Application of electrolyzed oxidizing water on the reduction of bacterial contamination for seafood

For reducing bacterial contamination, electrolyzed oxidizing water (EO water) has been used to reduce microbial population on seafood and platform of fish retailer. The specimens of tilapia were inoculated with Escherichia coli and Vibrio parahaemolyticus, and then soaked into EO water for up to 10 min. EO water achieved additional 0.7 log CFU/cm² reduction than tap water on E. coli after 1 min treatment and additional treatment time did not achieved additional reduction. EO water treatment also reduced V. parahaemolyticus, by 1.5 log CFU/cm² after 5 min treatment and achieved 2.6 log CFU/cm² reduction after 10 min. The pathogenic bacteria were not detected in EO water after soaking treatment. In addition, EO water could effectively disinfect the platform of fish retailer in traditional markets and fish markets.     

Supplemental dietary flaxseed oil affects both neutral and phospholipid fatty acids in cultured tilapia

This work aimed to evaluate the neutral lipid (NL) and phospholipid (PL) classes in tilapia (Oreochromis niloticus) muscle tissue. Tilapias were raised in captivity for a period of 5 months with increasing levels (0, 1.25, 2.50, 3.75, and 5.00%) of flaxseed oil [source of α‐linolenic acid (LNA), 18:3n‐3] in substitution for sunflower oil (control). The NL/PL ratio was 1.9, and 45 fatty acids were determined for both classes of lipid. The class totals of n‐3 acids always increased in all treatments, while the totals for n‐6 acids always decreased (p <0.05). For a given level of flaxseed oil, the LNA contents were consistently higher, including EPA (20:5n‐3) and DHA (22:6n‐3). Arachidonic acid (20:4n‐6) remained high in the PL but was reduced as levels of dietary flaxseed oil were increased. The n‐6/n‐3 ratios decreased significantly with the rise in flaxseed oil content in all treatments, and highly unsaturated fatty acid contents increased with the levels of flaxseed oil. Overall, the influence of flaxseed oil on the fatty acid composition in the contributing NL and PL classes was to increase n‐3 PUFA, thus raising the nutritional value of this freshwater fish meat and, consequently, contributing to the health of consumers.     

SPME-GC-MS测定红曲霉发酵半干罗非鱼的挥发性成分

利用红曲霉发酵半干罗非鱼,得到具有典型鱼腊味,香气浓郁的发酵制品.利用聚二甲基硅氧烷/二乙烯基苯型涂层纤维萃取头(PDMS/DVB),通过固相微萃取和气质联用技术(SPME-GC-MS)测定未发酵与发酵两组的挥发性成分,分别测定出51和75种物质,发酵组中醛类和醇类含量较高,胺类种类增多.其中发酵组中的壬醛、辛醛、辛醇、1-辛烯-3-醇、乙醇等是发酵罗非鱼的主要风味来源.     

冻罗非鱼片加工技术工艺研究

本文对冻罗非鱼片的加工工艺技术、操作要点和加工、贮藏注意事项作了详细的介绍.并提出了对冻罗非鱼片的产品质量要求.     

罗非鱼鱼皮鱼鳞蛋白的酶解及超滤分离

采用Alcalase2.4L、Protamex、Papain、PTN6.0S和Neutrase酶解罗非鱼鱼皮鱼鳞蛋白,探讨了超滤对酶解液分子质量分布和氨基酸组成的影响。结果表明,Alcalase2.4L、PTN6.0S酶解产物的蛋白质回收率、肽得率和水解度均较高,Alcalase2.4L∶PTN6.0S为1∶2添加时酶解效果最好,蛋白回收率为96.37%,水解度为13.24%,肽得率为83.13%。经超滤处理后,3000 u以下分子质量的肽段达到97.73%,比超滤前增加了5.37%,总氨基酸含量由84076.12 mg/100 g增加到97234.79 mg/100 g。     

尼罗罗非鱼暂养阶段挥发性成分的变化

以尼罗罗非鱼为原料,通过固相微萃取和气质联用仪对挥发性成分进行萃取和分离鉴定,测定尼罗罗非鱼肉的气味组成,并对暂养阶段的挥发性成分变化做初步分析。结果表明:从尼罗罗非鱼肉中检测出挥发性醛类、烷烃类、芳烃类、醇类、酯类和烯类等31种有效成分,其中含量由高到低依次为醛类、芳烃类和烷烃类,暂养初期和末期分别占挥发性化合物总量的36.97%、17.85%、20.70%和44.49%、34.65%、8.66%。暂养时间为8d时,辛醛和壬醛含量有明显的下降,有利于脱除不良风味;辛三烯和环己烯同时未检出,消除了不良气味的潜在因素;苯甲醛、苯环芳烃类物质含量相对于0d也有一定程度的增加,这有利于罗非鱼良好风味的形成。     

利用罗非鱼加工下脚料发酵鱼露的研究

本研究利用加工罗非鱼生产的下脚料来发酵鱼露,加入35%的海盐(m/m)发酵180 d,定期检测各项理化指标,并对鱼露成品进行了感官评定.试验结果表明:用罗非鱼加工下脚料发酵鱼露成品的T-N和A-N含量分别为18.27 mg/mL,9.05 mg/mL,均达到一级鱼露的标准,非酶褐变指数和TVB-N随着发酵时间的延长呈上升趋势,pH值随着发酵时间的延长,逐渐下降.所得鱼露中含有丰富的精氨酸、谷氨酸、丙氨酸、赖氨酸、亮氨酸等,并且QDA-test结果表明具有强烈的鲜味、咸味和氨味等.     

罗非鱼片热泵干燥时间及品质影响因素的初步研究

对罗非鱼片在不同干燥条件下的工艺进行了研究。结果表明,干燥温度、风速以及鱼片的厚度都是影响热泵干燥罗非鱼片的重要因素。在干燥温度35℃,风速1．6m／s,厚度0．4～0．5cm的工艺条件下,产品的干燥速度较快,在复水时间50min时复水率最高。     

罗非鱼骨制备CMC活性钙的工艺及生物利用的研究

为了充分利用罗非鱼骨这一丰富的钙源，本文采用柠檬酸和苹果酸混合酸对罗非鱼骨粉进行CMC钙的制备工艺研究，并以Wistar大白鼠为模型，评价该产品的生物利用率。结果表明：以柠檬酸和苹果酸按3：2的浓度比混合，在121℃的高温下提取罗非鱼骨粉1h，取上清液调pH中性，然后进行浓缩烘干，钙提取率为92．1％，产品在热水中溶解度达88％。动物代谢实验显示，与实验对照组比较，CMC活性钙组无论是在血钙、骨钙和存留率方面均有不同程度的增加，比碳酸钙更易被机体吸收利用。     

鲜姜汁对罗非鱼蛋白质水解作用的研究

利用鲜姜汁水解罗非鱼肉蛋白质。以水解度及水解液中可溶性蛋白、可溶性固形物为指标,分析了水解温度、时间、pH、料液比以及加姜汁量对水解效果的影响,并采用L16(45)正交实验优化水解条件。确定水解条件为:料液比1∶3(m/v,g/mL),姜汁加量为0.3mL/g(E/S),水解温度45℃,时间2.0h、pH8.0。实验结果:水解液中氨基态氮含量为1.412g/L,水解度为22.49%,可溶性蛋白19.28g/L,可溶性固形物5.75%。水解液无腥味,呈淡黄色。