CHAPTER ONE1.0 INTRODUCTIONFood is a biological material which has aesthetic appeal, good organoleptic qualities, which when ingested, digested and absorbed by the body will supply the needed nutrients for growth, maintenance of health and support of other metabolic activities within the body system. There are two major sources of food as a biological material, these include food from plant and animal sources food for plant sources include cereal, roots, tuber, pulses etc. while those from animal sources include meat, milk, eggs, fish etc. Food commodities of animal origin are of utmost importance in diets due to the presence of a variety of essential nutrients. The essential nutrient which this group of food commodities are noted is protein, which is the only nutrient that takes pant in all the functions which nutrients perform in the body. Even though plant food commodities like cereals and legumes, have appreciable amounts of protein in varying quantities, such proteins are of lower quality compared to that of animal sources due to the deficiency of plant protein in certain essential amino acids like lysinc, methionine and cysterine. Methionine and cysterine on the other hand, animal protein has a full complement of all essential amino acids, food play a major role in our physical and mental well-being and it is needed to nourish the body and also plays a significant role in our social life protein from animal origin are referred to as complete proteins.
Fish is an aquatic animal used as human food after processing. All true fish muscles is typical striated like other animal foods is a good source of protein of high biological value. However, unlike that of meat, the protein in fish contains small amount of connective tissues (which bind the muscle fibres together), but contains no elastin (the material the wall of the fibres is made of) this makes the cooking of fish muscle faster, and the cooked fish muscle more easily digested compared to that of meat. Fish varieties that are high in fat, e.g salmon, tuna and herring supply considerable amounts of energy from the fat, which is dispersed throughout the fish, flesh, and therefore normally invisible, unlike that fat deposited in meat carcass. Also, over 70% of protein comes from animal sources in developed countries. Generally animals fats contain more percentage of saturated fatty acids while vegetables of plants oils have a high proportion of unsaturated fatty acids. Protein from animal sources are of better quality than those from plant sources, since they are complete proteins while vegetable proteins are incomplete proteins in that they are deficient in one or more essential amino acids. Fish are good suppliers of phosphorus and iron, but very little calcium, unless the bones are eaten. The fatty fish are also valuable sources of fat soluble vitamins, especially A and D. the cod liver is particularly high in these soluble vitamins. (Adepeju, 2010).
1.1 Fish Protein Concentrate Fish protein concentrate (FPC) is any stable fish preparation intended for human consumption in which the protein is more concentrated than in the original fish. It is accepted as human food and not animal food while fish meal is not accepted as human food because of its comparatively poor flavor stability in general requiring antioxidants for flavor maintenance, its odor and also the fact that many countries will not permit the sale of foods made from unwholesome raw materials e.g fish guts. One way of supplementing the nutritional deficiency of a cereal diet lies in eating fish which supply high quality protein. Fish protein concentrate resolves the high problem in finding an inexpensive way of nutritional supplement.