Cold shock in fish: its characteristics in bighead

A strong cold shock effect was demonstrated in bighead, and this was contrasted with the absence of any such effect in rainbow trout. The influence of chilling temperature and delayed icing on this effect was investigated. Bighead exhibited only weak rigor, which could be distinguished from the profound stiffening that followed icing. The degree of cold shock was similar when fish were chilled to 0, 2, 5 and 11°C, but the effect was not observed at 15 or 30°C. Bighead that were allowed to remain at ambient temperature before icing exhibited less pronounced stiffening when iced; the longer these periods at ambient temperature, the less rigid the fish became when iced. Fish allowed to enter rigor showed no increase in stiffness when subsequently iced.     

油炸鳙鱼头加工及其保藏性的研究

研究了油炸鳙鱼头的加工工艺,对保藏期间鳙鱼头的感官指标、菌落总数和挥发性盐基氮数值的变化进行了观察和检测,评价了不同保藏条件对油炸鳙鱼头货架期的影响.实验结果表明:采用油炸工艺、真空包装并结合适当低温贮藏能使产品的货架期达到90d.     

东洞庭湖鲢鱼和鳙鱼中重金属富集差异分析

为分析东洞庭湖水体中重金属污染情况以及鲢鳙鱼间重金属富集存在的差异性,测定东洞庭湖沉积物以及鲢鱼和鳙鱼不同组织中5种重金属(Cr、Cu、Cd、Pb和Hg)的含量。结果显示,沉积物中Cr的含量低于国家一级土壤标准限值,Cu、Pb和Hg低于二级土壤标准限值,Cd的含量是国家三级土壤环境标准值的6倍;鲢鱼和鳙鱼中重金属的分布排序均为Cr:鳃肝脑肉,Cu:肝脑鳃肉,Cd:肝鳃脑肉,Pb:鳃肝肉脑,Hg:肉肝脑鳃;根据鱼类的生物-沉积物富集因子,相比Cr和Pb,鲢鱼和鳙鱼都更易富集Cu、Cd和Hg,而鲢鱼比鳙鱼更易富集Cd,鳙鱼比鲢鱼更易富集Hg;另外,鲢鱼和鳙鱼肝脏中Cd的含量超出行业标准限量,其它组织中重金属均未超标。表明东洞庭湖中Cd的污染最为严重;不同鱼类对重金属的富集确实存在差异性,不同组织对同一重金属的富集能力也存在显著差异;相比较鱼鳃和肝脏,鱼肉和鱼脑对重金属的亲和能力较弱。     

Extraction of Essential Oil from Laurel Leaves by Using Microwaves

Abstract

The effects of microwave power and time in solvent-free microwave extraction (SFME) on the yield and composition of the essential oil obtained from laurel (Laurus nobilis L.) leaves were studied. The extraction was also performed by hydrodistillation as a control. Specific gravities and refractive indices of the essential oils obtained by different methods and at various conditions were also examined. The main constituent of laurel essential oil was 1,8-cineole (630–730 mg/mL). Essential oils obtained by SFME and hydrodistillation were comparable with respect to both yield and composition while the process time was reduced by 55–60% when SFME was used.     

Evaluation of the Chemical Composition and Antioxidant Activity of the Peel Oil of Citrus nobilis

Peel oil of Citrus nobilis (Lour) was analyzed for determining its chemical composition. Fourteen identified components accounted for 99.1% (GC) and 100.0% (FID) of the total oil. Major component of the oil was limonene (76.8%-GC and 86.2%-FID). Essential oil was also evaluated for its antioxidant activity in four complementary test systems namely; β-carotene/linoleic acid, DPPH radical scavenging, reducing power and metal chelating activities. In the first system, antioxidant activity increased with the increasing concentration. At 20.0 mg.ml^?1 concentration, antioxidant property of the oil was 96.8% ± 0.2 and as strong as the positive controls BHT and α-tocopherol. Scavenging effect of the oil was superior to the positive controls BHT and α-tocopherol at 1.5 mg.ml^?1 concentration (96.4% ± 0.1). Reducing power and chelating effect of the essential oil increased with the increasing concentration.     

黑乳参多糖的分离和组成鉴定

通过木瓜蛋白酶酶解方法从黑乳参中提取粗多糖,再经H2O2脱色、乙酸钾除蛋白、柱层析后等程序后得到精制的酸性黏多糖。琼脂糖凝胶电泳试验表明该多糖为单一成分,经GPC法测定重均分子量为76008Da。黑乳参黏多糖中硫酸基、葡萄糖醛酸、氨基半乳糖、岩藻糖含量分别为28.08%、20.71%、15.38%、12.48%。     

木瓜蛋白酶水解鳙鱼

采用木瓜蛋白酶水解鳙鱼,分析各因素对鳙鱼蛋白水解的影响,通过正交试验对水解的工艺条件进行优化研究.结果表明,木瓜蛋白酶水解鳙鱼鱼肉蛋白的较适条件为:底物浓度为1.5%,酶浓度1.5%,温度为75℃,pH6.0,水解时间为3.5 h.     

华贵栉孔扇贝全脏器中糖胺聚糖的分离提取及其抗肿瘤活性研究

以湛江地区盛产的华贵栉孔扇贝全脏器为原料,经木瓜蛋白酶和枯草杆菌中性蛋白酶双酶水解．醇沉后得到华贵栉孔扇贝糖胺聚糖粗品,采用MTT法检测粗品体外对人宫颈癌细胞（Hela）活性的影响。实验结果表明：采用双酶水解法粗品得率为1.26%,总糖含量为41．4％,糖胺聚糖（GAG）含量为26．90／0。粗品具有对Hela肿瘤细胞的生长显著性抑制作用（p〈0．05）。     

自动QuEChERS结合液相色谱-串联质谱法测定香叶中的212种农药残留

目的 建立自动QuEChERS结合液相色谱-三重四极杆串联质谱法测定香叶中212种农药残留.方法 香叶样品用乙腈提取,使用300 mg十八烷基硅烷键合硅胶(C18)+75 mg Nano-Carb、4.0 g无水硫酸镁和1.0 g氯化钠进行净化,经自动样品制备系统进行制备后,应用液相色谱-三重四极杆串联质谱法进行检测,...