Vegetables Production

Vegetables Production: General Informations 

 

 A vegetable is any part of a plant that is consumed by humans as food as part of a savoury course or meal.

The term "vegetable" is somewhat arbitrary, and largely defined through culinary and cultural tradition. It normally excludes other main types of plant food, fruits, nuts and cereal grains but includes seeds such as pulses. The original meaning of the word vegetable, still used in biology, was to describe all types of plant, as in the terms "vegetable kingdom" and "vegetable matter".


Originally, vegetables were collected from the wild by hunter-gatherers and entered cultivation in several parts of the world, probably during the period 10,000 BC to 7,000 BC, when a new agricultural way of life developed. At first plants which grew locally would have been cultivated, but as time went on, trade brought exotic crops from elsewhere to add to domestic types.

Nowadays, most vegetables are grown all over the world as climate permits, and crops may be cultivated in protected environments in less suitable locations. China is the largest producer of vegetables, and global trade in agricultural products allows consumers to purchase vegetables grown in faraway countries.

The scale of production varies from subsistence farmers supplying the needs of their family for food, to agribusinesses with vast acreages of single product crops. Depending on the type of vegetable concerned, harvesting the crop is followed by grading, storing, processing and marketing.
Vegetables can be eaten either raw or cooked and play an important role in human nutrition, being mostly low in fat and carbohydrates, but high in vitamins, minerals and fiber. Many governments encourage their citizens to consume plenty of fruit and vegetables, five or more portions a day often being recommended.

Vegetables play an important role in human nutrition. Most are low in fat and calories but are bulky and filling. They supply dietary fibre and are important sources of essential vitamins, minerals and trace elements.


Particularly important are the antioxidant vitamins A, C and E. When vegetables are included in the diet, there is found to be a reduction in the incidence of cancer, stroke, cardiovascular disease and other chronic ailments.Research has shown that, compared with individuals who eat less than three servings of fruits and vegetables each day, those that eat more than five servings have an approximately twenty percent lower risk of developing coronary heart disease or stroke.

Vegetables are eaten in a variety of ways, as part of main meals and as snacks. The nutritional content of vegetables varies considerably, though generally they contain little protein or fat, and varying proportions of vitamins such as vitamin A, vitamin K and vitamin B6, provitamins, dietary minerals and carbohydrates.


Vegetables contain a great variety of other phytochemicals (bioactive non-nutrient plant compounds), some of which have been claimed to have antioxidant, antibacterial, antifungal, antiviral and anticarcinogenic properties.

However, vegetables often also contain toxins and antinutrients which interfere with the absorption of nutrients. These include α-solanine, α-chaconine, enzyme inhibitors (of cholinesterase, protease, amylase, etc.), cyanide and cyanide precursors, oxalic acid and others. These toxins are natural defenses, used to ward off the insects, predators and fungi that might attack the plant. Some beans contain phytohaemagglutinin, and cassava roots contain cyanogenic glycoside as do bamboo shoots. These toxins can be deactivated by adequate cooking. Green potatoes contain glycoalkaloids and should be avoided.

Some common vegetables

Some common vegetables
Image	Description	Parts used	Origin	Related cultivars
	Cabbage Brassica oleracea	Leaves, axillary buds, stems, flowerheads	Europe	Cabbage, red cabbage Savoy cabbage, kale Brussels sprouts, kohlrabi, cauliflower, broccoli Chinese broccoli
	Turnip Brassica rapa	Tubers, leaves	Asia	Turnip, rutabaga (swede) Chinese cabbage napa cabbage bok choy, collard greens
	Radish Raphanus sativus	Roots, leaves, seed pods, seed oil, sprouting	Southeastern Asia	Radish daikon seedpod varieties
	Carrot Daucus carota	Root tubers	Persia	Carrot
	Parsnip Pastinaca sativa	Root tubers	Eurasia	Parsnip
	Beetroot Beta vulgaris	Tubers, leaves	Europe, Near East and India	Beetroot sea beet Swiss chard sugar beet
	Lettuce Lactuca sativa	Leaves, stems, seed oil	Egypt	Lettuce celtuce
	Beans Phaseolus vulgaris Phaseolus coccineus Phaseolus lunatus	Pods, seeds	Central and South America	Green bean French bean runner bean haricot bean Lima bean
	Broad beans Vicia faba	Pods, seeds	North Africa South and southwest Asia	Broad bean
	Peas Pisum sativum	Pods, seeds, sprouting	Mediterranean area and Middle East	Pea snap pea snow pea split pea
	Potato Solanum tuberosum	Root tubers	South America	Potato
	Aubergine/Eggplant Solanum melongena	Fruits	South and East Asia	Eggplant (aubergine)
	Tomato Solanum lycopersicum	Fruits	South America	Tomato
	Cucumber Cucumis sativus	Fruits	Southern Asia	Cucumber
	Courgette/Squashes Cucurbita spp.	Fruits, flowers	MesoAmerica	Pumpkin, squash, marrow, zucchini (courgette), gherkin, gourd
	Onion Allium cepa	Bulbs, leaves	Asia	Onion spring onion scallion shallot
	Garlic Allium sativum	Bulbs	Asia	Garlic
	Leek Allium ampeloprasum	Leaf sheaths	Europe and Middle East	Leek elephant garlic
	Capsicum annuum	Fruits	North and South America	Pepper bell pepper sweet pepper
	Spinach Spinacia oleracea)	Leaves	Central and southwestern Asia	Spinach
	Yam Dioscorea spp.	Tubers	Tropical Africa	Yam
	Sweet potato Ipomoea batatas	Tubers leaves shoots	Central and South America	Sweet potato
	Cassava Manihot esculenta	Tubers	South America	Cassava

Fruit and vegetables, particularly leafy vegetables, have been implicated in nearly half the gastrointestinal infections caused by norovirus in the United States. These foods are commonly eaten raw and may become contaminated during their preparation by an infected food handler. Hygiene is important when handling foods to be eaten raw, and such products need to be properly cleaned, handled and stored to limit contamination.




 The aim of Vegetables production

The objective of preserving vegetables is to extend their availability for consumption or marketing purposes. The aim is to harvest the food at its maximum state of palatability and nutritional value, and preserve these qualities for an extended period. The main causes of deterioration in vegetables after they are gathered are the actions of naturally-occurring enzymes and the spoilage caused by micro-organisms.

Canning and freezing are the most commonly used techniques, and vegetables preserved by these methods are generally similar in nutritional value to comparable fresh products with regards to carotenoids, vitamin E, minerals and dietary fiber.



Canning is a process during which the enzymes in vegetables are deactivated and the micro-organisms present killed by heat. The sealed can excludes air from the foodstuff to prevent subsequent deterioration. The lowest necessary heat and the minimum processing time are used in order to prevent the mechanical breakdown of the product and to preserve the flavour as far as is possible. The can is then able to be stored at ambient temperatures for a long period.

Freezing vegetables and maintaining their temperature at below −10 °C (14 °F) will prevent their spoilage for a short period whereas a temperature of −18 °C (0 °F) is required for longer-term storage. The enzyme action will merely be inhibited, and blanching of suitably sized prepared vegetables before freezing mitigates this and prevents off-flavours developing.


Not all micro-organisms will be killed at these temperatures and after thawing the vegetables should be used promptly because any microbes present may proliferate more quickly than on fresh produce.
Traditionally, sun drying has been used for some products such as tomatoes, mushrooms and beans, spreading the produce on racks and turning the crop at intervals.


 This method suffers from several disadvantages including lack of control over drying rates, spoilage when drying is slow, contamination by dirt, wetting by rain and attack by rodents, birds and insects. These disadvantages can be alleviated by using solar powered driers. The dried produce must be prevented from reabsorbing moisture during storage.

Both high levels of sugar and high levels of salt can preserve food by preventing micro-organisms from growing. Green beans can be salted by layering the pods with salt, but this method of preservation is unsuited to most vegetables. Marrows, beetroot, carrot and some other vegetables can be boiled with sugar to create jams.



Vinegar is widely used in food preservation; a sufficient concentration of acetic acid prevents the development of destructive micro-organisms, a fact made use of in the preparation of pickles, chutneys and relishes.

Fermentation is another method of preserving vegetables for later use. Sauerkraut is made from chopped cabbage and relies on lactic acid bacteria which produce compounds that are inhibitory to the growth of other micro-organisms.