新型耐酸真菌淀粉酶在麦芽糖生产上的应用

麦芽糖生产中,糖液染菌是很难解决的问题,采用杰能科(Genencor)公司的一种新型真菌淀粉酶用于麦芽糖生产,与传统的真菌淀粉酶相比,可在pH4.5的条件下工作,这对解决生产中糖液易染菌的问题非常有效。     

大豆β-淀粉酶、产气杆菌异淀粉酶在虾壳几丁质上的固定化及在麦芽糖生产中的应用

本文研究了大豆β—淀粉酶和产气杆菌异淀粉酶在同一载体上的固定化作用。以虾壳几丁质和壳聚糖为载体,证明几丁质更适于固定化异淀粉酶。用5％甲酸和50％乙酸预处理载体可增加固定化异淀粉酶的活性和稳定性,这可能是由于载体中壳聚糖的溶解造成的。经甲酸处理的几丁质先与4～6％pH7～9的戊二醛反应1小时,再同酶液(10mg/ml,pH6)反应2小时,并添加0.2mol/1Ca~#,将有利于固定化作用。用本方法得到的固定化酶具有高度活性和稳定性。固定化异淀粉酶最适pH由6.5变为5.0,而固定化β—淀粉酶最适pH变化不大。固定化酶在60℃稳定,在70℃5分钟失活。固定化酶在水中贮藏稳定,并具有良好的操作稳定性,使其在麦芽糖生产中具有潜在的应用价值。     

高麦芽糖生产β—淀粉酶普鲁兰酶协同作用动力学研究

对β－淀粉酶和普鲁兰酶的作用特点以及淀粉分子的结构特征进行了研究，建立了高麦芽糖生产中β－淀粉酶，普鲁兰酶双酶系统动力学模型，实验结果与动力学模型吻合，对生产中优化用酶有指导意义。     

麦芽糖及麦芽糖醇的生产与应用

本文介绍了不同规格的麦芽糖和麦芽糖醇的生产技术,和在功能性食品、糖果、巧克力、果汁饮料和冷冻食品中的应用情况,表明麦芽糖和麦芽糖醇作为一种重要的食品添加剂和甜味剂,在我国食品工业中具有广阔的应用前景.     

麦芽糖α-淀粉酶基因在枯草芽孢杆菌中的分泌表达

采用重叠PCR方法在麦芽糖α-淀粉酶编码基因5’端添加地衣芽孢杆菌α-淀粉酶基因信号肽编码区,获得重组基因BlMa。重组基因与芽孢杆菌表达载体pHY-P43连接后直接转化枯草芽孢杆菌,获得重组质粒pHY-P43-BlMa。枯草芽孢杆菌淀粉酶基因缺陷株1A717被用作BlMa基因表达宿主菌,重组菌命名为Bacillus subtilis/pHY-P43-BlMa。酶活检测和SDS-PAGE电泳均显示,B.subtilis/pHY-P43-BlMa表达的重组麦芽糖淀粉酶(BlMa)全部分泌到培养液中。HPLC检测表明,BlMa催化可溶性淀粉水解产物主要为麦芽糖。对B.subtilis/pHY-P43-BlMa摇瓶发酵条件进行优化。获得优化发酵培养基配方:10%玉米淀粉,2.5%药媒,0.3%(NH4)2SO4,0.03%CaCl2,0.1%NaH2PO4,在优化条件下重组菌发酵酶活为5.9 U/mL。     

大麦麦芽替代大麦β-淀粉酶生产高麦芽糖的初步研究

对大麦麦芽替代大麦β-粉酶生产高麦芽糖进行了初步研究,结果表明:2.50～2.60g/kg(以固形物计,下同)的大麦麦芽添加量与0.23 g/kg的大麦β-淀粉酶添加量所生成的麦芽糖含量相当;在大麦麦芽和大麦β-淀粉酶中添加普鲁兰酶后都能够提高麦芽糖含量;随着糖化温度的升高,大麦麦芽的耐高温糖化能力高于大麦β-淀粉酶.     

麦芽糖制品在食品工业中的应用

介绍了麦芽糖制品的性质及在食品工业生产中的应用。     

低聚异麦芽糖在面包中的应用

低聚异麦芽糖具有良好的理化性质．如溶解性好、耐酸、耐热、糊精含量低等，同时还具有促进腩道内有益菌群——双歧轩菌等的增殖、预防龋齿等生理功能，是一种集营养、保健、疗效于一身的功能性低聚糖。研究了商品低聚异麦芽糖的部分理化特性，如甜度、耐酸性、耐热性、可溶性固形物、pH值、水分活度等，并探讨了低聚异麦芽糖在面包中的应用用低泉异麦芽糖产品部分代替蔗糖，应用于面包生产中，不仅质量较好，而且可以生产出新的功能性食品．     

结晶麦芽糖性质及其制备工艺

与传统淀粉糖品相比,结晶麦芽糖具有甜度低、口味纯、不易结晶、防龋齿、不依赖胰岛素代谢等优点,广泛应用于保健食品,医药等高附加值领域,其市场需求量不断增长。该文介绍结晶麦芽糖种类、性质和制备工艺,并对制备方法研究进展和不足进行探讨,为结晶麦芽糖工业化生产提供参考。     

麦芽糖生物合成海藻糖的途径及合成条件的研究

由土壤分离出一株能合成海藻糖的菌株T007,经验证含有特异性地将麦芽糖转化为海藻糖的酶系。对麦芽糖浓度、反应时间、反应温度和反应转速等因素对麦芽糖转化率的影响进行了研究。结果表明,麦芽糖浓度对转化率影响很微弱;反应初期,温度越高,生成海藻糖的初始速度越快,但是到反应末期,反应速度减弱得也越快,转化率反而不是很高;反应转速对麦芽糖转化海藻糖有较大影响,反应的最佳转速为200r/min。     

Indigo carmine degradation in the presence of maltose and ethanol

The majority of important reactions in beer are associated with the action of oxygen during malting and brewing. With respect to oxygen, beer is considered to possess a relatively strong reducing environment. The gradual reduction of oxygen gives rise to reactive oxygen species (ROS) capable of attacking beer components that are important to consumers. Indigo carmine (IC) bleaching was used to prove ROS formation formed by oxidation of beer energy sources such as maltose and ethanol. This paper examines oxygen radical oxidation of organic matter in the presence of the radical initiator potassium peroxodisulphate. A mixture of organic sources of energy such as maltose and ethanol, oxygen, radical initiator and cupric ions generates ROS formation in a broad range of concentrations even at room temperature. ROS irreversibly split blue dye IC into the colourless form and takes part in the radical transformation of organic matter, which is similar to its burning at low temperature or to radical oxidation of reducing agents. Other organic matter can suppress ROS formation and be incorporated into the radical chain of the pathway of its ‘cold burning’. Ethanol inhibited phenylalanine oxidation during its oxidative Maillard reaction. IC bleaching can serve as simple indicator of ROS generation in aerated food. Copyright © 2015 The Institute of Brewing & Distilling     

麦芽糖的粉末活性炭脱色研究

研究了六种不同的粉末活性炭对麦芽糖液的脱色效果,结果表明,粉末活性炭F的脱色效果较好,且对麦芽糖液中的色素吸附符合Freundlich方程。采用Plackett—Burman设计法,筛选出麦芽糖活性炭脱色的主要影响因素是活性炭用量,且最佳活性炭用量是麦芽糖液干物质质量的2．0％。     

酶促连续合成麦芽糖硬脂酸酯的工艺研究

利用连续循环反应器,固定化Novozym 435脂肪酶催化合成麦芽糖硬脂酸酯.通过单因素实验确定的最佳连续合成工艺条件为:以叔丁醇为溶剂,麦芽糖的起始浓度15 mmol/L,脂肪酸浓度100～200 mmol/L,麦芽糖补充量5 g/(L·d),分子筛添加量10 g/d,100 ～ 200 mmol/L的脂肪酸叔丁醇溶液以流速为0.2～0.3 mL/min进入反应器,麦芽糖硬脂酸酯的平均产量可达到5.9 g/(L·d).     

A statistical approach to the optimization of cold‐adapted amylase production by Exiguobacterium sp. SH3

Cold‐adapted enzymes produced by psychrotrophic organisms are interesting from both molecular and biotechnological viewpoints. The enzymes show superior catalytic activity than their mesophilic and thermophilic counterparts at room temperature. Therefore, the enzymes seem interesting for applications where high catalytic activity at ambient temperature is required. In this study, the production of cold‐adapted amylase by Exiguobacterium sp. SH3 was optimized and modeled. In the first step, single factor experiments using shake flask cultures were conducted for primary optimization. These experiments resulted in the improvement of amylase production up to 180 U/mL. In the next step, the Plackett–Burman design was used to identify significant factors affecting the amylase production. Starch concentration, tryptone concentration, and temperature were selected as significant factors; while time, shaking, yeast extract, pH, MnCl₂, CaCl₂, MgCl₂, and KH₂PO₄ were not significant in this step. Finally, the response surface methodology based on central composite design (CCD) was used for further optimization and modeling of the significant factors. The optimization efforts resulted in the maximum amylase production of 730 U/mL, which was four times higher than that achieved by the single‐factor optimization experiments.     

Purification of soybean amylase by superparamagnetic particles

Many studies of purification technology have focused on the development of supports of substrates for isolating enzymes. In this study, superparamagnetic particles modified by epichlorohydrin and other cross-linking agents to coat with starch were used as a purification support for isolating amylases from soybean proteins after precipitation with ammonium sulphate. The recovery of amylase activity from the crude amylase was 17.50% with a 194-fold purification. The molecular weight of the purified amylase was estimated to be 70 kDa by SDS–PAGE. Both crude and purified amylases showed an optimum pH of 6.0 with optimum temperatures of 70 and 60–70 °C and thermal stability of 20–70 and 20–60 °C, respectively. Since the affinity magnetic carrier could adsorb the target proteins efficiently, the superparamagnetic particles technology can be further combined with other separation technologies in the industries to enhance their purification efficiency.     

Evaluation of Brazilian ethanol production yeasts for maltose fermentation in media containing structurally complex nitrogen sources

Maltose and glucose fermentations are strongly affected by the structural complexity of the nitrogen source and by the presence of oxygen. In this study five industrial Saccharomyces cerevisiae strains were grown in synthetic medium, containing maltose or glucose, supplemented with different nitrogen sources, with or without agitation. All strains were able to grow and efficiently ferment glucose, but not all strains were able to grow and ferment maltose well. Peptone and ammonium sulfate induced improved fermentation for all strains and conditions. Under agitation, as expected, higher biomass accumulation was detected. Casamino acids supplementation induced efficient maltose fermentation for all of the strains under aerated conditions, but differing maltose utilization patterns were observed for the static cultures. Copyright © 2012 The Institute of Brewing & Distilling