eChapters

Canning : Process of preservation of various food stuffs including fruits and vegetables whole or in pieces, in sugar syrup or brine by heat processing them in hermetically sealed containers.

Jam : It is a product prepared by boiling to a suitable consistency, fruit pulp with sufficient quantity of sugar, acid and pectin so as to set and become firm enough to hold the tissues in position. About 45 parts of pulp are used with every 55 parts of sugar. The finished product should not contain less than 68 per cent total soluble solids.

Jelly : Jelly is prepared by boiling the fruit pectin extract with sugar in the presence of appropriate amounts of acid so as to set into a clear gel. A perfect jelly is transparent, devoid of haziness or any suspended material well set, but not too stiff and should have original flavour of the fruit. When cut it should retain its shape and show a smooth cut surface.

Marmalade : It is a fruit jelly like product in which slices of fruit or peel are suspended in the set gel. Mostly they are prepared from citrus fruits like oranges, lemons etc.

Pickles known to be good appetizers, aid digestion and pallate are edible products preserved and flavoured in a solution of common salt and vinegar. Spices and oil may also be added. There are a number of pickles very popular in India i.e. mango pickle, cauliflower pickle, lime and lemon pickles, ginger chilli pickle etc. But, some pickles like Sauerkraut are not very common in India but are very popular in European countries.

Essentials for Quality Product Preparation

Plant ripened red tomatoes should be selected. Yellow and green fruits on processing yield dull colour and turn brown due to oxidation.

Never use iron equipment for processing. Lycopene oxidizes and turns brown when comes in contact with iron. It also forms black compounds with the tannins present in tomatoes or the spices which are used for product preparation.

Avoid prolonged heating and cool immediately to avoid over-cooking.

Nature has made such a beautiful system that a fruit does not spoil unless its outer covering is removed and till it is there on the plant. For example banana will not spoil for long time if we do not remove its peel. Similar is the case with apple, guava, mango and many other fruits and vegetables. But as soon as the outer covering is removed the damage begins and the commodity is spoilt very soon.

Preservation is extending shelf life of fresh or processed food by using various methods and prevention or reduction of spoilage. Better the preservation, lesser the spoilage, more the spoilage poorer and inefficient is the preservation.

Therefore, in order to prevent or reduce the spoilage, we have to first identify and understand the causes of spoilage. There are chiefly 3 agencies that cause spoilage in fruits and vegetables i.e. (i) microorganisms, (ii) enzymes & chemical changes and (iii) man, animals, rodents, insects, etc. For effective preservation we have to check the growth and activity of these spoilage causing agencies. So, in order to prevent spoilage and preserve a perishable commodity for long time the following principles and methods are to be followed.

Packaging : Packaging of fruits, vegetables, flowers or any other commodity is chiefly done to assemble the produce in convenient units of different sizes, shapes & types for storage, transportation, marketing and distribution. The size of units may vary depending on the requirement e.g for retail marketing smaller units are preferred and for bulk transportation and storage, large units would be more convenient.

Why do we Require Packaging?

Imagine there is no packaging material and technology available. How we are going to transport apple, mango etc. to distant markets? Definitely as loose. Then how can we weigh or count the fruits being transported or marketed? This would be very difficult. Had there been no packaging the commodity would have suffered great physical, chemical and microbiological losses. It would have been very difficult to handle, manage, transport and market the produce as loose and unpacked. Therefore, the packaging of fresh as well as processed commodities was needed to contain, unitize and protect the produce.

Storage : It can be defined as keeping the commodity fresh or processed in safe condition with minimum of deteriorative changes for later use.

Reasons of Deterioration During Storage

Maturity Standards and Harvesting Indices

Harvesting : Harvesting is detaching a commodity from the point of its origin. This point of origin may be an above ground plant part i.e. shoot eg. apple, tomato etc. or an underground plant part eg potato, carrot, etc. or in water i.e. harvesting of fish from a pond (not to be covered in this book).

Physiological Development

Fruits and vegetables can be divided into 3 stages based n their physiological development i.e. growth, maturation and senescence.

Growth: This generally refers to cell division, enlargement and differentiation ultimately giving a particular size, weight and volume to the commodity.

Maturation: It is initiated before the ceasation of growth and lasts till the onset of senescence.

Senescence: The stage when anabolic (synthetic) processes almost terminate and catabolic (degradative) processes are initiated and speeded up causing ageing and finally death of tissues.

Ripening: Stage that begins with the last stages of maturation and lasts till the beginning (first stage) of senescence. Ripening is a very important event in the life of a plant as it transforms a physiologically mature but inedible (or not preferred to be eaten) plant part into an edible, visually and olfactorily attractive and tasty commodity. Ripening marks the completion of developmental phase and is an irrevessible event.

India, one of the largest food producer countries (I in milk production, II in fruit and vegetable production and III in food grain production at world level), possesses the potential of being the biggest with the food and agricultural sector contributing around 26 percent of the Gross Domestic Product (GDP). It is a paradox that people of the country producing such huge quantities of food including fruits, vegetables, milk, cereals grains etc. are still suffering from many nutritional deficiencies in their diet, and even in some places, the stomachs of people remain unfilled for the want of food. The credit of this would predominantly go to the poor postharvest infrastructure as well as knowhow and accessibility to the facilities. All this makes us one among those countries having largest postharvest losses. The reduction of losses occuring during food handling, processing, storage, distribution and use would be an indirect way of increasing the food production and making the country self-sufficient in nutritional requirements.

Weeds are the plants growing where and when they are not desired. They compete with crops for soil moisture, nutrients, solar radiation and space, and thus reduce crop yields. Weeds also act as alternate hosts that harbour insect pests and diseases and other microorganisms. Some weeds release poisonous substances into the soil which may be harmful to crop plants, human and livestock. Weeds reduce the quality of marketable produce and render harvesting difficult, leading to increased expenditure on labours, equipment and chemicals for their removal.

Classification of weeds

A. Based on life cycle

Annuals-Complete their life cycle in a year or in a single growing season. Based on the season they may be summer annuals and winter annuals.
Summer annual e.g, Echinochloa crusgalli

Removal of entire plants or the economic parts after maturity from the field is called harvesting. Portion that is left behind on the field is known as stubble. The economic product may be grain, seed, leaf, root or entire plant.

Time of Harvesting

If the crop is harvested early, the produce contains high moisture and more immature grains. The yields will be low due to unfilled grains. It is very difficult to store the produce as shriveled grains with high moisture are highly prone to infestation by pest. The quality of the grain as well as germination percentage is also reduced. Late harvest results in shattering of grains, germination even before harvesting in rainy season and breakage during processing. Hence harvesting during correct time is very important.

Plants may be harvested at physiological maturity or harvest maturity. Plants are said to be in physiological maturity when the translocation of the photosynthates ceases to the economic part.

The problematic areas for crop production may be soils affected with acidity, high concentration of salts, water logged soils or soils in steep sloppy areas. These soils have limitations or ill effects for crop growth and productivity.

Cropping system is the cropping patterns used on a farm and their interaction with farm resources, other farm enterprises, available technology and environment (Physical, biological and socioeconomic) which determine their makeup (Krantz et al., 1975). Cropping system is subsystem of the farming system.

The cropping system aims at increasing the benefits derived by crop production from available physical resources (land, climate, water resources etc.) that are not readily changed through optimization of input levels for a given crop or cropping pattern. The objective of any cropping system is to increase the efficiency of utilization of resources. The efficiency in measured by the quantity of product obtained per unit resource in a unit time in cropping system.

Adaptation is any feature of an organism which has survival value under the existing condition of its habitat. The basic of successful crop production is the selection of an adapted plant species and varieties. Plants may have morphological adaptation or physiological adaptation or both for the existing environment.

Adaptation to soil moisture

Hydrophytes: More number of stomata on the upper surface of the leaf, aerenchyma tissue in the roots of rice plants, stem is hollow/straw, internodes are longer in floating and submerged rice,

Mesophytes: Stomata are normal. Present both on upper and lower leaf surface, medium root growth.

An ideotype is a crop plant having desirable morphological and physiological characteristics or both for cultivation in a specific agroclimate situation. An ideotype is constructed by the breeder on the basis of indepth study of morphological and physiological characters including their interrelationships, and intuition of the breeder based on his experience.

Plant growth is defined as the progressive development which is irreversible. It is expressed in terms of dry weight plants, height of plants, girth or diameter of the stem or tree trunks, spread of the tree canopy, number of branches or tillers. Plant growth is a function or various factors which may be expressed as G = f (x, x₂, x₃ x_n ).Some factors may be controlled while some cannot be controlled. The following are the factors which influence the plant growth.

Knowledge of fertilizer dose, selection of fertilizer sources, time and method of application is essential for achieving efficient use of fertilizers and profitable yield.

A. Fertilizer Dose

Fertilizer dose for crops is determined based on the field experimentation. It varies with the crops and varieties, initial fertility of the soil, soil properties, cropping system, climate, season, rainfed or irrigated crop, expected yield etc. Fertilizer dose for rainfedcrops (Kg/ha)

Manures are the plant and animal wastes that are used as source of plant nutrients. They release nutrients upon their decomposition.

Bulky organic manures contain small percentage of nutrients and they are applied in large quantities. e.g,. farmyard manure, compost, green manures.

Criterion for essentiality of plant nutrients

Arnon’s (1954) criteria for essentiality of elements for plant growth:

1. The plant must be unable to grow normally or complete its life cycle in the absence of the element,

2. The element is specific and cannot be replaced by another and,

3. The element plays a direct role in metabolism.