鱿鱼皮蛋白质酶促水解研究

约占鱿鱼10%左右的鱿鱼皮在加工后作为废弃物而被处理。鱿鱼皮中蛋白质含量丰富,其水解物中含有生理活性肽。对鱿鱼皮的酶促水解进行了研究,结果表明,鱿鱼皮在45℃、pH6.5、水解时间4h、添加量1.50%条件下用胰蛋白酶或40℃、pH2.0、水解时间8h、添加量2.50%条件下用胃蛋白酶水解具有较高的水解度。     

Phospholipids of marine origin—the squid (Loligo vulgaris)

Squid (Loligo vulgaris) was found to contain 25 g kg^?1 lipids of which approximately 75% were phospholipids. The phospholipids were shown to consist of phosphatidylcholine (56% of total phospholipids), phosphatidylethanolamine (29%), phosphatidylserine (2%), phosphatidylinositol (2%). sphingomyelin (5%), lyso-phosphatidylcholine(3%) and the unusual lipid ceramide aminoethylphosphonic acid (3%). The major saturated fatty acid in both phospholipids and non-phosphorylated lipid was C16:0 (26% and 21%, respectively, of total fatty acids), while the major unsaturated fatty acid in both lipid fractions was C22:6n-3 (34% and 23%, respectively) followed by C20:5n-3 (14% in both lipids).     

Influence of Endogenous Proteases and Transglutaminase on Thermal Gelation of Salted Squid Muscle Paste

ABSTRACT: Thermal gelation of salted squid mantle muscle paste was studied in relation to endogenous proteases and transglutaminase. Myosin in the paste was preferentially degraded into 130-kDa and 90-kDa fragments at an optimum temperature of 30 °C. Degradation was inhibited with EDTA or 1,10 phenanthroline, suggesting the presence of metalloproteases. Myosin degradation was markedly reduced above 40 °C. Although 10 mM Ca²⁺ increased cross-linking of myosin heavy chains by activating the endogenous transglutaminase, setting effect on thermal gelation of the paste was offset by degradation induced by simultaneously activated calpains. Ca2+ and the alpain inhibitor, E64, significantly improved the breaking strength and strain of thermal gels preincubated at 40 °C.     

鱿鱼冷冻调理食品的加工

介绍了水产冷冻食品的概况和两种鱿鱼冷冻调理食品的生产工艺，并对生产中卫生指标的管理问题作了探讨。     

Effect of thermal processing and canning on cadmium and lead levels in California market squid: the role of metallothioneins

The effects of two common seafood preparation practices (roasting and industrial canning) on the heavy metal content – cadmium (Cd) and lead (Pb) – of various tissues of California market squid were studied. Emphasis was placed on the role of metallothioneins (MT) in Cd and Pb behaviour during processing. Cd and Pb analysis was conducted by a Zeeman GTA-AAS atomic absorption spectrometry system; MT analysis was performed by a mercury saturation assay. Results showed that Cd levels in the mantle and whole squid were considerably affected by both processing practices, reaching a 240% increase in mantle and a 40% increase in whole squid. Interestingly, Cd behaviour was associated with MT changes during squid processing. On the other hand, Pb content was not affected from either processing or associated with MT content in the raw or processed squid. Therefore, processing operations may affect Cd and Pb content differently due to the specific metal bioaccumulation and chemical features of each heavy metal type.     

ESR studies on the thermal decomposition of trimethylamine oxide to formaldehyde and dimethylamine in jumbo squid (Dosidicus gigas) extract

The effects of ferrous iron, heating temperature and different additives on the decomposition of trimethylamine oxide (TMAO) to formaldehyde (FA) and dimethylamine (DMA) and generation of free radicals in jumbo squid (Dosidicus gigas) extract during heating were evaluated by electron spin resonance (ESR). The thermal decomposition of TMAO to TMA, DMA and FA and free radical signals was observed in squid extract, whereas no DMA, FA and free radical signals were detected in cod extract or in aqueous TMAO solution in vitro at high temperatures. Significant increase in levels of DMA, FA and radicals intensity were observed in squid extract and TMAO solution in the presence of ferrous iron with increasing temperature. Hydrogen peroxide stimulated the production of DMA, FA and ESR signals in squid extract, while citric acid, trisodium citrate, calcium chloride, tea polyphenols and resveratrol had the opposite effect. Similar ESR spectra of six peaks regarded as amminium radical were detected in the squid extract and TMAO–iron(II) solution, suggesting that the amminium radical was involved in the decomposition of TMAO.     

Eleven Novel Polymorphic Microsatellite Loci for Oval Squid Sepioteuthis Lessoniana (Shiro-Ika Type)

The oval squid Sepioteuthis lessoniana is one of the most economically important squid species in Japan; however, its population structure is poorly understood due to the lack of hypervariable markers. Such information is critical for managing sustainable fisheries, as well as for ensuring the existence of wild S. lessoniana stocks. Eleven candidate microsatellite loci were isolated from a small insert genomic DNA library. Polymorphisms in these 11 loci were screened in 24 wild individuals. The number of alleles per locus was found to range from 5 to 19 alleles, and the observed heterozygosity ranged from 0.292 to 0.958. No evidence for linkage disequilibrium was detected among all the loci. The genotypic proportions conformed to Hardy-Weinberg equilibrium, except at one locus. In conclusion, these polymorphic microsatellite loci may be used to develop a genetic framework to manage S. lessoniana in the future.     

茶多酚去除鱿鱼中甲醛的实验研究

为去除水产品中的甲醛，本文探讨了茶多酚对鱿鱼中甲醛去除率的影响。根据茶多酚分子结构中的酚羟基与甲醛的醛基发生羟醛缩合反应，通过控制反应过程中的各个实验参数，考察茶多酚对鱿鱼中甲醛的去除效率。实验结果表明，鱿鱼中甲醛去除的最佳反应条件为：当pH值为9时，加入适量的茶多酚溶液，于100℃水浴中加热60rain。在此条件下，茶多酚与鱿鱼中的甲醛能够充分反应，甲醛去除率可达85％～88％。该研究为有效去除水产品中的甲醛提供了可靠依据。     

Potential for utilization of the lipid and DHA-rich fatty acid of integument of squid Ommastrephes bartrami

Lipid and fatty acid compositions of the integument of the squid Ommastrephes bartrami, which is an industrial waste, were assessed for appraisal as a possible new source of phospholipids containing docosahexaenoic acid. Total lipid of wet and dry bases were 2.5 and 14.7%, respectively. Phospholipids was 80–85% of the total lipid. The major phospholipids were sn-glycero-3-phosphocholine and sn-glycero-3-phosphoethanolamine. The sn-glycero-3-phosphocholine consisted of 1,2-diacyl and 1-O-alkyl-2-acyl types, and sn-glycero-3-phosphoethanolamine consisted of 1,2-diacyl, 1-O-alkyl-2-acyl and 1-O-alk-1′-enyl-2-acyl types. Docosahexaenoic acid was a major fatty acid in both 1,2-diacyl and 1-O-alkyl-2-sn-glycero-3-phosphocholine, comprising 49.1 and 77.3 mol% of the total compositional fatty acids, respectively. However, in 2-sn-glycero-3-phosphoethanolamines the major fatty acids were eicosapentaenoic acid (34.8 mol%) in 1,2-diacyl-, docosahexaenoic acid (65.1 mol%) in 1-O-alkyl-2-acyl-, and eicosapentaenoic acid and docosahexaenoic acid (42.9 and 41.2 mol%, respectively) in the 1-O-alk-1′-enyl-class. The carbon chain-lengths of the major alkenyl group in 1-O-alk-1′-enyl-2-acyl-sn-glycero-3-phosphoethanolamine were 16 and 18.     

Effect of storage at 0 °C on mantle proteins and functional properties of jumbo squid

Effect of iced storage of jumbo squid mantle with fin on gelling capacity and changes in protein fractions and functional properties of jumbo squid mantle protein during storage at 0 °C were assessed. Most values of texture variables in gels did not significantly change during storage. On average, they were: strength 65.07 ± 4.71 N; elasticity 68.14 ± 5.3%, fracturability 52.97 ± 1.28 N and cohesiveness 36.6 ± 0.1%. Protein solubility increased more than 40%. Whippability increased during storage for 16 days at 0 °C (81–162%), as did foam stability (73–94%). Results suggest that iced squid mantle protein is a suitable ingredient for food products where these functional properties are desirable. Muscle fibres of squid mantle undergo various changes during storage. At 0 °C, they are disrupted, whereas at −20 °C, they aggregate and develop empty spaces in the tissue.