自溶法回收鱼类加工废弃物中蛋白质成分(英文)

鱼头和鱼内脏为鱼类在加工过程中废弃的主要组织,其中含有丰富的蛋白质和脂肪等有益成分,有必要进行回收利用。双鳍舵鲣鱼的头部和内脏约占其鱼体重量的30％,富含蛋白质(14.4％-22.6％)。为了将这些废弃物中的蛋白质进行回收,分别采用双鳍舵鲣鱼内脏本身含有的内源性蛋白酶(自溶)和四种外源性的商业蛋白酶Papain W-40(E1),Pancidase NP-2(E2),Sumichiimu FP(E3)和Protease M(E4)对废弃物中的蛋白质进行水解(50℃,1～4h),考察自溶和不同酶解方法对蛋白质的回收率以及对回收液氨基酸组成的影响。结果显示,自溶法对废弃物中蛋白质的回收效果最好。当水解温度为50℃,水解时间为2h时,自溶法的蛋白质回收率最高,达到76％;其次为E2酶解法,回收率达到70％;E3酶解法效果最差,回收率为63％。进一步研究表明,自溶回收液(AE)的氨基酸总量也最高,达到11756 mg/100g,而采用E1、E2、E3和E4水解方法得到的酶解回收液(EE1、EE2、EE3和EE4)中氨基酸含量分别仅为10294、10642、8750、10121 mg/100g。感观评定结果表明,自溶回...     

Occurrence of intracytoplasmic inclusion bodies in the digestive epithelium of fallow deer (Dama dama L)

Intracytoplasmic inclusion bodies were observed in the digestive epithelium of fallow deer (Dama dama L) suffering from bovine virus diarrhea/mucosal disease. Similar inclusion bodies were also found in the ruminal epithelium of fallow deer subjected to overfeeding by supplementary food. Inclusion bodies were not found in the upper alimentary mucosa of clinically healthy deer but were frequently found when these tissues were subjected to autolysis. At electron microscopical studies the inclusion bodies were found to consist of granular protein-like material encircled by a single membrane. Such inclusion bodies may constitute a non-specific degenerative cell response which could be elicited by diverse factors including autolysis.     

扇贝加工废弃物自溶技术的研究

对扇贝加工废弃物的自溶水解技术进行了研究。结果表明:用紫外线照射扇贝加工废弃物后能够激活自溶酶,当照射40 m in时,自溶水解液中游离氨基酸态氮含量最高(3.389 g/L);pH对自溶水解影响较大,pH为7.0时水解效果最佳;采用40-65℃(5℃/h)的梯度升温自溶水解4 h或60℃恒温下自溶水解3 h,其水解效果最佳;无机离子Na 、Ca2 对自溶酶具有激活作用,当Na 的浓度为0.07 mol/L、Ca2 的浓度为0.03 mol/L时,自溶水解效果最佳,而Zn2 对自溶酶的影响很小;扇贝加工废弃物在最佳条件下自溶水解3 h后(60℃恒温),其水解液中氨基酸态氮的含量为4.006 g/L。用SephadexG-15葡聚糖凝胶柱层析法对扇贝加工废弃物的自溶水解产物进行分析,结果显示,水解液中蛋白肽相对分子质量集中分布在784.25左右,说明自溶水解产物多为小分子的蛋白肽,可进一步对其开发利用,制备海鲜调味料等。     

Thermal denaturation and autolysis profiles of myofibrillar proteins of mantle muscle of jumbo squid Docidicus gigas

ABSTRACT:    Jumbo squid was very similar to Japanese common squid in terms of myofibrillar Ca²⁺-, Mg²⁺- and K⁺(EDTA)-ATPase activities. Myofibrils of jumbo squid were significantly stabilized upon addition of Ca²⁺ and destabilized by increasing KCl concentration for heating. Incubation of muscle homogenate of jumbo squid induced a selective cleavage of myosin into two major fragments and the cleavage was inhibited by EDTA. Autolysis was prominent at and above 0.3 M NaCl where myosin filaments dissolve. The enzyme involved in the autolysis was proved to be unstable showing maximal autolysis rate at 25°C. Washing the homogenate partially reduced the autolysis activity.     

疏花疏果和硒处理对龙眼果实采收品质与贮藏性的影响

【目的】探讨采前疏花疏果对龙眼(Dimocarpus longan Lour.)果实采收品质与采后贮藏性的影响,以及补施硒肥的增效作用。【方法】以石硖龙眼为材料,设无疏花疏果对照(A)、疏花疏果(B)、疏花疏果+硒肥(C)3个处理,3个区组,比较各处理与区组间果实采收品质和采后5℃低温贮藏的效果。【结果】采收时,处理B果实单果质量、大小、外观色度品质和果肉TSS含量分别比对照提高19.66%、7.54%、-7.24%(a~*值)和8.62%;处理C增效作用不明显,但果实采收品质依然优于对照。贮藏后,处理B显著提高了果实贮藏性,贮藏35 d果皮褐变指数和贮藏51 d果肉自溶指数分别比对照降低28.26%和71.67%,而处理C增效作用不明显。贮藏期间,处理B果实保持了较好的外观品质,偏黄绿色,处理C果实偏褐色,而对照偏暗褐色。多元方差分析结果表明,不同处理多变量检验结果表现显著,是影响果实采收品质与贮藏效果的主要因素;区组间无差异。处理方式影响显著的指标有褐变指数、自溶指数、低温b~*值和单果质量;区组影响显著的指标有低温b~*值和C~*值。【结论】疏花疏果处理效果最好,补硒处理在一定程度上降低了果实采收品质与贮藏性,但差异不显著;区组设置不影响处理间果实的贮藏性与内外品质差异。疏花疏果是提高龙眼果实采收与贮藏品质的一项重要措施。     

Post-wounding changes in the oxygen consumption by slices from tubers of several potato cultivars

Summary Potato (Solanum tuberosum L.) cultivars differed markedly in their susceptibility to autolysis during the post-wounding period. Slices from cultivars susceptible to autolysis showed higher respiration rates than those sampled from resistant cultivars. The higher oxygen consumption of these cultivars was inhibited by imidazole. Application of the respiration inhibitors, KCN and SHAM, to the slices showed that the capacity of the alternative electron transport pathway was relatively high during the post-wounding period in fresh slices of cultivars resistant to autolysis. The capacity of that pathway was near zero in the susceptible tissues. Aging promoted the development of KCN-resistant respiration in both types of cultivars.     

南极磷虾酶解工艺的研究

以水解度为指标,探讨中性蛋白酶水解南极磷虾的效果,通过试验筛选木瓜蛋白酶和枯草杆菌中性蛋白酶酶解南极磷虾的工艺条件。结果表明:南极磷虾自溶水解度为28.63%,添加中性蛋白酶可显著提高南极磷虾水解度;木瓜蛋白酶酶解工艺为酶解温度50℃、pH值7.5、酶解时间5 h、酶添加量0.3%,水解度达(42.17±0.17)%;枯草杆菌中性蛋白酶酶解工艺为酶解温度50℃、pH值7.5、酶解时间5 h、加酶量0.4%,水解度达(41.86±0.23)%。     

海参组织蛋白酶K的部分酶学性质及其对海参自溶的影响

采用特异性荧光底物法检测海参体壁组织蛋白酶K(CTSK)的酶学性质并初步探讨其对海参自溶的影响。结果表明:CTSK的最适pH为5.0,最适温度为50℃,在20~40℃之间酶活力稳定性较好;Zn~(2+)、Fe~(2+)、Fe~(3+)、Cu~(2+)均对CTSK产生一定抑制作用,抑制率均超过60%;而Ca~(2+)和Mn~(2+)对其活性影响不大,Mg2+可增强该酶活性、CA-074、Z-Leu-Leu-Leu-H(ZLLL)、碘乙酸、E-64、抗痛素、PMSF对CTSK的抑制率均在85%以上,EDTA和1,10-菲啰啉对该酶的抑制率分别为39.7%和16%,而DTT和L-Cys可将该酶活力分别提高至127.46%和238.3%。在海参匀浆物中分别加入特异性抑制剂CA-074和ZLLL,25℃水浴加热使其发生自溶,并通过SDSPAGE检测CTSK对海参蛋白降解的影响。结果显示ZLLL能够在一定程度上抑制海参蛋白的降解。CTSK是一种巯基氨基酸含量较高的半胱氨酸蛋白酶,具有一定的金属离子依赖性,但又易被多种金属离子抑制;CTSK有可能直接参与海参自溶过程中蛋白质的降解。     

Biochemical and Sensory Changes of Low-Salt Anchovy (Engraulis japonicus) Sauce Prepared by a Novel Technique

Using a process spanning less than 10 days, a novel technique combining two-stage autolysis and external koji fermentation for the rapid preparation of low-salt anchovy sauce is presented. High-efficiency autolysis of anchovy was achieved by two-stage autolysis, and the second-stage autolysis exhibited a significantly positive effect on the improvement of hydrolysis yield and recovery of anchovy proteins. During the external koji fermentation of hydrolysates from two-stage autolysis, the optimum amounts of added water and salt were determined to be 20% and 8.0%, respectively. By investigating the effect of fermentation time on the biochemical and sensory changes of anchovy sauce, the optimal fermentation time was 8 days. The prepared anchovy sauce had an umami taste, was rich in free glutamate, and contained taurine and γ-aminobutyric acid. In addition, it contained 0.890 g/100 mL amino acid nitrogen (AAN), 1.886 g/100 mL total nitrogen, and 9.76% NaCl. Meanwhile, the recovery of total nitrogen (RTN) was 63.89%.