Effects of poultry raw material variation and choice of protease on protein hydrolysate quality

The aim of this study was to investigate the role of compositional variations in side-streams from the chicken and turkey industry on product characteristics after enzymatic protein hydrolysis (EPH). Variation was obtained using four raw materials, namely chicken and turkey carcasses, and mechanically deboned chicken and turkey residues. Alcalase 2.4 L, Corolase 2TS and Flavourzyme, three commercial proteases with different specificities, were used to investigate impact of protease choice on product characteristics. Besides protein yield, effects on product characteristics such as nutrient and amino acid composition, size distribution of peptides, degree of hydrolysis (DH%), rheological properties, and angiotensin-I-converting enzyme (ACE) inhibition, were investigated. Results show that choice of protease and industrially relevant variations in poultry raw material composition both have major effect on product composition and the other quality parameters studied. Protein yield, proximate composition, and bioactivity were more affected by protease than raw material variation. Raw material variation had a bigger impact on quality parameters such as peptide size distribution and amino acid composition, exemplified by the sum of essential amino acids. This means that raw material variation should be handled and accounted for to realize the true potential that exists in tailor-making EPH products with specified properties for targeted applications.