D-塔格糖的分离纯化

以化学法合成的D-塔格糖为原料,采用Ca~(2+)型离子交换层析、阴阳离子交换树脂脱盐脱色的方法分离纯化D-塔格糖。Ca~(2+)型离子交换柱层析条件为;柱温70℃,流速1.0 mL/min,进样体积20 mL,D-举格糖回收率达到了83%,纯度达到98%。经强酸性阳离子和弱碱性阴离子交换树脂一次串联脱盐脱色,脱盐率达93%,D-塔格糖回收率为87%。将分离得到的样品浓缩、乙醇结晶获得晶体。通过红外光谱分析,结果表明,分离纯化后的产物是D-塔格糖。     

化学法合成D-塔格糖的研究

研究了D-塔格糖的化学法生产工艺过程,通过单因素实验,确定了以D-半乳糖为原料进行化学法合成D-塔格糖的工艺条件。结果表明,当CaCl2（催化剂）的添加量在0.01～0.03mol/L,反应时间在20～40min,并用醋酸、CO2、磷酸中和时,D-塔格糖产率较高。通过正交实验优化反应条件,最终确定以0.02mol/L的CaCl2为催化剂,反应时间30min,用醋酸中和金属氢氧化物D-塔格糖复合物时,D-塔格糖的产率最高,可达到49.05%。      

塔格糖结晶条件的优化

塔格糖是一种具有优良特性的稀有糖品,本研究主要对塔格糖的结晶条件进行优化,优化得到塔格糖的最佳结晶条件为:料液浓度为75%,晶种添加量0.6%,冷却速度1℃/h(加晶种时的温度为65℃,冷却后温度为25℃),糖浆塔格糖含量为91.22%。在以上条件下,结晶收率可达45%。最终制得结晶塔格糖的含量达99.35%。     

一种新型功能甜味剂--塔格糖

本文围绕近年来新畅销的天然甜味剂塔格糖 ,主要介绍了它的一些基本物理化学性质及主要生理功能 ,并对它的生产和在食品工业上的应用进行了论述。     

发酵乳杆菌C6全细胞催化剂的制备及产D-塔格糖催化条件优化

以L-阿拉伯糖异构酶产生菌发酵乳杆菌(Lactobacillus fermentum)C6为全细胞催化剂,对其发酵制备工艺以及生物转化D-塔格糖的催化反应条件和细胞透性化学处理方式进行优化。结果表明,菌株C6以最优培养基配方(葡萄糖10 g/L,酵母浸粉20 g/L,蛋白胨20 g/L,无水乙酸钠10 g/L,MgSO₄·7H₂O 0.4 g/L,MnSO₄·2H₂O 0.05 g/L,K₂HPO₄0.4 g/L,L-阿拉伯糖3 g/L,ZnSO₄·7H₂O 0.04 g/L,生物素100μg/L,焦磷酸硫胺素400μg/L)在最优发酵条件(发酵温度37℃、初始pH值7.5、装液量70 mL/150 mL、接种量1%)下培养24 h,生物量(OD_{600 nm}值=1.25)和L-阿拉伯糖异构酶酶活(107.81 U/mL)较优化前分别提高了92.31%和116.44%;全细胞催化剂在优化的催化...     

铝酸钾法合成D-塔格糖的研究

研究了铝酸钾法合成D-塔格糖的工艺过程,通过单因素和正交实验,确定了以D-半乳糖为原料铝酸钾法合成D-塔格糖的工艺条件。结果表明,铝酸钾添加量为60g,反应时间为5h,反应温度为40℃,D-塔格糖产率最高,可达到83%。     

D-塔格糖与L-阿拉伯糖异构酶的研究进展

D-塔格糖是一种天然的低能量填充型甜味剂,并具有抑制高血糖、改善肠道菌群和不致龋齿等多种生理功效。D-塔格糖是一种稀有糖,因此通常利用化学转化或生物转化方法进行大量生产。L-阿拉伯糖异构酶是生物法工业化生产D-塔格糖的有效酶。文中对D-塔格糖的性质、功能及利用L-阿拉伯糖异构酶生产D-塔格糖的研究新进展进行了综述。     

新型甜味剂塔格糖的应用及生产

D-塔格糖是一种新型低热量甜味剂,用于食品和药品领域,有抗高血糖和益生保健等多种功能.本文综述了其基本性质和功能,抗高血糖的机制,食品和药品应用情况及生产技术开发的进展,重点阐述了塔格糖生产的工具酶--L-阿拉伯糖异构酶的基因克隆与筛选、酶工程化改造及固定化等方面的研究进展.     

新型甜味剂塔格糖的应用及生产

D-塔格糖是一种新型低热量甜味剂,用于食品和药品领域,有抗高血糖和益生保健等多种功能。本文综述了其基本性质和功能,抗高血糖的机制,食品和药品应用情况及生产技术开发的进展,重点阐述了塔格糖生产的工具酶——L-阿拉伯糖异构酶的基因克隆与筛选、酶工程化改造及固定化等方面的研究进展。     

D-塔格糖3-差向异构酶的固定化研究

从14种离子交换树脂和吸附树脂中,筛选出固定化效果较好的大孔弱碱性苯乙烯系阴离子交换树脂D301-Ⅲ为载体,以戊二醛为交联剂,通过先吸附后交联的方法对D-塔格糖3-差向异构酶的固定化进行研究。结果表明,最佳固定化条件为:加酶量为2.00mL/g（粗酶液/树脂）,吸附pH7.5,吸附时间为8h,吸附温度为30℃,戊二醛浓度为0.05%,交联时间为3h,固定化酶活回收率可达50%以上。固定化酶重复使用10次,酶活仍能稳定保持在初始酶活的65%以上,具有良好的操作稳定性。      

海藻酸钠-阿拉伯胶固定化糖化酶及其性质的研究

以海藻酸钠（SA）与阿拉伯胶（GA）为载体固定化糖化酶,以酶活回收率为评价指标,在单因素试验基础上,通过响应面法优化固定化条件,得到固定化糖化酶最佳工艺条件为SA-GA质量比2.7∶1,氯化钙质量浓度6.2 g/100 mL,固化时间0.8 h,此条件下固定化糖化酶酶活回收率为67.91%。通过对固定化酶酶学性质的研究得出：经固定化的糖化酶最适反应pH值与最适作用温度均与游离酶相同,pH值为4.6,温度45 ℃,热稳定性及操作稳定性均优于游离酶。     

阿拉伯胶在食品工业中的应用

本文综述了阿拉伯胶的组成、结构、制备、性质和目前其在食品工业中的应用现状，并对其作为多糖类食品添加剂在我国的发展前景进行了分析。     

酪蛋白酸钠和阿拉伯胶相互作用的研究及纳米粒的制备

通过对酪蛋白酸钠（SC）与阿拉伯胶（GA）复合体系浊度、粒径和Zeta电位的表征来研究p H、SC/GA浓度比、SC与GA总浓度和离子强度（Na Cl浓度）对两者相互作用及纳米粒形成的影响,利用透射电镜（TEM）表征纳米粒的微观形貌,并对纳米粒的贮藏稳定性进行考察,最后借助红外光谱（FTIR）和荧光光谱探讨SC与GA相互作用形成纳米粒的机制。结果发现:p H、离子强度可显著影响SC和GA两者相互作用及纳米粒的形成,表明两者形成纳米粒的主要作用力是静电相互作用。同时得到SC和GA相互作用形成稳定纳米粒的条件为:SC/GA浓度比1∶1,p H4.2,SC与GA总浓度3.0 mg/m L,Na Cl浓度10 mmol/L。在此条件下形成的纳米粒粒径约为142 nm,Zeta电位约为-21.43 m V,于4℃贮藏30 d后仍保持稳定。TEM结果显示纳米粒呈球形。FTIR证实两者之间的静电相互作用发生在SC中的-NH+3和GA中的-COO-之间。荧光光谱表明SC和GA通过静电相互作用形成纳米粒的结合是低亲和性的。      

Rheological behavior of aqueous dispersions of cashew gum and gum arabic: effect of concentration and blending

Rheological properties of cashew gum (CG) and gum arabic (AR), the exudate polysaccharides from Anacardium occidentale L. and Acacia, at different solutions (0.4–50% w/v) were studied. The intrinsic viscosity, [η], of CG in water at 20°C was ≈0.1 dl g⁻¹, while that of AR was ≈0.6 dl g⁻¹. The apparent viscosity of the unheated and the heated (at 80°C for 30 min) CG and AR solutions showed a progressive increase with increasing concentration. The flow curves of blends with equal viscosity solutions of AR/CG: 25/75, 50/50 and 75/25, showed no major interaction. The apparent viscosity (η_a) vs. shear rate data for both the AR and CG dispersions (4–50% w/v) exhibited shear-thinning characteristics at low shear rates (< about 10 s⁻¹) and Newtonian plateaus at shear rates >100 s⁻¹, and the Sisko model described well the η_a vs. data of all the dispersions.     

阿拉伯胶对玉米淀粉的共混改性

用阿拉伯胶对玉米淀粉浆料共混改性,使用快速黏度仪(RVA)测定阿拉伯胶-玉米淀粉体系的糊化性能,分析阿拉伯胶对淀粉成膜性能的影响。结果表明,阿拉伯胶会大大降低淀粉糊化的峰值黏度和衰减值,提高淀粉浆膜的断裂强度和断裂伸长,并改善淀粉浆膜的硬脆性。     

Comparison of molecular and emulsifying properties of gum arabic and mesquite gum using asymmetrical flow field-flow fractionation

The molecular and emulsifying properties of gum arabic (GA) and mesquite gum (MG) were characterized using asymmetrical flow field-flow fractionation connected to multi-angle light scattering and refractive index detection. Properties such as molar mass, root-mean-square radius (r_rms), hydrodynamic radius (r_h), conformation, apparent densities and distribution of proteinaceous matter over the whole molar mass range were determined. GA displayed a low molar mass (3.4 × 10⁵ g/mol), protein-poor component (population 1) and a high molar mass (1.9 × 10⁶ g/mol), protein-rich component (population 2). MG displayed one molar mass population with an average molar mass of 1.1 × 10⁶ g/mol. For both GA and MG, the conformation (r_rms/r_h) was increasingly spherical with increasing molar mass. However, MG had higher values of r_rms/r_h for a specific molar mass suggesting differences in structure between GA and MG. The protein content increased with increasing molar mass for both gums, although to a higher extent for GA. Selective adsorption, during emulsification experiments, could be observed of population 2 of GA which may be due to a combination of the higher protein content and a more flexible structure rendering it more surface active than population 1. Comparing GA and MG in terms of emulsion stability, it could be concluded that GA-stabilized emulsions have considerably higher stability against coalescence.     

阿拉伯胶种类对复合凝聚微胶囊成囊性质研究

研究了两种阿拉伯胶(Acacia senegal和Acacia seyal)对复合凝聚微胶囊成囊性质的影响。通过对阿拉伯胶性质的测定及复聚物的动态流变分析,发现由两种类型胶参与形成的复聚物随温度降低,体系的粘弹性转变存在较大差异:具体体现于Acacia senegal胶参与形成的复聚物,其粘性向弹性转变的温度大大高于Acacia seyal胶参与形成的复聚物。该流变特性进一步体现于微胶囊制备上的外观差异,并同时为采用不同类型的阿拉伯胶制备出形态优良的微胶囊提出了工艺上的相应改进措施。      

压力协同温度控制天然阿拉伯胶的熟化改性研究

阿拉伯胶由于具有良好的溶解性、稳定性、乳化性等优异性能,被广泛的应用于生物、医药、食品和工业领域。以天然阿拉伯胶为研究对象,分别考察了压力、温度和处理时间对阿拉伯胶熟化的影响。结果表明,温度是阿拉伯胶熟化改性的主要影响因素,温度越高阿拉伯胶的平均分子量越大,在100℃条件下处理,12 h后平均分子量可达到2.8×107g/mol;超高压不能改变阿拉伯胶的熟化程度,但是能够明显的缩短熟化时间,提高改性效率;红外光谱检测结果表明,高压没有改变阿拉伯胶组分。试验结果将为天然阿拉伯胶的改性提供一种新的方法和途径。     

Determination of the calorific value of gum arabic in rats using modified versions of the growth bioassay and the digestibility assay

The calorific values of gum arabic (GA), cellulose (Solka Floc) and sucrose were measured in a rat model using modifications to the growth assay and energy balance procedures simultaneously. Although the two procedures gave consistent results for cellulose (Solka Floc) and sucrose, i.e. 0 and >3.5 kcal g⁻¹, respectively, contradictory results were obtained for GA. The growth assay procedure indicated that GA had zero calorific value while the energy balance procedure indicated a value of 3.1 kcal g⁻¹. Similar results have been reported by other researchers using the two different techniques separately. Results of this type have led to confusion as to the actual calorific value of GA. The anomalous results for GA may be explained in terms of losses resulting from processes which provide no calories for the rat, for example bacterial fermentations in the caecum. Other sources of loss may also have a role. We have proposed that the calorific value of zero as determined using the growth assay is the correct value in the context of the nutritive value of GA.     

Microencapsulation of flaxseed oil by soya proteins–gum arabic complex coacervation

Application of soya proteins (SP) in flaxseed oil microencapsulation based on complex coacervation was investigated. The effects of SP/gum arabic (GA) mixing ratio (1:2, 1:1 and 2:1) and pH (2.80, 3.15 and 3.75) on coacervate preparation were studied firstly. The highest coacervate yields (CY) were achieved at SP/GA = 1:1, pH 3.15, and SP/GA = 2:1, pH 3.75, which were 81.2 ± 2.0%, 88.1 ± 0.6%, respectively. Thereafter, the microencapsulation of flaxseed oil was detected in accordance with the results of the coacervation of SP/GA, that is the optimal condition for microencapsulation was corresponded to the condition where CY was the highest. Under the conditions of SP/GA = 1:1, pH 3.15, and SP/GA = 2:1, pH 3.75, the microencapsulation efficiency and total yield reached 81.5 ± 0.1% and 81.7 ± 0.4%, and 77.4 ± 3.7% and 86.7 ± 2.4%, respectively. Microscopic morphology revealed that the formation of a biopolymer shell around the oil droplets was achieved at specific conditions.