Enzymatic hydrolysis of chicken bone for protein recovery

Chicken byproducts, such as chicken bones, are significant protein resources. The hydrolysis of chicken bones with proteases is a key approach for extracting chicken bone proteins. However, this method is associated with challenges, including low hydrolysis rates and unsatisfactory flavor. Therefore, in this study, we aimed to optimize the combination of enzymes as well as hydrolysis reaction conditions to maximize the amino acid retrieval efficiency and quality. Chicken bones were used as raw materials. The optimal combination of protease and lipase for hydrolyzing chicken sternal bones was determined, and the optimal enzymatic hydrolysis conditions were determined by integrating single-factor experiments and response surface methodology. We found that at 49 degrees C, in a system with a solid-liquid ratio of chicken bone paste to distilled water of 1:2, and the addition of 1% (w/w) compound enzyme (lipase to alkaline protease ratio 1:4.9), after 4 h, the hydrolysis rate of chicken bones reached a maximum (38.03%). The levels of glutamate, glycine, lysine, and leucine in the enzymatic hydrolysis supernatant also increased. The peptides were mainly concentrated at approximately 1100 Da. Compared to deep-boiled bone broth products, the hydrolysis products exhibited remarkably better flavor, nutritional value, and quality stability. This method enhanced the recovery efficiency of chicken bone proteins using a combination of lipases and proteases, and provides a method of salvaging the flavor and nutritional value of chicken bones that are generally discarded. Our findings provide theoretical and data support for the utilization of hydrolysis process to extract better quality proteins from chicken bone.