Department of Chemistry, Laboratory of Food Chemistry and Food Microbiology, University of Ioannina, Ioannina 45110, Greece.
Food Microbiol. 2010 Feb;27(1):115-21. doi: 10.1016/j.fm.2009.09.002. Epub 2009 Sep 15.
The present study evaluated the effect of salt, oregano essential oil (EO) and packaging on fresh rainbow trout fillets during storage at 4 degrees C. Treatments included the following: A1 (control samples, unsalted: air packaged), A2 (salted: air packaged), VP1 (salted, vacuum packaged), VP2 (salted, vacuum packaged with added oregano EO 0.2% v/wt), and VP3 salted, vacuum packaged with added oregano EO 0.4% v/wt). Lactic acid bacteria (LAB) (to a greater extent), followed by H(2)S-producing bacteria (including Shewanella putrefaciens), Pseudomonas spp. and Enterobacteriaceae reached higher populations in A1, A2 (as compared to VP1, VP2 and VP3) trout samples. Treatments VP1, VP2 and VP3 produced significantly lower (P < 0.05) total volatile basic nitrogen (TVBN) and trimethylamine nitrogen (TMAN) values as compared to the A1 and A2 samples after day 6 and until end of storage period. Changes in thiobarbituric acid values (TBA) values for A1, A2, VP1, VP2 and VP3 samples were variable, indicative of no specific trend in trout samples, irrespective of packaging in the absence and/or presence of salt and oregano EO. As determined by sensory analysis (overall acceptability attribute) the observed shelf-life of trout fillets was longest for VP2 (16-17 days) followed by VP1 (14 days), A2 (8 days) and control (A1) samples (5 days). The presence of salt and oregano oil (0.2%) in cooked VP1 trout samples produced a distinct but sensorially acceptable pleasant odor, well received by the panellists, in contrast to the combined effect of salt and oregano oil at the higher concentrations (0.4% v/wt) used. Addition of salt (treatment VP1) extended the product's shelf-life by 9 days, whereas the combination of salt, oregano EO (0.2% v/wt) under VP conditions (treatment VP2) resulted in a significant shelf-life extension of trout fillets (11-12 days) according to sensory data, as compared to the control sample, kept under aerobic conditions.
本研究评估了盐、牛至精油（EO）和包装对 4°C 下新鲜彩虹鳟鱼片的影响。处理包括以下几种：A1（对照样品，未加盐：空气包装）、A2（加盐：空气包装）、VP1（加盐，真空包装）、VP2（加盐，真空包装加 0.2%牛至 EO v/wt）和 VP3（加盐，真空包装加 0.4%牛至 EO v/wt）。在 A1 和 A2 鳜鱼样品中，乳酸菌（LAB）（在更大程度上）、其次是产生 H（2）S 的细菌（包括腐败希瓦氏菌）、假单胞菌属和肠杆菌科的细菌数量较高。与 A1 和 A2 样品相比，处理 VP1、VP2 和 VP3 在第 6 天和储存期结束时产生的总挥发性碱性氮（TVB-N）和三甲胺氮（TMA-N）值显著较低（P<0.05）。A1、A2、VP1、VP2 和 VP3 样品的硫代巴比妥酸值（TBA）变化各不相同，表明鳜鱼样品没有特定的趋势，无论是否存在盐和牛至 EO，包装都没有影响。根据感官分析（整体可接受性属性）确定，鳜鱼片的观察保质期最长的是 VP2（16-17 天），其次是 VP1（14 天）、A2（8 天）和对照（A1）样品（5 天）。在煮熟的 VP1 鳜鱼样品中添加盐和牛至油（0.2%）会产生一种独特但感官上可接受的宜人气味，受到品尝者的欢迎，而在使用较高浓度（0.4% v/wt）的盐和牛至油的组合中则会产生相反的效果。添加盐（VP1 处理）将产品的保质期延长了 9 天，而在 VP 条件下添加盐和牛至 EO（0.2% v/wt）（VP2 处理）则使鳜鱼片的保质期显著延长（11-12 天），与对照样品相比，在有氧条件下保存。
