内酯类化合物在食品中的风味贡献及形成机制

食品中的内酯类物质主要包括γ-内酯、δ-内酯、葫芦巴内酯、威士忌内酯,它们对食品整体风味的形成具有重要作用,能赋予食品奶香、水果香、坚果香、焦糖香等优良的风味特征,研究食品中内酯类化合物的风味贡献及形成机制具有重要意义。该研究综述了食品中常见的内酯类化合物,食品中内酯类化合物的组成及香气贡献,总结了对食品风味贡献较大的内酯类化合物的形成机制包括：δ-内酯和γ-内酯的羟基脂肪酸-内酯生成途径、一步分子内酯交换反应途径、葫芦巴内酯的羟醛缩合反应途径、果实中脂肪酸-酰基CoA-内酯形成途径、果实中不饱和脂肪酸-羟基脂肪酸-内酯形成途径等,并对当前研究中存在的问题和未来研究方向做了归纳与展望。为全面认知食品中内酯类风味化合物及其形成,改善食品风味并提高食品品质,实现食品产业转型和升级提供理论参考。     

微生物酶合成功能性低聚糖研究

主要介绍了功能性低聚糖生产中微生物酶制剂的种类，酶的来源，作用机制及在工业生产中的运用状况。     

降解烟碱微生物的筛选及其酶在烟草中的应用

从昆明卷烟厂附近的土壤中筛选出一株具有高效降解烟碱能力的细菌。该细菌在以烟碱为惟一的碳源和氮源的培养基中能生长良好,在液体培养基中培养(发酵)78h,培养基中的烟碱分解80%以上,且发酵期间培养液呈现颜色变化:无色、蓝色、深蓝色、黑色和褐色。根据生态特征和生理生化分析结果,初步鉴定该菌为节细菌属。在100g烟丝中分别加入2mL该菌酶液(酶蛋白浓度10.15mg/mL)和菌液(109个/mL),各培养2和7d,其烟碱降低了15.2%和22.1%。     

微生物酶在制浆造纸工业中的应用

制浆造纸工业是我国的国民经济重要支柱产业之一,也是我国环境污染的主要行业之一。随着生物技术的发展,微生物酶在制浆造纸工业中的应用也受到学者的重视及关注。文章综述了微生物酶在制浆、纸浆漂白及造纸废水处理等各工艺中的应用并展望了其前景。     

微生物酶在制浆造纸工业中的应用

随着生物技术的发展,微生物酶在制浆造纸工业中的应用受到学者的重视及关注,本文综述了微生物酶在制浆、纸浆漂白及造纸废水处理等各工艺中的应用并展望了其前景。     

微生物产几丁质酶的研究概况及其应用

本文就产生几丁质酶的微生物种类、生态分布,微生物几丁质酶的类型、酶学性质、作用机理及应用等方面的研究状况进行了综述.并且认为几丁质酶系的研究与开发在农业、工业、食品、医药等领域展现出良好前景.     

微生物酶合成功能性低聚糖研究

主要介绍功能性低聚糖生产中微生物酶制剂的种类，酶的来源，作用机制及在工业生产中的运用状况。     

以淀粉为原料利用微生物酶生成海藻糖的新方法

近年来 ,海藻糖 (Ｔｒｅｈａｌｏｓｅ)由于其独特而令人感兴趣的生物学功能 ,而广泛受到各国家的密切关注 ,以致引发了世界性的对海藻糖生产技术及其应用的开发研究热潮。简单地说 ,海藻糖可以保护蛋白质 ,生物膜及敏感细胞的细胞壁免受干旱、冷冻、渗透压的变化等造成的伤害 ,可用于工业上做不稳定药品 ,食品和化妆品的保护剂等 ,最近报导海藻糖还可保护ＤＮＡ防止放射线引起的损伤。但因海藻糖目前主要从酵母中提取 ,收率低、成本高 ,所以限制其应用 ,以至于各国都在研究低廉的制备海藻糖的方法。我国对海藻糖的研究刚刚起步 ,也只是近几…     

海洋微生物低温酶特性及其在食品工业中的应用

与海洋动物、植物一样，海洋微生物也是海洋生物的主要成员之一，它是一类重要的可再生海洋自然资源，尤其是它们所处的环境具有很大的特殊性，经过长期的适应，海洋微生物作为产酶资源就具有了突出的特点和优势，如：耐压、耐碱、耐盐、耐冷和多物种等特性，并由此赋予了海洋微生物酶独特的应用前景。因此从海洋微生物中提取有应用价     

Microbial enzymes involved in carbon dioxide fixation

This review focuses on the enzymes involved in two microbial carbon dioxide fixation pathways, the Calvin-Benson-Bassham cycle and the reductive tricarboxylic acid cycle. The function, structural features, and gene regulation of microbial ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), a key enzyme of the Calvin-Benson-Bassham cycle, is described. Some recent findings on Rubisco from archaea and Rubisco-like proteins are also outlined. In the final section, biochemical features of the key enzymes in the reductive tricarboxylic acid cycle are reviewed.     

食用伞菌海藻糖代谢相关基因调控及生物工程应用

海藻糖是一种能够在外界胁迫条件下发挥其特殊抗逆保护作用的二糖,广泛分布于古细菌、细菌、真菌及动植物体内。该文对海藻糖的理化性质及其生物学特性作了简要的概述,介绍了食用伞菌中海藻糖合成代谢途径及其相关酶基因调控的研究进展,对食用伞菌中与海藻糖代谢相关酶基因在生物工程中的应用进行了展望。     

食用伞菌海藻糖代谢相关基因调控及生物工程应用

海藻糖是一种能够在外界胁迫条件下发挥其特殊抗逆保护作用的二糖,广泛分布于古细菌、细菌、真菌及动植物体内。该文对海藻糖的理化性质及其生物学特性作了简要的概述,介绍了食用伞菌中海藻糖合成代谢途径及其相关酶基因调控的研究进展,对食用伞菌中与海藻糖代谢相关酶基因在生物工程中的应用进行了展望。      

Activities of enzymes involved in sugar metabolism in Passe-Crassane pears during cold storage

During cold storage, invertase, sucrose synthetase and α- and β-amylases reach a maximum activity towards maturity when protein synthesis is highest. However, when activities are expressed on a protein basis, no consistent changes appear except for sucrose synthetase and α-amylase which increase notably. The possible role of these enzymes in sugar accumulation and interconversion is discussed.     

基于乳糖水解酶的乳酸乳球菌乳糖代谢多样性研究

探究了磷酸-β-半乳糖苷酶和β-半乳糖苷酶对乳酸乳球菌乳糖代谢的影响。通过对12株乳酸菌在以乳糖为单一碳源环境下的生长、产酸、乳糖代谢情况、β-半乳糖苷酶和磷酸-β-半乳糖苷酶活力及发酵液中残留半乳糖含量进行测定,了解不同菌株乳糖代谢的差异。结果表明,不同的乳酸乳球菌乳糖代谢能力存在显著性差异;β-半乳糖苷酶活力较高的菌株发酵液中半乳糖含量为270～4 110 mg/L,而磷酸-β-半乳糖苷酶活力较高的菌株发酵液中半乳糖含量为40～900 mg/L;将磷酸-β-半乳糖苷酶活力较高的乳酸乳球菌与嗜热链球菌复配,发酵液中半乳糖含量较嗜热链球菌单菌发酵时显著降低。磷酸-β-半乳糖苷酶活力较高的乳酸乳球菌有助于降低发酵乳制品中的半乳糖含量。     

Characterisation of genes encoding key enzymes involved in sugar metabolism of apple fruit in controlled atmosphere storage

Sugars are essential contributors to fruit flavour. Controlled atmosphere (CA) storage has been proved to be beneficial for maintaining harvested fruit quality. To explore regulatory mechanism of sugar metabolism in fruit stored in CA condition, we cloned several genes, encoding key enzymes, involved in sugar metabolism in apple fruit, and analyzed sugar contents, along with gene expression and enzyme activities in fruits stored in air and CA. The results indicated that CA could maintain higher contents of sugars, including sucrose, fructose and glucose. Expression levels of key genes, such as sucrose synthase (SS), sucrose phosphate synthase (SPS), fructokinase (FK) and hexokinase (HK), were shown to be correlated with the corresponding enzyme activities. We found that activities of neutral invertase (NI), vacuolar invertase (VI), FK and HK were inhibited, but SPS activity was promoted in apple fruit stored in CA, suggesting that CA storage could enhance sucrose synthesis and delay hydrolysis of sucrose and hexose. These findings provided molecular evidence to explain why higher sugar levels in harvested fruit are maintained under CA storage.     

Ascorbic acid metabolism in fruits: activity of enzymes involved in synthesis and degradation during ripening in mango and guava

BACKGROUND: Ascorbic acid is a very important compound for plants. It has essential functions, mainly as an antioxidant and growth regulator. Ascorbic acid biosynthesis has been extensively studied, but studies in fruits are very limited. In this work we studied the influence of five enzymes involved in synthesis (L ‐galactono‐1,4‐lactone dehydrogenase, GalLDH, EC 1.3.2.3), oxidation (ascorbate oxidase, EC 1.10.3.3, and ascorbate peroxidase, APX, EC 1.11.1.11) and recycling (monodehydroascorbate reductase, EC 1.6.5.4, and dehydroascorbate reductase, DHAR, EC 1.8.5.1) on changes in ascorbic acid content during development and ripening of mangoes (Mangifera indica L. cv. Keitt) and during the ripening of white pulp guavas (Psidium guayava L. cv. Paloma). RESULTS: It was found that there was a balance between the activities of GalLDH, APX and DHAR, both in mangoes and guavas. CONCLUSIONS: Equilibrium between the enzymatic activities of synthesis, catabolism and recycling is important for the regulation of ascorbic acid content in mango and guava. These results have contributed to understanding some of the changes that occur in ascorbic acid levels during fruit ripening. Copyright © 2008 Society of Chemical Industry     

蒲公英总黄酮复合酶酶法提取工艺及抗氧化活性研究

在考察加酶量、pH值、料液比、乙醇浓度、酶解温度和酶解时间对蒲公英总黄酮得率影响的基础上,进行四因素三水平响应面试验,优化得到蒲公英总黄酮复合酶酶法的最佳提取条件为料液比122(g/mL)、pH 4.5、乙醇浓度52%、酶解温度51℃,该条件下蒲公英总黄酮的得率为15.09mg/g。体外功能性试验显示,蒲公英总黄酮提取液的抗氧化活性及对自由基的清除能力均较强。     

不同芦荟SOD复合酶的研究

研究了7种芦荟的SOD、CAT和POD,分析并比较不同芦荟复合酶的活性与比活力,结果表明:7种芦荟SOD活力差异不大;皂质芦荟CAT特别高;不夜城与巨无霸芦荟POD活性突出,库拉索芦荟测不出POD活性。CAT与POD之间未发现互补性。