eChapters

The term ecology was first of all proposed by zoologist H. Pietir in 1865. It was derived from the Greek word ecologic means oikos = living place and logos = study and some definitions of ecology presented below:

1. According to Ernst Haeckel, 1869 “The total relations of the animal to both its organic and inorganic environment is called as ecology”.
2. E. Warming 1895 “Ecology is the study of animals and plants in relation to their environment”.
3. According to Odum 1963 “Study of structures and functions of nature is defined as ecology”.
4. Krebs 1985 says that the “Ecology is the scientific study of interaction that determine the distribution and abundance of organisms”.

The life of insects is dependent on the adaptability of the environment, if the environment is unfavourable then the insect population ceases and vice-versa. This insect move one place to another to get the favourable environment so that they can pull on their life activities properly. There is a deep relationship between the living community and non-living environment. Both are affecting each other greatly. This inter-relationship between living community and non-living environment is called as ecosystem. The term ecosystem was first used by A.G. Tansley as early as 1935 and he defined, “Ecosystem is the system of resulting from the interaction of all the living and non-living factors of the environment”.

Flowers are the reproductive structures of Angiosperms. The apical shoot meristem of the vegetative plant continues to produce new leaves and vegetative buds, which may develop into branches, but after sometime, the meristem, instead of producing leaves and branches, becomes transformed into specialized reproductive structures called flowers. The transformation of vegetative shoot apex into re-productive structure is called flowering. The process of flowering is controlled by two main important environmental factors, i.e., (i) the duration of light received by the plant called photoperiod and (ii) the low temperature treatment given to the seed or the plant referred to as vernalization (Figure 6.1).

The transition from vegetative to floral meristems in higher plants is programmed by the coincidence of internal and environmental signals. The timing of floral transition has a direct impact on reproductive success. One of the most important environmental factors that affect the transition is the change in day length (photoperiod). Classical experiments imply that plants monitor photoperiods in the leaf and transmit that information coded within an elusive signal dubbed florigen to the apex to reprogram development. Recent advances in Arabidopsis research indicate that the core of the day-length measurement mechanism lies in the circadian regulation of CONSTANS (CO) expression and the subsequent photoperiodic induction of the expression of FLOWERING LOCUS T (FT) gene, which might encode a major component of florigen. The florigen paradigm was conceived in photoperiod-sensitive plants; nevertheless, it implies that although it is activated by different stimuli in different flowering systems but the signal is common to all plants. Flowering time, the major regulatory transition of plant sequential development, is modulated by multiple endogenous and environmental factors.

Respiration is the oxidative breakdown of complex substrate molecules such as starch, sugars, and organic acids normally present in plant cells to simpler molecules such as carbon dioxide and water. Concomitant with this catabolic reaction is the production of energy and intermediate molecules that are required to sustain the myriad of metabolic reactions essential for the maintenance of cellular organization and membrane integrity of living cells. Since respiration rate is so tightly coupled to the rate of metabolism, the measurements of respiration provide an easy non-destructive means of monitoring the metabolic and physiological state of tissues, e.g., the events of senescence and ripening are often signaled by abrupt changes in respiration.

Maintaining a supply of high-energy compounds like adenosine triphosphate (ATP), nicotinamide adenine dinucleotide (NADH) and pyrophosphate (PPi) is a primary function of respiration. Nicotinamide adenine dinucleotide plays very important role in mitochondrial matrix (Moller and Ramusson, 1998). The overall process of aerobic respiration involves regeneration of ATP from adenosine diphosphate (ADP) and inorganic phosphate (P_i) with the release of carbon dioxide and water. If glucose is used diphosphatas substrate, the overall equation for respiration can be written as follows:

Photosynthesis- the word photo refers to light and synthesis means preparation. Thus, photosynthesis is the process by which the green plants use light energy of the sun to synthesize carbohydrates. Carbohydrates like simple sugars (glucose) can be stored as starch.

The green plants are eaten by the herbivores, which in turn are consumed by carnivores. Ultimately, the decomposers derive their nutrition from the dead plants and animals. Thus, all organisms are dependent directly or indirectly on green plants, which synthesize food by photosynthesis. Thus, photosynthesis is the most important life sustaining process of nature (Calvin, 1976; Emerson and Arnold, 1932). Photosynthesis is a series of biochemical reactions, which can be essentially summarized as follows:

The capacity to reproduce is one of the most important characteristics of all living beings. Reproduction is a process of producing offspring and is aimed to preserve individual species. This is known for self-perpetuation. There are several modes of reproduction, which vary from species to species, in available conditions. All the reproductive methods of plants are broadly classified into two types, i.e., (i) asexual reproduction (apomixis) and (ii) sexual reproduction (amphimixis). In asexual reproduction, the new individuals are produced by any means other than the fusion of sex gametes. In sexual reproduction, the gametes from male (androecium) and female organs (gynoecium) of the flower are fused to produce a zygote (Schranz et al., 2005; Rodrigues et al., 2008). Amphmixis and apomixis are the two sides of same coin (Curtis and Grossniklaus, 2007).

Plant body consists of numerous microscopic box like components called cells. The word cell has been derived from the Latin word cellula, meaning a small room. The descriptive term for this smallest living biological structure was coined by Robert Hooke in a book he published in 1665. When he compared the cork cells, he saw through his microscope to the small rooms monks lived in. The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life, which is classified as a living thing and is often called the building block of life (Maton et al., 1997). It is defined as a mass of protoplasm surrounded by a membrane- the plasma membrane- within which complicated chemical reactions are going on.

Exocrine Glands Types: Exocrine glands are generally of ectodermal origin and are widely scattered over the insect. Exocrine glands release their secreations through ducts into the lumen of various internal organs. Example: Accessory reproductive glands, salivary gland, silk gland. Gland is mainly composed of secretory epithelial cells. These are simple unicellular, bicellular, multicellular, complex multicellular (compound glands). These glands are ectodermal in origin and are secreated over the insect body.

Examples. Wax glands, lac glands, cephalic glands, poison glands.

1. Glands pouring (secreting structural materials). Some insects secrete substances that are used in building their houses (beehive) as protecting them (lac or cocoon).

In insects nervous system is highly developed and serves to coordinate the activities of its various systems. Units of this system are known as neurons. Which carry information in the form of electrical impulses from external and internal sensilla (Sensory cells) to appropriate effectors e.g., glands, muscles and glail cells. Nervous system of insects may be divided into three parts.

1. Central nervous system
2. Sympathetic or visceral nervous system
3. Peripheral nervous system.

The respiratory system or tracheal system is involved in gaseous exchange in the insect with the environment. In this system there is a system of internal tubes, the tracheae that directly transport the oxygen to the parts of the body. Therefore, it does not use the circulatory system as the vehicle for gaseous exchange. The trachae open outside through segmental pores called spiracles having some system of closing and opening. Except proturans and some collembolans all insects possess tracheal system for respiration. These insects live in moist habitats where gaseous exchange takes place directly with the environment via the integument.

Insects show sexual Dimorphism i.e., the sexes are usually separate and are dioecious. Male reproductive system produces sperms, stores them and delivers them i.e., spermatozoa. It also produces the seminal fluid, which provides a suitable environment to the sperms and nourishes them. Male reproductive system also situmilates are the female for oviposition. The female reproductive system produces and stores eggs provide nutrition to them for embryonic development, recieves and stores the sperms, is a site of fertilization. Female reproductive system also deposite eggs and may provide additional protection to the embryos. The reproductive system of both male and female insect’s bearis a gononpore, which is an opening of a pair of gonads. Both the gonads open into the gonopore by a median duct. For the secondry sexual purposes, e.g., formation of spermatophore and egg-case or ootheca, some accessory glands are associated with the reproductive system.

Excretory system of an organism maintains its homeostasis i.e., a constant internal environment. Here in insects, the blood is haemolymph therefore it determines the excretion of an insect’s body. Excretion also eliminates the nitrogenous wastes and maintains the salt- water balance and also regulates the uniformily of haemolymph. The characteristic feature of insects is the presence of malpighian tubules to eliminate the metabolic wastes, whereas rectum walls carry out the function of reabsorption of salt and water. A minimum amount of water is excreted with nitrogen waste in order to conserve the water in body.

Insects, belonging to the phyllum-arthropoda, have an open circulatory system. An open circulatory system is that in which blood bathes the organs rather internal organs directly in the haemocoel, the coelom of the insects, which actually is not a true coelom. Almost entire haemocoel of insects is formed from the epineural sinus. The haemocoel is divided into the perineural sinus and perivisceral sinus by the dorsal and ventral diaphragm respectively. The characteristic of insects is the presence of dorsal vessel, which comprises of anterior aorta and a posterior heart and is the only conducting tube present in insects. The blood of insects mostly does not perform gaseous exchange, therefore it does not contain haemoglobin, and blood in insects is called the haemolymph, which is red-coloured. So in order to study the circulatory system of insects, the major focus must be on the dorsal vessel, which has been described as follows, along with its accessory structures.

The digestive system of insects comprises of two main sub-parts, one is the alimentary tract or also known as the digestive tract and the associated digestive glands. These digestive glands may be associated directly or indirectly such as, salivary glands, gastric, caeca (directly) and Malpighian tubules (indirect). If we have to describe an insect and its anatomy, or its histology, it is based on the orthopteroid plan, which is mostly shown by grasshoppers, crickets, and locusts, because their plan shows and describes the basic, primitive design from which other groups of insects have enolved and showed modifications and specialization. We can say that this orthoptera insect shows the general anatomical and histological features of a generalised insect.Today, we see that insects have invaded and adapted in almost all types of habitats and the major reason for their biological success is their ability to show digestion, utilization and their ability to eat an extremely vast diversity of food. It is due to this abilityof extremizm in food diversity that insects have undergone many specializations and modifications of the alimentary canal. What modifications a species of insects undergoes, depends upon the type of insects, depends upon the type of food it consumes. The diversity is also seen in the way of obtaining, storing, processing and absorbing the food. These differences may be structural or functional or both. It is not necessary that these differences must be present in different species only, those may be shown by different life stages of a single insect, by two sexes of a single species, etc. e.g., the difference between the mouths parts of mosquito species.

The dairy processing industry in India deals mainly with the fluid milk and/or short shelf life products, despite India being the largest producer of milk in the world, with an output bordering the 110 million ton mark. This feature offers immense potential in the area of R&D in dairy processing in terms of value addition. The potential gains are many, including higher returns for producers and advantages in terms of health, therapeutic, nutritional and/or gastronomy for the consumers. However, the Indian Dairy Industry can amass possible benefits by being a global contender in trade only when its products are at par with those available in the rest of the world in terms of price and quality. It is evident from the post-WTO scenario that for sustainability, Indian dairy industry will need to maintain wholehearted commitment to quality management right from the farm to the consumer, shedding its inhibitions and resistance to changes.

9.1. WTO Agreements and Food Industry

The General Agreement on Tariffs and Trade (GATT) was formed in 1947 and lasted until 1994, when it was replaced by the World Trade Organization (WTO) in 1995. The WTO is the only global international organization dealing with the rules of trade between nations. It provides a forum for negotiating agreements aimed at reducing obstacles to international trade and ensuring fair deal for all, thus contributing to economic growth and development. Currently, there are 16 agreements to which all WTO members are parties and two agreements to which only some WTO members are parties. WTO currently has 153 members, of which 117 are developing countries or separate customs territories. The Head Quarters of WTO is at Geneva (Switzerland) and the official languages are English, French and Spanish.

India has achieved a commendable position of being the highest milk producing country in the world. Nearly 110 million tons of milk per annum is contributed by small and marginal farmers having 2-3 milch animals which are scattered in lakhs of villages across the length and breath of India. The poor socio-economic conditions are serious constraints in producing raw milk of good quality. The quality of milk is further deteriorated during subsequent handling and transportation. Milk being a product of biological origin, is extremely vulnerable to attack by microbes. It is also a good vehicle for additives and adulterants without any apparent changes in its appearance. Thus, milk is susceptible to several post-secretion changes, some natural and some man-made.

Indian dairy industry faces a mammoth task to meet the world quality standards, particularly in the present context of globalization and increasing quality conscious consumers. In view of the highly perishable nature of milk soon after it is secreted, it is important to monitor its quality by having a firmly installed quality assurance programme along the entire production-to-supply chain. This can be possible with application of sensitive, accurate and rapid methodologies as a tool in quality assurance programmes.

Quality comprises of several attributes ranging from physical, chemical, technological and bacteriological through nutritional to aesthetic. All dairy plants have a quality assurance laboratory (Fig. 8.1) and usually follow chemical quality control with the intention of payments to contractors/producers, processing of milk and meeting mandatory requirements for end products. Quality is judged both by objective and subjective tests.

Cleaning and sanitisation are the two processes employed in dairy industry to ensure hygiene and product safety. The safety of milk and milk products is a very important aspect and every attempt should be made, during processing, to minimize contamination through handling and processing equipments. The accumulated dried milk solids (milk stones) consist largely of calcium phosphate, milk proteins (precipitated, coagulated and baked on by heat) and insoluble calcium salts from water and washing detergents. The surface can also contain biofilms, which are formed by the incorporation of bacteria into the accumulated inorganic and organic materials that attach to most surfaces. With time and in the presence of nutrients, a biofilm and the bacteria within the biofilm will grow and become strongly attached to the surface. The removal of dairy soil, milk stones as well biofilms is the prime objective of the cleaning process. International Dairy Federation (IDF) defines a clean surface as one which is free from residual film or soil that will not contaminate the food products coming in contact with it.

While cleaning refers to the removal of soil from the surface of the equipment, sanitisation implies destruction of all pathogenic and almost all non-pathogenic organisms. Cleaning and sanitisation are complimentary processes. Either of the processes alone will not achieve the desired result, which is to leave the surface as free as possible from soil and viable organisms. In actual practice cleaning and sanitisation overlap to some extent, as during cleaning a high proportion of bacteria are destroyed and others get removed in the detergent solution. Inadequate or faulty cleaning and sanitisation can have serious consequences, as milk is a prefect nutrient in which bacteria can multiply. A thorough understanding of the cleaning methods is, therefore, necessary for economic production of high quality food products.

Packaging is a tool that is used to contain the product, protect the product from environmental hazards and help in marketing the product. Examples of ideal natural packaging systems are that of a banana, orange, coconut and egg, where the packaging is provided by nature. The major step forward in the food processing arena has been the ability to protect and preserve products with packaging and hence ensuring the availability of fresh and processed products out of season and over long distances in various forms. Milk is a highly perishable product and is not uniformly available round the year to the whole country due to geographical and genetic variations. If dairy products are to be available all the year round the country, irrespective of the season and area, it must be presented in packages that are convenient to purchase and use.

Packaging has additional responsibilities of providing convenience, safety and facilitating, besides handling, storage and distribution of products. It should prevent spoilage of food by microbial or insect attack. It also preserves the quality and nutritive value of many foods by the exclusion of oxygen and the control of moisture loss or gain. It increases the shelf-life and ensures longer availability and contributes to the product image through structural and graphic design. Product information is also given out through the medium of labeling, which acts as a tool for marketing and advertising.

Milk, as secreted in the udder of a healthy animal is practically sterile, but during its transit to the processing plant, becomes heavily contaminated with a variety of micro-organisms. These may be responsible for spoilage of milk or for causing diseases in animals and human beings. It thus becomes imperative that adequate heat treatment is given to milk to destroy these micro-organisms, thus increasing the shelf-life of milk as well as making it safe. Varied heat treatments offer the potential of producing different kinds of processed milk to satisfy the needs of the consumer. To cater to the ever-increasing demand of consumers, several varieties of processed milk are available in the market, some of which are discussed below.

5.1. Pasteurised Milk

Pasteurisation was named after the renowned French scientist Louis Pasteur, who discovered that spoilage organisms could be inactivated in wine by applying heat at temperatures below its boiling point. The process was later applied to milk and remains the most important operation in the processing of milk.

It is the process by which every particle of milk is heated to such temperature-time combinations (usually to 63°C for not less than 30 minutes or to 72°C for not less than 15 seconds) and promptly cooled to 4°C or below so as to destroy any harmful bacteria that may be present without affecting flavour and food value. Pasteurisation does not involve the use of any additives. Apart from making milk safe to drink, pasteurisation increases the length of time it can be kept before it spoils. The nutrient losses due to pasteurisation are so small, that they are considered insignificant.

Milk, on reception at the dairy factory is subjected to various unit operations on its way to product manufacture. Processing is applied as a means to convert liquid milk into products or to render the milk (and products) safe from harmful organisms. The basic processing operations to which milk is subjected at processing units have been described in this chapter. The common processing operations employed are depicted in Fig. 4.1. Several of these operations are routine compulsory processes common to all dairies, while certain others are undertaken for specialized purposes in some dairies.

4.1. Filtration and Clarification

At the time of milking various foreign materials such as dirt, feed, manure, dandruff, hair, flies, dust particles, worn out cells, cell debris and many other undesirable substances may find their way into milk. The process of removal of this extraneous matter (solid particles of higher density than that of milk) is called filtration or clarification. This can be achieved either by simple filtration through specially woven filter cloth or continuous process of centrifugal clarification that helps