冷冻和冰鲜处理对新疆高白鲑鱼片理化指标和腐败菌的影响

Effects of frozen and fresh treatments on physical,chemical and spoilage bacteria of Xinjiang peled Coregonus peled fillets

为研究经不同加工处理后的高白鲑鱼Coregonus peled在低温贮藏过程中品质的变化,以冷冻和冰鲜处理的新疆高白鲑鱼片为研究对象,研究了其经物流运输后在4℃贮藏过程中物理指标(汁液损失率和剪切力)和化学指标[p H、硫代巴比妥酸(TBA)和挥发性盐基氮(TVBN)值]的变化,并建立了基于Baranyi模型的微生物生长动力学曲线,分析了菌落总数及假单胞菌、产硫菌和肠杆菌在贮藏过程中的动态变化。结果表明:冷冻和冰鲜处理的鱼片经物流运输后汁液损失率、TVBN值均随贮藏时间的延长而增加,TVBN值分别在第11天和第13天时超过20 mg/100 g的标准限值,p H值均呈先降低后升高的趋势,剪切力和TBA值在第5~7天时达到最高值;冷冻和冰鲜处理鱼片菌落总数分别在第6.8天和第7.0天时达到货架期限值[7 log(CFU/g)];贮藏初期鱼片的腐败菌以假单胞菌为主,而在贮藏过程中肠杆菌的生长速率高于假单胞菌和产硫菌,成为优势腐败菌,且冷冻处理的鱼片更有利于优势腐败菌的生长繁殖。研究表明,冰鲜处理更有利于新疆高白鲑鱼片的贮藏。

Drip loss rate,shear force value（ SFV）,p H,thiobarbituric acid（ TBA）,total volatile base nitrogen（ TVBN） and spoilage bacteria were monitored in fillets of frozen and fresh Xinjiang peled Coregonus peled stored at4 ℃ after transportation in order to investigate the influence of frozen and fresh treatments on susceptibility of microbiological and chemical spoilage after long-distance transport and stored during chilling storage. The microbial population changes against storage time were fitted to evaluate account of flora and dynamics of Pseudomonads spp.,thiogenic bacteria and enterobacteria during storage using the Baranyi equation. The results showed that the drip loss rate and TVBN of the fresh and frozen processed peled fillets were found to be increased as elapse of transport during the chilled storage,exceeding the limit TVBN value of 20 mg/100 g at 11 day storage in the frozen processed fillets and at 13 day storage in fresh processed fillets. The p H of all samples was increased first and then decreased,with the maximal SFV and TBA in 5 or 7 day storage. The shelf-life at bacterial flora count of log（ CFU/g） was observed in 6.8 day storage in the frozen processed fillets and in 7.0 day storage in fresh processed fillets. In the initial storage period,Pseudomonads spp. was the dominant microorganism,and members in Enterobacteriaceae became the dominant spoilage bacterium,which was suitable for growth in the frozen processed peled,during chilled storage due to better growth of Pseudomonads spp. and thiogenic bacteria. The findings indicated that the fresh processed peled fillets was of more suitable for storage.