Development of a Cabernet Gernischt Grape Polysaccharide Nanoemulsion for the Preservation of Fleshy Prawn ( Litopenaeus vannamei )

Fleshy prawns (Litopenaeus vannamei) have high moisture and protein contents as well as active endogenous enzme activity, so they are particularly susceptible to microbial spoilage and quality deterioration during storage. This underscores the urgent need for the development of green and efficient preservation technologies. In this study, homogeneous Cabernet Gernischt polysaccharides (CGP) were extracted from Cabernet Gernischt grape pomace through fermentation with Bacillus altitudinis. The molecular weight of CGP was found to be 153.82 kDa, with a galacturonic acid content of 49.57%. High-energy ultrasonic emulsification was employed to prepare four groups of CGP nanoemulsions (CGP-NE) at varying concentrations. A fleshy prawn coating preservation experiment was performed, with 0.5% CGP solution as the positive control and ultrapure water as the blank control. The results indicated that the 1.5% CGP-NE group exhibited the most effective preservation: after 8 days of storage, the fleshy prawn in this group showed a water loss rate of 12.67%, a pH value of 7.16, a total viable count (TVC) of 5.01 log CFU/g, and a thiobarbituric acid value (TBA) of 0.51 mg/100 g, significantly inhibiting microbial proliferation and lipid oxidation. This study demonstrates the high-value utilization of by-products from the wine industry, and the developed CGP-NE, as a novel type of edible preservation coating material, holds significant promise for enhancing the resource utilization of agricultural waste and reducing food loss.