eChapters

Lipids are a class of compounds that are defined by how they are isolated, rather than by their composition. Lipids are molecules that can be extracted from plants and animals by low polarity solvents such as ether, chloroform, or even acetone. They are not appreciably soluble in water. Fats and the fatty acids from which they are made belong to this group as do oils, waxes and steroids. Hydrolyzable lipids are those that contain a functional group that will react with water. The functional group is usually an ester and the list of compounds includes neutral fats, waxes, phospholipids, and glycolipids. Non- hydrolyzable lipids lack such functional groups and include steroids and fat-soluble vitamins (e.g. A, D, E, and K).

Fats and oils are composed of triacylglycerols. These are compounds prepared by the union of glycerol (1,2, 3-tri- hydroxypropane) and 3 fatty acids to form a triester. Fats and oils belong to a group of biological substances called lipids. Lipids are biological chemicals that do not dissolve in water. They serve a variety of functions in organisms, such as regulatory messengers (hormones), structural components of membranes, and as energy storehouses. Fats and oils generally function in the latter capacity. Fats differ from oils only in that they are solid at room temperature, while oils are liquid. Fats and oils share a common molecular structure. The fats and oils contain three ester functional groups. Fats and oils are esters of the tri- alcohol, glycerol (or glycerine). Therefore, fats and oils are commonly called triglycerides, although a more accurate name is triacylglycerols. Triglyceride molecules contain mostly carbon and hydrogen atoms, with only six oxygen atoms per molecule. This means that fats and oils are highly reduced (un-oxidized). Oils are particularly common in seeds, where the stored energy helps seedlings during germination, until they can exploit solar energy through photosynthesis. Fatty acids contain an even number of carbon atoms, from 4 to 36, bonded in an unbranched chain. Most of the bonds between carbon atoms are single bonds. If all of these bonds are single bonds, the fatty acid is said to be saturated, because the number of atoms attached to each carbon atom is the maximum of four. If some of the bonds between carbon atoms are double bonds, then the fatty acid is unsaturated. When there is only one double bond, it is usually between the 9th and 10th carbon atom in the chain, where the carbon atom attached to the oxygen atoms is counted as the first carbon atom. If there is a second double bond, it usually occurs between the 12th and 13th carbon atoms, while a third is usually between the 15th and 16th.

1. INTRODUCTION

Proteins are polymers of amino acids. Twenty different types of amino acids occur naturally in proteins. Proteins differ from each other according to the type, number and sequence of amino acids that make up the polypeptide backbone. Proteins are the important constituents of foods for a number of reasons. They are a major source of energy, as well as containing essential amino-acids, like lysine, tryptophan, methionine, leucine, isoleucine and valine which are essential to human health, but which the body cannot synthesize. Proteins are also the major structural components of many natural foods, often determining their overall texture, e.g., tenderness of meat or fish products. Isolated proteins are often used in foods as ingredients because of their unique functional properties, i.e., their ability to provide desirable appearance, texture or stability.

Proteins are complex organic molecules made up of carbon, hydrogen, oxygen, and nitrogen. Most proteins also contain sulphur and phosphorus and also play an important role in food preparation. The final quality of many food products are influenced by how the proteins are treated while food is being prepared.

Food is composed of three main constituents viz; carbohydrates, proteins and fats and their derivatives. In addition to these constituents, inorganic mineral elements and diverse organic compounds like vitamins, pigments, flavouring compounds, enzymes, and acids are also present. Carbohydrates, proteins, fats and vitamins are organic in nature. The percentage of water is large in certain foods. The variation in structure, texture, colour, flavour and nutritive value is because of the varying proportions and arrangements of these constituents.

Carbohydrates are important in foods as a major source of energy, to impart crucial textural properties, and as dietary fiber which influences physiological processes. Digestible carbohydrates, which are converted into monosaccharides, which are absorbed, provide metabolic energy. Carbohydrates account for more than 70% of the caloric value of the human diet. It is recommended that all persons should limit calories from fat to not more than 30% and that most of the carbohydrate calories should come from starch. Non-digestible polysaccharides (all other than starch) comprise the major portion of dietary fiber.

1. TERMS RELATED WITH BROWNING

1. INTRODUCTION

Quality, i.e. the degree of excellence or superiority, is a combination of attributes, properties, or characteristics that each commodity value in of human food. The relative importance of each quality component depends upon the commodity and its intended use (e.g. fresh or processed) and varies among producers, handlers, and consumers. Appearance of quality, firmness and shelf-life are important from the point of view of wholesale and retail marketers. Consumers judge quality of fresh fruits and vegetables on the basis of appearance and firmness, flavour (eating) quality of the product. Consumers are also concerned about the nutritional quality and safety of fresh fruit and vegetables.

1. FRUIT CROPS

1.1 Physiological Disorders

A wide variety of physiological disorders are found in apple fruit, but the susceptibility varies with variety, pre-harvest factors and post harvest conditions. Disorders can be considered in three categories:

1. Disorders that develop only on the tree: Most important is watercore in which intercellular air spaces in the core and cortical tissues become filled with liquid, Presence of watercore in fruit at harvest creates problems in certain varieties such as ‘Delicious’ because fruit with moderate or severe watercore can develop breakdown during storage.
2. Disorders that develop on the tree and during storage: Bitter pit is a disorder characterized by development of discrete pitting of the cortical flesh. Rapid cooling, CA storage and application of postharvest calcium drenches may be able to reduce its occurrence.
3. Disorders that develop during storage: Senescent breakdown disorders, chilling disorders and disorders associated with inappropriate atmospheres during storage are common disorders. The most common disorders associated with temperature and atmospheres are superficial scald, soft scald, low temperature breakdown, brown core, internal browning, low O2 injury, and high CO2 injury.

I. POST HARVEST DISEASES

A. Post-Harvest Diseases of Fruits

1. INTRODUCTION

Grading and packing of fruits ensure the safe transportation from the farm to the storage and consumer centre, while reducing the damage during transportation. The properly graded fruits should be packed in such a way that they do not collide with each other during transportation. Throughout the entire handling system, packaging can be both an aid and hindrance to obtaining maximum storage life and quality. Before the fruit is packed in a suitable container/package it is graded according to the standard grades accepted in the market. Packaging is one of the important components after grading during the handling of fruits. Packaging is meant to protect the commodity by immobilizing and cushioning it, but temperature management can be made more difficult if packing material block ventilation holes. Packing material can act as vapour barriers and helps in maintaining higher relative humidity within the package. Packaging material such as trays, cups, wraps, liners and pads may be added to help immobilize the produce. A wide variety of containers such as wooden boxes, plastic crates, corrugated fiberboard boxes are important package used in the transportation and distribution of fruits in most of the developing countries.

1. INTRODUCTION

Harvesting is the process of gathering the crops from the fields at maturity. The harvesting of a commodity means the end of the growing season for a particular crop. Harvesting is the most labour-intensive activity of the growing season. Harvesting in general includes an immediate post-harvest handling, the actions taken immediately after removing the crop are pre-cooling, sorting, cleaning, packaging and up to the point of on-farm processing or shipping to the wholesaler or consumer.

Harvest timing is a critical decision that balances the likely weather conditions with the degree of crop maturity. Weather conditions such as frost, rain and unseasonably warm or cold periods can affect yield and quality. These conditions can be avoided by harvesting the commodities earlier than the harvest date, but this may result in poor yield and quality. On the other hand, delayed harvesting also results in a better yield, but increases the risk of weather problems. Thus, proper harvesting timings of horticultural commodities often play an important role.

Assessment of harvesting time is a critical time for growers of fruit and vegetables to decide the accurate period of crop harvesting. Fresh produce is normally ready for harvest when it has developed to the ideal condition for consumption and the condition is usually referred to as harvest maturity. Harvest maturity thus refers to the time when the “fruit” is ready to harvest and the time required to reach market. The harvesting should be done earlier than its ideal maturity for proper marketing.

Most growers decide harvesting time for different commodities by looking and sampling. Judgments are based on colour, size and shape (Sight); texture, hardness or softness (Touch); odour/aroma (Smell); sweetness, sourness, bitterness (Taste) etc. Experience is the best guide for this kind of assessment. Harvest maturity can readily be observed in some fruit crops but it can be more difficult in case of some fruits like avocados remain unripe off the tree after maturity.

1. MATURITY INDICES

Maturity indices (right time of harvesting) are quality factors that give clues as to when a product should be harvested to allow marketing flexibility and ensure the attainment of minimum acceptable quality to the user. It also refers to the set of criteria used to determine the stage of maturity for harvesting the horticultural crops. Commodities harvested either pre-mature or too late are more susceptible to postharvest physiological disorders, diseases and have poor shelf life than harvested at right stage of maturity. The pickers/ handlers are trained in methods of identifying produce that is ready for harvest. However, optimum harvesting stages depends upon type of produce and their final use. Horticultural crops may be harvested at two main maturity levels i.e., physiological maturity and commercial or horticultural maturity. Therefore, the proper stage/maturity indices for harvesting of all horticultural crops should be identified for their implementation during harvesting. Horticultural maturity in relation to developmental stages of the plants is depicted in Fig 3.1.

I. INTRODUCTION

The fruits and vegetables we eat and flowers and ornamentals we enjoy are biological entities. They breath, produce heat, perspire, are easily damaged, get diseases and finally die. These carry on processes characteristics of all living things before or after harvest to perform the metabolic activities:

1. to maintain cellular organization
2. to transport metabolites around the tissue and
3. to maintain membrane permeability.

I. INTRODUCTION

Horticultural crops include fruits, vegetables, flowers, plantation crops, spices, and medicinal and aromatic plants have emerged as a major economic activity in India. It contributes 30% GDP from 11.73 % of its arable land area. Horticulture crops cover over 23.4 million hectares of area, which is approximately 12.7% of the total gross cropped area of the country and contributes 18-20% of the gross value of India’s agricultural output (NHB, 2013). India is the world’s second largest fruit and vegetable producing country accounting for 77.7 million metric tonnes of fruit and 159.5m M tonnes of vegetables (NHB, 2013). Besides, about 5.66 million tonnes of loose flowers, spices, mushroom and aromatic plants are also produced. The country produces 41% of world mangoes, 23% banana, 24% cashew nut, 36% green peas, 10% onion and 30% cauliflower and accounts for 12% of world fruit and 13.25% of vegetable production (NHB, 2013). Owing to wide diversity of agro climatic conditions, almost all types of temperate (apple, peach, plum, apricot, cherries and nuts), subtropical (mango, guava, papaya, etc), tropical (banana, pineapple etc), arid fruit (ber and aonla), plantation crops (coconut, cashewnut and arecanut) and diverse variety of vegetables are grown in India. The export of fresh fruit and vegetables from India in 2006-07 was estimated at 9.84 Lakh tonnes valued at Rs 2411.70 crores. Mango, grapes, apple, onion, potato, green vegetables like okra, bitter gourd and green chillies were the major items of export. Similarly, India exported 5.97 Lakh tonnes of processed foods comprising of mango pulp, juices, concentrates, dried and processed vegetables, pickle and chutney, alcoholic and non-alcoholic beverages worth Rs 2818.1 crores (APEDA, 2012) (Table 1 to 3).

Genetically modified organisms (GMOs) can be defined as organisms in which the genetic material (DNA) has been altered in a way that does not occur naturally. The technology is often called “modern biotechnology” or “gene technology”, sometimes also “recombinant DNA technology” or “genetic engineering”. It allows selected individual genes to be transferred from one organism into another, also between non-related species. Genetically modified (GM) foods are foods derived from genetically modified animals and marines. Genetically modified animals and marines are those in which specific changes introduced into their DNA by genetic engineering using a process of either Cisgenesis or Transgenesis. These techniques are much more precise than mutagenesis where animals and marines are exposed to radiation or chemicals to create a non-specific but stable change. Other techniques by which food animals can be modified are selective breeding and somaclonal variation. By this means desired quality of meat, egg and other animal products can be produced. But it is a common thinking that foods derived from genetically modified animals and marines are far from safe. They are likely to be contaminated by potent vaccines, immune regulators and growth hormones, as well as nucleic acids, viruses and bacteria that have the potential to create pathogens and to trigger cancer.

Organic meat food products are choice products for health conscious people. These are the products produced mainly in most natural way without using fertilizers, pesticides and growth regulators in their feed and fodders. In addition, meat animals are also reared without growth hormones, antibiotics drugs etc. and grazing of the animals is a prerequisite in organic farming system.

The term organic farming was first time used by Lord Northbourne. The term organic farming was derived from his concept of “the farm as organism”. It is a holistic, ecologically balanced approach to farming. In 1991, the European Commission formulated the first government system to regulate organic labelling. In India, standards for organic agriculture were announced in May 2001 and the National Programme on Organic Production (NPOP) is administered under the Ministry of Commerce. The concept of organic meat food products has been emphasized now a day due to animal welfare point of view, consumer’s conscious ness, less residue level of chemicals, antibiotics and drugs, Bovine spongiform encephalopathy (BSE), Foot and mouth disease (FMD), genetically modified food etc.

Organic meat food products as a whole are dependent on the life stages of the livestock like its origin, feeding, housing, health, breeding, transportation and slaughter. The other factors accounting for organic foods are its production, harvesting, preservation and processing. Inspite of low growth rate of organic red meat globally, growth in dairy, egg and poultry is increasing day by day. At present 1.2 million hectares (0.6%) of Indian land is producing organic products (Willer and Kelcher, 2011).

Meat and meat products industry is a sunrise industry in India having huge potential for upliftment of agricultural economy. India is the second largest food producer in world but the contribution of meat industry is still confined to localized handlers. So to uplift industry basic infrastructure, food chains, food security and safety along with standards and laws formulation and their implementations is today’s need. Standards are carefully drawn specifications with respect to a food product. These standards are mainly of three types i.e. government, trade and research standards. Government standards are formulated by the government of India or state government and also have the power to implement these standards while trade standards are implied by the individual company. Research standards are formulated on the basis of comparative study of the products by the researchers. Laws are the legislations enforced by the organisations either government or by autonomous bodies made under the constitutional acts of the country. At present numerous standards and laws are in existence in individual country or at international level. The need is to harmonize them as per the industry and trade requirement.

Domestic Organizations Involved in Standards and Laws Formulation

For the formulation, enforcement and control of standards and legislations at domestic level various organizations are of prime value. Some of these are:

Eggs are considered as Nature’s original functional food because they are abundant source of nutrients like vitamins and minerals. It contains valuable nutrients from the high-quality protein to significant levels of beneficial vitamins, antioxidants and other healthful compounds. The protein of eggs is considered as highest quality protein as compared to other animal protein sources which is readily available and most inexpensive. Eggs are good source of all well balanced nutrients for persons of all age groups. Egg is a unique combination nutrient like it is rich in protein and low in calorie. The nutrients concentration in eggs is dependent on breed, strain, species, feed, age, season, storage and processing methods.

The nutritional value of eggs lies chiefly in their proteins of good biological value; an average-sized egg (60 g) provides approximately 7 g of proteins. These proteins are rich in essential amino acids with a very good balance between these amino acids. So the egg protein can be regarded as a reference protein. On comparison we can say that 2 eggs provide as much protein as 100 g of meat or 100 g of fish. The energy value for an average egg (60 g) is approximately 376 Kj (90 kcal). The lipid content is 7 g, most of these lipids being contained in the yolk. Among the total fatty acids 2/3^rd of these are unsaturated. Egg also contains 180 mg of cholesterol and rich in vitamins (A, D, E) and trace elements (iron and zinc).

Sensory evaluation is a scientific method of evaluating foods including meat products that applies principles of experimental design and statistical analysis through the use of human senses like sight, smell, taste, touch and hearing. It is also called organoleptic evaluation in which we measure, analyse and interpret reactions to those characteristics of materials as they are perceived by the human senses. These attributes can be perceived well by the human sense organs as compared to instruments available for this purpose. It is a fact that no single instrument is able to assess all the attributes of meat products. With the help of these instruments we can very well evaluate the single quality attribute of meat product i.e. shear force instrument or penetrometer is good for knowing the texture and refractometer is for colour interpretation.

Physico-chemical and microbiological quality of meat and aquatic food and food products gives its overall safety and quality status as a food. The physico-chemical and microbiological qualities of raw material have great importance on the product development. It also affects the shelf life of the raw material as well as final product.

Fresh meat is a type of meat which has not been subjected to any processing whereas raw meat is a fresh meat which has undergone freezing. The qualities of fresh meat are important as far as merchandiser, purchaser and consumers are concerned and it is also important for adaptability in further processing. The important quality parameters of fresh meat are:

Formulation of meat and sea food products requires various ingredients which are commonly known as food additives. Food additives are those non-meat ingredients which are used to enhance colour, flavour, aroma and texture of the meat and sea food products. These food products can fulfil the demand of modern consumers. As per the definition of Food and Drug Administration (FDA) food additives are those substance which are used to provide a technical effect in foods. The use of food additives has become more prominent in recent years, due to the increased production of prepared, processed, and convenience foods. Additives are used for flavour and appeal, food preparation and processing, freshness, and safety. These additives can be classified as curing ingredients, extenders and binders, flavour enhancers and other additives. For the formulation of different products both raw materials and ingredients should be of food grade and sound hygienic strength. In the starting of this chapter we will discuss about ingredients used then the specific formulations will be discussed for better understanding of meat and sea food processing.

Curing Ingredients

Curing agents such as salt, phosphate, sugars, nitrite and nitrate, sodium ascorbate and erythorbate etc. have traditionally been used in various meat formulations from long back. The details of these ingredients have already been discussed in chapter-8 of this book. So we will try to discuss other ingredients which are relevant for meat and sea food products other than these ingredients. Cure accelerators such as ascorbates and erythorbates are used to speed the curing process. They also stabilize the colour of the final product. The examples are ascorbic acid, erythorbic acid, sodium erythorbate, citric acid, sodium citrate, sodium acid pyrophosphate, glucono delta lactone (GDL) etc. Glucono-delta-lactone (GDL) acts as a curing accelerator in meat and meat products. It is permissible up to 1% in sausages and up to this level it lowers the pH about 0.5 thus inhibits the growth of spoilage micro-organisms. GDL also facilitate the cured colour development.

Food packaging is an essential technique for preserving food quality and minimizing food wastage. It is a scientific technique of containing food against physical, chemical and microbiological contaminants. In addition package also display the product in most appropriate manner and provide product information to the consumers while at the same time allowing convenient handling and efficient distribution. The packaging of meat and meat products are particularly important because meat is highly nutritious food and provides good medium for the growth of micro-organisms. Meat and meat products are also susceptible to bacterial growth due to their high water activity. Exposure of meat and meat products on atmospheric temperature and sunlight leads to various types of deteriorative changes. For example when cut meat surfaces exposed to ambient air provide excellent breeding grounds for most bacteria. Minced meat is even more at risk due to the large exposed surface area. Packaging provides protection of food against external and internal factors but once food gets deteriorated it can not be controlled by packaging. For this reason rigorous hygiene in all processing and pre-packaging steps is vital for packaging of perishable food items like meat and meat products.