Valorization of meat and bone residue by ultrasound and high voltage electrostatic field assisted two-stage enzymatic hydrolysis: Nutritional characteristics and flavor analysis

Enzymatic hydrolysis has been used to extract protein and bioactive compounds. Choosing appropriate enzymes can improve the hydrolysis of meat and bone proteins and enhance the flavor of the final product. In this study, the by-products of meat and bone residue after cooking in food processing plants were hydrolyzed by a two-stage method of complex protease (neutral protease, flavor protease and alkaline protease), and the effects of ultrasound (US) and high voltage electrostatic field (HVEF) pretreatment before enzymatic hydrolysis on the nutritional characteristics and flavor of the enzymolysis solution were investigated. The results showed that pretreatment by US alone and combined with US and HVEF could promote proteolysis and increase the content of free amino acids. HVEF pretreatment alone had no significant effect on protein hydrolysis. The enzymatic hydrolysate pretreated by US-HVEF had the strongest umami flavor, the highest flavor nucleotide content and the strongest antioxidant capacity. And electronic nose and GC-MS analysis showed that the combination of US-HVEF pretreatment could enhance the flavor characteristic intensity of enzymatic hydrolysate and increase the volatile compound content, but the compound types decreased slightly. Therefore, physical field pretreatment before enzymatic hydrolysis can help to produce high value-added enzymatic hydrolysis products.