Development of a novel method for hot-pressure extraction of protein from chicken bone and the effect of enzymatic hydrolysis on the extracts

To investigate the hot-pressure extraction of protein from chicken bone (CB), chicken bone extracts (CBE) was prepared from CB by heating at 130 ± 0.5 °C for 120 min, followed by filtration, standing, defatting, and concentration. Effects of enzymatic hydrolysis on the properties of hydrolysates were examined. Results showed CBE contained 25.59% of protein, and showed a desirable value of protein digestibility-corrected amino acid score for adult. The total amino acid (AA) content of CBE is 21.99%, among which 40.62% and 54.66% are essential and fresh AA, respectively. Forty kinds of volatile compounds were identified after 24 h of hydrolysis, with 2,3,5-trimethylpyrazine as the key flavor compound. After 8 h of hydrolysis of CBE, the content of small MW of peptides (400–1000 Da) increased by 74 times compared with that of 1 h. CBE and its hydrolysates demonstrate a new kind of potential suitable nutritional supplement in various foods.