Antioxidant and antimicrobial activities of Ethanolic Jik (Barringtonia acutangula) leaf extract and its application for shelf-life extension of Pacific white shrimp meat during refrigerated storage

Plant extracts can serve as natural preservatives in seafood and they are gaining a tremendous amount of attention due to the deleterious effects of the synthetic counterparts. Despite the several advantages of plant extracts particularly in terms of safety, green color caused by chlorophylls limit their uses. In this study, ethanolic plant leaf extracts from some Thai indigenous plants including Noni, soursop, and Jik, were prepared, followed by dechlorophyllization via sedimentation method. Chlorophyll a, chlorophyll b and total chlorophyll were removed by more than 60%. The extraction yield, total phenolics and total flavonoids, antioxidant, and antibacterial activities of all the dechlorophyllized ethanolic plant leaf extracts varied. Among all the extracts, Jik leaf extract (JLE80) prepared using 80% ethanol showed the highest antioxidant and antibacterial activities. LCMS/MS profiling revealed that quercetin 3-(2-galloylglucoside) was the most abundant phenolic compound in JLE, which more likely played a significant role in its antioxidant and antimicrobial functions. When butterfly shrimp (BS) was treated with JLE (200-600 mg/L) and stored at 4 ᵒC for 15 days, BS treated with JLE at 400 and 600 mg/L had the retarded bacterial spoilage and chemical deterioration as indicated by lower microbial counts and lipid oxidation. As a result, the shelf-life of BS was extended to 12-15 days, whereas the control could be kept for 9 days.