籼米多孔淀粉的研制

试验以籼米淀粉为原料,通过α-淀粉酶水解籼米淀粉制备籼米多孔淀粉,探讨并获得了酶水解法制备籼米多孔淀粉的较优工艺：酶解反应温度为35℃,酶解反应时间为12 h,加酶量为酶解40%淀粉量,酶解体系pH值为4.0。并利用砂芯漏斗测定淀粉对液体的吸附能力,观察到大米多孔淀粉对液体的吸附能力大大强于大米原淀粉。     

多孔淀粉研究Ⅱ多孔淀粉形成工艺优化

本文主要研究以籼米为原料生产多孔淀粉的生产工艺。首先制备籼米淀粉，脱除蛋白质及纤维类物质；再确定酶解工艺条件，在单因子水平基础上进行RSA回归试验，分析得到最佳酶解参数；然后确定酶解下游工艺，即分离、提取及干燥等；最后是改善产品外观，主要是解决色泽问题。结果表明：讨论最佳酶解工艺参数是完全必要的。最佳工艺条件为酶组合（10：1），淀粉浆浓度（80％），加酶量（按水解淀粉40％的量，总酶活330IU／g生淀粉），pH3．6，温度（42℃），时间（22．5h），转速（100r／min）；其中冷冻干燥产品性能较好，产品色泽亦有了明显改善。本研究提供了一整套生产多孔淀粉的最佳工艺参数。     

多孔淀粉研究 II多孔淀粉形成工艺优化

本文主要研究以籼米为原料生产多孔淀粉的生产工艺。首先制备籼米淀粉,脱除蛋白质及纤维类物质;再确定酶解工艺条件,在单因子水平基础上进行RSA回归试验,分析得到最佳酶解参数;然后确定酶解下游工艺,即分离、提取及干燥等;最后是改善产品外观,主要是解决色泽问题。结果表明:讨论最佳酶解工艺参数是完全必要的。最佳工艺条件为酶组合(10:1),淀粉浆浓度(80%),加酶量(按水解淀粉40%的量,总酶活330IU/g生淀粉),pH3.6,温度(42℃),时间(22.5h),转速(100r/min);其中冷冻干燥产品性能较好,产品色泽亦有了明显改善。本研究提供了一整套生产多孔淀粉的最佳工艺参数。     

淀粉性质及预处理对多孔淀粉形成的影响

本文主要考察原料淀粉的性质及其预处理方式对多孔淀粉形成的影响。首先考察了不同来源的淀粉对形成多孔淀粉的影响，发现玉米和稻米淀粉适合制备多孔淀粉；接着考察了7种不同直链淀粉含量的稻米淀粉对制备多孔淀粉的影响，发现直链淀粉含量与水解率在1％水平上呈显著负相关。原料粒径越小，溶解度越大，多孔淀粉的吸油率越大，得率越低。淀粉中蛋白质含量高，酶解速度慢，但差别不显著，形成多孔淀粉的吸油率低；干法粉碎样品的起始反应速度要高于湿法粉碎样品的，但酶解后期，酶解速度与粉碎方式无关。     

酶复合处理制备多孔淀粉的研究

多孔淀粉是一种酶处理变性淀粉,是指由具有生淀粉酶活力的酶在低于淀粉糊化温度下作用生淀粉颗粒后形成的多孔性淀粉载体。实验根据生淀粉酶的水解作用机理,并结合扫描电子显微镜观察,从而确定酶复合处理制备多孔淀粉的最佳工艺条件和参数。     

酶法制备多孔玉米淀粉的影响因素研究

多孔淀粉是生淀粉酶在低于淀粉糊化温度下水解各种淀粉形成的一种中空的变性淀粉。作为一种高效、无毒、安全的新型有机吸附剂被广泛用于食品、医药、农业、化妆品、造纸等行业。本文以玉米淀粉为原料,采用酶水解法来制备多孔淀粉。以吸水率、吸油率为指标来评价酶的来源、淀粉的预处理条件、酶解条件等因素对多孔淀粉形成的影响。研究结果表明,选择玉米淀粉颗粒的粒度为100目,经过湿热处理后采用复合酶(α-淀粉酶与糖化酶配比为1:3)来制备多孔淀粉。通过正交试验确定酶解最佳工艺条件:酶用量 2．0％,时间20h,温度42℃,pH值4．2,搅拌速率120r·min-1,Ca2+浓度0．15％。     

不同酶处理对多孔大米淀粉性能的影响

使用麦芽糖α-淀粉酶（MA）和淀粉葡糖苷酶（AMG）分别处理制备多孔大米淀粉,对其表征特性进行对比分析。通过扫描电镜可知,这两种酶均使淀粉颗粒表面产生蜂窝状多孔结构。经酶处理的大米淀粉颗粒的相对结晶度（25.54%～33.26%）均高于天然淀粉的相对结晶度（23.74%）。MA处理增加了短支链淀粉链的数量,并且随着酶处理时间的延长降低了分子质量。与对照组相比,MA和AMG处理的淀粉颗粒溶胀度、表观直链淀粉含量、峰值黏度、崩解值、最终黏度和回生值均下降。MA处理的淀粉颗粒具有更高的溶解指数（1.46%～2.57%）,AMG处理的淀粉颗粒的溶解指数均小于0.42%。与对照组相比,经酶处理的大米淀粉糊化温度会延迟0.8～6.0℃,焓变增加范围在1.0～3.8 J/g。     

玉米多孔淀粉对茶多酚的吸附性能研究

采用α-淀粉酶与葡萄糖淀粉酶水解玉米淀粉制备多孔淀粉,扫描电子显微镜观察发现其表面具有独特的多孔结构,并向内部延伸,比表面积增大,说明多孔淀粉可以作为良好的吸附载体。研究探讨了玉米多孔淀粉作为载体吸附茶多酚的性能,确定了多孔淀粉吸附茶多酚的最佳条件为茶多酚初始浓度4mg/mL、温度20℃、吸附时间60min、pH值为7,在此条件下,多孔淀粉对茶多酚的吸附达到饱和,最大吸附量达到68.65mg/g,比原淀粉提高了2.1倍。     

淀粉预处理方法对多孔淀粉的影响

多孔淀粉的制备原料有玉米淀粉、木薯淀粉、马铃薯淀粉等。在制备过程中,淀粉原料某些性质的变化对多孔淀粉性质有一定影响,不同原料、或同一原料的不同处理方式都会影响多孔淀粉的形成。有效的预处理方法对改变淀粉原料的性质,提高多孔淀粉的生产效率,降低生产成本,改善多孔淀粉的性质十分重要。     

淀粉预处理对酶法制备多孔淀粉影响

多孔淀粉制备原料有玉米淀粉、木薯淀粉、马铃薯淀粉等,在制备过程中,淀粉原料某些性质变化对多孔淀粉性质有一定影响,不同原料、或同一原料不同处理方式都会影响多孔淀粉形成;有效预处理方法对改变淀粉原料性质,提高多孔淀粉生产效率,降低生产成本,改善多孔淀粉性质十分重要。该文对淀粉不同处理方式对多孔淀粉影响进行综述。     

Structure and Properties of Starch in Rice Double Mutants Lacking Starch Synthase (SS) IIa and Starch Branching Enzyme (BE) IIb

Starch biosynthetic enzymes form multi-protein complexes consisting of starch synthase (SS) I, SSIIa, and starch branching enzyme (BE) IIb, which synthesize amylopectin clusters. This study analyzed the starch properties in two double mutant rice lines lacking SSIIa and BEIIb, one of which expressed an inactive BEIIb protein. The ss2a be2b lines showed similar or greater seed weight than the be2b lines, and plant growth was not affected. The ss2a line showed increased short amylopectin chains resulting in a lower gelatinization temperature. Starch granule morphology and A-type crystallinity were similar between the ss2a line and the wild type, except for a mild chalky seed phenotype in the ss2a line. However, the starch phenotype of the ss2a be2b lines, which was similar to that of be2b but not ss2a, was characterized by increased long amylopectin chains, abnormal starch granules, and B-type crystallinity. The similarity in phenotype between the ss2a be2b and be2b lines may be attributed to the inability of the be2b mutants to generate short amylopectin branches, which serve as primers for SSIIa. Therefore, the presence or absence of SSIIa hardly affected the amylopectin structure under the be2b background. The amylose content was significantly higher in the ss2a be2b lines than in the be2b lines. Starch crystallinity was greater in ss2a be2b lines than in be2b lines, despite the fact that starch crystallinity is generally negatively correlated with amylose content. This suggests that the formation of a double helix between long amylopectin chains and amylose affects starch crystallinity in the ss2a be2b mutants.     

绿豆微孔淀粉酶法制备工艺优化研究

以水解率为指标,研究α-淀粉酶与糖化酶复合水解绿豆淀粉制备微孔淀粉工艺条件,通过单因素和正交试验确定酶解最佳工艺条件：α-淀粉酶：糖化酶=1：3,酶用量2．0%,时间20 h,温度42℃,pH4．2。经吸水、吸油率测试,对酶解前后绿豆淀粉进行性质分析表明,微孔淀粉吸水、吸油能力明显大于原淀粉。     

小麦粉粒度变化与淀粉损伤程度

从小麦淀粉的原生态(粒径大小与分布)出发,首先拿等级粉的粗细度与之比较,分辨淀粉损伤的综合程度和倾向,进而对工艺中各研磨部位的面粉粒度、淀粉损伤程度进行分析研讨,以化验的量化结果,揭示淀粉损伤的真实面貌。紧紧抓住面粉粒度变化和淀粉损伤程度的同步因素,逐渐深入,诠释不被重视的等级粉淀粉损伤原因和专用粉能适应不同面制品要求的理论基础,提出了研究淀粉损伤和面粉粒度是制粉工艺研究的当务之急。     

Physicochemical Properties and Starch Granular Characteristics of Flour from Various Manihot Esculenta (Cassava) Genotypes

ABSTRACT: Flour and starch were produced from 11 cassava genotypes. Starch and total dietary fiber contents were determined using a single-enzyme gravimetric procedure and high-performance anion exchange chromatography, pasting profiles by rotary viscometry, water holding capacity gravimetrically, and granular characteristics by scanning electron microscopy. Starch and total dietary fiber contents varied among genotypes. Flour peak viscosities, setback, and final viscosities differed significantly. Flour water holding capacity correlated with flour peak viscosity (r = 0.7). Starch granules ranged from 9 to 20 μm. Predominant granule shapes were oval, rounded, and truncated. The results provide insights into cassava genotype characteristics, and functionality of cassava starch and flour.     

动态超高压微射流对蜡质玉米淀粉颗粒结构的影响

以蜡质玉米淀粉为研究对象,采用动态超高压微射流进行处理,研究不同压力(40-160 MPa)处理对淀粉颗粒结构的影响。结果表明:经动态超高压微射流均质后,淀粉颗粒表面会出现小孔和凹坑并破碎,并且随着压力的增大,被破坏程度会逐渐增大,当压力达到160 MPa时,会出现团聚现象;随着压力的增大,淀粉颗粒比表面积呈上升趋势;偏光显微镜分析得出淀粉颗粒的偏光十字随着处理压力的增大而逐渐减弱后消失;X射-线衍射分析得出蜡质玉米淀粉晶型为A型,结晶度随着压力的增大而减小。     

乙醇生产的技术进步——新型酶技术给乙醇生料发酵生产带来的突破

由于能源价格的增长和乙醇的广泛应用,发酵乙醇日益具有竞争力。文中对发酵法生产乙醇的状况和技术进行了简单回顾,着重介绍了新型生料水解酶的作用原理及其研究进展,并对该项技术的使用和对生产带来的益处进行了分析。     

Comparison Between Granular Starch Hydrolyzing Enzyme and Conventional Enzymes for Ethanol Production from Maize Starch with Different Amylose: Amylopectin Ratios

The effect of enzyme treatments (granular starch hydrolyzing and conventional enzymes) and different amylose: amylopectin ratios of maize starch on ethanol production was evaluated. For starch treatments, amylose: amylopectin ratios were prepared by mixing commercially available Hylon VII (70% amylose and 30% amylopectin) and Amioca (˜100% amylopectin) starches. For maize treatments, waxy, high amylose and regular dent hybrids were used to represent varying amylose: amylopectin ratios. All hydrolyses followed by fermentations were conducted at 15% solids content. Differences were observed in ethanol yields among granular starch hydrolyzing and conventional enzymes. Differences also were observed in ethanol yields between different amylose: amylopectin ratios for pure starch and maize samples. For starch samples, final ethanol concentrations varied from 2.2 to 9.1% (v/v) for fermentation with granular starch hydrolyzing enzyme and from 6.7 to 9.3% (v/v) for conventional enzymes. Higher ethanol concentrations were observed for Amioca starch for both enzymes. For maize samples, final ethanol concentrations were highest for waxy maize for both granular starch hydrolyzing (8.2%, v/v) and conventional (8.2%, v/v) enzymes. Lowest ethanol concentrations were observed for high‐amylose maize samples for granular starch hydrolyzing (6.3%, v/v) and conventional (5.2%, v/v) enzymes.