EFFECT OF PROCESSING ON THE ANTINUTRITIVE FACTORS AND NUTRITIVE-VALUEOF RAPESEED PRODUCTS

The antinutritive factors and nutritive value of rapeseed products wer e evaluated. The reductions in antinutritional factors by heat process ing ranged from 47 to 94% for glucosinolates, from 9 to 43% for phytic acid and from 41 to 67% for tannic acid after toasting and autoclavin g treatments. Isolation of proteins eliminated 72-95% of glucosinolate s, 74-92% of phytic acid and 100% of tannic acid for protein concentra te and isolate. All processes destroyed trypsin inhibitor activity com pletely. Rapeseed products have a balanced amino acid composition and their proteins are relatively high in sulphur-containing amino acids a nd lysine. The chemical score and limiting amino acids of rapeseed pro ducts varied considerably, depending on the type of process. Heat trea tment and isolation of proteins improved the in-vitro digestibility of rapeseed proteins. The essential amino acid index of rapeseed product s ranged from 66 to 81%. Rapeseed meal has high levels of riboflavin, niacin and pyridoxine. Riboflavin and niacin are more stable to the he at process than thiamine, pyridoxine and pantothenic acid. Many of the se vitamins are lost during isolation of proteins. The meals are rich in Ca, K, P and Mg. Some minerals increased and others decreased durin g the processing.