加工工艺对麸皮酶处理全麦挂面品质影响的研究

为改善麸皮酶处理全麦挂面品质,采用单因素实验研究了面条加工工艺(加水量、和面时间、加水温度、熟化温度和熟化时间)对面条蒸煮品质和感官品质的影响作用。结果表明,加工工艺显著影响了全麦挂面感官品质,对其蒸煮品质影响不显著。根据单因素实验结果优选出最佳的全麦挂面加工工艺条件为:加水量40%,和面时间3 min,加水温度20℃,熟化温度30℃,熟化时间30 min,全麦挂面加水量比小麦粉面条高3%~7%;加工工艺各因素对全麦挂面品质的影响作用大小依次为:加水量熟化温度和面时间熟化时间加水温度。适当的加工工艺调控可有效改善麸皮酶处理全麦挂面品质。     

壳聚糖与阿拉伯胶静电复合作用研究及显微观察c

探讨了壳聚糖分子量、脱乙酰度及壳聚糖与阿拉伯胶配比、溶液pH及浓度对溶液浊度、复合物ζ-电位及显微结构的影响,研究了壳聚糖与阿拉伯胶静电复合过程中各条件的作用机制。结果表明:壳聚糖分子量为15 W时更易与阿拉伯胶复合,而壳聚糖脱乙酰度在阿拉伯胶远远过量时才对复合产生显著影响,且脱乙酰度较低更利于形成大的复合物颗粒;阿拉伯胶的加量显著影响PEC的显微结构,溶液的浊度也随之发生四阶段变化;pH介于3.0~4.0之间时溶液浊度高,PEC结构因pH改变而不同;复合物的结构及溶液浊度会随聚合物浓度发生改变。上述条件影响到壳聚糖与阿拉伯胶分子的电荷密度、分子链伸展程度及柔韧性,改变PEC的显微结构,进而使溶液浊度发生改变。     

浸泡和微波处理对三种高粱熟化的影响

为研究浸泡和微波处理对三种高粱熟化工艺参数的影响,采用单因素实验的方法,探讨浸泡时间和浸泡温度对高粱吸水率,以及微波时间和微波功率对高粱蒸煮熟化程度和熟化时间等工艺参数的影响。结果表明,随着浸泡时间的增加,三种高粱的吸水率均呈现先上升后平稳的趋势,龙米粮1号、龙杂13号和红糯高粱的最佳浸泡时间分别为2、2和3 h;随着浸泡温度的增加,三种高粱的吸水率呈上升的趋势,最佳浸泡温度分别为45、35和35 ℃。在最佳浸泡时间和浸泡温度条件下,当微波功率600 W和微波处理8 min时,龙米粮1号高粱熟化程度达到100%,蒸煮熟化时间缩短20 min;微波功率800 W和微波处理时间11 min时,龙杂13号高粱熟化程度达到100%,蒸煮熟化时间缩短20 min;微波功率800 W和微波处理时间11 min时,红糯高粱熟化程度达到100%,其蒸煮熟化时间缩短15 min。研究确定了三种高粱最佳浸泡和微波处理工艺参数,为高粱熟化工艺提供了技术参数。     

辛烯基琥珀酸酐酯化改性阿拉伯胶的工艺优化

提纯原始阿拉伯胶(OGA),采用乳化剂替代有机溶剂处理的辛烯基琥珀酸酐(OSA)对阿拉伯胶进行酯化改性.通过单因素和响应面试验优化工艺条件,并研究酯化改性后的阿拉伯胶的性质.试验结果表明:酯化改性的最佳工艺参数为OSA添加量3％(以OGA干重计),OGA质量分数40％,反应pH 8.5,反应时间1.56 h,反应温度2...     

棉织物的壳聚糖季铵盐改性与板栗壳色素染色

为了改善天然色素对棉织物的染色性能,在自制壳聚糖季铵盐的基础上,探讨了处理温度、处理时间和壳聚糖季铵盐用量对棉织物改性效果的影响。结果表明:对棉织物进行壳聚糖季铵盐改性可以提高板栗壳色素的染色性能,改性的最佳工艺条件为改性剂7 g/L、处理温度90℃、处理时间80 min。用板栗壳色素上染改性棉织物,耐摩擦色牢度、耐皂洗色牢度均达到服用纺织品要求。     

全籽粒莜麦微波预熟化工艺优化

以莜麦为原料,用微波技术对莜麦全籽粒进行预熟化处理,利用单因素法和响应面试验优化产品工艺,得到莜麦预熟化的最佳工艺参数为微波时间70 s、微波温度70℃、微波功率800 W,在此条件下,莜麦的糊化度为93.77%。影响莜麦预熟化的因素依次为微波温度>微波时间>微波功率。经预熟化处理后莜麦外观籽粒保持完整,可以达到产品售卖的效果。     

熟化处理对赤豆粉理化特性及冲调风味的影响

以赤豆为原料,研究挤压、炒制、微波熟化和热风熟化4种热处理方式对赤豆粉色度、水和特性、糊化、凝胶、冲调特性及冲调风味的影响。结果表明：与赤豆生粉相比,熟化处理粉的亮度降低,色泽偏向红黄色;吸水性指数、水溶性指数和膨胀势均显著增加（P＜0.05）,尤以挤压熟化粉最高,其吸水性指数、水溶性指数和膨胀势分别为生粉的1.26、1.92倍和1.44倍;熟化处理粉的糊化黏度、崩解值和回生值均显著降低（P＜0.05）,而糊化温度略升高,且起始糊化温度、峰值温度和终止糊化温度值高于赤豆生粉,各处理粉的焓变值显著降低（P＜0.05）;熟化粉凝胶的硬度、内聚性、胶着性、回复性显著降低（P＜0.05）。冲调试验表明微波熟化粉的分散时间、湿润时间最短,分别为19.45、26.61 s,其结块率最低;各熟化处理粉经冲调后酸味减弱,甜味、苦味明显增强,且挤压熟化粉与赤豆生粉滋味、气味相近,而炒制、微波、热风熟化粉冲调液的气味较接近。     

紫甘薯全粉冲调性研究

采用2因素3水平随机区组试验,研究了紫甘薯粉加工的熟化性状;采用2因素4水平随机区组试验研究了紫甘薯粉的干燥性状。试验结果显示,熟化性状表现好的3个处理为:切片厚度0.2~0.4 cm常压蒸汽熟化4 min、切片厚度0.6~0.8 cm熟化时间7 min、切片厚度1.0~1.2 cm熟化时间10 min;干燥性状表现好的3个处理为干燥温度60℃~65℃干燥时间10 h、干燥温度70℃~75℃干燥时间8 h、干燥温度80℃~85℃干燥时间6 h。试验选择最优的3个熟化处理、3个干燥处理、3种粉碎细度(60,80和100目)为因素,采用L9(33)正交试验研究了9个处理的冲调性,正交试验结果显示,熟化处理、干燥处理对冲调性影响不显著,粉碎细度对冲调性影响显著。其中切片厚度0.2~0.4 cm,常压蒸汽熟化4 min,恒温热风80℃~85℃烘干6 h,粉碎细度为100目时,紫甘薯粉的冲调性最佳。     

小麦麸皮膳食纤维的超声波-酶法改性研究

以小麦麸皮为原料,研究超声波功率、超声时间、酶添加量、酶处理时间对膳食纤维物理化学特性的影响,同时测定了改性后膳食纤维的抗氧化特性。结果表明:改性后膳食纤维分子量显著下降,单糖组分不变但组分含量比例变化较大;傅里叶红外测定表明,改性膳食纤维的组分没有改变,与单糖组成结果相符合;示差扫描量热法测定表明,改性后膳食纤维具有较强的热稳定性;抗氧化特性测定表明,改性膳食纤维具有较好的生物特性,为膳食纤维深层次开发利用提供了一定的试验依据。     

pH和阿拉伯胶对大豆分离蛋白/大豆蛋白酶解产物乳化性质的影响

研究了pH和阿拉伯胶对大豆分离蛋白(soy protein isolate,SPI)或低限度酶解改性产物的乳化性质的影响。结果表明:SPI酶解改性处理后制备的乳液颗粒粒径和液滴间絮凝程度明显降低;添加阿拉伯胶促进了SPI或大豆蛋白酶解产物(soy protein hydrolysate,SPH)在油水界面的吸附,SPH-阿拉伯胶复合物制备的乳液在pH4的条件下室温放置14 d具有较好稳定性;添加阿拉伯胶前后,SPH制备的乳液黏度均低于SPI。     

亚麻籽胶的乳化性质

重点研究了亚麻籽胶的乳化性质，实验结果表明。亚麻籽胶的质量分数、溶解温度、乳化温度、加油量以度贮存温度等对亚麻籽胶的乳化性质都有影响。质量分数增加，亚麻籽胶的乳化稳定性增强；加油量增多。亚麻籽胶的乳化稳定性下降；溶解温度升高能提高亚麻籽胶的乳化稳定性；而乳化温度和贮存温度越高，亚麻籽胶乳状液越不稳定。由于亚麻籽胶与阿拉伯胶在相对分子质量、均方旋转半径、粘度、疏水性氨基酸含量上的差异，导致了亚麻籽胶与阿拉伯胶乳化性质的差异．     

The effect of sterilizing doses of γ-irradiation on the molecular weight and emulsification properties of gum arabic

Experiments were performed on raw, kibbled and spray-dried gum arabic. Microbiological tests showed that following a radiation dose of 10 kGy the contaminating micro-organisms were effectively inactivated. The average molecular weight of kibbled and spray dried gum arabic was shown by viscosity measurements to be somewhat reduced as the result of γ-irradiation. No significant radiation-induced changes in the molecular weight of raw gum arabic could be detected. The yields of radiolytically produced strand breaks (breaks/100 eV of radiation absorbed) have been calculated for spray-dried [G(strand breaks) = 4.1 × 10⁻¹] and for kibbled [G(strand breaks) = 2.9 × 10⁻¹]. Gel permeation chromatography confirmed this order of radiation stability and indicated that gum arabic consists of at least three major components, the larger molecular weight fraction appearing to be the more radiation sensitive. There was no measurable change in the total hexuronic acid content (20%) of any of the samples on γ-irradiation. Finally, measurements showed no adverse effect of γ-irradiation, even up to doses of 30 kGy, on the ability of the gum arabic to stabilize emulsions. The extent of chemical change induced by irradiation with sterilizing doses has no practical adverse significance and demonstrates that this technique is suitable for processing raw gum arabic samples.     

Rheological properties of gum arabic solution: From Newtonianism to thixotropy

The influence of molecular association on the rheological behavior of gum arabic solution was studied. Using time-dependence of transient shear stress a reversible molecular association could be arrested and the thixotropy of gum arabic solution was interpreted. The structural breakdown, buildup and the effect of shear history due to molecular association could be related using the Casson’s equation. Stress jump measurements distinguished the effect of molecular association on the elastic and viscous contributions of shear stress. An elastic-like contribution dominated at low shear rates whereas the viscous component became important at high shear rates. The elastic contribution was strongly affected by the molecular association of gum arabic, with increased molecular association contributing to a larger elastic contribution. The elastic and viscous contributions were also investigated in transient flow. Both of the contributions increased with rest time, indicating a buildup of molecular association. With increasing the rest time the elastic contribution increased much faster than the viscous contribution to the total stress.     

Classification and physicochemical characterization of mesquite gum (Prosopis spp.)

Under environmental stress conditions, mesquite trees can excrete a proteinaceous arabinogalactan gum that is similar to gum arabic. Given the application potential of this type of gums a classification procedure for the mesquite gum is proposed. The main physicochemical properties of the best-quality mesquite gum were determined and compared with those of gum arabic. Additionally, the composition and molecular changes induced by purification processes were recorded. One batch (157 kg) of mesquite gum was categorized by subjective assessment into three classes (MGA, MGB and MGC) from high- to low-quality. Approximately 17.5% was classified as top-quality gum. It was found that this class of mesquite gum has lower humidity, inorganic and tannins content than the other classes, or even than the gum arabic sample used as a reference. All of the mesquite gum classes have higher protein content and lower intrinsic viscosity than gum arabic. The purification processes were shown to reduce the content of lower molecular weight compounds that modify the interface properties of the gum. The results indicate that the proposed classification method can be used to select mesquite gum with physicochemical properties comparable to those of commercial gum arabic.     

常用微胶囊壁材的分子结构及流变学特性研究

本文研究了五种壁材分子结构及其流变学特性。以喷雾干燥制备微胶囊的五种常用壁材变性淀粉、阿拉伯胶、明胶、大豆分离蛋白和羧甲基纤维素为研究对象,采用凝胶渗透色谱法(GPC)测定壁材的分子量分布;傅里叶变换红外光谱法(FT-IR)分析不同壁材的特征基团和蛋白类壁材的二级结构;旋转流变仪研究壁材的表观黏度、动态模量和蠕变柔量。研究结果表明:五种壁材溶液均呈现剪切稀化现象,随着温度的上升壁材溶液的表观黏度逐渐下降;壁材的弹性模量G'和黏性模量G'均随着振荡频率的增大而增大;相同时间下,壁材的蠕变柔量J(t)大小为:变性淀粉阿拉伯胶明胶羧甲基纤维素大豆分离蛋白;壁材分子量越大,表观黏度就越大;同一数量级分子量的壁材,分子量分布越宽,非牛顿"剪切稀化"现象越明显;分子结构越刚性,极性越大,表观黏度也越大。     

Rheological study of gum arabic solutions: Interpretation based on molecular self-association

This study deals with the rheological properties of aqueous solutions of gum arabic, the complex arabinogalactan polysaccharide containing about 2% protein. The flow behavior of control gum and a matured gum (EM2), which have different molecular associations, was investigated at different concentrations in water and added urea (6M) by rheological and dynamic light scattering methods. The influence of molecular association on rheological behavior of gum arabic solutions was studied. It was found that though Newtonian behavior was observed across a wide range of concentrations and at high shear rates, gum arabic solutions showed a pronounced shear thinning in low shear rate ranges. The maximum difference in viscosity between shear rate increasing and decreasing processes was observed at 6% for both control gum and EM2 in water, and at 3% for control gum and 9% for EM2 in urea solutions. The results demonstrated macromolecular association of gum arabic occurring in the solutions, and the observed time-dependent flow behavior reflected microstructural breakdown and re-building in the systems. This phenomenon was understood in view of the relationship between rheological properties and microstructural characteristics. A model was presented to interpret the rheological behavior, which is attributed to the occurrence of shear-induced breakdown and re-formation of gum arabic aggregates.     

柠檬醛纳米胶囊的制备及其稳定性研究

以明胶、阿拉伯胶为壁材,司班60(S-60)、吐温20(T-20)为乳化剂,制备柠檬醛纳米胶囊。采用高压乳匀法,通过正交试验设计优化柠檬醛纳米胶囊的制备。采用动态光散粒径仪对其性能进行检测,利用顶空固相微萃取气质联用对柠檬醛主要降解产物进行研究。结果表明,壁材总量0.4%(明胶∶阿拉伯胶为1∶1),乳化剂总量0.4%(S-60∶T-20为2∶3),pH为3.8的缓冲液(1mol/L柠檬酸和1mol/L柠檬酸钠),柠檬醛0.1%,经120MPa压力均质3次。所制备得到的柠檬醛纳米胶囊体系稳定,平均粒径为228.4nm±7nm,柠檬醛纳米胶囊储藏6d(45℃)后柠檬醛剩余量为54.4%±0.2%。     

阿拉伯胶对薏米醇溶蛋白-虾青素纳米颗粒性质影响

通过反溶剂沉淀法制备了薏米醇溶蛋白-虾青素-阿拉伯胶纳米颗粒（Coixin- Astaxanthin-arabic gum nanoparticle, C-ASX-AG-NP）。当薏米醇溶蛋白与阿拉伯胶比例为1:1时,C-ASX-AG-NP的平均粒径最小,为163.43 nm,PDI为0.123,虾青素包埋率为55.07%。通过比较薏米醇溶蛋白-虾青素纳米颗粒（Coixin-Astaxanthin nanoparticle, C-ASX-NP）和C-ASX-AG-NP的稳定性,发现阿拉伯胶的加入不仅可以增强醇溶蛋白基虾青素纳米颗粒在中性pH（pH为6~7）和12.5 ~37.5 mmol/L NaCl环境中的稳定性,还可以提高贮藏过程中的虾青素保留率。X射线衍射分析表明虾青素以无定形态被成功包埋在纳米颗粒中,阿拉伯胶通过非共价结合的方式复合至C-ASX-NP上,通过透射电镜分析得出虾青素被成功的包埋。C-ASX-AG-NP对DPPH?清除率和ABTS+?清除能力高于 C-ASX-NP ,高于游离虾青素,说明采用薏米醇溶蛋白荷载虾青素可以提高虾青素的抗氧化活性。     

Temperature-dependent complexation between sodium caseinate and gum arabic

Complex formation between sodium caseinate and gum arabic as a function of temperature was investigated using dynamic light scattering, fluorescence and NMR. At neutral pH, the turbidity and the particle size increased when sodium caseinate and gum arabic mixtures were heated in situ at temperatures above a critical temperature. The increases in turbidity and particle size were reversible. This effect was considered to be due to hydrophobic interactions, leading to the formation of a complex between sodium caseinate and gum arabic. ¹H NMR spectroscopy showed that ANS, which bound to caseinate at low temperatures in caseinate solution or a caseinate-gum arabic mixture, was released at high temperatures upon formation of a caseinate or caseinate-gum arabic complex. This supported changes observed in the fluorescence of 8-anilino-1-naphthalene sulfonate upon binding to caseinate, which decreased at high temperatures for caseinate alone or when sodium caseinate was mixed with gum arabic. Light-scattering (turbidity) and dynamic light-scattering studies show that the temperature-dependent complexation between sodium caseinate and gum arabic was sensitive to the mass ratio of protein to gum arabic (greater complexation at a 1:5 ratio than a 1:1 ratio) and the pH (maximum complexation at pH 6.5).     

Effect of gum arabic on the surface tension and surface dilational rheology of trisiloxane surfactant

The surface tension and surface dilational properties of trisiloxane surfactant silwet408, gum arabic, and their mixed solutions are reported. The dilational rheological properties are measured by means of oscillating drop method. The influences of dilational frequency, bulk concentration and aging time on dilational rheology properties have been investigated. The adsorption films of silwet408 behave elastic in nature at low bulk concentration. With increasing concentration, the dilational modulus becomes more frequency dependent and reaches a maximum value. The addition of 1 wt% gum arabic has no remarkable influence on the silwet408 films since the adsorption ability of silwet408 is much better than that of gum arabic. However, the maximum of dilational modulus and dilational elasticity are shifted toward a higher concentration, which has been correlated with the decreased molecular exchange in the presence of 1 wt% gum arabic.