Studies on the recovery of proteinaceous substances from chicken heads. I. An application of neutrase to the production of protein hydrolysate

Summary Minced heads of broiler chickens were hydrolysed under various conditions using neutral protease from Bacillus subtilis. It was found that hydrolysis goes at an optimum rate at 55°C and pH 7. Addition of 75% of water and 0.2% of the enzyme (w/w) to the hydrolysed raw material was sufficient to obtain a good hydrolysis yield. After 6 h of proteolysis, 1 kg of the raw material yielded 75 g of dry hydrolysate with 78.1% total protein content (N x 6.25). The nitrogen yield from this raw material amounted to 39.6%. The final product was brown coloured, of good microbiological quality, had no bitter taste and contained a number of mineral compounds. It also revealed good solubility in water but had relatively poor emulsifying properties. It was shown that nutritional quality of the product is limited by sulphur amino acids.