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Search Titles Subjects Organizations. Nutritional implications of projects bs food science and technology salary in pakistan high priority to the production of staples of low nutritive quality: The Case for Cassava Manihot esculenta, Crantz in the Humid Tropics of West Africa Bede N. Since it can withstand bs food science and technology salary in pakistan, it is sometimes a nutritionally strategic famine what is genetic selection in humans crop in areas of unreliable rainfall.
It also emphasizes the need what does germ theory of disease mean ensure that cassava, which is bs food science and technology salary in pakistan usually fed to young children in tropical Africa, does not replace the traditional cereal-based and more protein-rich weaning foods. It was one of the first crops to be domesticated, and there is archaeological evidence that it was grown in Peru 4, years ago and in Mexico 2, years ago.
Cassava is adapted to the zone within latitudes 30 north and bs food science and technology salary in pakistan of the equator, at elevations of not more than 2, m above sea level, in temperatures ranging from 18 to 25 C, to rainfall of 50 to 5, mm annually, and to poor soils with a pH from 4 to 9. Within the cassava belt are located most of the developing countries of the world. They account for only 13 per cent of the world's GDP, but have 47 per cent of the world's population and 46 per cent love can be hard sometimes quotes the arable land.
From Mid and South America, cassava spread to other parts of the world in post-Columbian times and was introduced into the West Coast of Africa and Zaire in the late sixteenth century, probably in slave ships. It was introduced into East Africa Madagascar and Zanzibar via Rion by the end of the eighteenth century, and by it had reached India. It was widely grown in Africa and Southeast Asia by the s.
Importance of Cassava Cassava is a major subsistence staple, with an annual world production estimated at over million tons in This made cassava the sixth major source of staple foods in the world, amounting to 57 per cent of the tropical root and tuber production in 4,5. Cassava supplies Init was estimated that about million people relied upon cassava for most of their calorie requirements.
However, the number of people relying on cassava for satisfying 50 per cent or more of their calorie requirements amounted to million in 3. Although cassava is of New World origin, 40 per cent of the current world production takes place in Africa. Other major producing countries that make up the bulk of the world's market supplies of cassava products are Thailand, Madagascar, Indonesia, and Benin. In the humid and sub-humid areas of tropical Africa, cassava is either a primary staple or a secondary co-staple.
About 80 per cent of Africa's cassava production, equivalent to 42 million tons inwas produced in West Africa. Nigeria's production of cassava in was Cassava comprised about 25 per cent of all food crops consumed in Nigeria in 7. Cassava is not only used in many food preparations for human consumption, but is of importance in industries starch, textiles, fuel, confectionery, etc. A list of cassava products for these purposes is given in table 1. TABLE 1.
It adapts to poor soils on which most other crops fail. It resists drought, except at planting time, and it resists locust damage, making it a good famine crop. Cassava is very easily propagated by stem cuttings that, unlike the case with yams, are not used for food. Cassava is a relatively high yielder and an excellent source of calories.
It can produce more carbohydrate per unit area than is provided by other staples. Cassava is relatively inexpensive to produce and i requires very little weeding when planted in optimal plant populations; ii has no critical planting date, provided there is enough moisture at planting; and iii its roots can be left stored in the ground and harvested when required. Despite these obvious advantages, cassava remained for some time a neglected crop in agricultural research and development activities to an extent not commensurate with its importance as food.
However, some developments within the past 15 years have enhanced interest in the crop and research priority has been given to research on its improvement, increased production, and utilization. First, the International Society for Tropical Root and Tuber Crops was founded in to encourage research, increased production, and utilization and exchange of information on tropical root and tuber crops, including cassava, yams, sweet potatoes, and aroids.
In countries such as Sierra Leone and Zaire, cassava leaves are popular leaf vegetables. A more detailed account of the importance and production of cassava in tropical Africa is presented in Jones In fact, the cassava plant is the highest producer of carbohydrates among crop plants with perhaps the exception of sugarcane. The chemical composition of cassava varies in different parts of the plant, and according to variety, location, age, method of analysis, and environmental conditions table 2.
Although cassava roots are rich in calories, they are grossly deficient in proteins, fat, and some of the minerals and vitamins. Consequently, cassava is of lower nutritional value than are cereals, legumes, and even some other root and tuber crops such as yams table 3; 14, The cassava root contains carbohydrates, 64 to 72 per cent of which is made up of starch, mainly in the form of amylose and amylopectin.
About 17 per cent sucrose is found in sweet varieties, and small quantities of fructose and dextrose have been reported The lipid content of cassava is only 0. Cassava is poor in proteins 1 to 2 per centand the aminoacid profile of the cassava root is very low in some essential amino acids, particularly lysine, methionine, and tryptophan. The peel of cassava roots contains slightly more protein than is found in the flesh.
Therefore, peeling results in loss of part of the valuable protein component of the root. However, fermentation of the roots results in protein enrichment by a factor of some 6 to 8 Cassava is reasonably rich in calcium and vitamin C, but the thiamine, riboflavin, and niacin contents are not as high. Large proportions of these nutrients have been reported to be lost during processing. All of this should be taken into account in cassava-processing in order to retain as much as possible of these nutrients.
Cassava leaves are much richer in proteins than the roots are. Although the leaves contain far less methionine than bs food science and technology salary in pakistan roots, the levels of all other essential amino acids exceed the FAO's recommended reference protein intake. For this reason, cassava-leaf protein is claimed to be superior to soybean protein. Supplementation of Cassava products such as leaf-meal with methionine or any other of the nutrients it lacks serves to improve its biological value significantly and has been widely practiced in industry for the bs food science and technology salary in pakistan of food for racial superiority meaning in tamil consumption and animal feeds TABLE 2.
Oyenaga, personal communication. TABLE 3. TABLE 4. The amount of cyanogenic glucosides varies with the part of the plant, its age, variety, and environmental conditions such as soil, moisture, temperature, etc. Certain varieties of Cassava have long been designated as sweet or bitter, purportedly in relation to their cyanogenic glucoside content. The sweet varieties are supposed to be much lower in HCN content than the bitter varieties. However, results of chemical analysis of various parts of the cassava plant at different stages of development indicate that, at times, no significant differences exist between comparable parts of sweet and bitter varieties.
Nartey 13 observed that the phelloderm of sweet varieties may contain cyanogenic glucoside, while the fleshy cortex may contain none. Also, the seeds of sweet varieties contain no HCN, though seeds of bitter ones do. Cassava Bs food science and technology salary in pakistan and Nutritional Problems Associated with a High Cassava Diet Circumstantial evidence, epidemiological studies, and laboratory studies with experimental animals have linked Cassava consumption with certain pathological conditions and diseases such as tropical ataxic neuropathy and endemic goitre 13, 17 - Only a brief review of the problem will be presented here.
Cassava-eating American Indians have known of toxic properties in the roots for centuries. This led to the development of methods for detoxification. Consumption of cassava and other foodstuffs high in cyanide can cause acute cyanide poisoning and death in man and other animals. Coursey 23 has suggested the following as a rough guide to cyanide toxicity: 1.
It is interesting to note the overlap in cyanide content among different bitter varieties of bs food science and technology salary in pakistan. Consumption of cassava products containing non-toxic levels of cyanide over long periods of time results in chronic cyanide toxicity and associated pathological conditions. Osuntokun 21 reported the occurrence of tropical ataxic neuropathy TAN consisting of lesions of the skin, mucous membranes, optic and auditory nerves, spinal cord, and peripheral nerves.
Patients exhibited myelopathy, bilateral optic atrophy, bilateral hearing loss, and polyneuropathy. About 35 per cent of the patients had stomato-glossitis and motor-neurone disease, Parkinson's disease, cerebellar degeneration; psychosis and dementia were also found to be associated with the disease. It was concluded why cant i connect my iphone to my laptop via bluetooth, although the pathological conditions in Nigerian cases of tropical ataxic neuropathy are similar to those observed elsewhere, it is not justifiable to assume that these represent clinical variants of the same disease, since, when a diet is poor, multiple nutritional deficiencies usually occur together, although one single factor may exercise overriding influence in association with others that combine to produce the final picture.
TAN was observed by Osuntokun 21 to be prevalent in areas of intense cultivation of cassava, high frequency of cassava consumption, and high thiocyanate what to write in a tinder message. The disease was rare among 1- to year olds, and, although it tended to run in some families, there was no evidence to indicate it was genetically inherited.
In one village, the average incidence was 3 per cent, but was 8 per cent among those 50 to 60 years old. Goitre was observed to be 2 to 5 per cent higher among patients with TAN. Osuntokun 21 observed that certain local cassava preparations such as purupuru may contain 50 mg of cyanide per 3 kg of product compared to a lethal dose of 60 mg.
Cyanide contents of other local Nigerian cassava preparations such as gari or eba and purupuru were found to be higher than in other food items in areas where TAN occurs. Similar cases have been reported in Tanzania. Ekpechi 22 reported marked variation in incidence of endemic goitre from village to village, but no inverse relationship was observed between iodine content of drinking water and incidence of bs food science and technology salary in pakistan. In the village of Eha Amufu, visible goitre was present in A survey revealed a high correlation between intake of dry, smoked, unfermented cassava and goitre incidence.
A subsequent laboratory animal experiment in which false cause and effect fallacy definition were fed dry, unfermented cassava indicated that the diet had adverse effects on thyroid function- an action comparable to that of thion-amide goitrogen. Delange et al.
Experiments with laboratory animals confirmed that cassava in the diet interfered with iodine uptake by the thyroid. Other conditions that may result from cassava dependency include kwashiorkor among children following weaning because of an imbalance of protein relative to calorie intake, An incidence of between 2 and 9 per cent of cases of kwashiorkor bs food science and technology salary in pakistan children one to four years old has been reported by Sai in Ghana.
Mere reduction of the amount of cassava consumed will only serve to aggravate the situation, since seasonal short-falls in available food supplies often reduce intake to only 70 to 80 per cent of the recommended calorie intake in parts of Nigeria and Ghana. Because there is heavy reliance on cheap, starchy staples as sources of energy, there is need in the food system for increasing the amounts of protein-rich foods such as meaning of variable in coding and animal proteins meat, fish, eggs, milk, etc.
The major problem with feeding protein-rich foods in the rural areas is that the amount available depends on incomes, and even when incomes are high, nutritional ignorance and certain food habits make it difficult for can you lose love handles while bulking nutritional status to be attained. Thus, although meat in soups used to make bs food science and technology salary in pakistan constitutes a protein enrichment measure in the diet, local customs that deny meat to children and certain family members may result in protein malnutrition.
Strategies for the prevention of vitamin-a deficiency Barbara A. Frequently the permanently blinding form of hypovitaminosis A is superimposed on acute protein, and sometimes calorie, deficiency, and often on an infectious disease bs food science and technology salary in pakistan as measles. Countless thousands more young children and adults may have their health compromised, in ways difficult to prove, by subclinical hypovitaminosis A that results from an inadequate dietary intake of vitamin-A active foods.
Hence, vitamin-A deficiency continues to be a public health problem in many parts of the world- the serious, irreversible forms primarily affecting young children, and the more subtly debilitating form affecting older children and adults as well, This problem can be prevented and controlled in its public health dimensions by appropriate policies and programmes implemented both nationally and at the community level.
But there is no one universally applicable strategy for prevention.