Application of Orange Peel Extract as a Natural Preservative for Refrigerated Nobashi Shrimp

Abstract

Pacific white shrimp, Litopenaeus vannamei, is one of the most extensively cultured shrimp species worldwide and is highly susceptible to biochemical and microbial deterioration during refrigerated storage. The present study aimed to evaluate the effectiveness of orange peel extract (OPE) as a natural preservative for improving the quality and shelf life of coated Nobashi shrimp under refrigerated conditions (<4 °C). Orange peel extract was prepared from dried orange peels by methanolic extraction (1:10 w/v) followed by concentration using a rotary evaporator. Stretched Nobashi shrimp were treated with 3.5% OPE, 150 ppm Butylated Hydroxytoluene (BHT), and distilled water as the control, packed in polypropylene pouches, and stored under refrigeration for 15 days. Quality changes were assessed through biochemical, microbiological, sensory, colour, and texture analyses. OPE-treated samples exhibited significantly lower microbial counts (6.6 log CFU/g on Day 15) than the control samples (7.4 log CFU/g), while the BHT-treated samples showed the lowest microbial count (3.9 log CFU/g). Lower peroxide value (1.10 meq O₂/kg fat) and TBARS value (1.10 mg malondialdehyde/kg meat) were also observed in OPE-treated samples compared to the control, demonstrating reduced lipid oxidation. Total volatile base nitrogen (TVBN) values of OPE-treated shrimp remained within acceptable limits up to the 12th day of storage, while control samples exceeded the permissible limit earlier. Sensory evaluation revealed better overall sensory acceptability than the BHT-treated shrimp while maintaining comparable texture characteristics. The study demonstrates that orange peel extract can serve as an effective natural preservative for coated Nobashi shrimp, extending refrigerated shelf life by approximately 3 days compared to the untreated control while maintaining acceptable biochemical, microbial, and sensory quality.