Foodstuffs carrot

Vitamin Ai (retinol) is derived in mammals by oxidative metabolism of plant-derived dietary carotenoids in the liver, especially -carotene. Green vegetables and rich plant sources such as carrots help to provide us with adequate levels. Oxidative cleavage of the central double bond of -carotene provides two molecules of the aldehyde retinal, which is subsequently reduced to the alcohol retinol. Vitamin Ai is also found in a number of foodstuffs of animal origin, especially eggs and dairy products. Some structurally related compounds, including retinal, are also included in the A group of vitamins. 

Chlorobenzenes are widely dispersed in the environment as a result of their industrial usages and emissions from incinerators. Chlorobenzenes have an increasing tendency to bioaccumulate and to become more persistent as the number of chlorine atoms increases. They are also present in sewage sludge and have been shown to be taken up by carrots via this route.55 There have been reports of some chlorobenzenes being found in foodstuffs in meat, fish, vegetables and crude seed oils in the UK,54 56 in cod from the North Sea,57 in fish and shellfish in Canada,58 in fish from contaminated waters in Europe59-61 and in human milk in Canada.62... 

The most commonly used natural carotenoid extracts for foodstuffs are annatto, paprika, and saffron. Many other sources, including alfalfa, carrot, tomato, citrus peel, and palm oil, are also utilized. 

Tliis is made up of the primary root ealled the tap root with lateral secondary roots branching out from it and, from these, tertiary roots possibly developing obliquely to form, in some cases, a very extensive system of roots (Fig. 1.14). The root of the bean plant is a good example of a tap root system. If this is split it will be seen that there is a slightly darker central woody eore, the skeleton of the root, which helps to anchor the plant and transport foodstuffs. The lateral seeondary roots arise from this central core (Fig. 1.15). Carrots and other true root crops such as... 

It is absorbed directly in the form of retinol esters from liver, butter and eggs and the esters are converted to free retinol by esterases in the body. Plant foodstuffs such as carrots and spinach contain vitamin A in the form of carotene (provitamin A) and this is converted in the body to retinol via the action of beta carotene diotggenase which produces two molecules of retinal from each molecule of beta carotene. It exists in a number of different forms (vitamers Fig. 26.1). 

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