Key points are not available for this paper at this time.
Enzymatic hydrolysis is an efficient processing method for valorizing chicken rest raw material by generating new food- or feed ingredients. This paper characterizes two types of chicken rest raw material: viscera and a mixture of bones, skin and remaining meat, and evaluates how industrially relevant hydrolysis process designs affect overall yield of all products, including hydrolysate, sediment, lipid, and emulsion. Eleven hydrolyses were performed using viscera and bone materials, endogenous and commercial enzymes, pre-treatments, variations in water addition and hydrolysis times. Compared to bone materials, viscera had higher proteolytic activity, more readily water-soluble components, and lower effect of adding commercial enzymes on product yields. The process of heating the raw material to hydrolysis temperature greatly impacted product yields, representing about 50 % of the overall hydrolysate production from viscera during hydrolysis. Pre-inactivation of endogenous enzymes reduced initial, but not final, hydrolysate yields. Adding commercial enzymes to pre-inactivated viscera had no effect on yields compared to not adding enzymes. Reducing water addition lowered initial hydrolysate yield from bone material. Lipid yield reflected lipid content in the raw material, and thermal pre-separation of lipids did not increase the total lipid recovery. In general, hydrolysis of viscera generated more emulsion than the bone material.
Five et al. (Sun,) studied this question.