Study on applying biological activity components from the extracts of ginger (Zingiber officinale) and galangal (Alpinia officinarum) for preserving whiteleg shrimp (Litopenaeus vannamei)

Abstract

Whiteleg shrimp (Litopenaeus vannamei) is a kind of brackish shrimp with high productivity, and the shrimp meat has high nutritional values; therefore, it has been raised in many regions throughout of Vietnam. The output of whiteleg shrimp has been constantly growing in recent years, so it is not only a plentiful raw material source for domestic consumption but also a large proportion for export. Seafood (in cluding shrimps) is a type of easily damaged materials after harvesting due to self-decomposition process and microbial contamination if improperly preserved. Exploiting of safe and natural components with antibacterial and anti-oxidant properties from ginger and galangal to preserve whiteleg shrimp after harvest to extend preservation time and ensure the quality, replacing unsafe chemicals is an essential direction in Vietnam today. The study has been conducted for the preservation of whiteleg shrimp after harvest with safe additives as well as ginger and galangal extracts in combination with additives. During the preservation process, the quality of whiteleg shrimp through the physicochemical criteria (pH, NH₃), microbiological and sensory indicators showed the clear effect of ginger and galangal extracts. When combining ginger and galangal extract in ethanol/water solvent at the ratio of 1/1 with the addition of nisin 200 ppm and chitosan 0.5%, the preservation time of the post-harvest shrimp was extended to 10 days at 0-2^oC while ensuring the quality and food safety criteria. The result was initially applied to the postharvest shrimp preservation model at some whiteleg shrimp preservation and purchasing establishments in Nui Thanh district (Quang Nam province), and exhibited good outcomes.