刚性分离栅对网板虾拖作业渔获物的分离效果

根据2002—2003年在福建中南部海区的网板虾拖网作业,应用刚性鱼虾分离栅进行释放经济幼鱼和鱼虾分离试验的资料,文章对试验期间的渔获物进行统计分析。结果表明：网板虾拖作业网具采用刚性分离栅对鱼类和虾类的分离特别明显,对体形较大的蟹类也有一定的分离效果,而对头足类的分离不是很明显。放大囊网网目尺寸的网袋可减少对主要经济种类幼体和其它种类的捕捞,从而达到有选择性的捕捞,保护渔业资源。     

Effects of Olive Leaf Powder on Mechanical Properties of Heat-Induced Surimi Gel

The effects of addition of olive leaf powder (OLP) to surimi on the mechanical properties of surimi gel were investigated. The OLP contained a high polyphenol content of 7% (w/w). The breaking stress and breaking strain of surimi gel increased with increasing OLP concentration. The addition of 0.3% OLP increased the breaking stress of surimi gel by 80% and the breaking strain by 38%. The addition of 2.0% OLP resulted in a 100% increase in the breaking strain. The OLP gels had finer and denser protein networks than the control gel, probably due to integration of additional crosslinks into the protein networks via polyphenols or their derivatives. Although the addition of OLP had a detrimental effect on whiteness of surimi gel, OLP is still a useful functional ingredient for improving mechanical properties of surimi gel products in which the color is not an important quality.     

加工方式对海水虾及其制品中SO2含量的影响

亚硫酸盐(以SO_2残留量计)超标是目前影响虾类及其制品质量安全的主要因素之一。本文研究了水煮、蒸、微波烘烤、油炸、风干等加工方式对海水虾中二氧化硫(SO_2)残留量的影响。结果显示,水煮、蒸、微波烘烤和油炸等加工方式可有效降低虾肉中SO_2残留量,降低效果从高到低依次为水煮、蒸、微波烘烤和油炸。在风干过程中,虾肉中SO_2残留量呈先升高后降低的趋势,温度越高,对SO_2的脱除效果越好。在20℃、40℃、60℃、80℃条件下风干加工虾米,当水分含量达到成品要求时,虾米中SO_2残留率分别为132.00%、146.70%、78.25%和48.90%。常温风干方式不利于海米中SO_2消除。脱壳处理可有效降低虾米和烤虾中SO_2残留量。本研究结果将为海水虾中SO_2残留量的控制和限量指标制定提供科学依据,对消费者和生产者利用加工手段降低海水虾中SO_2残留量也具有借鉴意义。     

干燥方法及保存条件对小球藻粉脂肪酸含量和种类组成的影响

研究了低温烘干、真空冻干和微波干燥3种干燥方式对蛋白核小球藻粗脂肪、脂肪酸含量和种类组成的影响及不同保存条件下脂肪酸的变化规律。试验结果表明,低温烘干藻粉的粗脂肪含量明显低于真空冻干藻粉和微波干燥藻粉。3种干燥方式对小球藻脂肪酸含量无显著影响,但藻粉颜色明显不同。藻粉脂肪酸含量与鲜藻之间无显著差异。在小球藻粉保存过程中,脂肪酸种类组成保持不变。藻粉在常温(14.5～18.5℃)下保存半年、4℃下保存1年时,多不饱和脂肪酸含量显著减少,饱和脂肪酸和单不饱和脂肪酸含量显著增加。在-24℃下保存1年时,各脂肪酸含量无明显变化。     

漂白粉蓄积对日本昭示(虫寻)4种组织超微结构的影响

根据急性毒性试验确定了漂白粉对日本的安全质量浓度为0.6mg/L,采用透射电镜技术研究了该质量浓度下漂白粉蓄积对日本4种组织细胞(肌肉、鳃、肝胰脏和心脏)超微结构的影响。试验结果表明:漂白粉主要损伤日本的鳃和肝胰脏,其次是心脏,肌肉基本无损害。鳃细胞的损害表现为鳃丝水肿,细胞器溶解,角质层变薄,线粒体、内质网的肿胀、解体;肝胰脏细胞的主要损害特征为肝管微绒毛减少、线粒体水肿解体、内质网扩张、细胞核空泡化、核膜水肿、脂肪滴增加;心脏细胞的毒理变化为线粒体内嵴肿胀、瓦解,肌原纤维不规则,内质网溶解。安全质量浓度的漂白粉经16d蓄积后,虽没有导致日本死亡,但已对其体内的鳃、肝胰脏、心脏等组织细胞的超微结构产生了不同程度的影响。     

Effects of dietary phenylalanine on growth,digestive and brush border enzyme activities and antioxidant capacity in the hepatopancreas and intestine of young grass carp (Ctenopharyngodon idella)

This study investigated the effects of phenylalanine on growth, digestive and absorptive ability and antioxidant status of young grass carp (Ctenopharyngodon idella). Young grass carp were fed diets containing 3.4 (basal diet), 6.1, 9.1, 11.5, 14.0 and 16.8 g phenylalanine kg^?1 diet with a fixed of 10.7 g tyrosine kg^?1 diet for 8 weeks. Percent weight gain (PWG), feed efficiency and feed intake of fish were the lowest in fish fed the basal diet (P < 0.05). Trypsin, lipase and amylase activities in the hepatopancreas, and antioxidants including glutathione contents and glutathione reducase activities in the hepatopancreas and intestine were all the highest in fish fed 11.5 g phenylalanine kg^?1 diet (P < 0.05). Trypsin, chymotrypsin and amylase activities in whole intestine, and creatine kinase, Na⁺, K⁺‐ATPase and alkaline phosphatase activities in the proximal intestine, and superoxide dismutase activities in the hepatopancreas and intestine were all the highest when phenylalanine at level of 9.1 g kg^?1 diet (P < 0.05). In conclusion, phenylalanine improved growth, digestive and absorptive ability, and antioxidant capacity of young grass carp. The phenylalanine requirement of young grass carp (256–629 g) based on PWG was 10.4 g kg^?1 diet or 3.44 g 100 g^?1 protein.