enhanced calcium and phosphorous absorption. Further, it was also noted by several workers that inclusion of lactose in poultry diets resulted in better growth and reduced mortality.

A prebiotic can be defined as “a non digestible food ingredient that beneficially affects the host by selectivity stimulating the growth and/or activity of one or limited number of bacteria in the colon, and thus improves host health” (Gibson and Roberfroid, 1995). Based on this definition, Russell (1998) formulated the criteria according to which a substance can be a prebiotic. First, prebiotics are always feed ingredients that are not digested by the host, not or little used and/or metabolised as they pass through the upper portion of the intestinal tract, so they can reach the f lora of the large intestine. Secondly, they have to be able to serve as a substrate for one or more bacterial species with a potentially beneficial effect on the host. Finally they have to be able to cause a shift in the microf lora that improves the health of the host. In principle only non-digestible, fermentable feed components are prebiotics.

Feed accounts for a significant cost of production in livestock and poultry. In case of poultry, it represents 65% cost of the production in broilers and 75% in layers. Presently the live stock industry faces a huge challenge due to the high cost of feed ingredients and shortage of the conventional feed ingredients. Over the years, efforts have been made to use unconventional feed ingredients. However, such feed ingredients have many anti nutritional factors that adversely affect the performance of livestock and poultry. Due to the presence of these incriminating factors, the unconventional feed ingredients are poorly digested in livestock and poultry. These poorly digested feed ingredients results in bacterial overgrowth, which becomes a potential substrate for bacterial fermentation leading to intestinal disorders and disease. Application of antibiotics and other anti-microbials help to overcome the ill effects. However, the ban on the use of sub therapeutic level of antibiotics in many countries has increased the relevance of use of exogenous enzymes in the feed of livestock and poultry. These exogenous feed enzymes improve the nutritive value of different feed stuffs, economize livestock and poultry rearing and reduce environmental pollution.

An organic acid is an organic compound with acidic properties. The most common organic acids are the carboxylic acids, whose acidity is associated with their carboxyl group –COOH. However, sulphuric acids, containing the group –SO₂OH, are relatively stronger acids. Alcohols, with –OH, may also act as weak acids. Some other groups may also act as weak acids viz. thiol group and phenol group. In biological systems, organic compounds containing these groups are generally classified under organic acids. Some common organic acids are lactic acid, acetic acid, formic acid, citric acid, oxalic acid, uric acid, propionic acid and butyric acid. Organic acids have been used for decades in commercial compound feeds, mostly for feed preservation, for which formic and propionic acids are particularly effective. Since the ban of antibiotic growth promoters in many countries, organic acids have been used increasingly, not only because of their preservative qualities, but also for their nutritive properties. Organic acids and their salts are generally regarded as safe and have been approved by most member states of EU to be used as the feed additives in animal production.

Fats are rich sources of energy. Fats provide 2.25 times more available enrgy than carbohydrates. Fats also increase the palatability and reduce the dustiness of feed. Fats and fatty acids decrease the heat increment in the body. Fatty acids are also involved in number of physiological functions of the body. Recently, considerable interest has been shown on studies pertaining to dietary supplementation of polyunsaturated fatty acids (PUFA) in animal feed and their role in animal health and production.

Phytobiotics are plant derivatives such as herbs, plant extracts or spices and have a wide range of activities such as stimulation of feed intake, growth and endogenous secretions in the gut. They act as immunomodulators resulting in decreased mortality and also have coccidiostatic, anti microbial, anthelminthic and anti-inf lammatory activities. Phytobiotics also possess hepatoprotective and hepatogenic properties, which tone up liver resulting in increased nutrient utilization and better performance. Herbs like Achyranthes aspera (Prickly Chaff Flower, Devil’s Horsewhip, Apamarga), Andrographis paniculata (Green chirayta, King of bitters, Kalamegha), Azadirachta indica (Neem), Boerhaavia diffusa (Spreading Hogweed, Punarnava), Eclipta alba (False Daisy, Bhringaraj), Ichnocarpus frutescens (Black creeper, Utpalagopa), Terminalia chebula (Black myrobalan, Haritaki). These herbs have hepatostimulant, hepato-protective, immunomodulatory and antioxidant activities (Sadekar et al., 1998; Manu and Kuttan, 2009; Michels et al., 2011, Dash et al., 2007). Further, they optimize digestion and metabolism resulting in better protein utilization, improved mucosal function and reduced cost of metabolic deamination. Andrographolide and 14-deoxy-11, 12-didehydro-andrographolide isolated from Andrographis paniculata inhibits free radical activities and lipid peroxidation. Inhibition of lipid peroxidation in meat prevents free radical production thereby preserving meat composition, colour and improvement in shelf life. In addition, it has been studied that a herb Terminalia chebula helps to reduce stress (Selvakumar et al., 2007).

1.1. Introduction

The green revolution has led our nation from the state of deficiency to the state of self-sufficiency in food production. The grain production has increased substantially from around 50 million tonnes to about 220 million tonnes per annum. As per the latest estimates, annual fruit production is 44 million tonnes from an area of 3.72million hectares.

Depletion of nutrients, from the soil is steadily increasing due to the adoption of modem agricultural technology through intensive and extensive cultivation of high yielding varieties with chemically pure, micronutrients free high analysis fertilizers. So in recent years, the potentiality of many crops could not be exploited owing to the widespread nutrient deficiency observed in many parts of our country. With nutrient removals by crops exceeding the additions, there exists a perpetual negative balance. Consequently, nutrient deficiencies have multiplied in Indian soils and crops.

Diagnosis is the art of recognizing diseases or deficiency symptoms manifested from their symptoms, a scientific determination of a disorder based on critical scrutiny.

2.1 Diagnosis and prognosis

Diagnosis is the estimation of nutritional status of a plant during sampling, while prognosis is the prediction of possibility of deficiency impairing plant growth at stages in the growth cycle after the sample is taken. Diagnosis is based on comparison of nutrient concentration in plant parts (mainly leaves) with standard values related to physiological requirements of the plants. In diagnosis, mainly plant analysis is used. Prognosis is also based on critical concentration of same plant parts. This sometimes has led to confusion between these two concepts, which have been used with the same meaning. In contrast, to diagnosis, prognosis may be based on their leaf or soil analysis. The main difference between prognosis and diagnosis lies in the time between sampling and appearance of the influence on plant growth.

Several diagnostic techniques are employed to asses the nutrient status of the crop. These are helpful in determining specific or multinutrient stresses and quantity of nutrients needed to eliminate the stress. Some of the techniques commonly used are:

Visual deficiency symptoms

Plant analysis

Rapid tissue testing

4.1. Deficiency symptoms in different plant parts

Nutrients are important for growth and productivity of crops. Apart from the N, P, K, Ca, Mg and S, micronutrients such as Zn, Fe, Cu, B, Mo, Mn, Cl, etc. are also necessary for maintaining normal health and metabolism of plants. However, nutrient deficiency can lead to poor and stunted growth of plants resulting in poor yield performances. The depletion of nutrients from the soil is increasing due to adoption of modern agricultural technology through intensive and extensive cultivation of high yielding varieties. Nutrient deficiencies are very common in horticultural crops rather than in field crops.

Identification of nutrient deficiencies in crop plants through visual symptom is the cheapest diagnostic technique. When a nutrient element insufficiency occurs, below the critical level, visual symptoms may or may not appear, although normal plant development will be slowed. When visual symptoms occur, such symptoms can frequently be used to identify the source of the insufficiency.

5.1 Foliar nutrition of fruit crops

Foliar application of nutrients is gaining importance in horticultural crops in general and fruit crops in particular. The important criterion of the effectiveness of nutrient spray is the rate at which the foliar applied nutrients are absorbed by the leaves and translocated within the plant. For getting optimum yield, foliar fertilization should be carried out when the plant’s requirements are particularly high and the nutrient uptake through the plant roots is restricted. The restriction may be due to either plant or soil limitations.

APPENDIX – 1: Basic Information

Table 1: Spacing and plant population

What is seed?

“A seed is an embryo, a living organism securely fixed in the supporting or the food storage tissue.”

A true seed is defined as “Structurally a true seed is a fertilized matured ovule, consisting of an embryonic plant, a store of food and a protective seed coat, a store of food consists of cotyledons and endosperm”. In broad sense, “seed is a material which is used for planting or regeneration purpose”. Scientifically, “seed is a fertilized matured ovule together covered with seed coat is called seed” or “it is a propagating material i.e., part of agriculture, sericulture, silviculture and horticultural plants used for sowing or planting purpose”.

The business of Seed Technology is to protect this biological entity and look after its ‘welfare’, while the focus of Food Technology is on the second component – the supporting tissue.

Human being as a hunter has depended mostly on animal food and some fruits. With the progress of civilization, he settled down and

started agriculture around 7000-10,000 B.C. He started depending on plant grains to take care of his energy and nutritional requirements in addition to animal foods. Initially cereal grains must have mostly accounted for his staple food requirements. Taste and health requirements must have prompted him to diversify his crop production programme. It is this need that must have made him to cultivate oilseeds, fibre and other crops.

Oilseeds, thus, have been under cultivation since antiquity. Rapeseed and sesame have been described in the Indian Sanskrit writings of 2000 BC. Historically, extraction of oil seems to have been a batch process. Seeds kept in gunny bags or boxes were pressed to remove oil. The separated oil on clarification was used for food and non food purposes. The resulting cakes were utilized as animal feed or thrown away into fields which helped in improving the soil fertility. Human beings slowly discovered the uses of oil and other oilseed products for various food and non-food purposes.

There are several species of plants in the world whose oil can be utilized for human consumption. Though around 40 oilseeds are known, only around a dozen oilseed crops have become commercially important. There are ten seed crops and three tree crops. The seed crops are groundnut, rapeseed- mustard, sesame, soybean, sunflower, cottonseed, safflower, niger, castor and linseed. These are mostly annual crops. The three major tree oil crops are palm, olive and coconut.

Groundnut

Groundnut roundnut is believed to have originated in Brazil and later spread to many countries all over the world. It is known to humanity since 950BC. Groundnut crop and its products have multiple uses. Being a leguminous crop it enriches the soil with nitrogen through symbiotic biological fixation by rizhobium. The economic product, groundnut in shell, contains the seeds, which are edible. The shell as well as the haulms serve as fuel and fodder. The seed oil serves as a good cooking oil while the cakes are good sources of protein for animals and even humans. Groundnut (Arachis hypogaea L,) belongs to leguminosae family and papilionacea sub family. It consists of two sub species each with two varieties. The first one hypogaea has the variety hypogaea (virginia group) and variety hirsuta kohla while the second one fastigiata has the variety fastigiata (valencia group ) and the variety vulgaris (spanish group). Hypogaea varieties are spreading types with branching and lack infloresence on the main stem. They are of longer duration and have fresh seed dormancy . Varieties of the fastigiata are of erect type with branching and flowering on the main stem also. The crop is of shorter duration than hypogaea types, but with little fresh seed dermancy.

The major groundnut producing countries of the world are China, India, Nigeria, U.S.A. Indonesia, Argentina, Sudan, Senegal and Myanmar. The cultivation is spread in tropical and sub-ropical regions. Groundnut is a self- pollinated crop and pollination takes place in the morning. After fertilization an elongated stalk namely peg develops which enters the soil, bends horizontally and swells to become a pod. Within the pod, two, three or four kernels are formed. The crop can be grown under rainfall conditions ranging from 50-125cm, with good distribution during flowering and pegging stages. Sandy loams, loamy soils, and black soils with good drainage are suitable for growing the crop.

Introduction

The seed industry has witnessed a substantial change in the 20th century, with farmers relying on purchasing seeds from market with better traits rather than relying on seeds from previous season’s harvest. Developments in seed technology have increased the momentum of the industry’s growth, and the introduction of genetically modified crops has further boosted the seed market. The value of global seed market has tripled since 2000 and reached US$ 54 billion in 2014 (Indian Seed Market (pdf), www.icfa.org.in).

In addition to cultivated oilseeds, many other seeds and related plant products serve as sources of vegetable oils. They are obtained from large trees, shrubs or from different crops and their products. It may be the seeds or the husk, or the germ or other parts of the fruit or seed which are rich in oil. These are in general, referred to as non-conventional vegetable oil sources. They are highly important for the food/feed and non-food industries. Non- food and industrial uses are plenty.

But for the availability of these non- traditional oilseeds and their products, there would have been great pressure on the cultivated seeds. The products, mainly oil, help run our machines and protect them from getting rusted. Some of them protect our crops from pests and deseases. They even serve as beauty aids in the form of cosmetics. Some of them serve as sources of medicine for men and animals.

In recent years, some non-conventional/ non-edible oilseeds have become the raw material for biofuel/bioenergy. They have gained prominence, due to shortage of conventional oils. Seeds of more than 100 species occurring in the wild or cultivated are known to contain oil in considerable quantities. There is a vast scope for production and utilization of oil from these sources (Ambasta, 1986, Bhattacharya, 2002 and Vimal and Naphade, 1980).

In this chapter, the major non-conventional oilseeds of tree origin, by product oilseeds or other minor sources, are being dealt with. They are ricebran, corn, sal, mahua, jatropha, kokum, melia, rubber, mango kernel, kusum, simarouba, neem, karanj, crambe, moringa, tumba, jojoba and tobacco seed etc. Emphasis is given to the composition and quality of oil, cake and other plant parts. Their food, non-food and medicinal uses are presented. Oil extraction and related post harvest technological aspects are also discussed.

Post Harvest Technology

Introduction

The demand for edible oil has grown with the increase in world population. Improvement in living standards have made the population increase the consumption of oils and fats. It also has become more discriminating with respect to the oil quality. Oil producers, have to meet the increasing demand for edible oil, and improve product quality and variety as these have become major factors in the market-place.

Agriculture has been tuned through selective seed breeding and improved crop production practices to take care of the increasing demand. The emphasis has been to improve yield per hectare or tolerance to climatic variations. The ability to modify seed through traditional breeding and biotechnological approaches promises a revolution in agriculture. Using various approaches, not only quantitative improvement but also the qualitative changes especially fatty acid changes have been brought about. Customer support is needed for the genetically modified crops. A lot of controversy exists at present in accepting genetically modified crops. This aspect has to be studied in depth and needs to be resolved at the appropriate level as quickly as possible.

A prerequisite for the production of top quality oils and meals is a high quality raw material. Some attempts have been made to improve the physical characteristics of oils and meals through genetic, agronomic as well as through post production handling and processing technologies. The harvested quality grain should not be damaged during transportation, storage and processing. To produce a crude oil, the industry uses a number of processing steps, the application of which depends on the type of seed and the scale of the operation.

The purpose of Post Harvest Technology of oilseeds is to recover the maximum quantity of good quality oil and also make the deoiled cake useful as food or feed. Oil in oilseeds is located in spherosomes, which are the oil bodies (Salunkhe et al, 1992). When seeds are broken into small particles and the cells get ruptured the oil becomes available and is easily extracted. From the time of harvest, till the seeds are fed to the oil extracting machines, various processes are carried out to make good quality of oil available to the consumer apart from providing remunerative prices to the producer, namely, the farmer. The various steps involved in the oil extraction are proper harvest, drying, storage, seed cleaning, heat treatment and different types of machinery. The basic objective of every step in the post harvest technology is to minimize losses and to sustain or improve the quality of the product.

Introduction

Germination is the growth of a plant contained within a seed; it results in the formation of the seedling, it is also the process of reactivation of metabolic machinery of the seed resulting in the emergence of radicle and plumule. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. The seed of a vascular plant is a small package produced in a fruit after the union of male and female reproductive cells. All fully developed seeds contain an embryo and, in most plant species some store of food reserves, wrapped in a seed coat. Most seeds go through a period of dormancy, where there is no active growth; during this time the seed can be safely transported to a new location and/or survive adverse climatic conditions until circumstances are favourable for growth. Dormant seeds are ripe seeds that do not germinate because they are subject to external environmental conditions that prevent the initiation of metabolic processes and cell growth. Under proper conditions, the seed begins to germinate and the embryonic tissues resume growth, developing towards a seedling. In short, seed germination is the ability of a seed to develop in to a normal plant under favourable conditions in the soil (ISTA, 1985) or the process by which the dormant embryo wakes up and begins to grow is known as seed germination.

Nutritional Quality of Edible Oils

Fats improve the taste and flavour of foods. Fatty foods satiate a hungry person fast because fats remain in the stomach for a longer period than either protein or carbohydrate (sugar) foods. Fats also carry essential vitamins like A, D, E and K. They also provide the body with essential fatty acids. Thus, fats have a very important role to play in human nutrition.

Spectrum of Fats and Oils

It is not just the butter and ghee that provide us the necessary fats. Vegetable oils, meat and fish too add fats in our diet. There is an array of vegetable oils available to human beings. They are groundnut, rapeseed, sesame, sunflower, safflower, soybean, niger, cotton seed, coconut, palm and rice bran oils. Ghee(butter fat), however, is the main animal fat utilized widely. The quality and composition of these oils vary as also the preference of people.

Antinutrients

Safety is the most important aspect among all the quality attributes of food. Food can be considered safe, only if it does not contain any factor which is hazardous to human or even animal health. The various factors which affect the safety of the foods may be broadly classified into three categories. The first category includes the toxic factors occurring naturally in foods. The second category comprises a group of incidental contaminants which find their way at various stages of processing, manufacture, preservation and storage of foods and the third category includes harmful intentional additives or adulterants.

Various categories of anti-nutritional factors are present in the traditional and non-traditional oilseeds, oils and oilcakes. Some of them are heat-labile and do not pose any harmful effects in the body, while the heat-stable factors may cause deleterious effects in human beings and animals. They belong to different groups of compounds. It is necessary to know their behaviour, significance and toxicities. Their avoidance or elimination is important to protect human and animal health.

Methods of Analysis

Organic material especially, seeds, grains, fruits and nuts contain mainly three groups of compounds. They are carbohydrates, proteins and fats/oils, mostly in that order. They also contain 3-5% minerals and smaller quantities of vitamins and other minor constituents. Cereal grains contain more of carbohydrates while oilseeds contain more oil. Tree nuts and even oilseeds may contain 30-50% protein while cereal grains contain 5-8% protein. The starch and sugar contents of oilseeds may be less than 10% while the oil content of cereal grains ranges around 5%. The actual content and the composition of these groups of compounds really account for the quality as well as their commercial value.

The composition and quality of grains and other plant products vary with respect to their genetic background, location or the soils under which they are grown, season or the environment, the maturity of the grain/product or its harvest stage and the post harvest processes including storage etc. Crop scientists have in recent years been bringing out made to order or designer seeds, whose quality and composition need to be examined to satisfy the needs of the quality conrol and consumer requirements. Keeping this aspect in view this chapter has been designed.

As this book deals with oilseeds, emphasis has been placed on methods of evaluation relating to thier composition and quality. This chapter deals with methods of oil, protein and sugar analysis. Oil being the major constituent of oilseeds, importance has been given to methods of oil quality evaluation including fatty acid profile. Antinutrients especially aflatoxins, glucosinolates, ricin, oxalate, phytic acid, oligosaccharides, etc. also find a place. Analytical methods of some vitamins and minerals have also been included. Only a few important and most essential procedures relating to oilseed quality have been presented. The analyst can find more details and methods of evaluation of other constituents in standard laboratory analytical manuals.

Introduction

Seed vigour is an important quality parameter, which needs to be assessed to supplement germination and viability tests to gain insight into the performance of a seed lot in the field or in storage. Several definitions have been offered to explain seed vigour. Isley (1957) defined vigour as “the sum total of all seed attributes, which favour stand establishment under unfavourable field conditions”. While, AOSA (2005) defined seed vigour as the sum total of all those properties in seed, which upon planting, result in rapid and uniform production of healthy seedlings under a wide range of environments, including both favourable and stress conditions and ISTA (1985) stated that seed vigour is the sum total of those properties of the seed, which determine the potential level of performance and activity of a non-dormant seed or seed lot during germination and seedling emergence.

Introduction

Seed certification is a legally approved system for quality control of seed multiplication and production. Seed certification procedures are designed to ensure physical and genetic purity, freedom from other crop seeds, objectionable and other weed seeds and designated diseases with good germinability of the foundation and certified seed. Seed certification is done by the State Seed Certification Agency of the concerned state (SSCA) notified under section 8 of the Seeds Act, 1966 or by National Seed Corporation (NSC), where State Seed Certification Agency does not exist. The General Seed Certification Standards are applicable to all crops, which are eligible for certification, while field and seed standards are applicable to individual crop, constituted as the minimum seed certification standards. The word ‘seed’ or ‘seeds’ as used in these standards also includes all the propagating materials. Seeds or propagating material, which does not meet the standards of seed certification prescribed in the Indian Minimum Seeds Certification Standards, 2013 (Gunasekaran and Trivedi, 2013), are not certified by the Seed Certification Agency. The general seed and field standards for various crops are given at the end of this chapter.

Introduction

Seeds are regarded as carriers of new technology and serve as basic catalytic input for enhancing the agricultural production. Hence the timely availability of quality seeds of the right variety in adequate quantity decides the strength of an agricultural economy. The intensive crop improvement programmes have resulted in the development of large number of hybrids and high yielding varieties in many important crops. Today, the Indian seed industry is the fifth largest seed market in the world, accounting for 4.4 per cent of global seed market. In terms of global trade, India is almost self-sufficient in flower, fruits and vegetables and field crops seeds (Anonymous, 2015). Economy of crops depends on good crop variety. Farmers choose these verities based on good quality traits and satisfactory yield. Thus, it is always essential to do fidelity check of all plant variety. The genetic purity is one of the most important aspects of quality control. Seed quality includes good germination, purity, seed health and vigour. With the increase in seed industry, there has been a refinement in the techniques used for testing genetic purity or genuineness of seed purity. Methods for testing genetic purity include different morphological, chemical, biochemical and molecular markers. Under PPV & FR Act, DUS (distinctiveness, uniformity, stability) testing procedure is performed with morphological descriptors. However, in agriculture, biotechnology has found applications in checking of true to type of clones and variety identification programs using molecular and chemical markers. Markers that reveal polymorphisms at the protein level are known as biochemical markers, while DNA markers reveal polymorphisms at the DNA level.

Heterosis

The superiority of F₁ hybrid over both its parents in terms of yield or some other characters or heterosis is increased vigours, growth, yield or function of a hybrid over the parents, resulting from crossing of genetically diverse organisms. The term heterosis was first coined by Shull in 1914. Generally heterosis manifested as an increase in vigour, size, growth, yield or some other characteristics. But in some cases, hybrid may be inferior to the weaker parent this is also regarded as heterosis.

Introduction

Quality seed plays seminal role in augmenting agricultural production as well as productivity. Only by using good quality seeds, productivity can be enhanced up to the tune of 15-20 per cent alone, but under optimum management, the increment may touch upon up to 45 per cent depending upon the crops since the efficiency and efficacy of all other inputs in the production technology gamut are contingent upon the quality of seeds being used. Since antiquity the importance of quality seed to enhance agricultural productivity is well evident as mentioned in old testimonials, literatures, scriptures, treatises, epics, and many other ancient documents.

Seed quality is the major decisive factor governing stand establishment of any crop and thus having immense importance and bears utmost priority in case of high value, low volume crops like vegetables in particular and for high volume low value crops in general for enhanced productivity and production as well (Mandal et al., 2015). A number of diverse materials/ treatments at varying doses have been used to increase the rate and uniformity of seedling emergence in wheat and rice, which are generally categorized for seed enhancement, which is a kind of value addition.

Seed enhancement may be defined as post-harvest treatments that improve germination and seedling growth or facilitate the delivery of seeds and other inputs/materials required at the time of sowing smoothly. Seed enhancement technology predominantly possess a central objective to further improve seed performance by treating with specific additives/ chemical/ organics/ botanicals, etc. under very specific regimes and with the aid of certain planting equipments to grow uniform crop obviously to harness higher productivity and production (Halmer, 2006). Various techniques have been employed to assure superior performance of additives in different crops and most have been found to have immense commercial application (TeKrony, 2006). This includes three general areas of enhancement: pre sowing hydration treatment (priming), coating, pelleting technologies and seed conditioning.

Introduction

In India, around 70 per cent of cultivated land is under rainfed condition, but it accounts for about 42 per cent of the total quantity of produced food grains (Sujatha et al., 2013). It was estimated that using quality seeds, productivity can be enhanced up to the extent of 15-20 per cent and under optimum management, the increment may touch upon up to 45 per cent depending upon the crops. Quality seeds play a major role, along with improved package of practices leading to enhanced productivity. Crops propagated with seeds face many problems: Poor seed germination, poor seedling establishment under several abiotic stresses such as, drought, salinity and poor seedling vigour. The capacity of a crop propagated with seeds to grow depends on its genetic constituent and its interaction with the environmental biotic stresses. A number of diverse materials/ treatments at varying doses have been used to increase the rate and uniformity of seedling emergence in many field crops, which are generally categorized for seed enhancement. Seed enhancement may be defined as “post-harvest treatments that improve germination and seedling growth or facilitate the delivery of seeds and other inputs/materials required at the time of sowing smoothly”. Seed enhancement technology predominantly possess a central objective to further improve seed performance by treating with specific additives/chemical/organics/botanicals etc. under very specific regimes and with the aid of certain planting equipments to grow uniform crop obviously to harness higher productivity and production (Halmer, 2006). There are several ways and means to enhance vigour of germinating seedlings while emerging from the seed, which produce a uniform crop stand and finally substantially more yield is achieved by adopting simple techniques.

Introduction

Seed pathology has been recognized as its own specialization for a relatively brief time, and the term “Seed Pathology” was first coined by Mary Noble in the 1940 (Agarwal and Sinclair, 1997). Seed pathology is an essential part of seed technology as well as a sub discipline of plant pathology. According toAgarwal and Sinclair (1997), it may be defined as the study of seed borne disease and pathogens carried with seed. It also includes studies on the mechanisms of seed infection, seed transmission, the role of seed borne inoculum in disease development, methods for the detection of seed borne pathogens and non-pathogens, seed certification standards, mycotoxins and mycotoxicoses, and various methods for control of seed borne disease. Seed pathology includes the study of diseases and deterioration caused by bacteria, fungi, nematodes, viroids, viruses, physiological and mechanical disorders.

Neergaard Paul is considered the father of seed pathology. He was one of the founding father and later served as Director of the Danish Government Institute of Seed Pathology for Developing Countries, Copenhagen, Denmark, from 1956 to 1974. He served as the Chairman of the Plant Disease Committee of the International Seed testing Association (ISTA). During his tenure as Chair of ISTA, he helped standardize methods for the detection of seed borne fungi.Neergaard (1977) authored a two-volume text entitled “A Seed Pathology”. This text has served as a reference and teaching standard for the science of seed pathology throughout the world (Agarwal and Sinclair, 1997). This text focused on a wide variety of seed pathology issues, ranging from the economic significance of seed borne diseases to the assessment of seed borne inoculum.

PESTS OF CEREALS

Rice (Oryza sativa)

Rice is the staple food of a vast majority of people throughout the world, especially in India. Rice crop is grown in about 75 million acres, which is about one-third of the total world area under rice. The warm and humid environment for the rice crop is best suited for invasion by several insect pests and as many as 85 species of insects are known to infest this crop. The damages caused by different pests extend from the seedling to harvest stages of the crop. Some of these pests are widely distributed and cause extensive damage. The more important pests are described below:

1. Rice stem borer or Rice yellow stem borer

Scirpophaga (Tryporyza) incertulas

Order - Lepidoptera

Family - Pyraustidae

Among the pests, which ravage rice crop, ‘rice stem borer’ is a major one and infests rice crop at all growth stages, from seedling to flowering. It is a specific pest of rice alone and is more serious during the months of October-January. The pest has a wide distribution in all Asian countries. The damages caused by this pest ranges from 5-20 per cent. Generally, late varieties of rice are more severely infested than the early maturing varieties, because of the possibility of the pest multiplying in larger numbers by the time the late varieties come to maturity. Cold weather with high humidity and low temperature prevalent during October-December is found to be conducive for the multiplication of the insect.

Mango (Mangifera indica)

1. Mango hoppers

(i) Amritodes atkinsoni (ii) Idioscopus niveosparsus and (iii) I. clypealis

Order - Hemiptera

Suborder - Homoptera

Family - Cicadellidae

Nature of damage. Three different species of hoppers are found to cause damage to mango trees. During some years, especially during the months of November-February, when the mango trees come to flowering, the pest appears in large numbers. During the other months, the pests are seen in much lesser numbers in an active form, while the other insects hibernate under the bark of the trees. Even in the peak period of pest occurrence, after a few heavy showers, the number of insects is considerably reduced.

During the cold season, when the trees put out the flower spikes, thousands of hoppers, young and adults appear in large numbers, pierce, suck and feed on the sap from the tender shoots, flower stalks, flowers and buds. This drain of the sap causes the buds and flowers to dry, wither and they are shed in large numbers, as a result fruit production may go down by 25-60 per cent. When a severely infested tree is approached, thousands of hoppers hop or fly about and make a rustling noise, as they dash against the foliage. The hoppers exude a sweet, sticky fluid excretion and this fluid thrown out by myriads of these insects after feeding on the tree sap, wets the soil underneath the trees and on the surface of the leaves of the trees. In case of severe infestation, the fluid may fall down in drops. The secretion attracts scores of flies, bees and other insects, which come to feed on the secretion. The infested tree presents a sickly appearance. The trees get devoid of buds and blossoms. The leaves appear shiny and are covered by ‘sooty mould’, a fungal disease. Thousands of caste skins of the nymphs are found on the shoots and leaves. The continuous damage caused to the trees year after year by the pest makes them loose their vigor gradually and eventually leads to severe reduction in their yielding capacity.

Life cycle of the pest. The female hopper inserts spherical, pale whitish eggs singly into the plant tissues through slits made in the young shoots, flower stalks and flower spikes. The eggs hatch in 4-6 days and the young nymph hatching out of the egg looks quite similar to the adult. The nymphs are very active and move about rapidly along the flower spikes and shoots, suck and feed on the plant sap. They are smaller in size, wingless and unable to fly or jump. The young ones moult their skin a few times during their growth and become adults in 10-15 days. The adult hoppers are small insects, about 3.0 mm. in length with a wedge-shaped body. The head is broader and the body gradually narrowing backwards. The legs are well developed, especially the hind legs. The general color is light greenish-brown. They are extremely active and can fly and hop around. They have a tubular, sucking mouthpart by which they puncture the tender plant parts and floral parts. The adults of Idioscopus clypealis are smaller, with two black spots on the prothorax and a few black spots on the front portion of the head, while those of Idioscopus niveoparsus are slightly bigger with three black spots on the prothorax and whitish, distinct cross bands on the light brownish forewings. The adults of Amritodes atkinsoni are bigger than the other two species, about 5.0 mm. in length, with two black spots on the prothorax. Two or more generations may appear during the flowering season of mango trees (Fig.71).

Insect and non-insect pests cause extensive damage to standing crops, stored grains and stored products resulting in huge economic loss. Besides these, several pests cause annoyance, as well as attack livestock such as, cattle, poultry and pet animals. Some others damage household articles such as, clothing, upholstery, carpets, paper, books, leather articles, wooden and bamboo furniture and all sorts of wooden structures. These obnoxious creatures besides consuming any kind of food materials, spoil them by contaminating and polluting them with their faecal matter and urine and impart a repulsive, bad odor and make them unfit for consumption by humans and livestock. The damages caused by them pave the way for easy access and infection by some of the saprophytic microorganisms, which hasten the deterioration process. A few of these microorganisms produce mycotoxins, which are poisonous and may even be fatal to the consumers.

Among the household pests, cockroaches, crickets, silver fish, ants, white ants, carpet and powder post beetles and clothes moths are quite important. These insects not only cause annoyance but different types of flies, mosquitoes, bugs, fleas and lice either suck and feed on the blood from humans, cattle, poultry etc. but are also responsible for disseminating several disease causing microorganisms.

“Hydrology is the science that treats the waters of the earth, their occurrence, circulation and distribution, their chemical and physical properties, and their reaction with their environment, including their relation with living things. The domain of hydrology embraces the full life history of water on the earth.” (Federal Council for Science and Technology, “Scientific Hydrology”, Washington, 1962)

This definition puts in a nutshell what is most often inadequately done before undertaking exploitation of water resources. In short, it is the scientific inputs that are likely to be missed while planning water resources management projects. It is the “full life history of water” part of the above definition that is of specific relevance to the theme of this book, Isotope Hydrology.

Conventional hydrology is strong on measurement and quantification of different parts of the hydrological cycle (Fig.1.1), be it precipitation, run-off, evaporation, transpiration, infiltration, groundwater dynamics etc. Through chemistry and isotopes, we try to understand the processes themselves in order to delineate the history of that part of the hydrological cycle that is being studied. For example, if we are measuring river flow, we would like to know the contribution of different components; base flow, rainfall run-off and snow melt, if any.

Let’s see what we know and what do not know in the conventional hydrological practice. We know surface waters evaporate, form into clouds and precipitation occurs under favourable weather conditions. What we often do not know is the source of moisture, oceanic or inland.