对虾营养丰富，但极易腐败变质，为研究紫菜多糖提取物对冷藏对虾品质的影响，延长冷藏对虾的货架期。本文将0.8%紫菜多糖处理的对虾和对照组贮存在(4±1) ℃的冰箱中8 d，在第0、2、4、6、7和8 d进行品质评价。通过测定生物指标（菌落总数）、化学指标（pH值、挥发性盐基氮(TVB-N)、硫代巴比妥酸(TBA)值和K值）和感官评分来评价冷藏过程中对虾的品质变化。结果表明，紫菜多糖处理的对虾，在冷藏过程中细菌总数、pH值、TVB-N、TBA值和K值显著低于对照组，感官评分也显著低于对照组。紫菜多糖处理的对虾相对对照组延长货架期3~4 d。紫菜多糖提取物在对虾冷藏保鲜过程中能有效抑制细菌繁殖，减缓脂肪氧化，延长对虾的货架期，在对虾冷藏保鲜中具有良好的应用前景。

Prawns are nutritious, but are susceptible to spoilage. The aim of this study was to investigate the effect of polysaccharides extracted from Porphyra on the quality of prawns during cold storage, in order to prolong the shelf life of cold-stored prawns. The prawns treated with 0.8% polysaccharides from Porphyra, and those from the control group were stored in a refrigerator at 4 ± 1 ℃ for 8 days. The sensory quality of the prawns was assessed on days 0, 2, 4, 6, 7, and 8. The biological index (total bacterial count) and chemical indices (pH value, total volatile basic nitrogen [TVB-N], thiobarbituric acid [TBA], and K value) were measured, and a sensory evaluation performed in order to assess the change in the quality of prawns during cold storage. The results of these analyses showed that prawns treated with polysaccharides from Porphyra had significantly lower total viable count, pH, TVB-N, TBA, K value, and sensory scores, compared to the control group. Polysaccharides from Porphyra extended the shelf life of prawns by 3 to 4 days than that of the control group, during cold storage. Hence, polysaccharides extracted from Porphyra effectively inhibited the propagation of bacteria and slowed the anti-oxidation of fat, thereby prolonging the shelf life of prawns. Therefore, this method could be applied for the preservation of prawns during cold storage.

“十二五”国家科技支撑计划(2012BAD29B06)；辽宁省食品安全重点实验室开放课题(LNSAKF2011016)