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根据国外资料以及国内制麦生产的实践，赤霉酸应用于麦芽生产，能提高麦芽质量，我省的麦芽厂和啤酒厂进行了试验和应用，结果表明采用了赤霉酸处理工艺，缩短了发芽期2天左右，增加浸出物2％左右，促进淀粉酶，β-葡聚糖酶，半纤维素酶，蛋白酶等多种酶的产生和活化，增加了色度，有利于休眠大麦的荫发，提高了发芽力。 相似文献
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纤维素酶是重要的水解酶,对植物的生长发育及新陈代谢发挥着重要作用。为了解茶树中纤维素酶的活性变化特征,以茶树品种‘凫早2号’为研究对象,测定其不同组织结构中纤维素酶3种主要组分内切葡聚糖酶、外切葡聚糖酶和β-葡萄糖苷酶的活性。结果显示,内切葡聚糖酶在茶树一芽四叶中随着叶片成熟度增加,酶活性增加,表现为:第四叶第三叶第二叶第一叶芽,与β-葡萄糖苷酶活性呈现相反趋势;外切葡聚糖酶和β-葡萄糖苷酶都是在第四叶活性最低。内切葡聚糖酶在茶树花朵中活性最高,而外切葡聚糖酶和β-葡萄糖苷酶分别在叶片、果皮中活性最高。胞质蛋白中内切葡聚糖酶和β-葡萄糖苷酶活性显著高于膜蛋白中的酶活性,但胞质蛋白、膜蛋白中都未检测到外切葡聚糖酶活性。 相似文献
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酶制剂体外酶解豆粕中抗营养因子的研究 总被引：2，自引：0，他引：2
为了评价几种单一酶、复合酶以及钙离子对豆粕中的相关抗营养因子的水解效果,进行了体外酶解试验。共有4种单一酶制剂（植酸酶、果胶酶、纤维素酶和木聚糖酶）和3种复合酶制剂被采用,其中复合酶SB由α-半乳糖苷酶和木聚糖酶组成,复合酶C3由植酸酶、果胶酶、纤维素酶组成,复合酶C5由植酸酶、果胶酶、纤维素酶、木聚糖酶和α-半乳糖苷酶组成。预试验显示上述酶有基本相似的最适水解反应参数：水分50％、pH4．8-5．0、温度50℃和时间45min。在此参数下,添加10．5U g^-1豆粕的植酸酶,豆粕中植酸的降解率达到69．63％;添加果胶酶16U·g^-1豆粕,豆粕中果胶的降解率达到45．93％;添加纤维素酶50U·g^-1豆粕,纤维素降解率达到66．21％;分别添加木聚糖酶80U·g^-1豆粕和α-半乳糖苷酶0．7U·g^-1豆粕,豆粕中还原糖的释放量增加率分别达到84．77％和65．19％。在豆粕中添加0．2％CaCl2,植酸的降解率与对照组相比微增至71．09％,还原糖的释放量分别增加到88．68％和65．23％。但果胶和纤维素的降解率分别显著地增加到90．01％和70．43％。研究发现复合酶C3和C5对相关的抗营养因子均呈现出不同程度的协同效应。说明使用复合酶制剂并适量添加CaCl2,体外水解豆粕中的相关抗营养因子是可行的。 相似文献
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根据国外资料以及国内制麦生产的实践,赤霉酸应用于麦芽生产,能提高麦芽质量,我省的麦芽厂和啤酒厂进行了试验和应用,结果表明采用了赤霉酸处理工艺,缩短了发芽期2天左右,增加浸出物2%左右,促进淀粉酶,β-葡聚糖酶,半纤维素酶,蛋白酶等多种酶的产生和活化,增加了色度,有利于休眠大麦的萌发,提高了发芽力。 相似文献
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以黄瓜（Cucumis Sativus L.）种子为材料,研究胡敏酸（Humic Acid,HA）对苯丙烯酸（Cinnamic Acid,CA）胁迫下黄瓜种子萌发的影响及其机理。结果表明： CA对黄瓜种子萌发有明显的抑制作用, 且抑制程度随CA浓度（0.10～1.0 mmol/L）的增加而提高。 CA胁迫下, 黄瓜种子总淀粉酶、 α-淀粉酶、 β-淀粉酶及蛋白酶活性降低, 种子活力、 种子物质消耗率下降,发芽势降低。25 mg/L HA处理可以缓解CA胁迫对种子萌发的抑制作用,表现为发芽势提高,种子活力、α-淀粉酶、β-淀粉酶和蛋白酶活性以及种子物质消耗率提高。 相似文献
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β-淀粉酶是与糖化力关系最为密切的淀粉水解酶,直接关系到麦芽生产的经济收益,而该酶的热稳定性影响制作过程中麦芽活力的表现。不同来源的大麦基因型在β-淀粉酶的热稳定性上存在着明显的差异,可以分为三种类型,呈一定的地理分布;遗传研究表明,β-淀粉酶的热稳定性受其结构基因位点和附近的复等位基因的共同控制,并受一些基因的修饰,不同热稳定性β-淀粉酶类型的形成是相关蛋白质顺序上少数氨基酸变化的结果。已经鉴定到控制大麦籽粒β-淀粉酶的三个基因Sd 1、Sd 2和Sd 3,它们分别控制着三种热稳定性类型。β-淀粉酶热稳定性显著影响麦芽汁发酵率,热稳定性等位基因不同的大麦,它们的麦芽汁发酵率也不同。通过构建β-淀粉酶热稳定性突变基因,并采用转基因技术导入该基因,可以显著提高大麦的β-淀粉酶热稳定性。最后就开展β-淀粉酶热稳定性的遗传和环境变异研究的意义进行了讨论。 相似文献
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The effect of hydrogen peroxide (HP) and ozone (O3) treatment during barley steeping on the quality of malt produced from two barley varieties (GrangeR and AC Metcalfe) by micro-malting was investigated. The two steeping oxidation treatments that was observed to promote barley acrospire growth. Ozone treatment improved the malt enzyme activity of endo-protease, α-amylase, free beta-amylase and total limit dextrinase to differing extents, with GrangeR improving to a greater degree. HP treatment contributed to the increase of α-amylase, β-glucanase and endo-protease. Surprisingly, HP or ozone oxidation during malting resulted in different and novel outcomes for total beta-amylase in GrangeR and AC Metcalfe. In GrangeR, total beta-amylase activity reduced with respect to the control in both treatments. In comparison with AC Metcalfe there was a substantial increase of 78% with HP and 90% O3 in total beta-amylase activity. Malt quality including wort free amino nitrogen, β-glucan, turbidity and diastatic power was differentially increased by the oxidation induction treatment during steeping in malting. Gene expression analysis indicated that the effects of the steep oxidation treatments on enzyme and malt quality were putatively linked with the up-regulation of certain genes involved in GA synthesis (GA20ox1) and ABA catabolism (ABA8′OH). Barley grain germination assay results also showed that moderate HP induction could improve barley germination tolerance to the ABA effect. Malting including steep oxidation induction was shown to be beneficial to malt quality by improving the resultant wort quality and the efficiency of the beer brewing process. These observations point the way towards improving malt quality and the efficiency of the malting process. 相似文献
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《Journal of Cereal Science》1996,24(1):55-63
The polymorphism of barleyalpha-amylases, as revealed by isoelectric-focusing (IEF), was studied in a population of 126 doubled-haploids from a cross between the cultivars Morex and Steptoe. In particular, the pattern was determined for an additional low pI alpha-amylase isozyme detected in cultivar Steptoe. No significant effect of this isozyme onalpha-amylase activity was observed, but a significant effect on β-glucanase activity was detected for two out of four trial locations. Quantitative Trait Loci (QTL) foralpha-amylase and β-glucanase activities were also investigated. The results suggest a potential location for the β-glucanase locusGlb2, on chromosome 1 close to theAmy2locus foralpha-amylase genes. 相似文献
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Influence of germination time and temperature on the properties of rye malt and rye malt based worts
Florian Hübner Beatus D. Schehl Kurt Gebruers Christophe M. Courtin Jan A. Delcour Elke K. Arendt 《Journal of Cereal Science》2010
The effects of germination time and temperature on the quality of rye malt and worts derived thereof were investigated using Response Surface Methodology. Amylolytic and proteolytic enzyme activities were increased by long germination periods, while β-glucanase activity was not influenced. Total and Soluble Nitrogen content were also not significantly affected by the variations in germination conditions. Free Amino Nitrogen (FAN) was found in higher amounts in worts prepared from rye malts with long germination times. Extract contents were higher in rye malt than in the control barley malt and could be increased by a favourable germination regime, while no such impact on wort fermentability was found. High wort viscosities could be significantly reduced by a long germination period at low temperatures, but were still unacceptably high. The same conditions favoured the development of endoxylanase activity. Arabinoxylan (AX) accumulated during the germination process and their extractability increased. The results suggest that longer germination periods resulted in an increased number of AX molecules with lower molecular mass. Optimal rye malt qualities within the limits of this study were found for a germination time of 144 h at 10 °C, which resulted in an acceptable FAN content and the lowest measured viscosity. 相似文献
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《Journal of Cereal Science》1995,21(2):173-183
The effects of extraction conditions (pH, temperature, enzymic treatment) on the extractability of rye meal non-starch polysaccharides were studied. The yield of pentosans and extractable matter increased with increases in both temperature and pH during extraction. The extract viscosity was correlated closely with the pentosan content of the extract. The molecular size of the extracted non-starch polysaccharides decreased as the extract pH decreased. Enzymic treatment during extraction increased the amount of pentosan solubilised. Xylanases almost doubled the amount of extractable pentosans, but these were degraded to oligosaccharides. With β-glucanase and protease, the pentosan content of the extract increased by 65% and 40%, respectively. In addition, the β-glucan extractability was increased with protease by 10% and with β-glucanase by 90%. Using size-exclusion HPLC it was observed that the molecular size of extractable rye β-glucans was lower than that of the extractable rye pentosans. β-Glucanase caused considerable hydrolysis of β-glucan and no more β-glucan could be detected by size-exclusion HPLC. Protease treatment decreased the molecular size of extractable β-glucan. All enzymatic treatments caused a disruption of the endosperm cell walls in the extract residue. 相似文献
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氮肥运筹对啤酒大麦籽粒品质及产量的影响 总被引：1，自引：0，他引：1
为了揭示氮肥运筹对啤酒大麦籽粒品质和产量的调节效应,以啤酒大麦花30为材料,在施纯氮总量225kg.hm-2条件下,研究了不同氮肥运筹对千粒重、β-淀粉酶活性、蛋白质组分含量动态变化和产量及其构成因子的影响。结果表明:(1)随花后天数的增加,大麦籽粒千粒重、β-淀粉酶活性、醇溶蛋白和谷蛋白含量呈现由低到高的变化,而清蛋白和球蛋白含量先急剧上升,后略微下降;(2)增加拔节肥比例能显著增加β-淀粉酶活性、醇溶蛋白和谷蛋白含量,而对清蛋白和球蛋白含量影响较小;(3)千粒重、β-淀粉酶活性及蛋白质组分含量的相关性均达极显著水平;(4)随着氮肥用量后移,有效穗数、产量呈上升趋势,千粒重呈下降趋势。综合考虑各项指标,建议在类似本试验条件下的啤酒大麦生产区,基肥、苗肥、拔节肥比例以6∶3∶1为宜。 相似文献
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F.J. Zhao S. Fortune V.L. Barbosa S.P. McGrath R. Stobart P.E. Bilsborrow E.J. Booth A. Brown P. Robson 《Journal of Cereal Science》2006,43(3):369-377
Eight field experiments were conducted at four sites in the UK in 2003 and 2004 to investigate the effects of sulphur (S) application on yield and malting quality of barley. Significant yield responses to S additions were obtained in five out of the eight experiments, with yield increases ranging from 0.2 to 1.2 t/ha (4.7–22.5%). At the two most S-deficient sites, S application significantly increased malt diastatic power, alpha-amylase activity, friability and homogeneity, and decreased (1→3,1→4)-β-glucan concentration in the wort, indicating an improved endosperm modification during malting. Sulphur applications also significantly increased the concentration of S-methylmethionine (the precursor of dimethylsulphide) in kilned malt, which could impact on beer flavour. When the supply of N was limiting, S applications decreased grain N concentration due to a dilution effect as a result of increased grain yield. In some cases, S applications resulted in decreased grain size. At sites non-deficient or marginally deficient in S, applications of S had little effect on grain or malting quality parameters. The need to maintain an adequate S supply to barley for both yield and malting quality was demonstrated. 相似文献
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Tamer H. Gamel El-Sayed M. Abdel-Aal Nancy P. Ames Ruedi Duss Susan M. Tosh 《Journal of Cereal Science》2014
The viscosity of the soluble fibre, β-glucan, has been shown to influence its ability to lower serum cholesterol and postprandial blood glucose levels. The impact of various amylases, proteases and lipase on the solubility and resulting viscosity of β-glucan extracted from oat bran cereals with a range of β-glucan concentrations and molecular weights was investigated. Addition of enzymes increased the final viscosity of high molecular weight β-glucan in cereals by facilitating the release of β-glucan from the food matrix. For cereals with partially depolymerized β-glucan, the addition of digestive enzymes decreased the final viscosity by eliminating the contribution of starch and protein to viscosity. Final viscosity varied depending on enzyme combinations including pancreatin, salivary and microbial α-amylases, microbial protease, porcine protease, trypsin and α-chymotrypsin. Addition of lipase did not significantly affect viscosity or solubility of β-glucan extracted from oat crackers. Addition of lichenase showed that β-glucan was the major contributor of viscosity to the system, with negligible interference from other components. The viscosity of the optimized protocol was compared to physiological results previously obtained. The viscosity of β-glucan extracted with pancreatin plus microbial α-amylase (pH 6.9) was predictive of LDL-cholesterol reduction (R2 = 0.847) and glycemic response (R2 = 0.883). 相似文献
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《Journal of Cereal Science》2004,39(2):273-281
The levels of xylanolytic activities ((1→4)-β-endoxylanases, β-d-xylosidases and α-l-arabinofuranosidases) and the levels of water extractable arabinoxylans (WEAX) in hot water extracts of malts were compared during malting of four barley cultivars of differing quality. Endoxylanase activity increased from day 1 after steeping showing a slight lag compared with the development of (1→3,1→4)-β-glucanase activity. The levels of endoxylanase activity were different between the cultivars. For example, at day 4, which would be a suitable endpoint for malting of good quality cultivars, total endoxylanase activities of Static and Chariot malts were twice that of Hart and Optic. This variation in level of endoxylanase between cultivars did not correlate with the content of water extractable arabinoxylans in hot water extracts of the malts. However, those cultivars that accumulated most water extractable arabinoxylan had a different set of endoxylanase isoforms. This suggests that expression of specific endoxylanase isoforms may influence the extent of arabinoxylan solubilisation and/or degradation.The β-xylosidases and α-arabinosidases increased from low levels after steep to a plateau of activity at day 6 or 7 of germination. Total xylosidase was always higher than the arabinosidase activity. There were differences between cultivars but these were small compared with the variation in endoxylanase activity. (1→4)-β-d-Endomannanase activity was detected in all four cultivars at 2 days germination then rose to a maximum around 5 days. 相似文献
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Leland C. Dickey David B. JohnstonMichael J. Kurantz Andrew McAloonRobert A. Moreau 《Industrial Crops and Products》2011,34(1):845-850
In previous aqueous enzymatic oil extraction (AEOE) experiments we reported a best free oil yield of 49% of the hexane extracted yield of dry fractionated corn germ. In the current experiments, a dispersion of 10% cooked, dry-fractionated germ in water was treated with α-amylase, glucoamylase and a cellulase complex. Free oil was collected by centrifuging a foam fraction of the dispersion. Several dispersion treatments were tried to evaluate their release of free oil and effect on the production of foam. The foam contained up to 8% free oil (dispersed from germ containing 26% oil) and fines oil (not centrifugally separable), protein and germ particles. Treatment with α-amylase and glucoamylase prior to treatment with the commercial cellulase used in previous AEOE studies increased the free oil yields about 25-61% of the hexane-extractable yield. A preliminary cost analysis indicates that oil separation with the amylase enhanced AEOE appears to be preferable to AEOE alone and profitable if crude corn oil cost exceeds $1.1/kg ($0.50/lb). 相似文献
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Pre-harvest sprouting (PHS) is a concern for barley (Hordeum vulgare L.) producers, grain processors, and researchers worldwide. Pre-harvest sprouting has been mainly attributed to low dormancy, which is determined by genotype, stage of plant maturation, and environmental conditions during caryopsis development. Fourteen barley genotypes were sown in field experiments at two sites in North Dakota in 2004 and 2005. Spikes were harvested at four different stages: ≈500 g kg−1 moisture content, physiological maturity, harvest maturity, and post-harvest maturity. Results indicated that barley genotypes were released from dormancy at different rates. The 14 barley genotypes were divided into three classes based on their dormancy loss rate during caryopsis development. C93-3230-24 was highly dormant, and ‘Stander’ and ‘Legacy’ were highly susceptible to PHS due to lack of dormancy from as early as 20 d after heading date. All other genotypes fell into the third group that had intermediate dormancy loss rate. No significant correlation was detected between barley α-amylase activity and germination percentage. A moderate association between malt α-amylase activity and caryopsis dormancy suggested that cultivars with increased malt α-amylase activity tend to have low dormancy and may be more prone to PHS. 相似文献