Nutritive value of the proteins of veal, beef and pork determined on the basis of available essential amino acids or hydroxyproline analysis.

Abstract

AbstractAvailable essential ammo acids and hydroxyproline in the proteins of different cuts of veal, beef and pork were determined. An indirect relationship between available essential amino acids and hydroxyproline was found which can be expressed as regression straight lines, if the amounts of each available amino acid in g/16 g N and hydroxyproline in log g/16 g N are plotted. This relationship is valid for veal, beef and pork and does not appear to be influenced by age, sex, or species of animal.Taking the protein content of the whole hen's egg as a standard, egg ratios were calculated from the content of available essential amino acids. the relationship between egg ratios and hydroxyproline is expressed by curved lines. the chemical score given by the egg ratio of the limiting amino acid shows a change at 1.175 g of hydroxyproline/16 g N at which point the limiting amino acids change. With lower amounts of hydroxyproline, phenylalanine is limiting; with greater amounts methionine is the limiting amino acid. At this turning point, valine values are similar to the values of limiting amino acids.Results are discussed with regard to the nutritive values of meat proteins and to the possibility of the evaluation of meat quality on the basis of nitrogen and hydroxyproline analysis.