eChapters

ABSTRACT

Atotal of 45 Gram positive, spore forming and rod shaped bacteria identified as Bacillus species were isolated from the rhizosphere of Chickpea plants. They were studied for their interaction with root borne fungal pathogens was studied using spot test method. Isolates CBS 29, CBS 113, CBS 123, CBS 132, CBS 153 and CBS 155 inhibited the growth of four or more fungi with inhibition zones varied from 1-5 mm. Two isolates CBS 153 and CBS 155 produced siderophores on CAS supplemented agar medium. Further inoculation of these Bacilli on seeds of Chickpea cultivar C235 and H8618 showed inhibitory, stunting or stimulatory effects on plumule and radicle growth depending upon cultivar, bacterium used and stage of seedling growth. Studies on co-inoculation of these isolates with Mesorhizobium and their plant growth promoting activity are being carried out. These co-inoculation studies are important areas of exploitation to improve crop productivity.

ABSTRACT

In Kerala, apart from cultivated sesame species (Sesamum indicum L.) three wild species were identified viz. Sesamum malabaricum, Sesamum mulayanum and Sesamum radiatum. An investigation was carried out to determine the intensity of arbuscular mycorrhizal fungal colonization in cultivated and wild species of sesame. The percentage of arbuscular mycorrhizal fungal infection in roots of different sesame species were found to be variable. The highest percentage of root colonization of arbuscular mycorrhial fungi was found in wild species S. malabaricum, which promotes tolerance to the plant under drought stress conditions.

ABSTRACT

Detection of disease tolerance with enhanced defense mechanism is a practical approach in crop variety improvement programme. Toxins being responsible for pathogenicity and virulence of the fungi, regenerating plants from toxin treated calli is an effective and easy approach. The response of tomato calli to the crude toxins of the foliar pathogens viz., Alternaria solani and Septoria lycopersici was studied and the changes in phenol metabolism due to toxin treatment were analysed. Crude toxins of A. solani and S. lycopersici extracted under optimum conditions were serially diluted and tomato calli were treated with different dilutions of the toxins to find out the optimum dilution at which minimum survival percentage was obtained, based on a 1-4 score. Minimum score of 1 was obtained at 1:10 dilution for A. solani and at 1:20 for S. lycopersici.

The calli of resistant (LE-625) and susceptible (CO-3) tomato varieties were treated with desired dilutions of the toxins of A. solani and S. lycopersici. Total phenolics and ortho- dihydroxy (OD) phenolics were estimated at 24 h interval to study the extent of necrosis on resistant and susceptible calli due to toxin treatment. The total and OD-phenol contents of calli of susceptible cultivar (CO-3) progressively decreased with increase in time interval consequent to the treatment of toxins of A. solani and S. lycopersici. In the resistant calli of LE-625, an initial reduction of total phenol and OD-phenol content was observed following the application of the toxins of A. solani and S. lycopersici at 24 hours after treatment. Later with lapse of time, the total phenol content and OD-phenol contents progressively increased reaching a maximum at 120 h after treatment. The results clearly indicated the enhancement of biochemical defense in the resistant calli and a fall in defense mechanism in the susceptible calli due to toxin treatment. Such techniques are useful in the preliminary screening of resistant genotypes in crops like tomato.

ABSTRACT

Apot culture experiment was conducted on tomato with cadmium and lead to identify the selective retention sites of the metals. For this a completely randomized design with five treatments and four replications were laid out at the College of Horticulture, Vellanikkara. The different levels of treatment ranged from 0.5 to 2.0 mg kg -1 soil. Cadmium and lead were directly supplied as a water-soluble source through cadmium chloride and lead nitrate respectively. In tomato the growth and fruiting was permitted only at lower levels of cadmium application. At 1.5 mg kg-1 soil, fruiting failed. While at 2.0 mg kg-1 soil, the very establishment of plant was totally affected. At higher levels of application, cadmium preferred to get accumulated in roots while on the contrary at lower levels, cadmium uptake increased in shoots than in roots with the least content of the metal in fruits. However, in the case of lead, all levels of application in soil permitted growth and fruiting. With increase in rate of lead application, significant selective retention was observed in roots (1.48-6.69 ppm), shoot (0.29-1.62 ppm) and fruits (0.39-1.45 ppm). On comparison of retention sites of lead in tomato, it could be seen that fruits maintained the maximum lead uptake (637.2-2933.0 mg pot-1). Hence, the consumption of such tomato fruits contaminated with heavy metals may result in kidney damage, lack of memory, dissolution of phosphorus in the bones etc.

ABSTRACT

The potato is one of the most important food crops both in developed as well as in developing countries. Developing countries today produce 37 per cent of world’s output of potatoes. Potato is an important food crop in India. Both area under potato cultivation and production has increased manifolds during past decades. The efforts are being made to improve potato quality and its post harvest life as well.

An experiment was conducted to isolate mitochondria from potato tubers and succinate dehydrogenase (SDH) assay and protein profiling were performed in the tissue. Three varieties namely, Kufri Bahar, Kufri Lauvkar and Kufri Jyoti were taken into consideration for the present investigation. Kufri Bahar showed the minimum values for SDH activity and Kufri Jyoti the maximum SDH activity. On the basis of SDH activity, the mitochondria in Kufri Jyoti were seemed to be more viable, functional and coupled as compared to Kufri Bahar and Kufri Lauvkar. This finding also suggested that the respiratory degradation of starch in Kufri Jyoti was higher as compared to Kufri Bahar and Kufri Lauvkar. Thus these result showed that the shelf life of Kufri Jyoti was less as compared to Kufri Bahar and Kufri Lauvkar. Protein profiling performed by SDS-PAGE was found to be similar in all the potato tubers.

ABSTRACT

Biological lipids are chemically diverse group of compounds. Lipids serve two major biological roles namely a structural one as component of membrane, and storage function, particularly in certain seed tissues. Fats and oils are the principal stored form of energy in many organism, and phospholipids and sterols makeup about half of the mass of biological membranes.

An experiment was conducted to study phospholipids composition qualitatively as well as quantitatively in the roots of mung bean seedlings. Among the four solvents used for phospholipids isolation, solvent II (methanol) and solvent III (chloroform: methanol: NH₃ salt) were proved to be the major phospholipids eluting solvents. The results indicated that Phosphatidyl Choline (PC), Phosphatidyl Inositol (PI), Phosphatidyl Serine (PS), Phosphatidyl Ethanolamine (PE) and Di Phospho Glyceride (DPG) were present in significant amount in the roots of ten days old mung bean seedlings. These phospholipids were also identified by their Rf values using thin layer chromatography. Among all the phospholipids isolated, PI showed the minimum Rf value, whereas PS showed the maximum Rf value. On the basis of column chromatography, four fractions of phospholipids were isolated. The highest amount of phospholipids was found in fraction II and the lowest in fraction I. Fraction II and fraction III contained the maximum phospholipids. In the fraction II PC showed the highest content (μg g-1) and one unidentified phospholipids showed the lowest content (μg g-1), whereas in fraction III, PI showed the maximum content (μg g-1) and PS showed the minimum content (μg g-1).

ABSTRACT

Astudy was undertaken at Department of Soil Science & Agrl. Chemistry, College of Horticulture, Vellanikkara to standardize different amelioration techniques to prepare enriched coirpith compost. Twelve treatments were tried using different combinations of coirpith, Pleurotus spp., Schizophyllus spp., urea, rock phosphate, cowdung slurry, mushroom waste, goat manure, glyricidia and water hyacinth. The results of the various enrichment techniques revealed that the temperature in the compost in general, increased to a peak value of 47oC on the 22nd day of composting and later decreased to a stabilized value. The observed temperature of 40-50 °C found during the thermophilic stage is essential for the rapid degradation of lignocellulose, as the thermophilic microfungi and actinomycetes involved in this process thrive at that temperature. Though the pH show a hike at the initial stage of composting, it decreased and stabilized at the later stage of composting which is conducive for growth and proliferation of microbes. The treatment coirpith with Pleurotus spp., glyricidia +20% cowdung slurry and goat manure was found to be ideal for compost preparation.

ABSTRACT

The Cry2A proteins are promising candidates for managing the development of Cry1Ac resistance in insects. The Cry2A class of proteins is different from that of Cry1A, and experiments have shown that insects resistant to Cry1Ac are not cross-resistant to Cry2A proteins. However, the Cry2A proteins are less toxic than Cry1Ac to the polyphagous pest Helicoverpa armigera. Structure-based protein engineering of Cry toxins may pave the way for directed evolution of variants with broad spectrum of insect species specificity, enhanced potency, and stability. In the present study homology modeling of Cry2Ac was done using DeepView software. The template for Cry2Ac protein sequence (accession number X57252) was selected using ExPdb template search. The raw sequence of the Cry2Ac was superimposed over the Cry2Aa PDB template (1I5P). The superimposed model was submitted to the SWISS Model server. After receiving the Cry2Ac model, energy minimization was done using Gromos96. The threading energy and force field energy were calculated. The homology model of Cry2Ac made by us along with the Cry2Ac model from the SWISS-MODEL Repository was used for comparative analysis of receptor binding regions of Cry2Aa. Results showed variation between the two highly homologous Cry2A proteins in their receptor binding regions which may account for differences in spectrum of insecticidal activity.

The Distributed Information Sub Center at Kerala Agricultural University, Thrissur was set up in May 1995 as the 23^rd center of the BTISNet of DBT, Government of India. The area of specilisation of the Centre is Agricultural Biotech- nology. The Centre passed through several phases involving Internet connectivity through the ordinary C band connectivity, then the Ku band connectivity etc. Now the commu- nication facilities of the Centre have been strengthened by procuring an ISDN Internet connection and a connection through ASIANET. The Center caters to the needs of the students (UG, M Sc & Ph D) and faculty of all departments of the Colleges in the main campus as well as of the other nearby academic and research centers of the University. Over the years, DISC has come to occupy a position in the KAU in the area of Infor- mation Technology , information sources and services based on Internet, CD-ROMs etc. The Centre has procured databases in the field of Biotechnology and developed several databases in the field of Agriculture and related fields. The center regularly conducts training programmes in Bioinformatics. The research activities in the field of Bioinformatics have been enhanced. The Centre has now been upgraded to DIC to facilitate intensive research on Bioinformatics in an effective manner. During the year 2004, the Centre has also started offering a course on Bioinformatics for the M.Sc Biotechnology students of the College of Horticulture.

Biotechnology research in KAU spread over various research stations and cam- puses includes Plant Biotechnology, Animal Biotechnology and Fisheries Biotechnol- ogy. Thrust areas for Plant Biotechnology include developing in vitro protocols for mass multiplication of elite types of fruit plants, ornamentals, medicinal plants, spices, plantation crops and forest species. The other thrust areas include checking clonal stability and genetic fidelity of in vitro derived plants using molecular markers, DNA finger printing and characterisation of germplasm with molecular markers, imparting biotic and abiotic stress tolerance in otherwise accepted crop varieties, genetic trans- formation for imparting/ improving expression of desired traits, in vitro germplasm conservation, enhancement of secondary metabolites production etc.

The crops identified for biotechnology research at KAU include spice crops like black pepper, ginger, turmeric, vanilla, cardamom; plantation crops like cashew, coco- nut and medicinal & aromatic plants such as Kaempferia, Trichopus, Gymnema, Holostemma and Coscinium. For improvement of such crops through molecular breed- ing, it is highly essential to identify/design specific probes/primers, micro-satellites, etc. By combining the research results generated at the Biotechnology Centre and informa- tion retrieved from the Bioinformatics Centre, suitable probes, primers are being de- signed for characterization and improvement of these unique crops through molecular breeding.

WHY, WHEN AND HOW FISH GET PARASITES

Parasites pose a real risk to fishes

All fish are potential hosts to many different species of parasites. Small numbers of parasites are common and probably do little harm. However, all parasites have tremendous reproductive potential and can, under ideal conditions, quickly overwhelm fish in the confines of a tank or pond.

Types of parasites

We can broadly class parasites into two groups. Ectoparasites are found on the external surfaces such as skin, fins and gills, while endoparasites are found in the internal tissues and organs.

Endoparasites are uncommon in ornamental fish. However, there is a wide diversity of blood parasites, worms that colonize the intestines and other parasites that can invade various organs and tissues. Many require an intermediate host, such as snails, birds or the introduction of an infected fish, and so are rare in pond/ aquarium fish. There are a variety of clinical signs which might indicate the presence of endoparasites. Lethargy accompanied by emaciation is a common sign, as are worms protruding from the anus. Identification of sporozoan and protozoan endoparasites often requires microscopic examination of tissues (Chanratchakool et al. 1994).

INTRODUCTION

Fish culture as a hobby or business is well established in India. Increased interest in fish culture has also increased awareness and experience with parasites that affect fish health, growth, and survival. Information provided in this chapter is intended for the novice fish culturist as a guide to common parasites of freshwater fish. Identification of parasites and their basic treatment is included; however, any herbal treatment alone or biological cum chemical treatment may be choosen for eradication purpose (Das et al., 1995a).

PREVENTION

This section will discuss ailments that affect the fish kept in our aquariums. We will simply not call them diseases because most are not true diseases but a response to some sort of stimuli such as poor tank water management or the presence of actual parasites. A list of the most common ailments, the reasons behind them and the appropriate action needed to “fix” the problem is given in this Chapter.

If you maintain good water quality, keep the right kind of fish together, feed good quality food and monitor all your water properties you will rarely have any problems. A few common sense precautions when you purchase new fish can save you a lot of trouble.

INTRODUCTION

It can be added that physiological stress as well as the physical offences contribute as primary factor for disease occurrence and fish mortality. Many parasitic diseases due to fluctuation in water quality leads to deplition of stock, and some times total stock will go eg. yellow grub disease.

EFFECT OF TEMPERATURE ON PARASITES

Heterophyid Trematode

Cyprinodon variegatus, an estuarine fish, is heavily parasitized in the bulbus arteriosus by the heterophyid trematode Ascocotyle pachycystis. Parasitized fish ventricles were hypertrophied due to mechanical blockage of normal blood flow by metacercariae in the bulbus Swimming performance generally was reduced by the presence of parasites, which had their most significant negative effect at cold temperatures and low dissolved oxygen level ( Felicia C. Coleman , 1993)

INTRODUCTION:

An association of two organisms, one living at the expense of other for food and shelter is called parasitism. Parasite factors associated with recognition and selection of the host and the mechanisms in the host responsible for acceptance or rejection of the invading organism were evaluated. Sensory structures in parasites are able to detect differences between different fish species and this ability to discern between fishes may be based on both chemical and mechanical stimuli on the host surface. Complex glycoproteins, proteins, carbohydrates and simple molecules attract parasites or modify their behaviour. (Kurt Buchmann and T. Lindenstrom, 2002)

INTRODUCTION

Zoonoses are diseases and infections which are naturally transmitted between vertebrate animals and humans. The pathogens that cause zoonotic diseases are bacteria, fungi, viruses, parasites or protozoa. Disease transfer occurs via direct or indirect exposure to the pathogen. A pathogen is contracted directly through skin to skin contact of an infected animal or through ingestion of diseased animal products (infected faeces, urine, saliva, blood, milk or other bodily fluids). A bite or sting from a diseased animal or through an infected invertebrate host directly transfers the pathogen to humans as well. Indirect exposure occurs through air, water or soil in which the pathogen can survive for a limited period of time without a host ( Acha, et al., 2003).

CLASSIFICATION OF ZOONOSES

The World Health Organization (WHO) Expert Committee on Zoonoses came up with the following classification system of zoonoses based on the type of life cycle of the pathogen.

For most people in their right mind, parasites are disgusting little creatures. The mention of them evokes images of tiny crawlers entering the body of innocent victims by devious means, encrusting themselves within various organs (often with very unpleasant effects), living off their host’s tissues, and then exiting the body, sometimes through scatological avenues, leaving behind hosts that are incapacitated, if not mere shells of their former selves (as is literally the case for some insects). The true facts are not always that gruesome (after all, parasites that have to spend a long time inside a host do not benefit if this host kicks the bucket, because then they die as well) but often enough parasitic reality is not pretty. Ask biology students about their parasitology course, and they will tell you that attending class is like visiting a little shop of horrors. I, for one, came out of my parasitology course with newly developed phobias (mercifully temporary) of such innocuous activities as eating meat and bathing in streams – they represent ways of transmission for some parasites. But students will also tell you that parasites are fascinating because of the complexity of their life cycles and the intricate ways in which they complete these cycles. So fascinating, in fact, that many students eventually become parasitologists and devote their entire lives to studying the little critters. Most of these people work with parasites of livestock or humans, but a few with an equal taste for ethology and ichthyology pursue the more esoteric questions that occupy this page: how fishes avoid getting parasitized, and how fishes alter their behaviour once they get parasitized (Barber et al., 2000)

Occasionally anglers catch fish that show signs of infection or parasitism. Is the fish safe to eat? The usual and safest response to this question is, “When in doubt - don’t.” However, very few fish diseases can be transferred to humans. Almost all fish are safe to eat when thoroughly cooked, smoked or frozen.

Fishes are a valuable resources for hill streams and temperate region people. Not only do they provide important recreation, but they are also a valuable supplement to the family food budget. The anticipation of any fisherman, whether he be a young boy with a cane pole and a can of worms or an “old pro,” is a quality fish for the table. It is the unwritten law of any true sportsman to utilize the fish he catches. The purpose of this publication is to help you, the angler, determine if the fish you’ve caught is worthy of your skillet. Remember, a sick fish will not take the hook (Taraschewski, 2000).

INTRODUCTION

A parasite is an organism which exploits another organism for the purpose of staying alive. Some parasitic relationships are harmless, while in other cases a parasite can damage or even kill its host. The word is borrowed from the Greek word ‘‘parasitos’’, meaning “one who eats at the table of someone else.” In case of exotic carps parasites causes a great loss by reducing economy. Some, cannot live once their host dies, while others can continue thriving on dead hosts until their nutrients are consumed. Parasites live inside a host are called endoparasites or internal parasites. Ectoparasites live outside the host, and are generally more capable of switching hosts. A parasite preys on other parasites, is called epiparasite (Anderson, 1974).

Silver Carp

The silver carp (Hypophthalmichthys molitrix) is a species of freshwater cyprinid fish, a variety of Asian carp native to north and northeast Asia. It is cultivated in China. Pound for pound, more silver carp are produced worldwide in aquaculture than any other species. Silver carp are usually farmed in polyculture with other Asian major carps, or sometimes Indian major carps or other species. It has been introduced to, or spread into via connected waterways, at least 88 countries around the world.Introduced in india in 1959 at the pond culture division of CIFRI. In India in 1963 breed sucessfully by hypophysation. The silver carp is a filter feeder, and possesses a remarkably specialized filtration apparatus capable of filtering particles as small as 4 µm. The gill rakers are fused into a sponge-like filter, and an epibranchial organ secretes mucus which assists in trapping small particles. A strong buccal pump forces water through this filter. Silver carp, like all Hypophthalmichthys species, have no stomachs; they are thought to feed more or less constantly. Silver carp are thought to feed largely on phytoplankton; they also consume zooplankton and detritus. It is used in controlling water quality, especially control of noxious cyanobacteria (blue-green algae), microcystis .

An extraordinary variety of viruses, bacteria, and organisms stand ready to attack us and feed off our bodies’ cells. Using microscopes of varying power, photographers show us a teeming microbial world that we could barely imagine without their help.

Soil is a mass of large variability and thus its sampling is the most challenging problem for any soil analyst. Practically, soil sampling is a two step process which includes (i) collection of soil from homogeneous unit and (ii) processing which in turn includes drying, grinding, sieving, mixing, partitioning and storing.

1.1. Sources of Error in Soil Chemical Analysis

Different sources of error involved starting from soil sampling to chemical analysis of a sample can be divided into three main groups:

1. Sampling error : This error results from variability among the different samples drawn from same soil unit with respect to the objective of sampling.
2. Sub-sampling error : This error is due to variability introduced among sub samples of the same soil sample.
3. Analytical error : This error introduced due to variability from one chemical determination to another on same sub sample.

2.1. Particle Size Distribution Analysis

Soil is composed of particles of varying size and shape. The expression of the proportion of the different size particles is termed as ‘soil texture’. It is one of the most important basic characters being little changed by cultivation or other practices. Particles are arbitrarily distinguished into following groups on the basis of their diameters.

3.1. Determination of Bulk Density of Soil

3.1.1. Determination of Bulk Density of an Undisturbed Soil

Bulk density of soil is expressed as the ratio of the mass (weight) of soil particle to their total volume including the pore space between the soil particles. Alternately, it is the weight of unit volume of dry soil. It is usually expressed in the unit of gram per cubic centimeter (g/cc) or mega gram per cubic meter (Mg/m³). In fine textured soil bulk density varies from 1.00 to 1.60 g/cc, whereas in coarse textured soil from 1.20 to 1.80 g/cc.

In natural condition primary soil particles cohere to each other to form a cluster or an aggregate through the cementing action of various agents like organic matter, oxides of iron and aluminium, carbonates, etc. Aggregate analysis tells one about the structural status, pore geometry which in turn influences the movement of air and water in soil, amount of water stable secondary particles (aggregate) as well as the extent of finer particles aggregated to the coarser particles and the erodibility status of surface soil against wind and water.

Methods of Analysis

Among the several methods of aggregate analysis the commonly used methods practiced in agriculture and related fields are wet sieving and dry sieving method of aggregate analysis.

5.1. Determination of Soil Moisture

5.1.1. Determination of Soil Moisture Content by Gravimetric Method (Direct method)

Traditionally water content in soil is expressed as the ratio of the weight of water present in the soil to the weight of dry soil. When this ratio is multiplied by 100, it becomes the percentage of water in the soil sample on dry weight basis.

6.1. Determination of Hydraulic Conductivity of Saturated Soil: Laboratory Methods

Hydraulic conductivity of a saturated soil indicates the ease with which water is transmitted through the soil pores. If a constant water head (h) is maintained on a saturated soil column of length (L) and the volume of water (V) percolating per unit time (t) through per unit cross sectional area (A) to the other end, then according to Darcy’s Law the rate of flow of liquid or flux (q) is proportional to the hydraulic gradient (ΔH/L) across the length of soil column.

Soil consistency is a term used to designate the manifestation of different physical forces acting within the soil at various moisture levels. The consistency limits, also known as ‘Atterberg Limits’ (Atterberg, 1911; 12) are defined by the water content of the soil to create specified degree of consistency. These limits are – (i) Liquid limit or upper plastic limit, (ii) Plastic limit or lower plastic limit and (iii) Sticky limit.

7.1. Determination of Liquid Limit or Upper Plastic Limit

Equipments and Materials

Liquid limit device (Casagrande, 1932) and accessories, spatula, dish, oven, moisture box, balance, desiccator

8.1. Law of Mass Action

Gulberg and Waage, the two Norwegian chemists in the year 1864 stated the law of mass action in this form: ‘The velocity of any chemical reaction at any instant at a given temperature is proportional to the active mass of each of the reactants at that instant present in the system, the active mass in a homogeneous system is defined as the number of gram molecule of the substance present per unit volume i.e., the molar volume’.

Mathematical Formulation of the Law of Mass Action

Let us take a simple case of a reversible reaction at constant temperature represented by the equation:

9.1. Balance and Weighing

9.1.1. Principle of Functioning of a Balance

It is one of the important tools used in the laboratory and one should have thorough knowledge about its assembly, use and care, otherwise it may be the initial step for introducing error in any physical or chemical analysis. Every balance has its maximum load limit and sensitivity depending upon its construction.

Essentially balance may be regarded as a rigid beam, BC having a central fulcrum, O and two arms of equal length, d₁, d₂ (Fig.9.1). The both ends of beam have prism edges upon which the balance pans are suspended by means of suitable suspension.

10.1. Determination of Soil pH

The soil pH value is the measure of hydrogen or hydroxyl ion activity in the soil solution and it indicates whether the soil is acidic, neutral or alkaline in reaction. The pH is the most important property of soil as it controls the availability of plant nutrients, microbial activity and physical condition of soil. Since crop growth is affected both under very low (strongly acidic) and very high (strongly alkaline) soil pH, reclamation of these soils are necessary. Soil pH in fact indicates the extent of active acidity (activity of hydrogen ion in soil solution) of soil. Depending upon the purpose of measurement and soil condition, soil pH is measured in several soil-water or soil-salt solution ratios. The saturated paste is used for identifying specific soil problems like degree of acidity or alkalinity. For making fertilizer recommendation, 1: 2 soil-water suspension is generally adopted. To mask the variability in salt content of the soil, the pH is measured in soil-CaCl₂ suspension (1:2 soil-0.1 M CaCl₂ solution). The soil pH value is independent of dilution over a wide range of soil-salt solution ratio, thus more reproducible than those obtained with soil-water suspension.

11.1. Determination of Electrical Conductivity of Soil Solution

The conductivity or more precisely the specific conductance of a soil at a given soil-water ratio is the reciprocal of the specific resistance offered by the solution at 25ºC between the electrodes of 1 sq cm cross section kept 1 cm apart. Thus, the electrical conductivity of any solution depends on the amount of soluble salt present in it. Knowledge on the extent of salinity is important for management of saline soil including the choice of the crop suitable for that soil. Soluble salt content in saturation extract is more reliable index of salinity level than in soil: water ratio of 1: 2 or 1: 2.5 because it simulates the extent of salinity experienced by crop in field moisture condition.

Salinity class of soil is based on the electrical conductivity (EC) of saturation extract at 25ºC. However, EC of water extract from 1:2 soil-water suspension can be transformed into the EC of saturation extract following the formula (except for soil containing gypsum).

Carbon may present in soil in four different forms:

1. Carbonates: Mainly as CaCO₃ and MgCO₃, active CO₃^2- and HCO₃^- ions and gaseous CO₂.
2. Highly condensed elemental organic form: Charcoal, graphite.
3. Completely decomposed resistant organic residues: Humus.
4. Undecomposed and partially decomposed organic residues.

13.1 Exchange Capacity

Soil colloidal particles carry both negative and positive charges on their surface which attract and hold equivalent amount of oppositely charged ions to their surface. The total number of negative charges present on a given mass of soil or capacity of a given mass of soil to exchange cations or total number of cation held by a given mass of soil is termed as cation exchange capacity (CEC). Similarly, the capacity of a soil to retain anions is known as anion exchange capacity (AEC). The ion exchange capacity of a soil depends upon the type and amount of colloidal particle (clay and organic matter) present in the soil. Ion exchange capacity (CEC / AEC) is expressed as milliequivalent ion (cation / anion, respectively) per 100 g of soil (meq / 100g). It is also expressed as centimoles of charge (positive / negative) per kg of soil [cmol (±) / kg]. Meq / 100g = cmol (±) / kg of soil.

14.1. Determination of Total Nitrogen in Soil (Modified Kjeldahl Method)

Nitrogen mostly present in soil in organic form. Relatively small amount of nitrogen usually occur in ammonium and nitrate form, the available form. The Kjeldahl method of total N determination includes both organic and ammonium form and with modification nitrate form of N can also be included.

Phosphorus in soil present both in inorganic form and organic form. The inorganic P can be divided into different pools. The major active inorganic forms are: P bound to aluminium (Al-P), iron (Fe-P), calcium (Ca-P) and silicate minerals and relatively less active forms are occluded and reductant soluble forms of P. On the other hand the principal organic P compounds present in soil are (i) inositol phosphate, (ii) phospholipids, (iii) nucleic acid and other unidentified esters and phosphoproteins.

15.1. Determination of Available Soil P

The availability of soil P to plant varies greatly depending upon the reaction, minerological composition and amount of the soil colloid. Very little P is present in the soil solution except in recently fertilized or sodic soils. The type of phosphate ions present in the soil solution depends on the soil pH. In soils of neutral to slightly alkaline pH, HPO₄^2- ion is the dominant form. In slightly or moderately acidic soils, both H₂PO₄^- and HPO₄^2- ions prevail. At strongly acidic soil H₂PO₄^- ion tends to dominate, while above pH 9.0, the PO₄^3- ion becomes more important than H₂PO₄^-.

16.1. Forms of Soil K

Ignoring potassium (K) in soil organism, total K in soil may be classified as (i) water soluble K, (ii) readily exchangeable K (exchangeable K), (iii) slowly exchangeable K (non- exchangeable or fixed K) and (iv) mineral or lattice K. The different forms are in dynamic equilibrium with one another.

Sulphur (S) occurs in soil in both organic and inorganic forms. Inorganic S fraction may occur as sulphate (SO₄^2-) and compounds of lower oxidation state such as sulphide (S^2-), polysulphide (S_n^2-), thiosulphate (S₂O₃^2-) and elemental sulphur (S⁰). In well drained soils inorganic S usually present as sulphate. Under anaerobic condition (reduced or waterlogged soil) inorganic S mainly occur as sulphide and under extreme condition as elemental S form. Estimation of S carried out in two steps:

18.1. Determination of Available Micronutrient Cations (Zn, Cu, Fe and Mn) in Soil

The available micronutrient cations (Zn, Cu, Fe and Mn) can be estimated in a single extraction with diethylene triamine pentaacetic acid (DTPA) as proposed by Lindsay and Norvell (1978). DTPA has the excellent property to combine with free metal ions in the solution forming soluble complexes. The stability constants of metal-DTPA complexes make DTPA as a most suitable extractant for simultaneous complex formation with Zn, Cu, Fe and Mn. In calcareous soil DTPA extractant may result overestimation due to excess dissolution of CaCO_3, thus releases occluded micronutrient cations which are not plant available. To avoid this excessive dissolution of CaCO₃, DTPA is buffered at pH 7.3 using triethanol amine (TEA). At this pH major part (3/4^th) of TEA is present as HTEA⁺ (protonation) and exchanges for Ca and Mg ion from the soil exchange site. This increases concentration of Ca and Mg in the solution phase and suppresses dissolution of CaCO₃. The DTPA has the capacity to complex each of the micronutrient cations 10 times of its atomic weight and it ranges from 550 to 650 ppm depending on the micronutrient cation.

The amount of cation in the extract is determined on an atomic absorption spectrophotometer (AAS). The experimental condition such as shaking time, DTPA concentration, pH and temperature during shaking influence the amount of Zn, Cu, Fe and Mn extracted. Increase in shaking time and temperature markedly influence the extractability of these cations.

19.1. Plant Available Fraction of Nickel, Cadmium, Lead and Chromium

The DTPA method was originally developed to extract Mn, Cu, Fe and Zn from slightly acidic to alkaline soils (Lindsay and Norvell, 1978), but in some cases it can be used for other metals also such as Nickel (Ni), Cadmium (Cd), Lead (Pb) and Chromium (Cr). Among them Ni is considered as an essential micronutrient. The DTPA is used to extract soil metals by forming chelates with free metals in solution, which lowers their ionic activities so that additional quantities of metal are released from the soil until equilibrium is attained. Triehanolamine (TEA) is used to buffer the extracting solution at pH 7.3 in an attempt to optimize the extraction of various metals. Calcium chloride is included in the extracting solution to minimize dissolution of CaCO₃.

1.0. Introduction

Any commodity, produce or harvest in organic or inorganic form to be fit to eat by a particular society, and contributes materially towards growth and repair of tissue is known as food. Food processing is application of techniques in a systematic manner for preventing losses through preservation, processing, packaging, storage and distribution to ensure greater availability of a wide variety of foods. It is a set of methods and techniques used to transform raw ingredients into food for consumption by humans or animals.

The early stages of food processing were largely confined to primary processing of food crops, commodities and produce whereby all these rendered fit for consumption or sale in the markets. Processing of rice and oil seeds were the necessities of that time for living. Later on, World War II gave a fillip to some of other food processing industries to meet the demand of the defence forces of the country. Fruits and vegetables processing; wheat and sugar milling drew support and sustenance from the exigencies created by war. Post war situation almost merged into the post-independence scenario. However, food processing industry received its first major impulse after independence. During this time, all the primary food processing industries received top most priority and all necessary support from the Governments in the country.

2.0. Introduction

Before dealing with the various processes involved in the processing of fruit and vegetables or any food commodity on commercial scale, it is necessary to consider certain important factors such as investment, site, building, water supply, staff, labour etc. which are essential for the successful running of the food processing plant. Processing plant is the premises, buildings, structure and equipment used in the preparation, processing, handling, transportation and storage of any food commodity / fruits and vegetables / the processed products. The design and layout of the food processing plant is of great importance, besides other important factors. The food processing plant may be single storeyed or multi-storeyed depending upon capacity of production and viability of the plant e.g. if the production of the plant is assumed to be small and processing plant have to run only for short duration during the year then single storeyed processing plant can serve the purpose. Plant layout, product layout and process layout are the most important components for setting up of food processing industry and can determine the working efficiency of unit. Sanitary requirements in food processing plant are also important for marketing of the prepared product in national and international market. Sanitary requirement is as important in food processing plant as is the treatment of the effluent waste. For setting up of the food processing plant certain guidelines have been laid out by FPO, 1955.

3.0. Introduction

A hazard is any factor that may be present in the food or food products and can cause harm to the consumer either through injury or illness. Hazards may be biological, chemical and physical. It may be a biological, chemical or physical property or condition of food with the potential to cause an adverse health effect. Therefore, these hazards can be grouped into three broad categories (Fig 3.1). Further, various stages during which processing hazard can takes place in a food industry is illustrated through Fig. 3.2. Effect of different potential hazards on human health along with symptoms is presented in Annexure IV.

4.0. Introduction

Quality is a measure of the degree of excellence or degree of acceptability by the consumer. By quality, one can differentiate the individual unit of a product from the other units and can determined the degree of acceptability of the individual unit by the consumer. The quality may also be defined in term of end use and may vary depending upon consumer’s perception and need. According to USDA Marketing Workshop Report (1951) “quality is the combination of attributes or characteristics of a product that have significance in determining the degree of acceptability of the product to the user”. For industry, quality is a measure of purity, strength, flavour, colour, size, maturity, workmanship and conditions or any other distinctive attributes of the product.

According to Code of Federal Regulations “Quality is the inherent properties of any processed product which determine the relative degree of excellence of such product and includes the effect of preparation and processing and may or may not include the effects of packaging or added ingredients/ additives”.

5.0. Introduction

Quality control is generally defined as the regulation by law of food manufacture, distribution and sale in order to prevent health hazards and fraud to the consumers. Thus, it becomes a criminal offence to sell adulterated, filthy or contaminated foods. Quality control is the scientific control of production. There are certain basic fundamentals which are required for successful running of the food processing industry. So, for successful quality control in an industry / organization certain management systems are needed. Depending upon consumer requirement and satisfaction, quality management system is based on four important pillars like management responsibility, resource management, product / service realization and measurement, analysis & improvement. This management system is also important for ISO certification in an organization / industry.

6.0. Introduction

Food is the basic need of all living organisms and hence, its quality should be given top priority. Food processing involves number of unit operations for material handling and there are always chances that the food may be contaminated or adulterated. The food is said to be contaminated if food is injurious to health and contain filthy, putrid rotten odour of insect pests etc. and can affect a large number of the populations at a time and hazards may occur. However, a food is said to be adulterated if it contains any other substance which affects the nature and quality product or substance is substituted with cheaper substance. So, it is essential to set the minimum limits of the desirable characteristics required and the maximum limits of the undesirable components that the food should contain. This helps to set common standards for commodities and to prevent confusion among the consumers.

7.0. Introduction

The food safety is one of the most important of assurance system required for global expansion of trade between developed and developing countries. Assurance that food will not cause harm to the consumer when it is prepared and/or eaten according to its intended use is known as food safety concept. It is set of conditions and measures taken during the food chain like production, processing, storage and distribution in order to ensure that, the product consumption does not represent a risk to the human health.

8.0. Introduction

Food additives are the substances not normally consumed as a food by itself and contain or not contain nutritive value but are added to food to improve freshness, sensory and keeping quality of food. So, a food additive is defined as a substance or a mixture of substances other than the food stuff incorporated in food either directly or indirectly as a result of any phase of production, processing, storage or packaging to improve or maintain the nutritional value, enhance quality, consumer acceptability and facilitate the preparation of materials e.g., acid, alkali, bleaching agents, emulsifying & sterilizing agents, flavours, colours, nutrient supplements, clarifying agents, humectants, chemical preservatives etc. Every food available in the market or at home contains food additives. So, now the question arises that whether additives are safe from consumption/toxicological point of view or not? What are the facts or fictions, if additives are to be used in the food preparation? These are the most important questions to be answered and discussed before their use in food industry.

9.0. Introduction

Enzymes are organic biocatalysts which initiate and control biological reactions. A catalyst is an agent affecting the velocity of a chemical reaction without appearing among the final products of the reaction. Unlike general catalysts, enzymes are specific in nature and function at a temperature of approximately 37^o C and pH close to neutrality. All enzymes are proteins but all proteins are not enzymes. These are distributed among the cell and tissues of plants and animals. Use of malted barley in brewing, yeast in the production of alcoholic beverages and wrapping of meat in the bruised leaves of papaya tree for tenderizing meat are techniques that have been used for centuries. In bread and cheese making also, enzymes have been exploited from generation to generation. Thus, enzymes have been used without knowing the nature of enzyme as catalysts and reactions involved. However, it is only recently that nature and action of enzyme is known and its importance in food industry is realized.

10.0. Introduction

Food processing is an important sector in agriculture, the scope of which has increased manifold that can help to prevent wastage of perishable commodities to a great extent. But, at the same time, food processing industries generate a large quantity and variety of food products, provide employment to a large number of people and uplift their economic status. The production, processing and preparation of food, all results in generation of huge quantity of waste material causing health hazards due to environmental pollution. The waste material may be in the form of leaf/ straw, waste during harvesting, food preparation waste, after processing waste, unused material as waste, food processing operation waste etc. The huge wastage of the food material is due to lack of control on such agri-economy practices. So, the disposal of waste material has become a challenge to the processors, as different agencies are pressurizing for an environment friendly treatment of waste material. The utilization of waste for the production of value added products is very important in the management of food processing waste. Different types of food industries wastes are: i) fermentation industry waste, ii) fruit and vegetable industry waste (Table 10.1) iii) Sugar and starch industry waste, iv) diary industry waste, v) meat processing industry waste, vi) coffee industry waste and vii) palm oil industry waste, viii) fish processing industry waste. So, there is great need to find out options which have positive values of food waste. The options having positive values are: i) minimization of the waste generation, ii) development of value added products. Most of fruit and vegetable wastes are a rich source of vital constituents like carbohydrates, proteins, fats, minerals, fibres etc. Mango seed kernel is rich in carbohydrates, fats, proteins, minerals; orange, melon and pumpkin seeds can provide fats and mineral matters. Apricot kernels are rich source of oil (45%) and proteins.

11.0. Introduction

Agricultural marketing is one of the important branches of agricultural economics. Farmers have one commodity or the other in surplus and need to be disposed off or sold to earn some money to satisfy other needs, which otherwise cannot be satisfied on the farm or in the village. Thus, agricultural marketing has two-fold objective i.e. Sale of surplus commodities and buy other commodities to satisfy family needs. In modern commercial agriculture, the surpluses with farmers are steadily rising, so also their family needs are changing with the change in lifestyle. Therefore, agricultural marketing has assumed important place. Traditionally, market is place or building where buying or selling of goods takes place. But, in modern times with fast and long distance communication facilities like telephone, market is no more restricted to a particular place only, but it has become wider and has assumed regional, national or even international status. Buying and selling is finalized on telephones only from distant places. Thus, the concept of market has radically changed.

So, marketing of food/ processed food is an important and vital constituent of modern business management. Knowledge about market is critical for the success of the product in such a highly competitive global market place. Now a day, in such modern time, marketing is itself a highly specialized and distinctive discipline. Based on marketing rules and laws, marketing is sometimes regarded as marketing science. Modern marketing strategies, tools and techniques have attained such complexity that marketing is linked with those of the modern warfare. The results of the marketing wars are witness by Cola wars and other brand bars being fiercely fought in the global market. So, the markets have become virtual battlefield for the brand wars. Markets and technologies are the two powerful forces driving the food processing industry. Further packaging has become a powerful tool in the promotion and marketing of the processed food products.

12.0. Introduction

The benefits of food laws to the consumers and the processing industries depend upon the efficacy with which the laws are implemented. The implementation of laws requires not only a well organized national infrastructure for inspection and quality control, but also requires reliable methods of analysis, that can be used to check the quality standards for improvement of the food product w.r.t. nutrition, safety and sensory attributes. Early and accurate analysis of food product prior to preservation, during preservation or post preservation is a crucial component for quality evaluation and their quality control. Quality control in food industries depends upon three principles viz. i) raw material control, ii) process control and iii) finished product inspection. Once a product has gone through the manufacturing process, little can be done to alter its quality or to overcome the faults. Examination of the finished product at the most represents analysis with respect to standards – to accept or reject. Effective control over the raw material and process minimizes the rejection of the products. The food spoilage can be managed most effectively, if control measures are introduced at an early stage of food preparation/contamination. Reliance on symptom is often not adequate because spoilage may occur before symptom appears. The spoilage of the food may affect sensory, physical, chemical or microbiological attributes. Therefore, now a day, food processors want to analyze their food samples quickly without any delay in shipment for which they have to depend on the different methods for their quality evaluation. The analysis and quality control of food products involve physical, chemical, microbiological and sensory methods. So, widely used standard procedures / methods for evaluation of quality of food prior to preservation, during preservation or post preservation has been given in this chapter for easy implementation.