以捏合机为反应器制备非晶颗粒态玉米淀粉

以捏合机为反应器,研究制备非晶颗粒态淀粉的新方法。将淀粉与水分按不同比例混合并在高温下反应,用偏光显微镜观测处理后的淀粉颗粒结构。结果表明,当淀粉与水分质量比为3∶6时,温度80℃维持30min,90%以上的原玉米淀粉多晶颗粒态转化成无定形结构的非晶颗粒态。     

高交联玉米淀粉的非晶化特性

研究了以三氯氧磷为交联剂的高交联玉米淀粉的制备方法,报道了高交联玉米淀粉颗粒随反应取代度增加而逐渐非晶化的现象.采用偏光显微镜和广角X-射线衍射对其由多晶态向非晶态的渐变过程进行了研究,提出高交联玉米淀粉中存在不同于原淀粉多晶颗粒态的只含无定形结构的非晶颗粒态。对非晶颗粒态高交联玉米淀粉颗粒的粒度分布的进一步研究结果还表明,此时的淀粉颗粒发生了轻度的膨胀。     

非晶颗粒态玉米淀粉制备方法

系统地报道了水分散体系高温溶胀、常温碱分散体系强碱溶胀作用非晶颗粒态玉米淀粉制备方法,采用偏光显微镜对多晶态向非晶态的变化进行了确认,提出在一定条件下,高交联玉米淀粉可以由原淀粉多晶颗粒态制备成只含无定形结构的非晶颗粒态淀粉。     

硫酸钠保护法制备非晶颗粒态玉米淀粉

硫酸钠具有抑制淀粉颗粒糊化的特性,可以在碱处理制备非晶颗粒态过程中抑制淀粉颗粒的膨胀。将玉米淀粉在按不同的比例的氢氧化钠和硫酸钠混合溶液在室温下处理,用偏光显微镜观测处理后的淀粉颗粒结构变化。结果表明：当质量分数3％的氢氧化钠溶液和质量分数为15％的硫酸钠溶液等体积使用时,可以制备出较好的非晶颗粒态玉米淀粉。     

非晶颗粒态玉米淀粉制备羧甲基淀粉的研究

以原玉米淀粉、氯乙酸为主要原料,先用乙醇制备非晶颗粒态玉米淀粉,然后将氢氧化钠和氯乙酸加入反应瓶中制备羧甲基淀粉.研究了氯乙酸用量、氢氧化钠用量、反应体系水分含量、反应温度、时间对样品取代度(DS)的影响.结果表明:在m(氯乙酸)/m(淀粉)为0.2,n(氢氧化钠)/n(淀粉)为0.4,反应体系水分25%条件下,温度55℃反应4 h得到较高取代度的羧甲基淀粉CMS.     

非晶颗粒态玉米淀粉的制备及接枝共聚改性

以玉米淀粉为原料,采用乙醇溶剂一高温加热制备了非晶颗粒态玉米淀粉,通过X-射线衍射和偏光显微镜研究了非晶颗粒态玉米淀粉的结晶性质与颗粒形貌;以中和的丙烯酸为单体,过硫酸铵为引发剂,N,N'-亚甲基双丙烯酰胺为交联剂,对非晶颗粒态玉米淀粉进行接枝共聚改性,制备出具有高吸水性的接枝共聚物,并对其吸水性能做了研究,其吸水率和吸盐水(0.1%NaCl)率分别为590.1g/g和232.6 g/g;用扫描电子显微镜、红外光谱对其进行结构表征.     

非晶颗粒态玉米淀粉制备羧甲基淀粉

以非晶颗粒态玉米淀粉、氯乙酸为主要原料,用乙醇溶剂法制备羧甲基淀粉。研究了反应温度、时间、氯乙酸、淀粉乳浓度、水分含量对样品取代度(DS)的影响。结果表明:在淀粉乳浓度20%,n(氯乙酸):n(淀粉) =1:4,n(NaOH):n(淀粉)=1:2,乙醇溶剂含水30%条件下,55℃反应4h得到较高取代度的羧甲基淀粉。     

非晶颗粒态玉米淀粉老化特性

实验通过非晶颗粒态玉米淀粉不同环境下黏度变化分析其老化特性及其影响因素.结果表明:非晶颗粒态玉米淀粉糊静置贮藏过程中会发生老化现象,在4℃下老化比常温下快:非晶颗粒态玉米淀粉乳的临界浓度小于10%,13%～14%的淀粉乳,老化作用明显;加入葡萄糖和蔗糖均能促进非晶颗粒态玉米淀粉老化,浓度越大,老化效果越明显,老化后期高浓度蔗糖又抑制淀粉乳的老化;在偏酸或者偏碱的环境或无机盐存在,抑制非晶颗粒态玉米淀粉的老化.     

先非晶后交联制备非晶颗粒态交联淀粉及其特性的研究

通过乙醇溶剂法制备非晶颗粒态淀粉,再交联改性,制备非晶大颗粒交联淀粉,以交联度(溶胀法)为评价指标,采用正交试验设计优化条件,确定最佳工艺条件为:交联剂用量为淀粉干质量的1.5%、pH9.8、反应温度45℃、反应时间2 h;并对非晶交联淀粉的老化性、耐酸性、抗剪切性进行了研究.     

高温水分散体系交联玉米淀粉的非晶化现象研究

研究了用三偏磷酸钠为交联剂制备高交联玉米淀粉的方法,采用偏光显微镜和广角X-射线衍射对交联玉米淀粉由多晶态向非晶态的渐变过程进行了详细报道,发现了随着温度的升高交联玉米淀粉逐渐非晶化现象,提出在高温条件下交联玉米淀粉存在着只含无定型结构的非晶颗粒态,并用扫描电镜对非晶颗粒态玉米淀粉的结构进行了详细研究.     

中等水分含量湿热处理对玉米淀粉颗粒非晶化的影响

控制中等水分含量,利用湿热处理的手段处理原玉米淀粉,考察了淀粉与水不同的质量比及处理温度对淀粉颗粒结构的影响。用偏光显微镜观测处理后淀粉样品以验证淀粉颗粒结构的变化,结合X射线衍射曲线验证淀粉颗粒结构的变化,利用扫描电镜观测颗粒保持的状态。结果表明:当淀粉浓度为65%时,80℃处理,原玉米淀粉可以均匀地转变为非晶颗粒态淀粉。     

微波辐射处理对玉米淀粉颗粒非晶化的影响

采用微波辐射的手.段处理原玉米淀粉,考察了分散剂种类,淀粉与分散剂的质量比及微波处理的温度对淀粉非晶化的影响。用偏光显微镜观测处理后淀粉的颗粒结构,结合X射线衍射曲线验证淀粉颗粒结构的变化,利用扫描电镜观測颗粒保持的状态。结果表明:当分散剂为水,淀粉与水分的质量比为3:4时,原玉米淀粉可以均匀的转变为非晶颗粒态淀粉。     

不同干燥工艺对非晶颗粒态玉米淀粉颗粒形貌的影响

非晶颗粒态淀粉是一种特殊的淀粉物态形式,具有颗粒性,但不具有结晶性,其具有较高的酶降解性、反应活性和吸附性能等。为了使非晶颗粒态淀粉工业化生产,对非晶淀粉颗粒进行了乙醇洗涤+常压烘箱干燥、真空烘箱干燥、常压烘箱干燥、真空冷冻干燥、喷雾干燥等不同干燥工艺。结果表明,不同的干燥工艺对非晶淀粉颗粒产生了不同的颗粒形貌。对其形貌的产生机理进行了科学的分析。     

高直链玉米淀粉添加对挤压荞麦面条结构、蒸煮品质及消化特性的影响

制备挤压荞麦面条,研究不同添加量（10%、20%、25%、30%）的高直链玉米淀粉（m/m,基于全粉）对挤压荞麦面条结构、蒸煮品质及消化特性的影响。结果表明,随着高直链玉米淀粉添加量的增加,挤压面条直径减小,糊化度降低。X射线衍射结果表明添加高直链玉米淀粉后,面条除了V型结晶峰外还存在未完全糊化的直链淀粉的典型B型峰。热力学性质结果也表明直链淀粉发生部分糊化。添加高直链玉米淀粉后,面条色泽变浅变亮,最佳蒸煮时间缩短,蒸煮损失率由9.90%增加到12.43%。当高直链玉米淀粉添加量为25%时,面条开始出现断条。面条硬度由2 105.709 g显著增加至3 680.401 g,弹性由0.961降低至0.866。扫描电镜结果表明,随着高直链玉米淀粉添加量的增加,致密的面条结构逐渐出现裂纹,且面条截面有较多未完全糊化的淀粉颗粒。淀粉体外消化实验表明,随着高直链玉米淀粉添加量的增加,淀粉水解率逐渐下降,预计血糖指数减小,抗性淀粉含量增加。当高直链玉米淀粉添加量为30%时,挤压荞麦面条的预计血糖指数从74.28降至66.31,抗性淀粉含量从34.43%增加至47.86%。     

Changes in unreacted starch content in corn during storage

In the dry grind process, corn is ground, mixed with process water and cooked; starch is enzymatically hydrolyzed to sugars, and subsequently fermented to ethanol by yeast. The conversion of starch into ethanol, however, is not complete as distillers dried grains with solubles (DDGS) often contain more than 5% starch. The amount of unreacted starch represents inefficiencies in the process and reducing this amount is important to improving profitability of the ethanol industry. Additionally, dry grind facilities have reported seasonal variation in ethanol yields. In order to minimize variation in ethanol yields and the amount of unreacted starch in DDGS, it is important to understand the effects that storage temperature and time have on the digestibility of the corn starch. While starch quality is largely controlled by genetics and growing conditions, postharvest practices (handling, storage, and processing conditions) also affect starch composition and structure. In this study, changes in unreacted starch content of corn during storage were monitored to provide an explanation for the seasonal variation in ethanol yields observed by dry grind facilities. Yellow dent corn was harvested in 2011 and 2012 and stored indoors, outdoors, and under refrigeration for 5–12 mo. Results with the 2011 harvest corn showed unreacted starch content ranging from 2.17 to 14.1% over a 48 wk period. Unreacted starch was more influenced by storage time, initially decreasing at a rate of 0.31% per wk during the first 10 wk and steadily increased at an average rate of 0.16% per wk for the duration of storage. Results with the 2012 harvest corn, however, showed a higher average unreacted starch content of 13.0% during 20 wk of storage and no appreciable change in unreacted starch content regardless of storage temperature.     

Development and Physicochemical Characterization of New Resistant Citrate Starch from Different Corn Starches

Resistant starch has drawn broad interest for both potential health benefits and functional properties. In this study, a technology was developed to increase resistant starch content of corn starch using esterification with citric acid at elevated temperature. Waxy corn, normal corn and high‐amylose corn starches were used as model starches. Citric acid (40% of starch dry weight) was reacted with corn starch at different temperatures (120–150°C) for different reaction times (3–9 h). The effect of reaction conditions on resistant starch content in the citrate corn starch was investigated. When conducting the reaction at 140°C for 7 h, the highest resistant starch content was found in waxy corn citrate starch (87.5%) with the highest degree of substitution (DS, 0.16) of all starches. High‐amylose corn starch had 86.4% resistant starch content and 0.14 DS, and normal corn starch had 78.8% resistant starch and 0.12 DS. The physicochemical properties of these citrate starches were characterized using various analytical techniques. In the presence of excess water upon heating, citrate starch made from waxy corn starch had no peak in the DSC thermogram, and small peaks were found for normal corn starch (0.4 J/g) and Hylon VII starch (3.0 J/g) in the thermograms. This indicates that citrate substitution changes granule properties. There are no retrogradation peaks in the thermograms when starch was reheated after 2 weeks storage at 5°C. All the citrate starches showed no peaks in RVA pasting curves, indicating citrate substitution changes the pasting properties of corn starch as well. Moreover, citrate starch from waxy corn is more thermally stable than the other citrate starches.     

无水有机醇介质中盐酸对蜡质玉米淀粉性质的影响

以无水甲醇、无水乙醇、异丙醇及正丁醇作溶剂,用盐酸对蜡质玉米淀粉进行改性。研究了蜡质玉米淀粉在有机醇溶液中酸改性前后的物化性质。结果表明经酸处理的蜡质玉米淀粉随有机醇介质(从甲醇到正丁醇)碳原子数量的增加,颗粒表面逐步出现小孔直到产生裂纹,冻融稳定性依次减弱,溶解度逐渐增大,膨胀度逐渐降低;淀粉的晶型基本没有变化,但对应衍射峰强度减弱。以上结果表明酸在不同有机醇介质中对淀粉的作用程度不同,从甲醇到丁醇依次增强。     

3种玉米淀粉的性质比较

研究了高直链玉米淀粉、糯玉米淀粉、普通玉米淀粉的粒度分布、糊流变、质构、冻融稳定性等物理化学性质,结果表明:3种玉米淀粉的颗粒形状差异不大。高直链玉米淀粉的粒度分布一致性较高,同样条件下糯玉米淀粉糊粘度大于其他2种淀粉,糯玉米淀粉的冻融稳定性大于普通玉米淀粉和高直链玉米淀粉,为玉米淀粉在食品中的应用奠定了基础。