用淀粉酶提高雪糕中淀粉用量的研究

采用淀粉酶对雪糕中的淀粉进行水解,改变淀粉的分子结构,可以防止淀粉老化返生,消除淀粉味感;增加淀粉的用量,降低白砂糖、奶粉、奶油的用量,从而降低产品的生产成本,同时也可使产品口感细腻、柔软,质量得到改善,膨胀率在90-100%。     

磷酸酯化直/支链淀粉的性能测试与比较

为了研制应用性能可以在一定范围内定量调整的磷酸酯化淀粉,采用干法制备了磷酸酯化直链淀粉和磷酸酯化支链淀粉,并用IR光谱、X-衍射光谱进行了表征;测定和比较了质量比分别为3∶1、1∶1、1∶3的磷酸酯化直/支链淀粉的透光率、抗凝沉性、冻融稳定性、吸水性、吸油性、黏度及黏度热稳定性等应用性能。试验结果表明:磷酸酯化直/支链淀粉的透光率、抗凝沉性、冻融稳定性、吸水性、黏度及黏度热稳定性随着磷酸酯化支链淀粉比例的增加而逐渐增大,吸油性则逐渐减小。     

Immobilization of α‐amylase in polyelectrolyte complexes

Herein, we report the formation of α‐amylase containing polyelectrolyte complexes (PECs). The method for the encapsulation of α‐amylase is based on interactions between two oppositely charged polyelectrolytes, poly(acrylic acid) (PAA) and polyethylenimine (PEI). We could show that electrostatic interactions ensure the incorporation of the enzyme into the formed polyelectrolyte complexes. The encapsulation has no negative effect on enzyme activity and protects against denaturation of the enzyme initiated by low pH values. The resulting PECs are 150–250 nm in size with narrow size distribution, appear in a spherical shape and are colloidally stable. The complexation of both polyelectrolytes and the immobilization of α‐amylase are investigated using fractionating techniques mainly the analytical ultracentrifugation and asymmetrical‐flow field‐flow fractionation. The formation of PECs represents a simple method for the encapsulation of α‐amylase without the use of organic solvents and requires no additional purifications steps. This one‐step approach, yielding high encapsulation efficiencies, shows the potential as a drug delivery system for sensitive hydrophilic actives in future. α‐amylase is immobilized in polyelectrolyte complexes made of polyethylenimine and poly(acrylic acid). Optimized encapsulation conditions and the resulting polyelectrolyte complexes are investigated via determination of IEP, α‐amylase activity assays, nanoDSC measurements, zeta potential values, dynamic light scattering, microscopy, and fractionating techniques. The encapsulated enzyme is protected against denaturation initiated by low pH values. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45036.     

酶解淀粉-苯乙烯/丙烯酸丁酯接枝共聚物乳液的制备研究

采用无皂乳液聚合的方法,以过硫酸铵(APS)为引发剂,制备了酶解淀粉与苯乙烯(St)和丙烯酸丁酯(BA)的接枝共聚物。探讨了淀粉与单体配比、过硫酸铵用量、单体配比和反应温度对接枝反应的影响。结果表明,反应的优化条件为:m(淀粉)∶m(单体)=1∶3,(NH4)2S2O8的加入量为淀粉与单体总质量的0.5%,单体质量比为1∶1,反应温度为82℃,在此条件下,接枝率可达103.8%,接枝效率为37.4%,单体转化率为91.9%。红外光谱分析表明,苯乙烯和丙烯酸丁酯参与了接枝反应;SEM结果显示,接枝反应之后,淀粉形貌发生了变化,球状颗粒已经消失。     

α－淀粉酶发酵工艺条件试验研究

本文以枯草杆菌ＢＦ－７６５８的诱变菌株Ｎｉｎｇ作为试验菌株，分别在摇瓶条件下和１０升发酵罐上进行α－淀粉酶的发酵工艺条件的试验研究。结果表明：该菌株的发酵培养基碳氮比为１．４∶１，最适ｐＨ为６．５，通风量的变化极大地影响产酶能力；在较佳的培养条件下，摇瓶产酶活力为４０９．０ｕ／ｍｌ，１０升发酵罐的产酶活力为３９７．２ｕ／ｍｌ，比原菌提高约１００ｕ／ｍｌ。     

激光对黑曲霉糖化菌株诱变的探讨

25mw He—Ne激光对黑曲霉N_(213)菌株经不同时间照射后,发现其对该菌株部分孢子分别有杀灭作用和促进生长作用,而且孢子存活率随照射时间的延长呈下降趋势。 选择照射40分钟后生长旺盛的孢子,用25mw He—Ne激光重复照射4次,筛选后,获得N_(213)变异株,用其制备麸曲,测其糖化酶活力较出发菌株麸曲的糖化酶活力增加33％,达10,000U/g。     

TISSUE DISTRIBUTION OF α-AMYLASE AND PHOSPHORYLASE IN DEVELOPING BARLEY GRAIN

Approximately half the total α-amylase and phosphorylase activity detectable in crude homogenates of the tissues of developing barley grain was localized in the pericarp. This tissue is particularly active in the early stages of grain development. It is suggested that this activity may influence the starch type and content of the mature barley grain.     

糙米酵素发酵工艺条件的研究

以糙米为原料,以淀粉酶活力为指标,研究发酵条件对糙米酵素淀粉酶活力的影响。结果表明:酵母用量为4%,发酵时间5h,发酵温度30℃时,淀粉酶活力最强。     

面粉中的淀粉组分对面条蒸煮品质的影响

从面粉中提取淀粉、直链淀粉和支链淀粉,按不同的梯度添加到原面粉中制作面条.然后测定面条的蒸煮特性,寻找出淀粉、直链淀粉和支链淀粉对面条蒸煮品质影响的规律.实验表明:随着淀粉添加量的增加,面条的干物质吸水率、干物质损失率、蛋白质损失率都出现了上升的趋势;随着直链淀粉添加量的增加,面条的干物质吸水率出现了下降的趋势,而干物质损失率、蛋白质损失率都出现了上升的趋势;随着支链淀粉添加量的增加,面条的干物质吸水率出现了上升的趋势,而干物质损失率、蛋白质损失率都出现了下降的趋势.     

浅谈酶在非接触印刷废纸脱墨中的应用

简要地介绍了纤维素酶、半纤维素酶和淀粉酶在非接触印刷废纸脱墨中的研究及其应用