超高压处理对牡蛎（Crassostrea gigas）杀菌及贮藏品质的影响

摘要

Oyster (Crassostrea gigas) is popular seafood with delicious taste and rich nutrients. The produce of oyster in China was as large as 4,352,000 tons in 2014. In this study we investigated the effects of high pressure processing (HPP) and cold storage on microbial inactivation, the total volatile basic nitrogen (TVB-N), and the pH of oysters. Tastes of oysters after HPP and heat processing were compared. It was found that there was an over 2-lg reduction in the total number of bacterial colonies after 300 MPa processing for 15 min. Similar results were observed under conditions such as 400 MPa for 10 min or 15 min, and 500 MPa for 5 min, 10 min or 15 min. Particularly when treated at 500 MPa for 10 min, no colony in oysters could be detected. The results above indicated that HPP treatment could effectively suppress the microorganisms in oysters. The shelf life of raw-eaten oysters could be extended to 15 days when stored at 4℃ after HPP treatments such as 300 MPa for 15 min, 400 MPa for 10 min, and 500 MPa for 5 min. TVB-N was also effectively inhibited by HPP treatments. The TVB-N level remained<10 mg/100 g in 20 days when stored at 4℃ after HPP at 300 MPa for 15 min. Oysters treated with HPP had significantly higher pH value and hardness compared to the untreated (P<0.05), and the springiness was also increased. The electric nose test detected no significant difference in taste between HPP-treated and the untreated oysters. However, the taste of heat-treated oysters was apparently different from those of HPP-treated and the untreated. These results indicated that HPP treatment might be an effective non-thermal processing technology. HPP with proper conditions could efficiently extend the shelf life of raw-eaten oysters and improve their quality.%以牡蛎(Crassostrea gigas)为研究对象，研究了不同超高压处理条件对牡蛎体内微生物的消减作用，分析了冷藏过程中挥发性盐基氮(TVB-N)和 pH 值的变化情况，对比了热加工和超高压处理对牡蛎滋味的影响。结果显示，经300 MPa 处理15 min、400 MPa 处理10、15 min 和500 MPa处理5、10和15 min 后，牡蛎体内的菌落总数均有2个对数以上的减少，表明超高压处理能有效消减牡蛎体内的微生物；牡蛎经300 MPa 处理15 min、400 MPa 处理10 min 和500 MPa 处理5 min，在4℃冷藏条件下保存，货架期延长至15 d；超高压处理能有效抑制牡蛎在4℃贮藏过程中挥发性盐基氮的产生，牡蛎经300 MPa 处理15 min，冷藏20 d 后 TVB-N 值仍小于10 mg/100 g，符合生鲜牡蛎要求；滋味方面，与加热处理相比，超高压处理后牡蛎更接近生鲜牡蛎，尤其300 MPa 处理15 min 的牡蛎同生鲜牡蛎最为接近。研究表明，选取300 MPa 处理15 min 作为牡蛎加工的最佳处理条件，即能有效消减牡蛎体内的微生物，同时能很好地保持牡蛎品质。