Proteins energy content

Nuts are rich in protein and fat most commercially important nuts supply about 28 MJ /kg (6600 kcal/kg) of kernel, more than most other foods (Table 2) cereals supply about 15 MJ /kg (3640 kcal/kg) meats about 7.5 MJ /kg (1790 kcal/kg) and fresh fmits less than 2.8 MJ /kg (660 cal/kg). The energy content in kilojoules (1 food calorie or cal = 4.184 kJ) per kilogram of food is calculated by the following formula ... 

Hopkins was careful to apply the governing rule of nutrition to his experiments all the dietaries were more than adequate with respect to their energy content. With rare exceptions the rats used in his studies consumed sufficient food, fats and carbohydrates in particular, to supply them with the calories deemed necessary for growth. The quantities of protein and of mineral salts were also adequate. With all this in mind, attention can now be focused on the specific diets, experimental procedures and results. 

J to their molecular components. Then one of two things happens either your body burns these molecular components for their energy content through a process known as cellular respiration, or these components are used as the building blocks for your body s own versions of carbohydrates, lipids, proteins, and nucleic acids. The sum total of all these biochemical activities is what we call metabolism. Two forms of metabolism are catabolism and anabolism, and Figure 13.41 shows the major catabolic and anabolic pathways of living organisms. 

Proteins are useful for their energy content, just as starches, sugars, and fats are, but perhaps the greatest importance of proteins lies with how our bodies use them for building such structures as enzymes, bones, muscles, and skin. 

Dawson, A.S. and Grimm, A.S. (1980). Quantitative seasonal changes in the protein, lipid and energy content of the carcass, ovaries and liver of adult female plaice. Journal of Experimental Biology 76,493-504. 

Zduhczyk et ol. (1996) studied the nutritive value of low-alkaloid varieties of white lupin and found that the lysine contents were relatively low (4.70-5.25g/16g N), with methionine as the limiting AA. Roth-Maier and Paulicks (2004) studied the digestibility and energy contents of the seeds of sweet blue lupins (L. angustifolius) and found digestibility coefficients of 0.43-0.5 for organic matter, 0.36-0.43 for protein, 0.69-0.83 for fat, 0.46-0.58 for NFE and an ME concentration of 7.54-8.22 MJ. 

The first law of thermodynamics allows us to rate foods in terms of their energy contents. These are really AH of combustion values. Thus, carbohydrates, fats, proteins, and ethanol yield approximately 4, 9, 4, and 7 kcal/g, respectively when combusted. A normally active person requires between 2000 and 2500 kcal/day in foodstuffs to function normally. Persons doing heavy work may require as much as 5000 kcal/day or more. 

Fig. 11.1 Relationship among catalytic intermediates of peroxidases. The formal oxidation state of each species is indicated by the numbers +2 to +6. The formal oxidation state of the species directly correlates with the relative energy content of the intermediates. The entry and exit of external electron donors/acceptors is indicated. In spite of its high oxidation state, Compound III is relative inert given the stability provided by the Fe(II) 02, Fe(III) 02 and Fe(IV) 022 resonance forms. Nevertheless, amino acid residues may rescue the free radical of Compound III, restore the iron atom ferric state, and allocate the free radical into a low redox potential site in the protein backbone. When the porphyrin performs as an electron donor, a different reaction occurs, resulting in tetrapyrrole bleaching and iron release...

Ist of menu items and weights (g). Analyzed values for key nutrients were done prior to and throughout the experiment. Zinc contents were 6.10 and 5.98 mg, respectively. The mean protein content was 56 g and the mean energy content was 2000 kcals. Adapted from (2). 

The amounts and species of proteins in the cell membrane depend on the functions of the particular cell. The protein weight content of the myelinforming protein that covers nerve cells is only 25%. The inner membrane of a mitochondrion, which performs energy conversion, contains 75% by weight of proteins. 

Effect on Nutritional Value The beneficial nutritional effects of extrusion vary with species, age, and type of ration being fed, but, in general, these benefits can be expected of the protein, energy, and fiber content of the ration by the following factors. 

Tl ie energy content of food carboliydrate and food protein is J7 kj/g, whereas that of food fat is 38 kj/g. The energy content of ethanol is 3 kJ/g. Though fairly accurate, these values are only generalizations. For example, consider the energies of different carbohydrates 17,2 kJ/g of starch, 16.6 kJ/g of sucrose, 15,9 kJ/g of glucose. 

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