Khositanon, Petlada, et al. “Effects of Fermentation Periods on Antioxidant and Angiotensin I-Converting Enzyme Inhibitory Activities of Peptides from Fish Sauce by-Products.” LWT, Elsevier BV, Jan. 2021, p. 110122. Crossref, doi:10.1016/j.lwt.2020.110122.
Manufacturing of fish sauce results in a large number of underutilized by-products. The fish sauce by-products (FSBs) contain peptides derived from enzymatic hydrolysis of the fish proteins by proteases from their gastrointestinal tract and halophilic microorganisms. Commercial fish sauce can be divided into different grades based on their fermentation period. The 1st, 2nd and 3rd grade FSBs are solid wastes produced after the 1st, 2nd and 3rd grade fish sauce fermentation. This work aims to evaluate the effect of fermentation periods on antioxidant and angiotensin I-converting enzyme (ACE) inhibitory activities of the FSBs. Based on bioassays against different mechanisms, the 1st grade FSB possessed stronger DPPH and hydroxyl radical scavenging activities and reducing ability than the 2nd and 3rd grades. The top two grades of FSB showed higher % ACE inhibition than the 3rd grade FSB. All FSBs had equally strong H2O2 quenching and iron chelating abilities. It was observed that FSB fractions with smaller molecular weight and higher hydrophobicity possessed higher antioxidant and anti-ACE activities. This work demonstrated that the manufacturing fermentation time affected activities of FSB peptides. Understanding of composition and bioactivities of the FSBs may lead to the development of value-added functional products from these manufacturing wastes.