eChapters

1. INTRODUCTION

Amongst the common fermentations employed in food are alcoholic, lactic acid and acetic acid. Lactic acid fermentation is a potent tool of biopreservation of foods by the use of biological means i.e. microorganisms or their metabolites having antimicrobial action. It deals with the extension of storage life and increased safety of edible products by employing natural microflora or their antimicrobial products such as in food fermentation. Though many problems in food processing and microbiological safety of food have diminished, yet these are certainly not eliminated altogether. These include the likelihood of food-related illness and product spoilage in industrialized countries. The increasing consumption of pre-cooked food, prone to temperature abuse, are among the main causes of this scenario. The bacterial pathogens that account for many of these foodborne illness cases include Salmonella, Compylobacter jejuni, Escherichia coli 0157:H7, Listeria monocytogenes, Staphylococcus aureus, and Clostridium botulinum. Until now, approaches to seek improved food safety had relied heavily to find out more efficient chemical preservatives or on the application of more drastic physical treatments (e.g. high temperatures) of food processing. Nevertheless, these types of solutions do have some drawbacks also: the proven toxicity of some of the commonest used chemical preservatives (e.g. nitrites), the alteration of the sensory and nutritional properties of foods (thermal processing) especially recent consumer trends in purchasing and consumption, with demands for safe but minimally processed products without additives.

1. INTRODUCTION

According to the Food, Drug and Cosmetic Act (1968) food is “an article that provides taste, aroma or nutritive value”. The term 'health food' is generally used to describe foods that are considered to be beneficial to health beyond a normal diet required for human nutrition. Though, the term is not precisely defined by any regulatory agencies such as the US Food and Drug Administration (FDA) however, “Health food” is sometimes used as an umbrella term encompassing natural foods, organic foods, whole foods, and sometimes dietary supplements or may also refer to functional foods. The use of foods for promoting health and relieving symptoms is as old as the practice of phyto-medicine for treating or preventing various types of illness and have been documented in Hippocratic and Vedic texts and the canons of Traditional Chinese Medicine. Therefore, “Let food be thy medicine and medicine be thy food”, quoted by Hippocrates about 2,500 years ago, is certainly the tenet of today which is receiving overwhelming interest. In the recent years, rapid urbanization, industrialization, increase in per capita income etc. in developing countries like India, have resulted in dramatic lifestyle changes leading to lifestyle related diseases like coronary heart disease, obesity, diabetes, cancer and hypertension. The transition from a traditional to modern lifestyle, consumption of diets rich in fat and calories combined with a high level of mental stress has compounded the problem further.

1. INTRODUCTION

The growing demand of consumers for fresh, safe, chemical, additive or preservative free and minimally processed foods has compelled the food scientists and technologists to develop many non-thermal food processing technologies which cause minimum nutritional and sensory qualities impairment in the processed foods. In this endeavour, consumers prefer minimally or non-thermally processed foods rather than the thermally processed one. Today, non-thermal technologies like High Pulse Electric Field (HPEF) processing, High Hydrostatic Pressure (HHP) processing or Hight Pressure Processing (HPP) food irradiation, ultraviolet light, ultra sound, arc discharge, oscillating magnetic fields, light pulses, plasma, chemicals (ozone, carbon dioxide, argon), and the combined methods of these technologies are the major areas of research in the process and food engineering in order to find their suitability for processing of various food products.

1. INTRODUCTION

Mushrooms are edible fungi of commercial importance and their cultivation has emerged as a promising agro-based land-independent enterprise. There are about 20 varieties of mushrooms being cultivated throughout the world for food. In India, only white button mushroom (Agaricus bisporus J.E. Lange Imbach), oyster mushroom (Pleurotus spp. [Fr.] P. Kumm) and paddy straw mushroom (Volvariella volvacea [Bul.] Singer) are grown commercially. Of these, white button mushroom contributes ~90% of the total production. Mushrooms have been recognized as an alternate source of good quality protein and produce the highest quantity of protein per unit area from agro-wastes. Besides, they provide potentiality for generating employment, improving economic status of growers, help in checking pollution and earn foreign exchange.

Out of the total production about 45% of mushrooms produced are consumed in the fresh form while the other 55% are processed, with 5% in dehydrated form and 50% in canned form. This is because their shelf-life in the fresh form is very short and hence mushrooms are traded in the world market mostly in the processed form. Fruiting bodies (reproductive phase) of Agaricus are appreciated not only for texture and flavour but also for their chemical and nutritional characteristics.

1. INTRODUCTION

In recent years, fruit and vegetable consumption has grown rapidly. Today’s society is characterized by an increasing health consciousness and growing interest in the role of food for maintaining and improving human well-being and consumer health. Due to consumer’s profile being ‘‘rich in cash/poor in time’’, there is a demand for ready-to-eat products As a result of changes in consumer attitudes, the market of minimally processed (MP) fruits and vegetables has grown rapidly. In addition to their nutritional and sensory properties, foods are currently recognized as active and protective agents. Among the others, minimally processed products stand out as convenient novel foods that fit the many needs of a modern lifestyle as they combine technical content with an innovative food concept. Fresh fruits and vegetables are an essential component of a healthy diet, able to decrease the risk of cardiovascular diseases and cancer. Their consumption has continued to grow rapidly, linked to the increased public awareness of their health benefits.

Minimal Processing’ (MP) is a concept describing approaches to food safety and preservation that are designed to retain the natural and as-fresh properties of foods. Minimally processed fruits are new forms of product marketing, intended to meet the consumers’ desires for convenience and fresh-like quality. Minimally processed fruits and vegetables, also called ready-to-use, fresh-cut or pre-cut produce, are raw fruits and vegetables that have been washed, peeled, sliced, chopped or shredded into 100% usable product that is bagged or packaged to offer to the consumers high nutrition, convenience, and flavour while still maintaining its freshness.

1. INTRODUCTION

Wild pomegranate (Punica granatum L.) is one of those fruits which has got a great economic importance. The name “pomegranate”is derived from Latin pomum (apple) and granatus (seeded) which has influenced the common name for pomegranate in many languages (like in German Granatapfel, seeded apple). It has widely been cultivated throughout India and drier parts of South-East Asia, Malaysia, the East Indies and tropical Africa. The most important growing countries of pomegranate are are Egypt, China, Afghanistan, Pakistan, Bangladesh, Iran, Iraq, India, Mayamar and Saudi Arabia. In India, it grows in the vast tract of the hill slopes of Jammu and Kashmir and Himachal Pradesh. One of the important centers of wild pomegranate, in Himachal Pradesh is Darlaghat, located about 50 Km from Shimla. The fruit provides substantial income to the farmers particularly where it is found growing wild such as in Mandi, Kullu, Sirmour, Solan, Shimla, and Chamba districts of Himachal Pradesh. It is found very common and gregarious in drier and sub-marginal land of mid hill regions of outer Himalayas at an elevation of 900-1800 m above mean sea level (a.m.s.l). Wild pomegranate is considered as one of the commercial fruits of Himachal Pradesh in the form of dried arils popularly known as “Anardana”. Besides Anardana, other value added products can also be prepared from this fruit as detailed in this chapter.

1. INTRODUCTION

India is blessed with all types of vegetation because of the diversified climatic and physiographic factors like tropical, subtropical, temperate and alpine. Due to its wide ranging environmental regimes and diverse biological communities, it is one of the world’s 12 “Mega diversity” nations. Out of nearly 425 families of flowering plants in the world, 328 families with 21,000 species are found in India. Further, in India about 20.64 % area is under forest where various species of trees are found, depending upon the climatic conditions.

There are about 29 species of pine which produce edible nuts and utilized at least by indigenous tribal culture in the world. Most of these nut bearing pines are haploxilon (soft) pines, although several species are of diploxilon (hard) pine group. Spain is the largest producer of Pinus pinea and China is the largest producer and exporter of Pinus koriences and Pinus sibrica nuts. Some of the famous edible pine nut species are listed in Table 1. Chilgoza (P. gerardiana Wall.), commonly known as ‘chilgoza’ or ‘Neoza’ is a member of genus Pinus that maintains a very unique position of being an integral part of the vibrant, but fragile ecosystems of the great Himalayas in the Indian sub-continent. The chilgoza pine is the only pine which is of immense social forestry importance. The earning for the bread and butter of most of tribals in HP is from the chilgoza nuts. Further, it also forms an important part of their diet as well as an item essential for some social obligations. Tribals are still adopting the age old practices for chilgoza nut extraction and further their selling to the agents at throw away prices during peak season of nuts.

1. INTRODUCTION

Indians are known to prepare preserves from the ancient times. They were also familiar with ther therapeutic values associated with the preserves. Besides, candies, reathers and toffees are the other food products prepared and consumed. In this chapter, the methods of their preparation are described.

2. PRESERVES

A preserve is made from properly mature fruit, by cooking it whole or in the form of large pieces in heavy sugar syrup, till it becomes tender and transparent. In its preparation not less than 45Kg of the fruit are used for every 55Kg of sugar, and cooking is continued till a concentration of at least 68 per cent of TSS (Total Soluble Solids) is reached.

Freshly made preserves are wholesome and have an attractive appearance. When they are stored for a long period, their natural colour and flavour deteriorates on account of oxidative changes. They should therefore, be made only during the season, unless there should be adequate facilities to keep the fruits so that they are available in the off-season also.

1. INTRODUCTION

Juices and pulps are produced from a wide variety of fruits and vegetables around the world, while some medicinal plants and herbs are also used for preparation of extract of beneficial bioactive compounds. These juices and extracts contain very high proportions (upto 75-90%) of water. Due to their seasonal nature, these products can not be produced round the year in various parts of the world. Preservation, storage, transportation and marketing of single strength juices, pulps and extracts is not at all economical due to the presence of large quantities of water. Under these circumstances, the technology of concentration offers many advantages.

In chemistry, concentration, as a state, may be defined as “the abundance of a constituent divided by the total volume of a mixture” and can be mathematically explained in four types i.e. mass concentration, volume concentration, molar concentration and number concentration. Generally, the term concentration can be applied to any mixture (solid or liquid) but most frequently it refers to the presence of solutes in solvents. Mass concentration is defined as mass/volume (m/V) of mixture and represented in kg/m³, volume concentration as volume of a constituent divided by the volume of all constituents of the mixture (v/V) and represented in m³/m³, molar concentration as moles of a constituent divided by the volume of all constituents of the mixture (n/V) and represented in mol/m³, while, number concentration is defined as the number of entities of a constituent in a mixture divided by the volume of the mixture (N/V) represented in 1/m³.

In food technology or fruit juice industry in particular, concentration refers to a process of separation of water (or any other solvent) from the solids of the pulp, juice, extract by making use of any of the three basic methods i.e. evaporation, freezing and membrane technology. Pulps, juices and extracts are the basic material used for preparation of various types of processed products. But due to their bulk and presence of large quantities of water they are difficult to store and transport. Concentration of juices, not only provides microbial stability, but also reduces the costs of packaging, transportation and storage by reducing the bulk of the material. Concentrated juice, contains far less water than normal, or “not-from-concentrate” forms of juice.

1. INTRODUCTION

Preservation of foods by drying is perhaps the oldest method known to mankind. Drying is a thermo-physical action and its principles are governed by heat and mass transfer laws inside and outside the product. The weight of the product is reduced to the extent of 1/4^th to 1/9^th of its original fresh weight. Drying of foods and biological products is a widely applied process for different purposes such as increasing the shelf-life, reducing packaging costs, lowering shipping wastes, encapsulating flavours, making food available during off-season, adding value by changing the phase structure of the native material and maintaining nutritional value. Drying or dehydration of fruits and vegetables can be accomplished with low capital while maintaining high quality and obtaining less perishable food products.

1. INTRODUCTION

Thermal processing means preservation by application of heat. It involves heating of foods in hermetically sealed containers for a specific time at a specific temperature to eliminate the microbial pathogens that endanger public health and that micro-organisms that deteriorate food during storage. The credit for invention of thermal processing (Canning) goes to a French Confectioner, Nichola Appert. The application of heat is an important method of preserving foods and is also a means of developing texture, flavour and colour in some foods.

1. INTRODUCTION

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

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

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

1. INTRODUCTION

The Green Revolution and subsequent efforts through the application of science and technology for increasing food production in India, have brought self-reliance in food. The imputs given by the Government, State Agricultural Universities, State Departments of Agriculture and other organizations through the evolution and introduction of numerous hybrid varieties of fruits and vegetables and improved management practices have resulted in increased food production. However, the nation still faces the problem of the use of improper methods for the storage of food stuffs and their preservation leading to great wastage of the food produced. So, there is a urgent need for the application of food preservation and processing methods.

Food preservation involves all the processes used to maintain foods with the desired properties or nature for longer time. The process is has moved from an art to a highly interdisciplinary science. Food safety now the first priority of the food production and preservation industry, incorporating innovations and sustainability. The preservation and processing of food however, is not as simple or straight forward as it was in the past. A number of new preservation techniques have been developed to satisfy the current demands of economic preservation and consumer satisfaction in nutritional and sensory aspects, convenience, and safety, absence of chemical preservatives, and environmental safety. Understanding the effects of each preservation method on food has therefore, become critical in all the aspects.

1. INTRODUCTION

In the changing global scenario, food nutrition, health care and livelihood security are the matter of great concern to human, social and economic development. Fruits and vegetables is one of the most important and fast growing sub-sectors as they form an indispensable part of healthy diet. The current trend shows that dietary habits are changing with increasing income, from cereal based diet to nutritious diet. Resultantly, there is a growing demand for horticultural produce.

World production of vegetables amounts to 1169.45 million tonnes, while that of fruits is 689.39 million tonnes (NHB, 2017). India is the second major producer of fruits and vegetables in the world and ranks next to China. India produces 92.85 million tonnes of fruits from an area of 6.5 million hectares and 175.00 millions tonns of vegetables from an area of 9.2 million hectares annually. The productivity of vegetables in India is 17.6 tonnes per hectare. Potato (28.9%), tomato (11.3%), onion (10.3%) and brinjal (8.1%) are the 4 major vegetables contributing 58.6% of total vegetable production in our country. Other important vegetables are cabbage (5.4%), cauliflower (4.6%), okra (3.9%) and peas (2.4%)

1. INTRODUCTION

To over come the problem of glut of perishables and to regulate the market, storage of such commodities is a 'common' practice. Storage of fruits and vegetables also makes available these commodities in the off-season. Needless to say, storage is a powerful tool in the prevention of postharvest losses and to give remunerative prices to the farmers. The management of temperature and relative humidity are the most important factors determining storage life of horticultural produce. The natural means like ice, cold water, night temperature have been used for long time for protecting food materials from spoilage and these are still common. However, with the development of innovative technologies, it is possible to achieve optimal environments in the insulated stores. All these aspects are discribed in this chapter.

1. INTRODUCTION

Fruits and Vegetables are heighly perishable crops and have to be handled carefully after harvest. Postharvest handling of these perishables is essential to prevent the post harvest losses and maintain the quality of the fruits and vegetables. Various treatments (chemical, physical and biological agents) have been standardised and used for retaining the storage quality of different horticultural commodities. All these aspects have been discussed in this chapter.

1. INTRODUCTION

When the fruits and vegetables are ready for the intended purpose, these have to be harvested. What is meant by harvesting and how the produce is harvested, what are the harvesting methods, how these are packaged in what type of packages have been discussed in this chapter.

2. HARVESTING

Harvesting of produce at proper maturity is of paramount importance for maintaining quality during storage and marketing. When the produce is harvested immature or over-mature, it will affect the quality and storage life adversely. After the proper maturity stage has reached, the produce needs to be harvested for various markets. While harvesting, it must however, be kept in mind that all horticultural produce (with the exception of some dry fruits/nuts) is very delicate and mishandling at harvesting may lead to mechanical injury, compression injury that is irretrievable. The injury on fruits/vegetables enhances ethylene production, moisture loss and serves as an entry point for a wide range of pathogens, hence causing quick loss in quality and storability of produce. The injury caused to the produce during harvesting not only spoils the commodity but also makes it unfit for long-term storage or long-distance transportation. Proper training to the labour engaged in harvesting on what to harvest, and how to harvest and the use of proper harvesting tools can reduce considerably the postharvest losses.

1. INTRODUCTION

Every fruit or vegetable is harvested keeping in view, its intended use. At what stage it should be harvested, is indicated by the maturity index. The chapter focuses on these and postharvest quality of fruits and vegetables.

2. FRUIT MATURITY

"Maturity of a fruit can be defined as that stage at which a commodity has reached a sufficient stage of development that after harvesting and postharvest handling, its quality will be at least the minimum acceptable to the ultimate consumer”. Maturity is of two types:

1. INTRODUCTION

India produces a large variety of fruits and vegetable due to varied agro-climatic conditions. These include mango, citrus, banana, apple grapes, strawberry, pineapple, litchi, guava, papaya, plum, peach, pear apricot etc. Astonishingly, it may appear but it is a fact that postharvest losses of fruits and vegetables in India are staggering. Infact the postharvest losses of fruits and vegetables are equivalent to the annual consumption of fruits and vegetables in U.K. In this article, a focus is made on the causes of postharvest losses of fruits, overview of various techniques used to prevent the postharvest losses constrains in postharvest technology and future strategies.

1. FOOD AND ITS SIGNIFICANCE

Food is the basic necessity of all the living world and the man is no exception to this. The basic purpose of food is to provide energy for the routine body functions and protect the body from various diseases. Life cannot be sustained without adequate nourishment for a healthy and active life, diets should therefore, be planned and consumed on sound nutritional principles (Fig. 1). For want of nutritious foods, consequence is the prevalence of malnutrition. There are several diseases that are related with deficiency of nutrition food, if not consumed. Such diseases include Kwashiorkor that can develop in children consuming insufficient protein even if total calories are sufficient. Marasmus is often due to the cessation of breast feeding and the attempt to replace it with foods, inadequate in protein such as rice broth. Other nutritional diseases still found particularly in the developing world are childhood blindness (vitamin A deficiency), rickets (vitamin D deficiency), beri-beri and infantile beri-beri (inadequate thiamin intake), pellagra (inadequate niacin intake), anemia (iron deficiency), goiter (iodine deficiency), etc. To cope up with this, the diet needs to be supplemented with nutritious food components including fruits and vegetables to make it more suitable for the growth and development of body.

Out of different types of foods, the fruits and vegetables constitute an important component of the food. Horticultural crops occupy a prominent position both in the importance and production in the world. The temperate fruits and vegetables are an important part of the horticultural crops, in terms of production and role in human health. These crops assume all the more importance due to their antioxidant activity, and presence of minerals and vitamins. Both fresh and processed fruits and vegetable, their different products are consumed. They are also called as protective foods. Fruits and vegetables are major sources of important vitamins like B and C and minerals such as Ca, Fe, P and K.