中国水产食品质量及安全控制研究进展

随着经济全球化的深入发展和食品贸易的不断扩大,中国水产食品加工业发展非常迅速,其质量和安全性已成为影响大众消费和工业健康可持续发展的关键因素,引起社会的广泛关注。为了充分掌握现阶段中国水产食品的质量安全控制状况,以便有效控制水产品的质量安全,本文对我国水产食品及质量安全控制现状、国外的先进质量控制技术和监管体系进行分析,并在对我国水产食品目前存在的问题进行总结的基础上,提出改善水产食品质量及安全控制的建议和改进措施。     

三种添加物对聚乳酸复合膜性能影响

目的 研究聚乳酸复合膜的降解性能,加快聚乳酸材料降解速率。方法 选取淀粉、羧甲基纤维素钠（CMC）、聚乙二醇（PEG）等3种材料,与聚乳酸混合制备4种不同的复合膜。测定复合膜的透光率、力学性能、热性能等指标,使用红外光谱仪对复合膜的基团组成进行表征,使用磷酸盐缓冲液浸泡,测试其降解性能。结果 红外光谱结果显示PLA膜与PLA复合膜的吸收峰没有明显的差别,这证明改性材料与聚乳酸没有发生化学反应。复合膜的DSC曲线显示,添加改性剂后,熔融温度变化不大,无明显影响。降解性能方面,按PLA与复合物的质量比9∶1,8∶2,7∶3,6∶4,5∶5制备多种复合膜,其中质量比9∶1,7∶3,5∶5的PLA/淀粉复合膜在第70天降解率分别为24.11%,24.8%,35.6%;PLA/CMC复合膜的3种质量比降解率为27.64%,30.37%,45.2%。按照PLA与PEG质量比为99∶1,98∶2,97∶3,96∶4,95∶5制备了PLA/PEG复合膜,其中质量比为99∶1,97∶3,95∶5的PLA/PEG复合膜在第70天的降解率分别为25.45%,38.83%,45.83%。PLA/淀粉/PEG复合膜是在PLA/淀粉复合膜的基础上添加PEG制备的,复合膜成分与PEG的质量比为99∶1,98∶2,97∶3,96∶4,95∶5,其中99∶1,97∶3,95∶5这3种复合膜的降解率为40.52%,49.54%,55.67%。各种复合膜的降解率均远优于PLA膜2.5%的降解率。结论 复合材料的添加改变了聚乳酸薄膜的透光性能,增强了薄膜的拉伸强度和断裂伸长率。改性材料的添加能够在不影响聚乳酸本身结构的情况下,显著增强聚乳酸的降解率。     

杂交(鱼骨)鱼鱼肉的营养成分分析及比较

为了了解培育新品种杂交?鱼与父母代营养价值的差异,本文以罗非鱼对参照,比较了花?、唇?和杂交?鱼的基本营养成分、氨基酸和脂肪酸的营养价值。结果表明：与罗非鱼相比,三种?鱼具有高灰分低脂肪的特点,但基本营养成分差异不大;三种?鱼的甜味氨基酸Gly含量依次为杂交?（5.48%）>唇?（5.41%）>花?（5.05%）>罗非鱼（4.50%）,但三种?鱼的Gly含量及必需氨基酸含量之间无显著性差异（p>0.05）;三种?鱼的脂肪酸种类基本相同,但多不饱和脂肪酸（PUFA）含量更高,PUFA唇?（47.24%）显著性高于（p<0.05）PUFA杂交?（42.24%）和PUFA花?（35.02%）,PUFA杂交?（42.24%）显著性高于（p<0.05）PUFA花?（35.02%）,其中二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）总含量依次为唇?（18.39%）>杂交?（13.71%）>罗非鱼（11.90%）>花?（8.90%）。总之,花?鱼的氨基酸营养价值更高,是优质蛋白源;唇?鱼的脂肪酸营养价值更优;杂交?鱼的营养更全面。     

滚揉技术在肉制品加工中的应用研究进展

为进一步促进滚揉技术在现代肉制品加工中的应用,本文在阐明滚揉技术工作原理及其主要影响因素（真 空度、滚揉温度、滚揉时间、转速及滚揉方式）基础上,分析滚揉技术在肉制品加工中的应用现状以及滚揉技术与 现代食品加工新技术的联合应用研究进展。通过分析发现,滚揉技术在传统腌腊肉制品、西式肉制品和预调理肉制 品加工中的应用研究较多;在与食品加工新技术联合应用方面,主要有超声波、充气变压、脉动真空技术与滚揉技 术联合应用的报道。总之,滚揉技术在肉制品加工中的应用主要集中在产品品质改良和质量安全控制方面。     

Flavour formation in meat and meat products: a review

The characteristic flavour of cooked meat derives from thermally induced reactions occurring during heating, principally the Maillard reaction and the degradation of lipid. Both types of reaction involve complex reaction pathways leading to a wide range of products, which account for the large number of volatile compounds found in cooked meat. Heterocyclic compounds, especially those containing sulfur, are important flavour compounds produced in the Maillard reaction providing savoury, meaty, roast and boiled flavours. Lipid degradation provides compounds which give fatty aromas to cooked meat and compounds which determine some of the aroma differences between meats from different species. Compounds formed during the Maillard reaction may also react with other components of meat, adding to the complexity of the profile of aroma compounds. For example, aldehydes and other carbonyls formed during lipid oxidation have been shown to react readily with Maillard intermediates. Such interactions give rise to additional aroma compounds, but they also modify the overall profile of compounds contributing to meat flavour. In particular, such interactions may control the formation of sulfur compounds, and other Maillard-derived volatiles, at levels which give the optimum cooked meat flavour characteristics.     

Atlantic salmon (Salmo salar,L.) as raw material for the smoking industry. I: effect of different salting methods on the oxidation of lipids

The changes in total fat content, fatty acid composition, tocopherol, ascorbic acid, pH and oxidation were analysed in response to different salting methods, either dry or brine, in cold-smoked (20 or 30 °C) Atlantic salmon (Salmo salar, L.). The fish were lean ocean-ranched salmon caught at Iceland in June 1998 and farmed Norwegian salmon slaughtered in November 1998 and April 1999, differing in fresh fillet fat content from 84 to 169 g kg⁻¹ wet weight. The total fat content decreased in all groups during processing, whereas the relative fatty acid composition of the fillets was not severely affected during salting and cold-smoking. The most conspicuous process consumption of antioxidants in all the groups was the relative ascorbic acid loss (58–82%). Generally, no clear effect of different salting methods was observed on the tocopherol loss during processing, but brine salting had a stronger effect on both fat and ascorbic acid loss than dry salting. The fattiest fish showed the highest oxidation during processing and they lost more tocopherol, but the final oxidation levels were generally low (thiobarbituric acid reactive substances, TBARS: 6.0–14.7 μmol kg⁻¹), reflecting the antioxidative protection offered by the vitamins during processing.     

鱼体中汞残留量检测的样品前处理工艺优化

为了提高鱼体中重金属汞残留量检测的准确性,减少因为样品前处理工艺不当引起的样品中汞的损失,本研究以外加汞标液的方式,对鱼肉样品进行预处理,然后分析样品前处理过程中的赶酸温度、消解温度、双氧水助消解量、硼氢化钾浓度,对样品中汞的回收率影响。在此基础上,采用响应面法,对鱼肉样品的前处理工艺进行了优化。显著性分析结果显示,所构建的汞的回收率与各影响因素间的拟合模型具有显著性(p0.05),所得汞的回收率与各影响因素间具有较好的相关性(R2=95.33)。在对所得拟合模型的可靠性进行验证基础上,以汞的回收率最高为优化目标,对样品前处理工艺进行优化的结果显示,在赶酸温度88℃、消解温度171℃、双氧水用量1.2 mL、还原剂硼氢化钾浓度13 g/L时,鱼体中重金属汞的回收率最高,其回收率可达98.90%。总之,所得优化工艺对鱼肉样品前处理具有实际指导意义。     

Nano eggshell calcium enhanced gel properties of Nemipterus virgatus surimi sausage: gel strength,water retention and microstructure

The effects of nano eggshell calcium (NEC) at different levels (0–1.5 g/100 g) on the gel properties of Nemipterus virgatus surimi were investigated. The results indicated that under the condition of adding 1.0 g/100 g, the gel strength of surimi was the highest, the water-holding capacity (WHC) was the best, and the cooking loss was the lowest. Sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE) revealed that the addition of NEC promoted the covalent cross-linking between myosin heavy chains (MHC). Raman spectroscopy demonstrated that low contents (0.5–1.0 g/100 g) of NEC promoted the conformational transition of surimi protein from α-helix to β-sheet. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) showed that the surimi gel with 1.0 g/100 g NEC had a denser network structure. Nevertheless, in the mixed gel with 1.25–1.5 g/100 g NEC, the network structure of the mixed-protein matrix was disrupted, and the mechanical and physicochemical parameters were deteriorated.     

不同卤制方法对白鹅腿肉品质及挥发性风味成分的影响

以四川白鹅腿肉为原料,研究定量卤制、传统老汤卤制和白煮对其品质及挥发性风味成分的影响。感官品质分析结果表明,定量卤制鹅肉的感官评定得分高于传统卤制和白煮鹅肉;质构分析结果表明,定量卤制和传统卤制鹅肉剪切力和系水力均较白煮鹅肉有很大的提高,其中定量卤制效果最好。通过气相色谱-质谱联用(GC-MS)分析鹅肉的挥发性成分发现,定量卤制鹅肉中共鉴定出挥发性风味化合物61种,老卤鹅腿肉中共56种,白煮鹅腿肉中仅30种。在定量卤制鹅腿肉中,烃类、醇类、酮类、酯类和醚类成分的相对含量较老卤和白煮鹅腿肉高,而在老卤和白煮鹅腿肉中醛类成分的相对含量较高。定量卤制能够很好的保留香辛料的风味,以及鹅腿肉本身特征风味,使产品整体香味更加丰富浓郁,提高了香辛料的利用率和产品风味。