抗性淀粉对淀粉理化性质和酶解速率的影响

将抗性淀粉和蜡质玉米淀粉按不同的比例混匀制成复配粉,研究不同含量抗性淀粉对复配粉的膨胀度、溶解度、糊化特性和酶解速率的影响。结果表明:随抗性淀粉含量增加,复配粉溶解度降低,膨胀度增大,酶解速率逐渐降低。快速黏度分析仪(RVA)分析表明:抗性淀粉所占比例增加,复配粉的糊化温度逐渐升高,抗性淀粉含量为60%时,糊化温度达到最高,为75.25℃,而峰值黏度、谷值黏度、末值黏度、衰减值和回生值逐渐下降,抗性淀粉含量为100%时,复配粉的峰值黏度、谷值黏度、末值黏度均达到最低。     

莲子淀粉加工特性的研究

研究莲子淀粉的加工特性。结果表明:莲子淀粉的溶解度、膨润度均较低,属限制型膨胀淀粉;糊的透明度较低;莲子淀粉起糊温度较高(72℃),随着温度升高黏度先增加后呈减小趋势,淀粉开始降温时黏度逐渐上升;酸性条件下淀粉糊黏度降低,碱有促进淀粉糊化的作用;添加蔗糖、NaCl后淀粉糊黏度增大,蔗糖对其影响相对较小,随着蔗糖、NaCl添加量的增加黏度也相应增加。     

酶法及压热-酶法制备大米抗性淀粉的理化性质比较

对酶法及压热-酶法制备的大米抗性淀粉和淀粉凝胶的理化性质进行比较。结果表明,酶法及压热-酶法制备的大米抗性淀粉含水量从11.88%分别下降到4.05%和3.98%;大米淀粉凝胶水分含量也明显下降。酶法和压热-酶法制备的大米抗性淀粉的溶解度和膨润力都随温度的升高而增加。但两种大米淀粉凝胶的溶解度随温度呈现缓慢下降趋势。酶法制备的抗性淀粉的糊化黏度和回生值比压热-酶法大,而两种淀粉凝胶峰值黏度、谷值黏度、最终黏度、衰减值、回生值均明显降低。压热-酶法制备的大米抗性淀粉和淀粉凝胶偏光十字较弱。两种淀粉凝胶的硬度和弹性均显著增加,并且压热-酶法的硬度和弹性最大,但胶黏性较小。     

超高压处理对莲子淀粉理化特性的影响

目的:为优化莲子淀粉品质特性提供理论依据。方法:以莲子淀粉为原料,采用超高压技术对淀粉进行改性处理,研究不同超高压时间对莲子淀粉颗粒粒径分布和理化性质的影响。结果:淀粉颗粒大小及分布随超高压处理时间的增加而增大;超高压处理提高了莲子淀粉在55,65,75℃的溶解度和膨胀度,降低了其在85℃和95℃的溶解度和膨胀度;超高压处理降低了莲子淀粉的透光率,随着贮藏时间的延长,透光率呈下降趋势;500MPa超高压处理10~50 min,有利于改善莲子淀粉的凝沉性和冻融稳定性;随着处理时间的增加,淀粉颗粒被破坏程度加大,导致凝沉性增大,析水率增加。结论:超高压处理可以改善莲子淀粉的理化特性。     

可溶性大豆多糖对大米淀粉物化特性的影响

目的 探究可溶性大豆多糖(soluble soybean polysaccharides, SSPS)对大米淀粉物化特性的影响。方法 以大米淀粉为原料,将SSPS以不同比例与米淀粉进行混合,分析SSPS对大米淀粉膨胀度、透明度、冻融稳定性、糊化特性以及流变学特性的影响。结果 与对照组相比,在大米淀粉中加入SSPS可显著降低淀粉的膨胀度及溶解度,当SSPS添加量为10%时,膨胀度和溶解度最低,分别为10.99 g/g (95℃)和70.52%。随着SSPS添加量和冻融次数的增加,体系的析水率呈上升趋势。糊化性质表明,SSPS的添加使淀粉的峰值黏度、低谷黏度、最终黏度、崩解值及回生值均降低,但是糊化温度上升。动态流变学结果表明样品体系G’均大于G”,且呈现出频率依赖性,说明具有典型的弱凝胶特性。结论 可溶性大豆多糖在一定程度上可以改善大米淀粉的特性,为SSPS在淀粉基食品中的应用提供理论指导。     

脂类和颗粒结合蛋白对小麦A、B淀粉理化性质的影响

淀粉颗粒中的脂类和颗粒结合蛋白对其理化和结构性质存在一定影响,研究了小麦A、B淀粉经脱脂、脱蛋白处理后其化学组成、颗粒形态、糊特性等性质。结果表明:脱脂处理对小麦A、B淀粉的晶体类型、溶解度、膨胀度、起始温度、峰值温度、终值温度、热焓值、峰值黏度、谷黏度、衰减值、最终黏度、峰值时间、成糊温度均无显著性影响,相对结晶度降低。脱蛋白处理使小麦淀粉溶解度和膨胀度随温度的增长趋势显著增加,相对结晶度、起始温度、峰值温度、终值温度、峰值黏度、衰减值、回生值显著增大,谷黏度和峰值时间显著降低,对晶体类型、热焓值无显著影响。脱蛋白处理对小麦A、B淀粉理化性质的影响显著高于脱脂处理。     

微细化莲子淀粉的流变特性研究

本实验以球磨粉碎后的莲子淀粉为研究对象,研究粉碎时间、淀粉糊浓度、温度对微细化莲子淀粉糊流变特性的影响。结果表明：莲子淀粉糊为假塑性流体,球磨时间对莲子淀粉糊的表观黏度有显著影响;莲子淀粉糊的表观黏度随着浓度的增加迅速增大,剪切速率越低,这种影响就越明显,但球磨时间达到96h后,浓度对表观黏度变化影响不大;温度对莲子淀粉的流变特性影响显著,随着温度的增加,表观黏度迅速增大,但是经过长时间球磨后的莲子淀粉糊的流变特性对温度的依赖性减小。     

热处理对不同直链淀粉含量的玉米淀粉理化性质的影响

采用快速黏度分析法、离心法、差示扫描量热分析法、动态流变仪分析法等,研究了干热与湿热处理对3种不同直链淀粉含量的玉米淀粉糊化性质、膨润性质、热力学性质、流变性质的影响,为淀粉的物理改性研究和加工应用提供理论依据。结果表明,干热处理使淀粉更易糊化,表现为3种玉米淀粉糊化温度降低,溶解度、膨胀度增加。湿热处理加大糊化难度,使3种玉米淀粉的糊化温度升高,膨胀度降低。热处理使玉米淀粉糊稠度、糊化焓值降低。蜡质玉米淀粉经热处理后,溶解度和老化率增加。流变性质测定结果表明,湿热处理不利于高直链玉米淀粉黏弹性凝胶的形成。     

水分含量对双螺杆挤压处理山药淀粉理化性质的影响

使用同向双螺杆挤出机研究了水分含量对山药淀粉理化和流变性质的影响.结果 表明:挤压后山药淀粉颗粒受到破坏,出现不规则碎片,其结晶度降低,且随着水分含量的增加而增加.挤压后淀粉的溶解度升高,膨胀度下降,随着水分含量升高,溶解度减小,膨胀度增加.流变学结果表现为弱凝胶性质,山药淀粉的储能模量(G')和损耗模量(G")随水分...     

橡子淀粉制备及其理化性质研究

以橡子粉为原料,制备橡子淀粉以及研究橡子淀粉的理化性质。采用热水脱单宁、H2O2脱色制备橡子淀粉,运用理化检测方法对橡子淀粉的理化性质进行研究。研究表明,橡子粉中淀粉含量为63.58%;橡子淀粉的溶解度和膨胀度都不大,膨胀度随温度的上升出现初始膨胀阶段和迅速膨胀阶段,属限制型膨胀淀粉;橡子淀粉糊的透光率和冻融稳定性相对较好,淀粉糊的透光率为35.9%,析水率为34.69%;橡子淀粉糊具有很强的凝沉稳定性,但凝沉速度较快,易老化;橡子淀粉的黏度随浓度的增加而增加,出现跃变的浓度为25%。     

Effect of the production method on the properties of RS3/RS4 type resistant starch. Part 2. Effect of a degree of substitution on the selected properties of acetylated retrograded starch

Resistant starch displays health-promoting properties. Starch preparations produced through acetylation of retrograded starch may be applied as a food additive. Apart from prebiotic properties, they may as well model the texture of a food product. The objective of this study was to determine the effect of retrogradation and acetylation conditions on properties of the produced RS3/4 type resistant starch. Native potato starch was used to produce starch pastes (1, 4, 10, 18 or 30g/100g), that were frozen, defrosted and dried. The resultant preparations of retrograded starch were acetylated with various doses of an acetic acid anhydride (3.25, 6.5, 13.0, 26.0 or 52.0ml/100g). The acetylated preparations of retrograded starch were characterised by increasing solubility in water and swelling power as well as a lower amylose content along with an increasing degree of their substitution with residues of acetic acid. Dependencies of: pasting temperatures, viscosity of the prepared pastes, and resistance of acetylated starch to the action of amyloglucosidase on the degree of substitution with acetic acid residues were described with a second degree polynomial function. The extent and range of changes were found to depend on the concentration of paste used to produce a retrograded starch preparation. The maximum resistance of RS3/4 preparations to the action of amyloglucosidase ranged from 28.7 to 45.9g/100g.     

Effects of organic acids and starch water ratios on the properties of retrograded maize starches

The effects of organic acid types and concentrations as well as starch water ratios on resistant starch (RS) levels and the properties of retrograded maize starches were studied. The pH of the starch slurry decreased with increasing water ratio and organic acid concentration, but the addition of succinic acid slightly reduced pH compared to the other organic acids. The RS level of RS3 was increased 160–169% for the high starch ratio and was increased 137–146% for the low starch ratio with organic acid addition (p<0.01). The color difference between the RS3 powder added with citric acid and native starch showed the lowest value. All samples had B type crystallinity. Their swelling power and solubility increased, but the water binding capacity decreased with organic acid addition. The added organic acids rapidly decreased the pasting viscosity of RS3, but patterns were different by organic acid type (succinic acid) and starch water ratio.     

不同品种马铃薯淀粉物化特性与组成结构的关系

马铃薯淀粉因其特殊性质而具有广泛的用途和潜在的应用价值。淀粉的理化和功能性质受淀粉来源的影响,本实验以8 种不同品种的马铃薯为原料提取淀粉,并对其化学组成和淀粉的物化特性进行了研究与相关性分析。结果表明：马铃薯淀粉的结晶度与淀粉的储能模量最大值温度TG′max 显著负相关,与膨润度呈显著负相关;直链淀粉含量和磷含量分别与储能模量最大值温度TG′max、储能模量峰值G′max、糊化起始、峰值和终止温度To、Tp 和Tc,溶解度和膨润度呈显著正相关,与结晶度呈显著负相关;直链淀粉含量与糊化热焓呈显著负相关。     

芡实粉和芡实淀粉理化性质和消化性研究

以芡实为原料制取芡实粉和芡实淀粉样品,研究了其糊化性、溶胀度、可溶指数、质构性和消化性等性质.结果表明,芡实淀粉样品的黏度明显高于芡实粉样品,芡实粉的峰值黏度与芡实淀粉相比降低了57.75％;随温度升高,芡实粉和芡实淀粉的溶胀度和可溶指数呈现递增趋势,但在较高温度下,芡实粉样品的溶胀度和可溶指数明显高于芡实淀粉样品;与芡实淀粉样品相比,芡实粉的凝胶的硬度减少了91.86％;芡实淀粉样品的快速消化淀粉含量明显高于芡实粉样品,但慢速消化淀粉的含量要低于芡实粉样品,抗性淀粉的含量高于芡实淀粉样品.     

Properties of retrograded and acetylated starch preparations Part 2. Dynamics of saccharification with amyloglucosidase and rheological properties of resulting pastes and gels

Various procedures have been used to produce preparations of retrograded starch, by subjecting it to acetylation with methods used in the food industry. The resultant starch preparations were evaluated for their degree of acetylation through titration, swelling power and solubility in water at 80 °C, and saccharification dynamics as affected by amyloglucosidase. Rheological properties of pastes and gels of native starch and modified starch preparations were characterized with the use of a sweep temperature test as a dependency of the storage modulus (G′) and loss modulus (G″) on temperature. In addition, flow curves of pastes were plotted and mechanical spectra of gels of the preparations examined were determined. These modifications had a significant effect on the preparations produced. Retrograded and acetylated starch preparations were characterized by greater solubility in water and greater swelling power, and were less susceptible to amyloglucosidase than the non-acetylated preparations. Rheological properties of the pastes and gels were affected by the methods of their production. Acetylation was found to significantly affect a decrease in the storage modulus value during heating. Pastes of the native starch and modified starch preparations were characterized by the non-Newtonian flow, shear thinning with a tendency to yield stress. In turn, the mechanical spectra demonstrated that - in the concentration applied - both native starch and modified starch preparation were forming weak gels.     

Enhancement of Resistant Starch (RS3) in Amylomaize,Barley, Field Pea and Lentil Starches

Native starches isolated from amylomaize. Glacier high amylose barley, field peas and lentils contained 3–5% (w/w) resistant starch (RS3). Retrograded gels that were prepared from these starches had higher RS3 (6–9%) contents. The effects of gel concentration (% starch), storage temperature and time on the RS3 content of the retrograded gels were investigated; the optimum RS3 content was determined in gels prepared at = 10% (w/v) starch concentration and stored under = 20°C for = 5 days. Annealing of the retrograded starch gels by heating and cooling cycles, further enhanced RS3 content to 9–19%; the effect of annealing temperature and number of heat-cool cycles on the RS3 content of the annealed gel were studied. The hydrolysis of retrograded starch gels by pulanase enzyme or acid (2.2 N HCl), prior to annealing, enhanced the RS3 formation during annealing; the enzyme or acid treatment increased RS3 content of the annealed gel to 15–24% or 17–24%, respectively. The potential molecular mechanism that is responsible for the RS3 increase is discussed.     

六种杂豆淀粉的理化性质研究

以绿豆、奶花芸豆、红小豆、豌豆、英国红芸豆、小扁豆为材料,采用湿磨法提取淀粉,以大米、小麦淀粉为对照,对杂豆淀粉的理化特性进行分析研究。结果表明:6种杂豆淀粉颗粒形貌相似,颗粒普遍较大,呈圆形或椭圆形,均匀度较好。在相同制备条件下,杂豆淀粉间的水分、灰分和蛋白质差异较明显。杂豆淀粉间的直链淀粉和回生淀粉含量差距不大,均达40%以上。淀粉的溶解度和膨润力均随温度的升高而增加。杂豆淀粉间的透光率差异显著,普遍较小麦、大米淀粉的透光率要好。杂豆淀粉间的糊化特性差异显著,热特性差异不显著,淀粉分子结晶度相近,糊化难易程度比较接近。杂豆淀粉与小麦、大米淀粉理化性质差异显著。     

冻融循环处理对玉米淀粉凝胶结构及颗粒理化特性的影响

本文研究了不同次数(0、1、2、3、4、5和6次)的冻融处理对糊化后的普通玉米和糯玉米淀粉凝胶理化性的影响。采用扫描电子显微镜对淀粉凝胶的微观结构进行分析,测定了凝胶化淀粉的碘蓝值、碘结合力、最大吸收波长、透明度、持水性、溶解度与膨胀力、水解特性和体外消化性。普通玉米淀粉凝胶呈孔状结构,糯玉米淀粉凝胶冻融2次后出现层状结构,二者孔径和层距都随冻融次数增加而减小。冻融循环处理对两种凝胶化玉米淀粉的碘蓝值、碘结合力、最大吸收波长和直链淀粉含量均无显著性影响。随冻融次数增加,普通玉米淀粉的透明度、持水性、RDS与SDS含量逐渐减小,而溶解度、膨胀力、水解率和RS含量逐渐升高;而糯玉米淀粉的透明度、持水性、溶解度和膨胀力逐渐减小,RDS、SDS和RS含量及水解率均无显著性变化。     

Thermal and viscoelastic properties of starch gels from maize varieties

The aim of this work was to determine the thermal, functional and rheological properties of maize (Zea mays) starch isolated from seven varieties. Chemical analysis was undertaken in all starch samples. The gelatinization and retrogradation temperature at different storage times, as well as the enthalpy of the isolated starches, were determined using differential scanning calorimetry (DSC). Swelling and solubility were also measured in individual samples. Dynamic oscillatory tests (amplitude and frequency sweeps) were undertaken on starch samples with 10% (w/v) of total solids during a cycle of three stages (kinetics) of heating/cooling, using a strain‐controlled rheometer. The samples presented an amylose content which ranged from 22% to 29%, typical in normal starches, the lipid values were under 1%, while the protein contents were just over 1%. The calorimetric profile for the studied starches showed a peak temperature (gelatinization) over the temperature range from 72.5 to 75.7 °C and enthalpy values between 13.68 and 17.58 J g^?1. Four starches presented enthalpy values of the retrogradation transition that increased with the storage time, showing differences among the starches analysed. Maximum swelling and solubility were usually found at the second stage of the above‐mentioned cycle. The rheological profile showed that the gels formed during the first stage of the above‐mentioned kinetics presented the behaviour of weak viscoelastic gels with the storage or elastic modulus (G′) higher than the loss or viscous modulus (G″) over the applied strain and frequency ranges. All samples showed a more elastic character as the kinetics progressed. Starches isolated from diverse maize varieties showed differences in their characteristics studied, and might produce different functional properties in the products where they are used. Copyright © 2006 Society of Chemical Industry