Vibrio parahaemolyticus in granulated ark shell clam (Tegillarca granosas): accumulation from water and survival during cold storage and thermal process

This study investigated accumulation of Vibrio parahaemolyticus in granulated ark shell clam (Tegillarca granosas) exposed to contaminated water and survival of V. parahaemolyticus in the clams during cold storage and heating processes. Vibrio parahaemolyticus could be accumulated in clams to a level similar to that of contaminated water within 12 h of exposure of clams to contaminated water at temperatures between 9 and 33 °C. Keeping clams stored at 5 and 0 °C for 10 days resulted in 1.98 and 2.32 log MPN g^?1 reductions of V. parahaemolyticus, respectively, in the clams. Frozen storage at ?18 °C for 15 days or at ?30 °C for 30 days were capable of reducing V. parahaemolyticus from 4.05 log MPN g^?1 to non‐detectable levels (< 3 MPN g^?1). A heating process in hot water at 80 °C or higher for 1 min also reduced V. parahaemolyticus in the clams to non‐detectable levels.     

A strategy to significantly improve the classification accuracy of LIBS data:application for the determination of heavy metals in Tegillarca granosa

Tegillarca granosa, as a popular seafood among consumers, is easily susceptible to pollution from heavy metals. Thus, it is essential to develop a rapid detection method for Tegillarca granosa. For this issue, five categories of Tegillarca granosa samples consisting of a healthy group; Zn, Pb, and Cd polluted groups; and a mixed pollution group of all three metals were used to detect heavy metal pollution by combining laser-induced breakdown spectrometry(LIBS) and the newly proposed linear regression classification-sum of rank difference(LRC-SRD)algorithm. As the comparison models, least regression classification(LRC), support vector machine(SVM), and k-nearest neighbor(KNN) and linear discriminant analysis were also utilized. Satisfactory accuracy(0.93) was obtained by LRC-SRD model and which performs better than other models. This demonstrated that LIBS coupled with LRC-SRD is an efficient framework for Tegillarca granosa heavy metal detection and provides an alternative to replace traditional methods.     

Evaluation of the hepatoprotective and antioxidant effects of <i>Tegillarca granosa</i> flesh body extract against potassium bromide toxicity via targeting the histomorphometry,chromosomal and expressions of TGF-β1, VEGF and COX-2 genes in rats

The hepatotoxic effect of potassium bromide (KBr) on rat liver tissues were determined, as well as the potential protective effect of Tegillaraca granosa (T. granosa) flesh body extract. Twenty adult male albino rats were equally distributed into four groups; Group (I) treated with physiological saline (control group), Group (II) was orally gavaged by 200 mg/kg of T. granosa body extract day after day, Group (III) was intoxicated by KBr (150 mg/kg bwt day after day orally) and finally, Group (IV) was given a combination of T. granosa flesh body extract plus KBr with similar doses in the second and third groups. At the end of one month, blood, liver tissue and bone marrow samples were collected to be used for the required laboratory examinations. In response to KBr toxicity, there was a significant increase in serum antioxidant biomarkers, which was accompanied by a significant change in hepatocyte ultrastructure and a significant change in carbohydrate and protein levels within the liver organ. In addition, KBr intoxication resulted in a substantial increase in the incidence of chromosomal aberrations such as holes, splits, deletions, fragments, ploidy, and ring chromosomes, as well as significant upregulation of TGF-1, VEGF, and COX-2 gene expression. The hepatotoxic effect of KBr was counteracted by treatment with T. granosa flesh body extract. T. granosa flesh body extract has a curative antioxidant and numerous protective effects against KBr hepatotoxicity.     

Effects of high pressure on biochemical properties and structure of myofibrillar protein from Tegillarca granosa

The effects of high-pressure (HP) treatment parameters (300 MPa for 5 min, 350 MPa for 3 or 5 min and 400 MPa for 1 min) on the biochemical properties and structure of myofibrillar protein (MP) from Tegillarca granosa were investigated. The results showed that HP significantly affected the biochemical properties of MP. Under the HP treatment at 400 MPa for 1 min, the MP extraction yield was reduced from 32.21 to 18.34 mg g⁻¹, and its surface hydrophobicity was increased from 89.29 to 104.69 µg. Ca²⁺-ATPase activity of MP decreased from 0.019 to 0.011 µmol (pi) mg⁻¹ (pro) min⁻¹, and both total and reactive sulfhydryl contents significantly declined. Furthermore, HP caused MP to undergo conformational changes. This study provides a reference data for the processing of T. granosa using HP treatment.     

泥蚶遗传多样性的研究

采用垂直聚丙烯酰胺同工酶电泳技术对我国及周边海域的7个泥蚶群体的11种同工酶、近28个位点的表型变异及遗传分化进行了研究,结果发现,绝大多数同工酶在7个群体之间谱型上都存在较大差异。遗传变异统计结果表明：7个泥蚶群体多态位点比例（P．99）和（P．95）分别在39．3％～53．6％和28．6％～44．4％之间;平均杂合度观测值在0．035～0．083之间,平均杂合度预期值在0．086～0．186之间;而平均位点等位基因数在1．786～2．381之间。比较了7个群体之问的遗传相似度和遗传距离表明,7个泥蚶群体明显地分为两大类群,第一个类群包括釜山、荣成、奉化、乐清、福鼎5个群体,它们的平均遗传距离是0．0072;第二个类群包括汕头和湛江两个群体,它们的遗传距离是0．0320;而这两个类群问的不同群体问的平均遗传距离为0．4279。因此这两个类群的分类学地位值得进一步探讨。     

电子束辐照对泥蚶肉挥发性风味成分的影响

目的:分析电子束辐照对泥蚶肉挥发性风味成分的影响。方法:以泥蚶为原料,采用固相微萃取-气质联用分析不同剂量电子束辐照后泥蚶肉的挥发性风味成分。结果:1)经1～9kGy剂量辐照,泥蚶肉挥发性风味成分的种类由46种分别增至55、57、52、58和66种;各剂量组羰基化合物含量最高,是泥蚶肉的主体风味成分;酮类赋予泥蚶肉甜花香,醛类则赋予泥蚶肉的脂香及瓜果香味。7kGy组泥蚶肉的异味可能与其高含量的挥发性羰基化合物有关。2)3kGy、5kGy组泥蚶肉的挥发性醇类相对含量增加,其中烯醇类化合物可赋予肉品柔和的香味。辐照后部分烯烃含量降低,一定程度上减少了泥蚶肉的腥味。3)辐照后杂环化合物的相对含量有所增加,其中呋喃类物质赋予泥蚶多种果香味,而吡啶、噻唑等贡献泥蚶炸肉、坚果等风味。5kGy组泥蚶肉中芳香族化合物相对含量最高,其中苯甲醛具杏仁香,可改善泥蚶固有风味。结论:3～5kGy辐照剂量对泥蚶肉原有风味不会产生明显的影响,甚至在一定程度上改善其风味。     

牡蛎和泥蚶过氧化氢酶的性质比较

对牡蛎和泥蚶过氧化氢酶(Cat)的性质进行比较。结果表明两者的PAGE谱带于同一位置，相对分了质量约为230kD，含有4个亚基。影响酶活力的温度相同，50℃以上酶活力明显下降；酶的最适pH5～8，但牡蛎Cat在酸碱条件下酶活力下降明显。     

电子束辐照对泥蚶杀菌保鲜效果的影响

目的：研究电子束辐照对泥蚶微生物数量及其感官质量的影响。方法：泥蚶经不同剂量电子束处理,测定辐照后及冷藏期间菌落总数、大肠菌群及其感官评分。结果：电子束辐照能有效地杀灭泥蚶中的微生物,经过0、1、3、5、7、9kGy 不同剂量处理,泥蚶的菌落总数逐步下降,当泥蚶的初始菌落总数为3.10 × 105CFU/g时, D10=3.12kGy;泥蚶的感官质量与辐照剂量有关,经过7、9kGy 剂量处理后样品产生令人不愉快的异味。结论：结合辐照后及冷藏期泥蚶的微生物和感官指标,泥蚶电子束冷杀菌的适宜剂量为3～5kGy,经3～5kGy 处理后,泥蚶的货架期由对照组的5d 延长至15～19d。     

泥蚶抗氧化作用研究

采用化学发光法测定泥蚶不同组织清除氧自由基及抑制脂质过氧化(LPO)作用。结果表明,泥蚶血液、内脏团和肌肉都具有清除O2、•OH、H2O2和抑制LPO作用。血液的抑制作用最明显,IC50分别为0.08、0.05、0.10和0.24mg/ml。内脏团抑制作用次之,肌肉明显小于血液和内脏团。