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Raw corn starch granules were hydrolysized by glucoamylase in a chemostat. The hydrolysis of three different-sized granules shows that smaller granules undergo more hydrolyzation than larger ones. After 78 h, 97% of the granules was hydrolysized with diameter between 0.15 mm and 0.3 mm at 50℃. When corn starch concentration increased from 100 g/L to 250 g/L, the amount of reducing sugar produced was proportional to the initial substrate concentration and no substrate inhibition phenomenon appeared. In order to study the product inhibition exactly, the product from hydrolysis reaction itself was added into the hydrolysis system at the beginning of starch hydrolysis.Product inhibition with different quantities of product added were studied in the initial several hours,during which period enzyme inactivation could be neglected and product inhibition could be studied separately. The experiments indicate that product inhibition happens when the additional quantity exceeds 9.56 g/L. 相似文献
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以菠萝蜜种仁淀粉为原料,采用β-淀粉酶（酶活为91500U／g）单酶法制备麦芽糖浆,在单因素实验的基础上,通过正交试验对工艺条件进行了优化,最佳工艺条件确定为：淀粉乳质量浓度20g／100mL、按质量分数加酶8％、pH5．5、（糖化）水解温度54℃、糖化时间8h。结果表明,在此条件下得到的产物淀粉转化率为41．6％,麦芽糖得率为47．5％。粗产品再经浓缩,得到的麦芽糖浆可溶性固形物含量（质量分数）为75％,色泽淡黄、体态均一透明、粘稠,具有麦芽糖香味,适合作为食品和食品辅料。 相似文献
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以木薯淀粉为原料,高碘酸钠作氧化剂在拟均相体系中制备了双醛淀粉,研究了反应时间、反应温度、高碘酸钠的浓度、反应pH值、高碘酸钠与淀粉摩尔对产品中双醛含量的影响。在选定的实验范围内,制得了双醛含量在64．1％～90．3％的双醛淀粉。 相似文献
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以稀硫酸预处理的麦秆为底物,通过单因素试验和正交试验优化了底物的酶解条件.结果表明：酶解条件的主次顺序为底物质量浓度、酶质量浓度、酶解时间、酶解温度和pH;最佳酶解条件为底物质量浓度0.25 g/L、酶质量浓度2 g/L、酶解时间36 h、酶解温度45℃和pH为5.0,此时总还原糖含量最大为707.07 mg/g,糖含量显著增加.酶解对于提高麦秆的糖化率是非常有必要的. 相似文献
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讨论了对以淀粉、磷酸、蜜胺为原料合成淀粉磷酸酯蜜胺盐的方法和产品性能。采用正交试验设计法对合成工艺条件进行优化,采用热重分析法、加热膨胀法和红外光谱法对产品的性能和结构进行了表征。淀粉磷酸酯的最佳反应条件为:反应温度100℃,反应时间4小时,磷酸为淀粉用量的75%;淀粉磷酸酯蜜胺盐的最佳反应条件为:反应温度110℃,反应时间2小时,磷酸与蜜胺的摩尔比为1∶1.1。在最佳反应条件下,淀粉磷酸酯蜜胺盐的收率为51.3%。产物在398.5℃开始明显分解,温度升高到567.5℃时,失重为73.8%,膨胀率为119.4cm3/g。结果表明,目的产物具有良好的热稳定性和膨胀性。 相似文献
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以一氯乙酸为醚化剂,在水相中制备了低取代度(DS)的羧甲基淀粉。在淀粉乳浓度29%,投料比n(ClCH2COOH)∶n(淀粉)=0.15∶1,反应温度50℃,反应时间10h的条件下,羧甲基淀粉的取代度为0.027 9。以此取代度的羧甲基淀粉作为抑制剂对红铁矿进行浮选实验,当用量为220g/t原矿时,精品位可达66.02%,回收率可达80.15%。 相似文献
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Dong-dong CAO Jin HU Xin-xian HUANG Xian-ju WANG Ya-jing GUAN Zhou-fei WANG 《Journal of Zhejiang University. Science. B》2008,9(12)
The changes of kernel nutritive components and seed vigor in F1 seeds of sh2 sweet corn during seed development stage were investigated and the relationships between them were analyzed by time series regression (TSR) analysis. The results show that total soluble sugar and reducing sugar contents gradually declined, while starch and soluble protein contents increased throughout the seed development stages. Germination percentage, energy of germination, germination index and vigor index gradually increased along with seed development and reached the highest levels at 38 d aider pollination (DAP). The TSR showed that, during 14 to 42 DAP, total soluble sugar content was independent of the vigor parameters determined in present experiment, while the reducing sugar content had a significant effect on seed vigor. TSR equations between seed reducing sugar and seed vigor were also developed. There were negative correlations between the seed reducing sugar content and the germination percentage, energy of germination, germination index and vigor index, respectively. It is suggested that the seed germination, energy of germination, germination index and vigor index could be predicted by the content of reducing sugar in sweet corn seeds during seed development stages. 相似文献
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采用闪式提取法对杨梅中活性成分进行提取,以出酒率、花色素含量、自由基清除率和还原糖含量作为考察指标,采用L9（34）正交试验对提取工艺进行优化。结果表明：闪式提取法制备杨梅酒的最佳工艺条件是：料液比1：1．2．闪式提取电压50V,闪式提取时间3min。在此条件下,杨梅酒出酒率为112．68％,花色素含量为179．31μg／mL,自由基清除率为83．85％,还原糖含量为18．33％。该工艺提取时间短,酒色鲜艳透亮,口感较佳,是一种快速高效制备杨梅酒的方法。 相似文献
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在红曲霉发酵酿造茶酒的原料中添加制茶下脚料,实验对比测定了发酵前后各营养成分的变化,结果表明：发酵前物料中各营养含量分别为,总糖（302.2±3.29） mg/g,还原糖（126.3±7.46）mg/g,多糖（175.9±9.05） mg/g,粗纤维27.1%,氮（40.64±1.06） mg/g,游离氨基酸（47.04±0.75） mg/g。发酵后物料中总糖（199.1±1.64） mg/g,还原糖（29.07±0.34） mg/g,多糖（170.0±1.30） mg/g,粗纤维18.8%,氮（37.02±0.86） mg/g,游离氨基酸为0 mg/g。发酵前后物料总重量利用率39.4%,各营养物质的转化率分别为总糖60.06%,还原糖86.01%、多糖3.35%、粗纤维30.62%、氮8.91%、氨基酸为100%。发酵茶酒的酒精度达到13%。 相似文献
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Hu-zhe Zheng In-Wook Hwang Shin-Kyo Chung 《Journal of Zhejiang University. Science. B》2009,10(12):912-919
The effects of process variables such as enzyme types, enzyme ratio, reaction temperature, pH, time, and ethanol concentration on the extraction of unripe apple polyphenol were investigated. The results indicated that Viscozyme L had the strongest effect on polyphenols extraction and was selected to study the polyphenol composition. The ratio of enzyme (Viscozyme L) to substrate (2 fungal beta-glucanase units (FBG)) at 0.02, reaction at pH 3.7,50 ℃ for 12 h, and ethanol concentration of 70% were chosen as the most favorable extraction condition. Total phenolic content (TPC), reducing sugar content (RSC), and extraction yield increased by about 3,1.5, and 2 times, respectively, compared with control. The contents of p-coumaric acid, ferulic acid, and caffeic acid increased to 8,4, and 32 times, respectively. The enzyme-aided polyphenol extraction process from unripe apples might be applied to food industry for enhancing bioactive compound production. 相似文献
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酶辅助法提取大青叶中总黄酮及抗氧化性研究 总被引：1，自引：0，他引：1
本论文采用酶辅助法提取大青叶中的总黄酮,先用纤维素酶酶解,再用乙醇回流提取大青叶中总黄酮。分别固定乙醇提取液的浓度为70%,料液比为1∶20g∕mL,回流时间为2h。初步探究了纤维素酶浓度、酶解pH、酶解温度、酶解时间四个单因素对大青叶中黄酮提取率的影响。设计正交实验确定酶辅助法提取大青叶中总黄酮的较佳条件为:纤维素酶浓度为4U/mL、酶解pH=4.5、酶解温度为40℃、酶解时间1.5h,总黄酮提取率高达2.85%。另外还研究了大青叶总黄酮提取液对羟自由基的清除活性,与BHT的抗氧化剂活性作对照实验,结果表明大青叶中的总黄酮对羟自由基有较强的清除活性。 相似文献
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以花生壳为原料,以SO42-/TiO2-Al2O3固体酸为水解催化剂制备乙酰丙酸,探讨了固体酸用量,水解时间,水解温度,液固比对乙酰丙酸得率的影响。研究结果表明,当固体酸用量3.5%、水解时间150 min、水解温度250℃、液固比21:1(L/mg)时为较优的制备工艺。在该工艺条件下,乙酰丙酸得率为12.35%。 相似文献
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以"紫罗兰"紫甘薯为材料,薯苗扦插成活后30d叶面喷施50mg/L、150mg/L和250mg/L三种浓度PP333溶液,并以清水作对照.用药后7d测定叶片叶绿素含量;种植3.5月采收后测定产量和品质.结果表明:三种浓度PP333处理中,150mg/L为最佳,增产率19.37%,花青素含量、淀粉含量、可溶性糖含量分别较对照提高9.60%、17.87%、11.06%,含水量降低1.60%,各项指标的影响较对照均达显著水平. 相似文献