Effect of pepsin on antioxidant and antibacterial activity of protein hydrolysate from salted jellyfish (Lobonema smithii and Rhopilema hispidum) by-products

Protein hydrolysates are products of protein degradation that provide various sizes of peptides and free amino acids. Protein hydrolysate from the different types of enzymes and raw materials provides different bioactivity, such as antioxidant and antibacterial activity. Salted jellyfish by-products have the potential to be a source for protein hydrolysate production because of their low price and having collagen protein. This research aimed to evaluate the antioxidant and antibacterial activity of protein hydrolysates from jellyfish by-products. The dried salted jellyfish by-products from the umbrella and oral arm part of white-type ( Lobonema smithii ) and sand-type ( Rhopilema hispidum ) were desalted and enzymatically hydrolyzed by 5% (w/w) pepsin for 24 h at 37°C. Bioactivity assays showed that the hydrolysate of the oral arms part of white-type jellyfish exhibited the highest antioxidant activity (13.27%). While protein hydrolysate of umbrella part of sand-type jellyfish showed the highest antibacterial activity against Vibrio parahaemolyticus up to 13.61%. The results demonstrated that peptic hydrolysate of different types and parts of jellyfish by-products provided different antioxidant or antibacterial activity, thereby increasing the potential uses of jellyfish protein hydrolysate as a functional food.