酶法制备马铃薯抗性淀粉的工艺研究

以马铃薯淀粉为原料,经糊化后,先后使用耐高温a-淀粉酶和普鲁兰酶进行酶脱支处理,以生成更多的直链淀粉,利于分子重新结晶,提高抗性淀粉含量.试验表明,在耐高温a-淀粉酶添加量为4 NU/g干淀粉,反应时间为30min,普鲁兰酶添加量为4NPUN/g干淀粉,反应时间6 h,反应温度55℃时,抗性淀粉含量最高,可达到12.6%.最大影响因素为：普鲁兰酶反应时间.     

油莎豆复合酶法抗性淀粉的制备及纯化工艺

以油莎豆淀粉为原料,通过高温α-淀粉酶水解,普鲁兰酶脱支,对淀粉进行连续处理,研究复合酶法油莎豆抗性淀粉的制备及纯化工艺条件,单因素及正交实验结果表明,油莎豆淀粉双酶法制备抗性淀粉酶解的最佳工艺条件是:高温α-淀粉酶添加量2μ/g、酶解温度95℃、酶解时间15 min。普鲁兰酶添加量15μ/g、酶解温度50℃、酶解时间20 h。此条件下制备的油莎豆抗性淀粉得率为39.48%,抗性淀粉含量为57.72%。     

酶法联合压热-冷却循环处理制备抗性淀粉

本研究以玉米淀粉为原料,通过酶法联合压热-冷却循环处理制备抗性淀粉,测定酶解过程中淀粉的水解度(DE值)、脱支度和直链淀粉含量、样品抗性淀粉含量及其热稳定性,采用差示扫描量热仪(DSC)、扫描电子显微镜(SEM)分别测定抗性淀粉的热力学特性和颗粒形貌。结果表明,耐高温α-淀粉酶酶解能显著提高淀粉的水解度,耐高温α-淀粉酶联合压热-冷却循环制备的抗性淀粉含量为10.51%~12.16%;淀粉脱支度、抗性淀粉含量、直链淀粉含量随着普鲁兰酶酶解前压热-冷却循环处理次数增加而显著下降,抗性淀粉的热稳定性却得到提高;先普鲁兰酶酶解后压热-冷却循环处理3次得到的抗性淀粉含量最高,达到17.94%;抗性淀粉的糊化峰值温度为119.5℃~121.1℃,糊化焓随抗性淀粉含量的增大而增大,颗粒形状为不规则的碎石型。     

小麦抗性淀粉的制备研究

以小麦淀粉为原料,通过正交试验研究了压热法制备抗性淀粉的最佳工艺参数.在压热法制备的基础上,进行酶法处理,研究了耐热α-淀粉酶、普鲁兰酶及淀粉乳浓度对RS形成的影响.通过酶法处理,抗性淀粉产率得到很大提高.     

压热-酶法制备泽泻抗性淀粉的工艺

以泽泻淀粉为原料,研究压热-酶法处理对抗性淀粉形成的影响.结果表明:淀粉经高温高压糊化后,先后使用耐高温α-淀粉酶和普鲁兰酶进行淀粉降解脱支处理,生成更多的直链淀粉,促进淀粉分子重新结晶,提高抗性淀粉含量.试验表明,30%淀粉乳在120℃高温糊化50min,耐高温α-淀粉酶添加量为每克干淀粉6U,反应时间为30min,普鲁兰酶添加量为每克干淀粉4 PUN,55℃反应时间12 h,4℃冷藏36 h时抗性淀粉得率较高.正交试验表明普鲁兰酶反应时间影响最显著.     

酶法处理和超声波作用对抗酶解淀粉形成的影响

本文以木薯淀粉为原料,研究了α-淀粉酶、普鲁兰酶和超声波作用对抗酶解淀粉形成的影响。结果表明,酶作用对抗酶解淀粉形成的最佳条件为:淀粉浓度为5%,耐热α-淀粉酶量为10mL(酶活力为3U/mL),普鲁兰酶量为30mL(酶活力为22.5NPUN/mL),冷却升温次数为2次。得到的产品中抗酶解淀粉含量可达到14.52%。超声波频率为25kHz,作用时间为120s时,产品中抗酶解淀粉含量最高,为19.19%。     

鲜淮山抗性淀粉的研究

为了提高鲜淮山抗性淀粉的含量,该研究以鲜淮山为原料,采用压热-双酶解法制备抗性淀粉,通过单因素试验确定鲜淮山抗性淀粉的最佳制备条件为:25%淀粉乳在105℃压热50min,添加耐热α-淀粉酶0.288 KNU/g,作用15 min,添加普鲁兰酶3U/g,作用4h,老化时间24h。该条件下抗性淀粉的质量分数为43%。     

不同酶制备木薯抗性淀粉的性质比较

以木薯淀粉为原料,用耐高温α-淀粉酶和普鲁兰酶分别制备了RS3型抗性淀粉,并对其直链淀粉含量、冻融稳定性、持水性进行测定与比较.结果表明,α-淀粉酶制备抗性淀粉含量在9.4％ ～ 12.4％之间,直链淀粉含量随着酶解作用降低,且直链淀粉含量高的抗性淀粉其冻融稳定性略低,持水性保持在3.7～5.8g/g之间波动不明显.普鲁兰酶制备抗性淀粉含量在4％～7.9％之间,直链淀粉含量不一定随着酶解作用而增加,且直链淀粉含量高的抗性淀粉其冻融稳定性和持水性高.耐高温α-淀粉酶制备的木薯抗性淀粉含量、冻融稳定性高于普鲁兰酶,对直链淀粉含量的影响较直观,但持水性低于普鲁兰酶.     

复合酶法制备马铃薯抗性淀粉工艺研究

以马铃薯淀粉为原料，采用α-淀粉酶和普鲁兰酶相结合处理的方式制备马铃薯抗性淀粉，通过单因素试验分别考察了α-淀粉酶和普鲁兰酶的pH值、反应温度、反应时间、酶添加量对抗性淀粉(RS)得率的影响；进而采用Box-Behnken设计法对复合酶法制备马铃薯抗性淀粉的工艺参数进行优化；最终，采用Englyst法对马铃薯抗性淀粉消化性进行分析。结果表明，制备马铃薯抗性淀粉的最佳工艺条件为：α-淀粉酶，pH6.5、反应温度70℃、反应时间15 min、酶用量4 U/g；普鲁兰酶，pH值5.0、反应温度60℃、反应时间24 h、酶用量8 U/mL。此条件下，马铃薯抗性淀粉得率为(44.48±1.37)%。马铃薯淀粉经α-淀粉酶与普鲁兰酶联合处理后，不仅提高了其抗消化性，还使抗性淀粉(RS)得率显著提高，同时将马铃薯淀粉中快消化淀粉(RDS)降低至21.23%，而慢消化淀粉(SDS)增加至36.32%。该研究为后续马铃薯深加工及慢消化型食品开发提供一定的理论参考。     

米曲霉今野菌株所产α-淀粉酶性质的研究

采用硫酸铵盐析 ,再透析提纯得到米曲霉今野菌株的α -淀粉酶 ;该酶能耐受 5 0～ 65℃的高温 ,在 65℃处理 2小时后剩余酶活力为 85 % ;采用正交实验得其在反应过程中所受因素影响大小为酶液浓度 >底物浓度 >pH值 >温度 ,酶反应的最适pH为 6 0 ,最适温度为 60℃ ;以可溶性淀粉为底物时 ,该α -淀粉酶的Km值为 5 8× 10 - 1mol/L ;当NaCl浓度超过 30 %时 ,对酶活有明显的抑制作用 ,剩余酶活力只有 15 %。当NaCl浓度在 18%以下时 ,剩余酶活力在 90 %以上     

嗜冷普鲁兰酶制备玉米抗性淀粉工艺优化及其表征

以玉米淀粉为原料,采用嗜冷普鲁兰酶脱支处理和压热处理相结合的方式制备玉米抗性淀粉,考察了玉米淀粉乳质量分数、耐高温α-淀粉酶添加量、嗜冷普鲁兰酶添加量、嗜冷普鲁兰酶作用时间对抗性淀粉得率的影响,采用正交试验对压热-酶解法制备玉米抗性淀粉的工艺参数进行了优化。采用扫描电子显微镜、X-射线衍射和差示扫描量热仪对玉米抗性淀粉形貌、晶体结构、热特性进行了观察与分析。结果表明,制备玉米抗性淀粉的最佳工艺条件为:玉米淀粉乳质量分数18%、耐高温α-淀粉酶添加量7 U/g、嗜冷普鲁兰酶添加量10 U/g、嗜冷普鲁兰酶作用时间9 h。在最佳条件下,玉米抗性淀粉得率为16.84%。玉米淀粉经复合酶法处理后,抗性淀粉形成了致密的层状晶体结构,表面形态结构呈现出不同于玉米原淀粉A型晶体结构的V型晶体结构;玉米抗性淀粉的起始温度、峰值温度、终止温度和相变焓值分别为117.07、140.69、153.03℃和1 858.12 J/g,均高于玉米原淀粉。     

响应面法优化板栗抗性淀粉制备工艺

为了提高板栗抗性淀粉含量,并获得抗性淀粉制备方法的最适工艺参数,本研究优化了压热—普鲁兰酶法制备板栗抗性淀粉的工艺,在单因素试验基础上,采用响应面法研究淀粉悬浮液质量分数、普鲁兰酶添加量、酶解时间和冷凝时间对抗性淀粉得率的影响,建立各因素与抗性淀粉得率关系的数学回归模型。最终根据实际工艺操作确定最佳的制备工艺条件为淀粉悬浮液质量分数11.00%,酶添加量9 PUN/g、酶解时间10 h、冷凝时间15 h。在该制备条件下,测得抗性淀粉得率为64.90%,基本符合理论预测值(65.70%)。试验证明,响应面法能够提高板栗抗性淀粉的制备率。     

Substituent distribution within cross-linked and hydroxypropylated sweet potato starch and potato starch

Revealing the substituents distribution within starch can help to understand the changes of starch properties after modification. The distribution of substituents over cross-linked and hydroxypropylated sweet potato starch was investigated and compared with modified potato starch. The starches were cross-linked with sodium trimetaphosphate and/or hydroxypropylated with propylene oxide. The native and modified starches were gelatinized and hydrolysed by pullulanase, β-amylase, α-amylase and a combination of pullulanase, α-amylase and amyloglucosidase. The hydrolysates were analysed by HPSEC, HPAEC and MALDI-TOF mass spectrometry. Cross-linking had only a slight effect on the enzymatic hydrolysis, where hydroxypropylation evidently limited the enzymatic hydrolysis. The results obtained suggest that the hydroxypropyl substituents are not distributed regularly over the starch chains. Although the average substitution was around 2 hydroxypropyl groups per 10 glucose units, in the enzyme digests of hydroxypropylated starches, oligomer fragments of 10–15 glucose units, carrying 5–8 hydroxypropyl groups, were identified. It is hypothesised that higher levels of substituents are present in the amorphous regions and periphery of clusters of starch granules. This is the first time that the location of hydroxypropyl groups within sweet potato starch has been examined in this detail. Despite significant differences in granule architecture between starches from potato and sweet potato, similar patterns of hydroxypropylation have been found.     

酶解法制备荞麦抗性淀粉的工艺优化

为确定荞麦粉制备抗性淀粉的工艺条件,采用普鲁兰酶酶解脱支法,并通过单因素和正交试验研究了影响抗性淀粉得率的因素。结果表明：影响抗性淀粉得率的因素主次顺序依次为荞麦粉浓度、普鲁兰酶用量、酶解时间和酶解温度。酶解法制备荞麦抗性淀粉的适宜工艺条件为荞麦粉浓度5 g/（100 mL）、普鲁兰酶用量7.2 PUN/g、酶解温度45℃、酶解时间8 h,在此条件下测得的抗性淀粉含量为15.82%。与原粉相比,普鲁兰酶酶解脱支与湿热法相结合制备荞麦抗性淀粉使其抗性淀粉含量显著提高。     

芡实淀粉的酶解特性及体外消化模拟分析

研究芡实淀粉的酶解特性及其在模拟过程中的消化特性。采用α-淀粉酶水解法,以酶解液中还原糖释放率为指标,对芡实淀粉的酶解特性进行分析。结果表明,α-淀粉酶的最优酶解条件为:α-淀粉酶用量350U/g、底物质量浓度为10g/100mL、pH值为6,于50℃水浴中水解60～80min。在此条件下,芡实淀粉酶解液中还原糖释放率可达79.61%。体外消化模拟结果显示,芡实淀粉在模拟消化中的还原糖和可溶性糖释放率均远低于酶解过程;且与米淀粉相比,芡实淀粉较难消化。研究认为,芡实淀粉在α-淀粉酶作用下,较易水解;消化模拟过程中,芡实淀粉的可消化性稍低于米淀粉,可能与其中残留的植物多酚类物质有关。     

响应面法优化抗性糊精制备工艺

以玉米淀粉为原料，在单因素试验的基础上，利用响应面试验设计优化酶解法制备抗性糊精的工艺条件，研究α-淀粉酶作用温度、添加量和转苷酶作用温度、添加量及其交互作用对抗性糊精产率的影响。结果表明，最佳酶解工艺为α-淀粉酶作用温度94 ℃，α-淀粉酶添加量0.4%，转苷酶作用温度56 ℃，转苷酶添加量0.3%。在此优化工艺条件下，抗性糊精产率为82.56%，与预测值相对误差为1.46%，表明运用响应面试验法优化得到的该模型有一定的实践指导意义。     

Molecular cloning and characterization of a thermostable α-amylase exhibiting an unusually high activity

An α-amylase gene was cloned from the thermophilic bacterium Bacillus subtilis isolated from Indonesian oil palm shell waste. The gene expressed an extracellular enzyme. Optimal hydrolysis conditions for the enzyme were 70°C and pH 6.0. The specific activity of the enzyme was 16.0 kU per mg of protein, which was higher than for other thermostable amylases. Hydrolytic products of the enzyme using starch and glycogen were mainly maltohexaose and maltopentaose. The enzyme had a K _m value of 0.099 mg/mL for amylopectin, more than 10 times lower than for amylose. The catalytic efficiency of the enzyme using amylopectin was 39,200 mL/mg·s and was 3,270 mL/mg·s using amylose. The enzyme liquefied corn starch at pH 5.0, which was successfully converted to glucose using commercial glucoamylase and pullulanase without pH adjustment. The enzyme has advantages for industrial applications.     

响应面试验优化晶种诱导-双酶复合法制备RS_3型籼米抗性淀粉工艺

以微波预糊化籼米淀粉为原料,自制RS_3型马铃薯抗性淀粉为晶种,研究RS_3型籼米抗性淀粉的晶种诱导-双酶复合法制备工艺。利用扫描电子显微镜对淀粉颗粒形貌进行表征并研究淀粉的抗酶解性。在单因素试验的基础上,固定其他酶解条件,以RS_3型籼米抗性淀粉产率为响应值,确定晶种添加量、异淀粉酶添加量、普鲁兰酶添加量和普鲁兰酶酶解时间作为影响产率的主要因素,进行Box-Behnken响应面优化试验。得到RS3型籼米抗性淀粉的最佳制备工艺条件为:晶种添加量5%、异淀粉酶添加量8 U/g、普鲁兰酶添加量8 U/g、普鲁兰酶酶解时间3.50 h。在此最佳制备工艺条件下,RS_3型籼米抗性淀粉产率为27.42%,RS3失去原有的淀粉颗粒形貌,表面变得粗糙,结晶结构致密,具有较强抗酶解能力。     

微波-酶法制备马铃薯抗性淀粉工艺参数的优化

以马铃薯精制淀粉为原料,抗性淀粉得率为评价指标,通过单因素及正交试验确定了微波-酶解法制备马铃薯抗性淀粉的最佳工艺条件:在淀粉乳质量分数15%,微波作用时间90 s,微波作用功率800 W,耐高温α-淀粉酶添加量10 CU/g干淀粉,耐高温α-淀粉酶作用时间30 min,普鲁兰酶添加量0.10 PUN(G)/g干淀粉,普鲁兰酶酶解时间6 h,普鲁兰酶作用温度55℃的条件下,4℃老化24 h。经重复验证,RS得率最高达14.0%。     

Preparation and properties of RS III from waxy maize starch with pullulanase

Waxy maize starch was treated by pullulanase debranching and retrogradation at room temperature to produce resistant starch (RS). Physicochemical properties, crystalline structure and in-vitro digestibility of starch samples with different RS content were investigated. Compared with native starch, apparent amylose content of RS products increased. Based on Gel Permeation Chromatography (GPC) the Molecular Weight Distribution (MWD) of resistant starches significantly changed. Scanning Electron Microscopy (SEM) showed that upon pullulanase debranching and retrogradation treatment the granular structure of native starch was destroyed and all RS samples exhibited irregular shaped fragments. Crystal structure of samples changed from A–type to a mixture of B and V–type. The crystallinity of resistant starch also improved as compared with native starch. Moreover, samples with higher resistant starch showed higher relative crystallinity. Differential Scanning Calorimetry (DSC) determination showed that To、Tp、Tc and ΔH all increased which was in agreement with RS content. The resistance of waxy maize starch with Pullulanase treatment to α-amylase digestibility also increased, while the in-vitro digestibility of products decreased.