Benders'dictionary of nutrition and food technology

170from the end of the protein chain. The main endopeptidases indigestion are chymotrypsin, elastase, pepsin and trypsin.endosperm The inner part of cereal grains; in wheat it constitutesabout 83% of the grain. Mainly starch, and the source ofsemolina. Contains only about 10% of the vitamin B 1 , 35% ofthe vitamin B 2 , 40% of the niacin and 50% of the vitamin B 6 andpantothenic acid of the whole grain.See also flour, extraction rate.endothelium-derived relaxation factor See nitric oxide.endotoxins Toxins produced by bacteria as an integral part of thecell, so cannot be separated by filtration; unlike exotoxins, theydo not usually stimulate antitoxin formation but the antibodiesthat they induce act directly on the bacteria. They are relativelystable to heat compared with exotoxins.See also tx numbers.Energen rolls TM A light bread roll of wheat flour plus addedgluten.energy The ability to do work. The SI unit of energy is the Joule,and nutritionally relevant amounts of energy are kilojoules (kJ,1000 J) and megajoules (MJ, 1 000 000 J). The calorie is stillwidely used in nutrition; 1 cal = 4.186 J (approximated to 4.2).While it is usual to speak of the calorie or joule content of afood it is more correct to refer to the energy content or yield.The total chemical energy in a food, as released by completecombustion (in the bomb calorimeter) is gross energy. Allowingfor the losses of unabsorbed food in the faeces givesdigestible energy. Allowing for loss in the urine due to incompletecombustion in the body (e.g. urea from the incompletecombustion of proteins) gives metabolisable energy.Allowing forthe loss due to diet-induced thermogenesis gives net energy, i.e.the actual amount available for use in the body.See also energy conversion factors.energy balance The difference between intake of energy fromfoods and energy expenditure for basal metabolic rate andphysical activity. Positive energy balance leads to increased bodytissue, the normal process of growth. In adults, positive energybalance leads to creation of body reserves of fat, resulting inoverweight and obesity. Negative energy balance leads to utilisationof body reserves of fat and protein, resulting in wastingand undernutrition.energy conversion factors Various factors are used to calculatethe energy yields of foodstuffs:The complete heats of combustion (gross energy) as determinedby calorimetry are: protein 23.9 kJ (5.7 kcal), fat 39.5 kJ(9.4 kcal); carbohydrate 17.2 kJ (4.1 kcal)/g.