羧甲基酸解淀粉的制备及特性表征

通过酸解醚化复合变性方法制备了羧甲基酸解淀粉(CMAS),探讨了水分含量、氯乙酸用量、氢氧化钠用量、温度、时间对取代度(DS)和反应效率(RE)的影响,对产物进行了FTIR、XRD、SEM、TG分析,研究了其黏度与pH和盐质量分数的关系。结果发现,在nNaOH/nAGU=2.835,nMCA/nAGU=1.39,V水/V乙醇=0.11,温度为50℃,时间为3h的条件下,羧甲基酸解淀粉的取代度达到0.8052,反应效率为57.92%,颗粒大小在5~10μm;黏度随pH的下降而降低,随NaCl质量分数的升高而下降,达到0.6%时溶液黏度下降到4.37 mPa.s,下降了46.31%。     

干法制备黄糊精工艺的研究

以玉米淀粉为原料,干法制备黄糊精。通过单因素试验,确定出影响黄糊精糊精含量的因素有,体系含水量、浓HCl量占淀粉质量的比例、反应温度、反应时间。由L9(34)四因素三水平黄糊精正交实验确定出制备黄糊精的最佳工艺参数为:体系含水量为18%,反应温度145℃,反应时间2.5h,浓HCl量占淀粉质量的比例为0.2%。     

一种聚羧酸型助剂的合成与应用研究

对(甲基)丙烯酸、顺丁烯二酸酐、衣康酸等单体进行自由基聚合,并对单体比例、引发剂用量进行正交试验及应用研究。结果表明:最佳聚合条件为n((甲基)丙烯酸)∶n(顺丁烯二酸酐)∶n(衣康酸)=1∶0.3∶0.3,w(过硫酸铵)=1.0%,w(亚硫酸氢钠)=0.6%,反应温度为60~65℃,反应时间为180min。较佳用量为1.5%,此时裸皮对铬的吸收率为95%,废液中Cr_2O_3的含量为350mg/L,革呈湖蓝色、粒面平细。谱图表明其具有适度的分子质量及分布,结构中含有较多的羧基。另外,在对绵羊蓝湿革复鞣中,其最佳用量为4%,革的增厚率为17%,成革丰满、紧实。     

铬吸收促进剂的制备及应用

基于系列有机酸配体与Cr~(3+)配合物的稳定性规律,制备了皮革铬吸收促进剂,并将其应用于铬鞣工艺中,通过废液中Cr_2O_3含量的测定评价铬吸收促进剂的应用效果;测试皮革的收缩温度、增厚率、物理机械强度、Cr_2O_3分布,说明铬吸收促进剂对皮革物化性能的影响。结果表明:与常规铬鞣相比,当加入皮革铬吸收促进剂2%~3%时,废液中Cr_2O_3含量至少减少了85%,可降低到0.10 g/L以下,即是铬鞣废液中的铬几乎被吸尽,说明铬吸收促进剂能大大提高铬的吸收和利用率,降低废液中Cr_2O_3含量。此外,铬吸收促进剂可提高皮革的丰满性和收缩温度,改善成革的物理机械性能。     

改性牛蹄油制备聚合物加脂剂及其应用的研究

用不同用量的醇胺和马来酸酐分两步改性牛蹄油 ,并用改性牛蹄油与丙烯酸共聚制备聚合物加脂剂 ,通过正交试验探讨油 /酸、温度、过氧化苯甲酰 (BPO)和低碳醇用量对合成反应的影响 ,得到最佳条件 :n (油 )∶n(丙烯酸 ) =1∶1 ,反应温度为 85℃ ,BPO用量是单体质量的 0 .5 % ,醇用量是单体质量的 2 0 %。将其用于铬鞣革复鞣加脂 ,材料吸收率和成革增厚率高 ,革柔软、粒面细致、富有油感、弹性 ,具有一定防水性 ,用于铬鞣中。试验表明 :有助于铬的吸收 ,不降低收缩温度 ,使铬鞣革更加柔软。     

一种聚羧酸型助剂的合成与应用研究北大核心

对(甲基)丙烯酸、顺丁烯二酸酐、衣康酸等单体进行自由基聚合,并对单体比例、引发剂用量进行正交试验及应用研究。结果表明:最佳聚合条件为n((甲基)丙烯酸)∶n(顺丁烯二酸酐)∶n(衣康酸)=1∶0.3∶0.3,w(过硫酸铵)=1.0%,w(亚硫酸氢钠)=0.6%,反应温度为60~65℃,反应时间为180min。较佳用量为1.5%,此时裸皮对铬的吸收率为95%,废液中Cr_2O_3的含量为350mg/L,革呈湖蓝色、粒面平细。谱图表明其具有适度的分子质量及分布,结构中含有较多的羧基。另外,在对绵羊蓝湿革复鞣中,其最佳用量为4%,革的增厚率为17%,成革丰满、紧实。     

硒、铬共同富集酵母培养的最佳工艺及稳定性研究

本研究明确了制备富硒、铬酵母的最佳工艺条件,即培养基中硒离子浓度为 20μg/ml、铬离子浓度为40μg/ml、培养时间为48h、接种量为15%.在最优工艺条件下所制备的富硒、铬酵母中硒、铬含量分别为 499.02、257.63μg/g,吸收率分别为55.53%和14.33%.有机硒和有机铬的转化率分别为97.72%和90.09%,均达到较高水平.     

多金属鞣剂性能研究

以铬、铝、钛盐和自制的新型有机配体LA为主要原料制备铬铝钛多金属鞣剂,探讨合成方法并研究其组成、性能.结果表明,LA用量为金属离子总摩尔数的20%,摩尔比n(Cr3+)):n(A13+):n(Ti4+)为4:3:3时制备的鞣剂可以节省60%的铬用量,鞣制时铬的吸收率达到90.3%,远高于常规铬鞣的吸收率68.24%,废液中的Cr2O3为0.2365 g/L,只有常规铬鞣的1/7.     

纳米复合少铬鞣助剂在山羊皮鞣制中的应用

采用单因素试验法研究了纳米复合少铬鞣助剂(T112)在山羊皮无盐小浸酸铬鞣工序中的应用,以蓝湿革的收缩温度、铬鞣废液中Cr2O3含量为考察指标,优化了鞣制工艺。结果表明:最佳鞣制工艺为T112用量2.0%,T112鞣制结束pH值为3.5,铬粉用量3.0%。采用最佳鞣制工艺鞣制后蓝湿革收缩温度达到106.0℃,废液中Cr2O3含量降至176.2mg/L,复鞣后,坯革的抗张强度达15.8N/mm2,撕裂强度为59.3N/mm,断裂伸长率为76.5%,物理机械性能均达到山羊服装用革行业标准,并且坯革的柔软度可达4.4mm。扫描电镜结果表明:T112的引入能够有效提高纤维的分散性能,同时未破坏胶原的微观结构。     

含铬鞣剂QUIMITAN ABC应用性能

通过对比QUIMITAN ABC、铬粉及含铬鞣剂在主鞣和复鞣中的鞣制性能,测定坯革相应物性.结果表明:QUIMITAN ABC主鞣后的坯革的收缩温度为101.4 ℃,且其坯革物理力学性能高于用6%的铬粉主鞣后的坯革;QUIMITAN ABC主鞣后的废液Cr2O3含量(0.4142 g/L)明显低于用6%的铬粉主鞣后废液Cr2O3含量(1.9481 g/L),用QUIMITAN ABC主鞣有益于清洁化生产;在Cr2O3含量相同的情况下,用QUIMITAN ABC复鞣的坯革在增厚率、柔软度、物理力学性能等方面都要好于含铬鞣剂及铬粉复鞣的坯革.     

抗性糊精对κ-卡拉胶凝胶特性的影响

通过在κ-卡拉胶中添加不同浓度的抗性糊精,研究抗性糊精对κ-卡拉胶凝胶的冻融稳定性、热稳定性、压缩模量及微观结构的影响。结果表明,加入抗性糊精的κ-卡拉胶凝胶在冻融循环中水分析出明显减少,且与抗性糊精的添加量呈正相关。热稳定性结果显示,在抗性糊精添加量4%时,κ-卡拉胶凝胶的分解温度和反应活化能时达到最大（257.86 ℃,106.20 kJ/mol）。另外,κ卡拉胶凝胶的压缩模量随抗性糊精的添加量增加先增加后减少,在添加量为4%时达到最大值43.83 kPa。红外结果表明,抗性糊精的加入增加了凝胶体系中氢键的数量。扫面电镜结果表明,抗性糊精的加入使κ卡拉胶凝胶的蜂窝状结构变得更加光滑致密。然而,过量抗性糊精（5%）使κ-卡拉胶凝胶出现破损。抗性糊精的加入可以改善κ-卡拉胶的凝胶特性,且在抗性糊精添加量为4%时,κ-卡拉胶的凝胶特性最好。     

RICE WINE BREWING WITH SPROUTING RICE,SPROUTING RICE INFECTED WITH ASPERGILLUS ORYZAE AND RICE KOJI

Fermentation tests were performed with sprouting rice, sprouting rice infected with koji mold, i.e. Aspergillus oryzae and rice koji, as saccharifying agent. Characteristics of the various rice wines were compared by gas chromatography and organoleptic testing. The rice wine made with sprouting rice was colorless and had light and refined characteristics in terms of both aroma and taste. The rice wine made with sprouting rice infected by Aspergillus oryzae was rich in isoamyl alcohol, isoamyl acetate and acetaldehyde; it was faintly yellow in color and had rich and mild characteristics. This rice wine had something in common with conventional Japanese sake as compared with the sprouting rice wine, and it might be a transitional intermediate between ancient sprouting rice wine and conventional Japanese sake. In accordance with the traditional method for sake brewing, starchy materials, tap water and sprouting rice as the saccharifying agent were added to the initital mash as first and second additions. The rice wine was somewhat improved by these additions, as assessed by organoleptic testing. The body of the resultant rice wine was fortified with dextrin and its acidic taste was masked by sugar and dextrin.     

The tartaric acid-modified enzyme-resistant dextrin from potato starch as potential prebiotic

Enzyme-resistant dextrin, obtained as a result of heating potato starch with tartaric acid, was tested as the carbon source for selected strains of probiotic bacteria and also bacteria isolated from feces of healthy 30-year old men volunteers. The dynamics of growth of bacterial monocultures in broth containing tartaric acid (TA)-modified dextrin was estimated. It was also investigated whether probiotic lactobacilli and bifidobacteria cultured with intestinal bacteria in the presence of resistant dextrin would be able to dominate the intestinal isolates. Prebiotic fermentation of resistant dextrin was analyzed using prebiotic index (PI). Fermentation products were determined by HPLC. It was shown that all of the tested bacteria were able to grow and utilize TA-modified dextrin as a source of carbon, albeit to varying degrees. In co-cultures of intestinal and probiotic bacteria, the environment was found to be dominated by the probiotic strains of Bifidobacterium and Lactobacillus, which is a beneficial effect.     

非线性化学指纹图谱法检测羊奶粉中掺杂的糊精

采用"硫酸-丙二酸-溴酸钠-溴化钠-硫酸铈铵"为振荡体系,利用非线性化学指纹图谱法测定羊奶粉中掺杂的糊精含量。先向羊奶粉中掺入不同量的糊精,配成掺杂糊精的羊奶粉标样,每份羊奶粉标样的总量为0.7 g。通过非线性化学指纹图谱法对羊奶粉标样进行测定,运用最小二乘法,拟合出其诱导时间相对于羊奶粉中掺杂糊精含量之间的一元线性关系,可求出羊奶粉中掺杂的糊精含量。实验表明该方法可以达到以下指标:当羊奶粉中掺杂的糊精含量在0~30%范围内时,糊精含量与诱导时间值线性关系良好,相关系数R2为0.9991~0.9998,回收率为94.00%~108.75%,RSD为0.31%~1.96%,检测范围为0~0.30 g/g,检出限为8~9.3 mg/g。方法准确度高,操作简单,是一种切实可行的测定羊奶粉中掺杂糊精的方法,也可作为复杂样本中其它成分定量分析借鉴的方法。     

Effect of potato starch modification on mechanical parameters and granules morphology

Research was conducted to recognise the interrelations between morphology and mechanical properties of powders used in the food industry (dried potato protein, granulated starch, gelatinising starch, potato starch, pudding flour, starch thickener, and six kinds of dextrins: 40% white dextrin, 60% white dextrin, yellow dextrins: S, N, W, WB). Microscopic examination, determination of particle size distribution, particle shape index, as well as direct shear tests were performed. Single particles of dextrins were found to have similar shapes and dimensions. Classification of materials based on the results of mechanical testing was found to be in close agreement with classification based on morphology. The values of unconfined yield strength of dextrins and other materials investigated were found to be close, and characteristic of easy flowing and cohesive materials. Oscillations in the shear stress-strain curves were observed for two experimental materials: potato starch and white dextrin 60%, while those for other experimental materials run smooth. The highest values of unconfined yield strength σ_c were found in a range from 4.5 to 8 kPa for dried potato protein, at major consolidation stress values of 4 and 10 kPa, respectively. The lowest values of σ_c, characteristic for easy flowing and free flowing materials, were found for potato starch and granulated potato starch. The results of this study confirmed the relevance of morphology to the mechanical properties of powders.     

不同线性糊精基DHA微胶囊结构和性质的比较

该研究采用高直链玉米淀粉为原料,经盐酸和普鲁兰酶改性后制备得到具有不同链长分布的线性糊精聚集物,并构建二十二碳六烯酸（Docosahexaenoic Acid,DHA）微胶囊,系统研究了链长分布对微胶囊有序结构、包埋效率、氧化稳定性及抗消化性的影响。研究表明,酸解0～96 h后,线性糊精聚集物中长链线性糊精（聚合度大于100）的比例从95.22%减少到65.76%,而短链线性糊精（聚合度10～100）比例由4.62%提高到33.73%。微胶囊的短程有序结构含量随着短链线性糊精占比的增加而提高,说明降低链长有利于线性糊精-DHA络合物与双螺旋结构的形成。随着短链线性糊精含量的增加,微胶囊中V型结晶结构含量从1.18%逐渐增加到8.44%,而B型结晶结构含量则从7.84%降低为2.57%。线性糊精聚集物含有22.17%的短链线性糊精和77.46%的长链线性糊精时,微胶囊表现出最佳的包埋效率、氧化稳定性和抗消化性。结果表明,可通过缩短线性糊精分子链长来促进双螺旋结构和线性糊精-DHA络合物的形成,进而改善DHA微胶囊的性能。     

喷雾干燥荔枝固体饮料制备工艺及配方研究

研究了喷雾干燥荔枝固体饮料的工艺配方,实验以荔枝汁为原料,麦芽糊精、蔗糖、羧甲基纤维素钠(CMC)、β-环状糊精为辅料,利用均质与喷雾干燥相结合的工艺制成荔枝固体饮料。试验得到荔枝固体饮料的最佳配方为:荔枝汁65%、麦芽糊精27.55%、β-环状糊精2.30%、CMC 0.15%、蔗糖含量为5%。     

乳粉中糊精的检测方法

研究了乳粉中糊精含量的检测方法。样品经过质量分数为85％的乙醇溶液处理，提取物经过盐酸水解后进行还原糖含量的热滴定，从而计算出样品中糊精的量。结果表明，该方法用于检测乳粉中糊精在0．8％以上含量具有良好的重现性和回收率，同时方法操作简单，结果准确，适用于乳品企业进行原料及产品中糊精的检验。     

Preparation of aqueous dispersion of β-carotene nano-composites through complex formation with starch dextrin

Aqueous dispersions of β-carotene nano-composite were prepared through a blending process with a dextrin of high amylose corn starch in immiscible phases of aqueous dextrin and organic β-carotene solutions and water solubility and stability against oxidation of β-carotene were examined. Gradual evaporation of organic solvent during the mechanical stirring allowed the formation of aqueous solutions in which β-carotene was homogeneously dispersed with dextrin. Proper control of the solid concentrations effectively induced the complex formation between dextrin and β-carotene whereas an excess amount of β-carotene (>8 mg) in a dextrin solution (200 mg in 50 mL) induced crystallization and precipitation of β-carotene. The complex particles showed an irreversible endothermic transition of V-amylose (via DSC). X-ray diffraction analysis, however, revealed that the complex had no typical V-type crystalline arrangement. Hydrodynamic size of the complex particles in the aqueous solution could be decreased to nano-scale (16–30 nm) by a mild ultrasonication. The nano-composite contained β-carotene at approximately 30% on a weight, with improved stabilities against oxidation and enzymatic digestion.