Utilization of Parapeneopsis stylifera shrimp shell waste for the production of chitooligosaccharides using different non-specific enzymes and their characterization

Two different non-specific proteolytic enzymes (papain and pepsin) and two carbohydrase enzymes (alpha-amylase and beta-amylase) were used for the depolymerization of chitosan to produce chitooligosaccharides (COS). The COS produced using papain, pepsin, alpha-amylase, and beta-amylase were characterized for physicochemical, structural, thermal properties and antioxidant activities. COS produced using pepsin enzyme had higher solubility compared to other three COS. Structural variation of chitosan and their oligosaccharides were studied by FTIR analysis, and it revealed the existence of various structural differences. The thermal behavior of chitosan and oligosaccharides is examined using DSC analysis, and it exhibited differences in the glass transition temperature among the four oligosaccharides and native chitosan. Antioxidant analysis such as DPPH radical scavenging activity and reducing power revealed the antioxidant ability of COS. Pepsin-COS had the highest DPPH radical scavenging and reducing power activity among the four COS. According to the patterns of molecular weight reduction, antioxidant activities, thermal behavior properties, four enzymes alpha-amylase, beta-amylase, pepsin, and papain were found suitable for hydrolyzing chitosan into COS. As it is superior to chitosan, COS can be utilized in the food industry as bio-preservatives to enhance the products quality, safety, and shelf life.