Nutritive Value of Rapeseed Meals and Rapeseed Protein Isolates

Abstract

Defatted meals of two new varieties of rapeseed, Brassica napus, Erglu and Lesira, and protein isolates prepared therefrom, were fed to chicks that had been depleted of their embryonic protein reserve. First, the animals were fed at a 12 % protein level, half of it from rapeseed meal, or a rapeseed protein isolate and, subsequently, at a 20 % level, all of it from rapeseed products. Feed consumption, weight gain and protein efficiency ratio revealed better performance of the protein isolates as compared to the corresponding meals. This is attributed to the favorable amino acid patterns of these isolates and the absence of glucosinolates. Erglu meal, too, is eminently suitable as a supplement to chicken feed, whereas Lesira meal, although its amino acid pattern is adequate and similar to that of Erglu meal, showed detrimental effects, probably due to its high glucosinolate content.

Rapeseed protein isolates by countercurrent extraction and isoelectric precipitation

“…Nutritional studies with chicks (El Nockrashy et al, 1975a) revealed superior performance of these protein isolates as compared to the corresponding meals, both with regard to growth and protein efficiency ratio. The improved nutritive value of the rapeseed protein isolates is attributed to their favorable amino acid patterns and the absence of glucosinolates.…”

“…Factors which favor the use of rapeseed protein in human nutrition include: (a) rapeseed is cultivated in countries which do not have suitable agricultural or environmental conditions for growing other oilseeds (Ohlson, 1972); (b) the concentration of essential amino acids in rapeseed protein compares favorably with the amino acid requirements of human adults (FAO, 1957;El Nockrashy et al, 1975a); (c) rapeseed protein is characterized by Bundesanstalt fur Fettforschung, Institut fur Biochemie und Technologie, H. P. Kaufmann-Institut, D-4400 Munster (Westf. ), Germany.…”