Conservation and quality of grumatã (Prochilodus lineatus) fillets after different depuration periods and frozen storage

Abstract The aim of this study was to evaluate the physicochemical, microbiological, sensory and meat quality characteristics of grumatã fillets after different depuration (0, 48, 72 and 96 h) periods and frozen storage (0, 2, 4 and 6 months). The fish collected in a dam were distributed in tanks at a density of 3.8 kg m3 -1. After depuration periods, all fish were filleted and the fillet samples stored (−18 °C) until analyses. Lower fat content was found in fish submitted to depuration for 48 and 96 h compared to the non-depurated and those depurated for 72 h. Muscle protein was preserved in 48 and 96 h treatments. Coagulase-positive Staphylococcus, coliforms at 45 °C and Salmonella spp. were not observed in the fillets, but aerobic mesophilic microorganisms and coliforms at 35 ºC were detected. Sensory analysis showed no significant differences in appearance, colour, texture, flavour attributes and overall acceptance. During frozen storage, pH, total volatile basic nitrogen (TVB-N), peroxide and thiobarbituric acid reactive substance (TBARS) values were evaluated in fillet samples every two months. The pH values increased up to four months of storage. The TVB-N values ranged in fillets from fish depurated for 48 and 96 h. Peroxide values increased from the fourth month of storage, with the highest values observed in the sixth month. For TBARS values, increased values were found in fillets from non-depurated fish and lower values in other depuration periods. Thus, depuration is more efficient in maintaining the quality of grumatã fillets in frozen storage.

摘要 本研究旨在评估不同净化（depuration）时长（0、48、72及96小时）及冷冻储存时长（0、2、4及6个月）后，grumatã鱼片的理化、微生物、感官及肉品质特性。
从水库采集的grumatã鱼以3.8 kg·m⁻³的密度放养于养殖槽中。经对应时长的净化处理后，对所有试验鱼进行取片操作，所得鱼片样品均储存于−18 ℃环境中直至后续检测分析。
与未净化组及净化72小时组相比，净化48小时与96小时组的鱼体脂肪含量显著更低。肌肉蛋白含量在净化48小时与96小时组中得以有效保留。
鱼片样品中未检出凝固酶阳性葡萄球菌、45 ℃条件下的大肠菌群及沙门氏菌属，但可检测到需氧嗜温微生物与35 ℃条件下的大肠菌群。
感官分析结果显示，鱼片的外观、色泽、质地、风味属性及总体接受度均无显著差异。
在冷冻储存期间，每2个月对鱼片样品的pH值、总挥发性盐基氮（total volatile basic nitrogen, TVB-N）、过氧化值及硫代巴比妥酸反应物（thiobarbituric acid reactive substance, TBARS）水平进行检测。
结果显示，pH值随储存时长延长至4个月时呈上升趋势。净化48小时与96小时组鱼的鱼片总挥发性盐基氮值处于特定区间范围内。过氧化值自储存第4个月起开始上升，并于第6个月达到峰值。
对于硫代巴比妥酸反应物水平，未净化组鱼片的该指标显著升高，而其他净化时长组的该指标水平更低。
综上，净化处理可更有效地维持冷冻储存期间grumatã鱼片的品质。