中西太平洋鲣栖息地指数预报模型比较研究

鲣(Katsuwonus pelamis)是太平洋热带海域重要的金枪鱼种类之一,也是目前我国金枪鱼围网渔船的主要捕捞对象之一。根据1995—2012年中西太平洋海域(5°N-10°S;125°E-135°W)延绳钓生产统计数据,结合海表面温度(SST)和海表面高度(SSH)的遥感数据,利用频次分布法分析了中西太平洋围网鲣分布的SST和SSH适宜范围;采用了外包络法,按季度分别建立了SST、SSH的适应性指数(SI),采用算术平均法(AMM)和几何平均法(GMM)建立栖息地指数(HSI)模型计算其栖息地指数,并用2013年度的捕捞数据进行验证。结果表明,中西太平洋围网鲣多分布在SST为28~30.5℃、SSH为65~95 cm的海域。以捕捞努力量(作业天数)为基础,采用外包络法建立SST、SSH的适应性指数最为合适,各个季度的SST权重分别为0.7、0.6、0.3、0.6的算数平均法适合中西太平洋围网鲣栖息地指数模型。不同季节的环境因子对中西太平洋围网鲣渔场分布有着不同的影响。     

水对蚕豆根尖细胞有丝分裂的影响

[目的]为饮用水的处理提供依据。[方法]以蚕豆根尖细胞为材料,采用微核试验方法,以蒸馏水处理为对照,研究凉开水及分别放置0、12、24、36、48h的自来水对蚕豆根尖细胞微核千分率和染色体畸变率的影响。[结果]随着自来水放置时间的延长,蚕豆根尖细胞的微核千分率和染色体畸变率逐渐降低,放置0、12、24h的自来水诱发蚕豆根尖细胞的微核千分率和染色体畸变率均明显高于对照和放置36和48h的自来水处理。不同放置时间自来水处理后,蚕豆根尖细胞产生多种类型畸变,如间期微核、前期微核、染色体断片等。[结论]凉开水对染色体的损伤小于自来水,放置0h的自来水对蚕豆根尖细胞的遗传毒性较大。     

蛋白酶解对鲣鱼肉乳化特性的改善

天然鱼蛋白乳化性不佳,难以满足实际生产需求,但鱼蛋白的酶解改性可改善其功能特性,并拓展应用范围。以鲣鱼白色肉为原料,以水解度和乳化性为主要指标,比较了不同蛋白酶(胰蛋白酶、风味蛋白酶、木瓜蛋白酶)和水解时间对酶解液制备和鱼蛋白乳化性的影响,优化了酶解工艺参数。将鱼蛋白进行冷冻干燥后,分析鱼蛋白酶解前后溶解性、乳化性和起泡性等功能特性的差异。结果表明,当胰蛋白酶添加量2 000 U·g^-1,酶解10 min时,鱼蛋白水解度(DH)达到8.2%,此时鱼蛋白乳化特性最佳。与酶解前样品相比,酶解后鱼蛋白的乳化活性和乳化稳定性显著提高,其溶解度、起泡性和起泡稳定性均有一定程度的改善。酶解制备的鲣鱼蛋白在广泛pH范围内具有更好的功能性质,在食品工业具有更高的应用价值。     

Phospholipase A<Subscript>1</Subscript> activity of crude enzyme extracted from the ovaries of skipjack tuna

The phospholipid class composition, fatty acid composition and phospholipase A₁ (PLA₁) activity from the ovaries of skipjack tuna were compared with those of six other species of marine fish. In the skipjack ovaries, the lysophosphatidylcholine (LPC) proportion for the phospholipid, the docosahexaenoic acid (DHA) percentage for the total fatty acids of the phospholipids and the PLA₁ activity of the crude enzyme were the highest among those of the seven species. The optimum pH and temperature for the PLA₁ activity of the crude enzyme from the skipjack ovaries were in the range of pH 6–7 and 20–30°C, respectively, and calcium ions were not required. As a substrate, phosphatidylcholine was more easily hydrolyzed than phosphatidylethanolamine by this enzyme, and the plasmalogen-type phospholipid was much lower than the acyl-type phospholipid. After a 6-h hydrolysis reaction of the purified phospholipid extracted from the mixed ovaries of skipjack and yellowfin tuna by this enzyme, the LPC ratio of the phospholipid increased from 20 to 72.6% and the percentage of DHA for the total fatty acids of the phospholipid also increased. Thus, skipjack ovaries might possibly be used as a source of PLA₁.     

Skipjack velocity, dwell time and migration

Apparent velocities (distance travelled/time at liberty) of tagged Pacific skipjack tuna, Katsuwonus pelamis, observed over the 1978 to 1982 Skipjack Survey and Assessment Program (SSAP) of the South Pacific Commission (SPC) were very low (less than 10 cm s^-1in 90% of observations) compared with the minimum swimming speed of skipjack tunas of 70–100 cm s^-1. Such low apparent velocities are not biologically meaningful and therefore the extrapolation of biological properties from mathematical models, such as diffusion and advection models, based on the tagging data is difficult, if not impossible. This paper explores alternative approaches to the 1978 to 1982 SSAP data set. Dwell time and migration analysis indicate a north to south seasonal migratory pattern with the skipjack home range located along an arc from the Solomon Islands, through Fiji and Samoa, to the Marquesas. Ancillary evidence supports a purposeful rather than advective migration pattern that oscillates between southern feeding areas and northern breeding areas. many hands. Most of the previous analyses have focused on the issue of interactions between fisheries for K. pelamis that are in different political jurisdictions (Kleiber et al., 1984) and estimates of the size of the standing crop of K. pelamis (Kleiber et al., 1983; Kearney et al., 1984). Models of interactions between fisheries for K. pelamis in different jurisdictions (Sibert, 1984; Hilborn, 1990) have pointed towards the use of diffusion and advection models in studying fish movements (Sibert and Fournier, 1994; Sibert et al., 1995).     

葡萄酒渣多酚-壳聚糖-CMC可食性复合膜在水煮羊肉贮藏中的应用

为开发一种适用于水煮羊肉贮藏的可食性复合膜,以迷迭香(3%)复合膜、茶多酚(3%)复合膜和保鲜膜为对照组,利用不同浓度(1%、3%、5%)的葡萄酒渣多酚-壳聚糖-CMC复合膜和对照组膜处理水煮羊肉,分析其在冷藏[(4±1)℃]期间的感官特性、pH、色度、硫代巴比妥酸(thiobarbituric acid, TBA)值、挥发性盐基氮(TVB-N)、菌落总数,根据结果筛选最佳复合膜,并对其贮藏期间的挥发性物质进行研究。结果表明:5%葡萄酒渣多酚-壳聚糖-CMC复合膜处理效果最佳,可以有效改善羊肉的色泽,延缓脂质氧化;贮藏至第9天时,5%多酚膜处理组感官特性、抑菌性显著(P<0.05)优于其他复合膜处理组,TVB-N低于限值;贮藏至第12天时,5%多酚膜处理组pH显著(P<0.05)低于其他复合膜处理组;羊肉的贮藏时间可延长至9 d;贮藏时间不同,5%多酚膜处理组挥发性物质含量存在一定的差异。总体上,葡萄酒渣多酚-壳聚糖-CMC复合膜可以有效保持羊肉在贮藏期间的色泽,抑制氧化,减少腐败,延长货架期,有效保持羊肉在贮藏期间的食用品质。     

水煮毛竹笋片罐头保脆工艺优化研究

针对水煮笋片在加工和贮藏过程中出现脆度下降而导致口感不佳的问题,进行了保脆工艺优化的研究.试验结果表明:在水煮笋片罐头加工过程中添加适量三聚磷酸钠(STPP)和氯化钙(CaCl2),可提高产品的脆嫩度; L9(34)正交试验表明,各因素对保脆作用的大小依次为:保脆剂配比＞保脆剂质量浓度＞保脆浸泡时间＞保脆温度.当复合保脆剂比例为m (STPP)∶m(CaCl2) =1∶ 2、保脆剂质量浓度为1.5g·L-1、处理温度为45℃、浸泡时间为25 min时,保脆效果最佳.     

急烧:日本煎茶文化视域下的闽南茶器

18世纪中叶,名为"急烧"的闽南侧把砂铫传入日本,受到煎茶家的追捧,并发展为生活饮茶常用的煮茶器。19世纪中后期,随着散茶瀹饮法的普及,急烧由煮茶器向煮水器转化,"急烧"之名亦逐渐被"保富良"等日本俗称取代;然后,随着金属材质煮水器的普及,急烧便退出了日本饮茶生活的舞台,只有煎茶道至今还使用古雅的急烧煮水。     

不同播种期小豆生态类型的生育特性和生产力

来自不同地区的２０个小豆品种在杭州进行两期播种的结果表明，随着纬度的增加，小豆感光性减弱，全生育期缩短．早播（５月３０日）比迟播（７月２日）生育期延长．高纬度地区的品种主要表现为花期延长，而低纬度地区的品种主要表现为营养生长期延长，花期基本不变．除辽宁品种外，其它品种皆以迟播产量和产量性状为优．小豆的硬实率早播明显高于迟播，不同地区之间以山东品种为低，随着纬度的增加，小豆的煮烂性变差，两播期间无显著差异．种皮比率两播期间和不同地区间也较相近．     

Effect of vacuum treatment on smoke penetration into boiled skipjack loins for production of smoke-dried skipjack

ABSTRACT: The present work evaluates the effect of vacuum treatment on smoke penetration into boiled skipjack loins for the production of smoke-dried skipjack. Using a vacuum freeze-dryer, the boiled skipjack loins were vacuumed immediately after being boiled at a pressure of 400 Pa for 30 min in order to reduce the lipid and water contents. The vacuumed boiled meats were then smoked and dried at 90 ± 10°C for 3 h a day for 6 days in a metal kiln (internal diameter 24 cm × 24 cm × 70 cm height), using an electric heater (1.2 kW) to heat and generate smoke from cherry tree wood chips. Also, non-vacuumed boiled meats were smoked in the same manner as a control. The vacuum treatment reduced the lipid and water contents by as much as 0.6% and 2.7% on the wet weight basis, respectively. Histological observations showed many clearances among the muscle fibers of the vacuumed boiled meats. The content of phenols that had penetrated the vacuumed boiled meats during the smoke drying procedure was significantly larger ( P < 0.05) than that of the non-vacuumed boiled meats. Accordingly, the vacuum treatment accelerated the penetration of phenols into the boiled meats and enhanced the function of antioxidant substances, which improved the quality of the smoke-dried skipjack.