Chemical quality and sensory attributes of marinated Pacific saury (Cololabis saira) during vacuum-packaged storage at 4 °C

This study was carried out to evaluate the chemical changes and sensory attributes of Pacific saury (Cololabis saira), brined (12% NaCl brine solution) or marinated (12% NaCl + 2% acetic acid; or 12% NaCl + 3% acetic acid solutions) followed by vacuum-packaging and storage at 4 °C for 90 days. The chemical analysis revealed a significant reduction in the pH value, total volatile bases nitrogen (TVBN), and trimethylamine (TMA) contents in marinated versus brined fillets. Lipid oxidation, as indicated by the 2-thiobarbituric acid (TBA) values, was significantly delayed in marinated fillets in comparison with the brined fillets. The growth rate of psychrotrophic bacteria was significantly (P < 0.05) reduced in marinated versus brined fillets. No significant differences were detected for the sensory attributes between the two marinating conditions although the overall acceptability was significantly higher in marinated versus brined fish. Both conditions of the marinating process resulted in an extension of the shelf life of the product to more than 90 days versus only 60 days for the control brined fillets. The study concluded that marination of Pacific saury can delay the undesirable chemical changes, retard lipid oxidation, improve the sensory attributes and extend the shelf life of the product during refrigerated storage.     

盐浓度及温度对秋刀鱼干制作中组胺生成的影响

鱼在海水中易被组胺菌污染,并且秋刀鱼干在制作过程中,是在常温下晒干,易造成组胺菌的生长繁殖,可能会产生相应的组胺。本实验以不同的盐浓度(5%、10%、20%)制备鱼干,以不同的温度(20℃,25℃)保存6 d,每天取样测定鱼肉中组胺的变化量。结果表明随着盐浓度的增高,组胺生成量逐渐减少,而且25℃比20℃生成的组胺含量高。     

腌制时间对清蒸刀鱼食用品质及组织结构的影响

针对刀鱼不腌制即熟制存在质地粗糙、鲜味不足、腥味较大等缺陷,对其宰后的合理腌制时间进行研究。取江苏连云港产刀鱼腌制不同时间后蒸制成熟,检测其品质指标的变化,并通过微观表征鉴定其组织结构的食用状态。结果表明：刀鱼肉在25 ℃腌制30 min最佳,此时清蒸刀鱼肉硬度最低,约为3.13 N,黏附性和胶黏性较小,分别为0.57 Pa和1.76 N,弹性达到8.22 mm,同时持水率高达22%,此时鱼肉失水率小,易于咀嚼,口感较好,同时微观组织结构表征也印证了以上结论。     

秋刀鱼抗氧化肽制备及其抗氧化活性的研究

本文选择胰酶对秋刀鱼蛋白进行酶解,以蛋白质利用率和氧化自由基吸收能力(ORAC值)为指标,运用响应面分析法优化秋刀鱼蛋白制备抗氧化肽的酶解工艺,并且对酶解产物的特性进行了研究。结果表明:最优酶解条件为加酶量1085 U/g蛋白,水料比3:1,酶解时间8 h时,此时蛋白质利用率和ORAC值分别为76.86%和883.40μmol Trolox equivalent/g。秋刀鱼酶解产物的总氨基酸含量为4576.69 mg/100 mL,其中游离氨基酸和肽态氨基酸分别占34.28%和65.31%;总氨基酸中必需氨基酸占34.76%,抗氧化活性氨基酸和支链氨基酸占26.25%,说明秋刀鱼酶解产物具有较高的营养价值。秋刀鱼酶解产物中相对分子质量在1000~3000 Da之间的组分最多,占44.18%。秋刀鱼酶解产物清除DPPH·的IC50值为3.32 mg/mL,清除O2-·的IC50值为5.08 mg/mL,当秋刀鱼酶解产物的蛋白浓度为10 mg/mL时,其吸光值为0.67,说明秋刀鱼酶解产物具有较高的抗氧化活性。     

充氮气热泵干燥对秋刀鱼干燥特性和品质的影响

为提高富含多不饱和脂肪酸的海水鱼的干燥品质,实验以秋刀鱼为原料,分别研究热风干燥、空气热泵干燥和充氮气热泵干燥3种干燥方式对半干秋刀鱼的干燥曲线、感官性质、色差、高铁肌红蛋白含量、酸价、过氧化值、硫代巴比妥酸值、挥发性盐基氮值及脂肪酸组成的影响。结果表明:热风干燥半干秋刀鱼的干燥效率高,但干燥品质差,脂肪氧化严重,感官评分最低;空气热泵和充氮气热泵干燥能提高半干秋刀鱼的干燥品质,经充氮气热泵制得产品脂肪氧化程度最低,产品的色泽好,感官评分最高。其酸价为10.01±0.20 mg/g,过氧化值为0.12±0.002 g/100 g,硫代巴比妥酸值为3.15±0.05 mg/kg,多不饱和脂肪酸的保留量为36.13%±4.31%,其中二十碳五稀酸和二十二碳六稀酸保留量为24.78%±2.70%;色差值为11.66±0.52,高铁肌红蛋白的相对含量为26.11%±0.64%。充氮气热泵干燥适用于富含多不饱和脂肪酸的海水鱼的干燥,是制备高品质半干秋刀鱼的理想干燥方式。     

Quality assessment of ready-to-eat Pacific saury (Cololabis saira) using microwave-assisted thermal sterilisation combined with olive oil vacuum impregnation

Although microwave-assisted thermal sterilisation (MATS) held great potential to sterilise ready-to-eat (RTE) products compared with traditional retort sterilisation, the quality improvement effect of MATS treatment on shelf-stable RTE products has not been extensively studied. This study was performed to evaluate the efficacy and applicability of MATS combined with olive oil vacuum impregnation against lipid oxidation and microbial growth in RTE Pacific saury during storage. MATS combined with olive oil vacuum impregnation (MTSO) effectively reduced processing time (by 57%) compared to retort-treated RTE Pacific saury at the same thermal lethality value. The lower cooking loss (6.19%) and colour damage indicated that MTSO enhanced water retention and the stability of tissue structure compared to retort-treated group (9.88%) or no olive oil group (7.11%). Lipid oxidation and protein degradation were effectively inhibited in MATS groups compared to retort-treated ones during storage; such effect was more effective in olive oil impregnated group. Likewise, microbial activity and electronic sensory evaluations showed that the shelf life of MTSO group was extended by 1 week compared to retort-treated groups. Overall, MTSO had considerable industrial potential to yield RET Pacific saury and even RTE products with better quality attributes than retort-treated ones.     

Effect of marinating process on the microbiological quality of Pacific saury (Cololabis saira) during vacuum-packaged storage at 4 °C

This study was carried out to evaluate the microbiological quality of Pacific saury ( Cololabis saira ) treated with marinating solutions containing either 12% NaCl + 2% acetic acid or 12% NaCl + 3% acetic acid, followed by vacuum packaging and storage at 4 °C for 90 days. The fish-to-marinating-solution ratio was 1:1.5. The growth rate of aerobic, halophilic, lactic acid bacteria and Pseudomonas spp. were significantly ( P  < 0.05) reduced in marinated vs. brined (12% NaCl + 0% acetic acid) fillets. Complete inhibition in the growth of both Enterobacteriaceae and Staphylococcus aureus was detected in fillets marinated in 3% and 2% acetic acid by the days 30 and 50 of storage, respectively. Both marinating conditions resulted in shelf life extension of the product to more than 90 vs. 60 days only for the brined fillets. Listeria monocytogenes , Vibrio parahaemolyticus and Salmonella spp. could not be detected in any of the analysed raw or treated samples.     

Changes of radical-scavenging capacity and ferrous reducing power in chub mackerel Scomber japonicus and Pacific saury Cololabis saira during 4 °C storage and retorting

To clarify the effects of freshness of raw fishes and boil-retort process on the antioxidant activities, we determined stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging capacity and ferrous reducing power in the ethanol extract solution of chub mackerel Scomber japonicus and Pacific saury Cololabis saira meat before and after retort process (115 °C for 80 min). The antioxidant activities in boiled (mizu-ni) and canned fish were also investigated. The mizu-ni can products contain only fish meat and little salt. The radical-scavenging capacity was increased about ten times in chub mackerel and about six times in Pacific saury by the retort treatment. Both antioxidant activities of raw chub mackerel meat increased during 10 days storage at 4 °C. On the other hand, the increasing of antioxidant activity in the stored and retorted meat was observed until four days storage. In the case of mizu-ni canned products, the antioxidant activities were high in common-grade cans rather than high-grade cans. Almost the antioxidant activities shown in this study were correlated with absorbance at 245 nm. We consider that the results about differences of antioxidant activities between raw and retorted fishes or fresh and several day stored fishes are useful for the food functions and safeties.     

响应面法优化秋刀鱼酶解制备抗氧化活性肽的工艺

采用酶解法从秋刀鱼肌肉中提取抗氧化活性肽,以水解度(DH)、TCA-可溶性肽含量、DPPH自由基清除率、Fe3+还原力、·OH清除率以及O2?·清除率为指标,从六种商业用酶中(中性蛋白酶、碱性蛋白酶、风味蛋白酶、木瓜蛋白酶、菠萝蛋白酶、胰蛋白酶)筛选出最适蛋白酶.以料液比、酶添加量、酶解时间、温度、pH五个因素进行单因...