超声波辅助提取苦豆子胶的工艺研究

采用超声波辅助萃取法提取苦豆子胶,通过单因素及正交实验研究超声波处理时间、超声波功率、提取温度、溶液pH对提取率的影响。结果表明,苦豆子胶的最佳提取工艺为:超声波功率135W,超声波处理时间45min、提取温度95℃、溶液pH10,该条件下提取率达90.02%。     

苦豆子胶多糖组分气相色谱与薄层色谱分析

利用铜沉和醇沉法提取纯化多糖，以薄层色谱和气相色谱法进行定性和定量分析，建立苦豆子胶多糖组分分析方法。结果苦豆子胶多糖是由甘露糖和半乳糖组成，其百分舍量分别为39．9395％和17．8849％；相对标准偏差为3．5602％-5.0763％，回收率为98．63％-99．68％；二者配比为半：甘=1：2．23；总糖含量为57．8244％：结论：该方法便捷，可靠，可作为苦豆子胶多糖组分定性和定量的分析方法．     

黄原胶冷水溶部分和热水溶部分的流变特性及其协同作用研究

研究了低浓度黄原胶冷水溶和热水溶部分的流变性,黄原胶在冷水和热水中溶解,其流变性有所不同。考察了浓度、温度、剪切力、pH值、冻融变化等参数对黄原胶溶液的黏度的影响。黄原胶与魔芋胶具有明显的协效性,与卡拉胶、CMC-Na无协效性。     

低浓度黄原胶冷水溶部分和热水溶部分的流变性研究

研究了低浓度黄原胶冷水溶和热水溶部分的流变性,黄原胶在冷水和热水中溶解,其流变性有所不同。考察了浓度、温度、剪切力、pH值、冻融变化等参数对黄原胶溶液的黏度的影响,对黄原胶与魔芋胶、卡拉胶、CMC-Na的协效性进行了研究。     

黄原胶流变学特性及其协效性研究

研究了不同浓度的黄原胶溶液的黏度变化以及剪切速率和时间对其流变学特性的影响,此外还对黄原胶与瓜尔豆胶、CMC、果胶的协效性进行了研究.研究结果表明,黄原胶溶液的黏度值随浓度的增加而逐渐增大,对其进行线性回归得方程y=157.8x-182.07,其相关系数达到0.9838.触变性的测定发现,在升速过程中黄原胶的表观黏度随剪切速率的增加而逐渐降低,而在降速过程中,表观黏度有一定的回升,具有很明显的假塑性,并且能够形成触变环,不同浓度黄原胶溶液的黏度值都是随剪切速率的增加而逐渐减小,这些现象表明,黄原胶溶液是一种正触变性流体.此外还发现,黄原胶和瓜尔豆胶具有一定的协效性,当黄原胶同瓜尔豆胶的比例为9 ∶ 1时,表观黏度值达到最大,为768.2mPa.s.黄原胶与CMC、果胶无协效性.     

微波法提取苦豆子生物碱的研究

苦豆子资源在国内比较丰富,其有效成分生物碱含量较高,目前国内外对苦豆子的研究和利用重点放在了生物碱上,本文对苦豆子生物碱传统提取法和微波辅助提取法进行了试验比较,在单因素实验的基础上,采用正交设计方法,考察微波时间、微波功率、料液比3个因素对苦豆子生物碱提取的影响,结果表明：微波辅助提取生物碱效果较好,最佳条件是微波提取时间为30S、微波功率为360W、料液比为（g/mL）1∶5。利用这种方法生物碱的提取效率较高,生产成本较低,工序较为简单,适宜于工业化生产。     

葫芦巴胶溶液流变特性研究

通过测定和分析浓度、剪切力、温度、pH和冻融等变化对葫芦巴胶溶液表观粘度的影响及与黄原胶等食品胶的协效性,对葫芦巴胶溶液的流变性进行了研究。研究结果表明:冷水溶和热水溶葫芦巴胶溶液的表观粘度都随浓度的升高而呈指数规律的上升;葫芦巴胶溶液为非牛顿流体,其剪切稀化具有瞬时恢复性;随着温度的升高,葫芦巴胶溶液的表观粘度呈半对数规律下降;且溶液具有很强的耐热性;葫芦巴胶溶液在酸性和碱性条件下较为稳定;冻融处理可使葫芦巴胶溶液的表观粘度下降;葫芦巴胶与黄原胶、海藻酸钠有一定的协效性,但其协效性较低,而与CMC却有很强的相互增效的协同效应。     

决明子胶泠水溶部分和热水溶部分的流变性研究

本文研究了决明子胶冷水溶和热水溶部分的流变性,决明子胶在冷水和热水中溶解,其流变性有所不同。考察了浓度、温度、剪切力、pH值、冻融变化、盐度等参数对决明子胶溶液的粘度的影响。决明子胶与黄原胶、卡拉胶具有明显的协效性,与瓜尔豆胶无协效性。     

沙蒿胶冷水溶部分和热水溶部分流变性研究

研究了沙蒿胶冷水溶和热水溶部分的流变性,沙蒿胶溶于冷水和热水中,其流变性有所不同.考察了浓度、温度、剪切力、pH、冻融等参数对沙蒿胶粘度的影响.沙蒿胶与瓜尔豆胶、黄原胶、海藻酸钠具有明显的协效性,与卡拉胶、壳聚糖、决明子胶、魔芋粉无协效性.     

苦豆子总生物碱提取工艺的优化研究

对汉中苦豆子中总生物碱的提取工艺进行了研究,结果表明:提取在A2B3C1D2条件下,即乙醇浓度为65%,料液比(g/mL)为1∶15,浸提时间为5 h,浸提温度为60℃。此时,提取得到苦豆子生物碱含量为6.7%。     

亲水胶体对糯玉米汁稳定性影响

为进一步提高糯玉米汁稳定性,比较研究不同亲水胶体(黄原胶、海藻酸钠、瓜尔豆胶和刺槐豆胶)对糯玉米汁体系稳定系数、离心沉淀率、相对黏度和感官的影响,并探讨糯玉米汁体系的静电稳定性。结果表明：黄原胶具有一定的乳化效果,可以在一定程度上缓解糯玉米汁脂肪圈的形成;海藻酸钠、瓜尔豆胶和刺槐豆胶对糯玉米汁的稳定效果较好,并且随着添加量的增加,体系稳定系数和相对黏度逐渐提高;而黄原胶与海藻酸钠、瓜尔豆胶、刺槐豆胶分别以不同质量比复配时,在黄原胶、刺槐豆胶质量比1:4时,糯玉米汁体系稳定性最佳。     

黄原胶对酪蛋白酸钠乳状液稳定性的影响

研究了一定pH条件下,黄原胶浓度及剪切稀化效应对酪蛋白酸钠乳状液稳定性的影响。结果表明,在酸性条件下,黄原胶无法抑制酪蛋白的变性沉淀,乳液在制备之初,即产生严重絮凝。在中性和弱碱性条件下,黄原胶在一定浓度范围内,诱发了乳状液的排斥絮凝;体系的pH显著影响了乳状液的稳定性,pH6条件下,较低的黄原胶浓度(0.2wt%)便可赋予乳状液良好的稳定性。均质过程大大降低了黄原胶的粘度,导致乳状液的稳定性下降,与添加未经均质处理的黄原胶相比,添加量增大近一倍,才能获得稳定的乳状液。     

食品级黄原胶酶法脱蛋白及其主要性能的研究

黄原胶发酵液在适宜的条件下经碱性蛋白酶处理,并用酒精沉淀可制得黄原胶粉剂。测定结果表明,碱性蛋白酶处理能使黄原胶产品含氮量降低41.8％,且有良好的增粘性、触变性和冷热稳定性,与槐豆胶协同使用有显著的增粘性,可作为食品添加剂。     

Conformational Role of Xanthan Gum in its Interaction with Guar Gum

ABSTRACT: :
Ubbelohde viscometry, texture analysis, and centrifugation were used to investigate the effects of chain conformational changes of xanthan or deacetylated xanthan gum on its interaction with guar gum. Guar gum was not effective in denaturing xanthan gum when the xanthan helical structure was stabilized by salt. The intrinsic viscosities of deacetylated xanthan and guar blends were higher than those calculated from the weight averages of the 2. Conformational change was not observed for deacetylated xanthan, presuming deacetylated xanthan was in the exact conformation for guar to bind so that the most stable heterotypic structure between deacetylated xanthan and guar was formed directly, thus the strongest interaction was observed between deacetylated xanthan and guar.     

黄原胶对玉米淀粉糊化性能的影响

将黄原胶引入到淀粉浆料中,采用快速黏度分析法(RVA)研究了黄原胶的加入对玉米淀粉糊化性能和浆液表观黏度的影响,讨论了黄原胶与玉米淀粉分子之间的相互作用.结果表明:黄原胶可促进淀粉糊化,降低淀粉的糊化温度,缩短糊化时间;随着黄原胶质量分数的增加,淀粉的糊化峰值黏度增加,表现了2种高分子的相互作用;黏度衰减值随黄原胶增加...     

面筋蛋白粒子-黄原胶Pickering乳液的制备及其表征

制备黄原胶与面筋蛋白纳米粒协同稳的Pickering乳液,表征Pickering乳液的物理化学性能和微观结构。结果显示：通过黄原胶与面筋蛋白纳米粒协同作用,可制备出稳定性较好的Pickering乳液。低质量分数的黄原胶（0.2%）会促进乳析;当黄原胶质量分数不小于0.3%时,乳液于4 ℃贮存30 d仍无乳析现象;当黄原胶质量分数为1%时,贮存30 d乳液出现析油的现象。不同乳化顺序得到乳液的稳定性不同。乳液M-WG-XG（面筋蛋白纳米粒与玉米油乳化得粗乳液,然后加入黄原胶二次分散）的稳定性最好,同时乳液的平均粒径最小（21.4±0.314）μm。黄原胶的加入增大了乳液的净电荷,乳液的稳定性提高。共聚焦显微镜结果表明,乳液M-WG-XG液滴分布均匀,界面层呈现出多层结构。相比于其他方式制备的乳液,乳液M-WG-XG有更好的黏弹性和离子稳定性。     

Rheological Behavior of Soya Oil-Water Emulsions: Dependence upon Oil Concentration

Stress-strain measurements have been performed in the linear region for soya oil-water emulsions stabilized with xanthan gum for various oil concentrations and for xanthan gum solutions for various xanthan gum concentrations. The big increase observed in the shear modulus for the emulsions (as compared to the solutions) is primarily due to the interaction between xanthan gum molecules and emulsion droplets. The results obtained are in broad agreement with the existing theories for concentrated dispersions and tend to show that the interdroplet interaction is similar to that expected for ‘soft’ deformabe spheres. The results for xanthan gum solutions can be explained if the xanthan gum solutions are not true solutions, but some form of dispersions.     

Physical and Oxidative Stabilities of O/W Emulsions Formed with Rice Dreg Protein Hydrolysate: Effect of Xanthan Gum Rheology

The shortening of shelf-life of food emulsions is frequently due to poor creaming and lipid oxidation stability. The lipid oxidation of O/W emulsions can be inhibited by rice dreg protein hydrolysate (RDPH); however, emulsions were stabilized by Tween-20. Polysaccharides can control the rheology and network structure of the aqueous continuous phase by increasing viscosity and yield stress, hence retarding phase separation and gravity-induced creaming, especially for xanthan gum. The objective of this research was to evaluate whether emulsions formed with 2 wt% RDPH and stabilized by xanthan gum (0–0.5 wt%) could produce 20 % (v/v) soybean oil-in-water emulsions that had good physical and oxidative stability. The degree of flocculation of droplets as a function of xanthan gum concentration was assessed by the microstructure, rheology, and the creaming index of emulsions. Addition of xanthan gum prior to homogenization had no significant effect on the mean droplet diameter in all emulsions studied. Increase in xanthan gum concentration led to the increase in creaming stability of emulsions, due to an increase in viscosity of the continuous phase and/or the formation of a droplet network with a yield stress, as well as the enhanced steric and electrostatic repulsion between the droplets. Lipid oxidation of the emulsions was significantly inhibited at xanthan gum concentrations of 0.12 wt% or above with RDPH, which could due to the fact that xanthan gum increases the viscosity of the aqueous phase and hindered the diffusion of oxidants to the oil droplet surface area, synergistic effect between RDPH and xanthan gum to suppress oil peroxidation, and metal ion chelation capability of xanthan gum. Thus, stable protein hydrolyzates-type emulsions could be obtained with increasing concentration of xanthan gum.