高效液相色谱法测定醋酸羟丙基甲基纤维素琥珀酸酯中的酰基含量

醋酸羟丙基甲基纤维素琥珀酸酯是一种重要的药物肠溶缓释材料,其中的乙酰基和琥珀酰基含量对于产品的功能具有重要影响,因此准确测定这些酰基十分必要。目前,有关该化合物中乙酰基和琥珀酰基含量测定方法存在操作复杂、耗时长、准确性差等许多不足。本文采用高效液相色谱法,使用反相C18型(5μm,250×4.6mm)色谱柱,以0.02mol/L pH=2.8KH2PO4缓冲溶液为流动相,215nm为检测波长进行测定,乙酸和丁二酸在0.03-0.8mg/mL范围内线性关系良好,其线性相关系数分别为R2=0.9992、R2=0.9993,相对标准偏差分别为3.04%、2.32%(n=6),平均加标回收率分别为99.3%、99.4%。该方法操作简便,重现性好,与化学滴定法相比,可得到一致的测定结果。     

辛烯基琥珀酸淀粉酯的特性分析及在鸡肉灌肠中的应用

以早籼米淀粉为原料,采用水相体系制备不同黏度的辛烯基琥珀酸淀粉酯,并对其糊化特性、冻融稳定性及在鸡肉灌肠中的应用进行研究。结果表明:淀粉经酸解和辛烯基琥珀酸酐改性后,可以得到不同黏度的辛烯基琥珀酸淀粉酯,具有良好的冻融稳定性。在鸡肉灌肠中应用时,加入早籼米辛烯基琥珀酸淀粉酯的鸡肉灌肠与加入木薯变性淀粉的鸡肉灌肠相比较,其硬度、弹性和咀嚼性都有不同程度的提高(P<0.05)。扫描电子显微镜分析显示,添加木薯变性淀粉的样品,内部结构比较蓬松,而添加早籼米OSA-H6的样品,其内部组织则相对紧实细腻。该研究表明,辛烯基琥珀酸酐改性淀粉(烯基琥珀酸淀粉酸)可以改善肉制品的质构特性,在肉制品中具有潜在的应用价值。     

辛烯基琥珀酸淀粉酯作为微胶囊壁材的应用研究

以低黏度的纯胶为壁材制得的微胶囊产品,其干燥速度、油的包埋率、货架稳定性、粉末在水中的分散溶化能力及自由流动性和斥水性,都优于阿拉伯胶、糊精、麦芽糊精等壁材原料做成的产品。具有良好的自由流动性和分散性,在不同温度和相对湿度条件下十分稳定。本文就低黏度纯胶作为微胶囊壁材的应用详细地介绍了这类产品的结构、品种、性能、应用情况。     

Preparation and characterisation of octenyl succinate starch as a delivery carrier for bioactive food components

The octenyl succinic anhydride (OSA) modified corn starch (OSAS) was synthesised with different degrees of substitution (DS) and the influences of three factors namely OSA/starch ratio, reaction temperature, and reaction time on the DS of OSAS were studied by response surface methodology (RSM). As a delivery carrier material, the characteristics of OSAS were investigated. The resistant starch (RS) content of OSAS was increased with increasing DS, indicating the improvement of colon-targeting property. The swelling ratio (SR) of the OSAS in simulated gastrointestinal fluids was higher than that of native starch and its hydrophilicity was decreased with increasing DS. For in vitro release study, the percentage of released bioactive components was less than 7% within the first 8 h and close to 100% over a period of 36 h when the DS was 0.60. These results demonstrate that OSAS can be a potential carrier for colon-targeted delivery of bioactive food components.     

Breeding of high malate‐producing diploid sake yeast with a homozygous mutation in the VID24 gene

Malate is an important taste component of sake (a Japanese alcoholic beverage) that is produced by the yeast Saccharomyces cerevisiae during alcoholic fermentation. A variety of methods for generating high malate‐producing yeast strains have been developed to date. We recently reported that a high malate‐producing strain was isolated as a mutant sensitive to dimethyl succinate (DMS), and that a mutation in the vacuolar import and degradation protein (VID) 24 gene was responsible for high malate productivity and DMS sensitivity. In this work, the relationships between heterozygous and homozygous mutants of VID24 and malate productivity in diploid sake yeast were examined and a method was developed for breeding a higher malate‐producing strain. First a diploid yeast was generated with a homozygous VID24 mutation by genetic engineering. The homozygous integrants produced more malate during sake brewing and grew more slowly in DMS medium than wild‐type and heterozygous integrants. Thus, the genotype of the VID24 mutation influenced the level of malate production and sensitivity to DMS in diploid yeast. Then a homozygous mutant from a heterozygous mutant was obtained without genetic engineering by ultraviolet irradiation and culturing in DMS with nystatin enrichment. The non‐genetically modified sake yeast with a homozygous VID24 mutation exhibited a higher level of malate productivity than the parent heterozygous mutant strain. These findings provide a basis for controlling malate production in yeast, and thereby regulating malate levels in sake. Copyright © 2016 The Institute of Brewing & Distilling     

不同辛烯基琥珀酸木薯淀粉酯(OSCS)与壳聚糖质量比对OSCS与壳聚糖-ZnO复合薄膜性能的影响

以壳聚糖和辛烯基琥珀酸木薯淀粉酯（OSCS）为主要成膜基质,甘油为增塑剂、纳米ZnO为增强剂,研究不同OSCS/壳聚糖质量比对薄膜的性能变化。首先制备采用石油醚脱脂和碱法提取木薯淀粉,随后将木薯淀粉改性成OSCS。使用溶液共混法制膜,将壳聚糖溶液、OSCS糊化液及纳米ZnO均质混合,然后超声脱气,烘干成膜。分析不同OSCS/壳聚糖质量比对复合膜力学性能、吸水性、水蒸气透过系数和不透明度的影响。当OSCS/壳聚糖的质量比为1:1时,所得膜的力学性能最佳,抗拉强度为13.85 MPa,断裂伸长率为46.57%。吸水性和水蒸气透过系数随着OSCS和壳聚糖的质量比增加呈现上升的趋势,不透明度呈现先下降后上升的趋势,而OSCS/壳聚糖质量比为1.5:1时不透明度最低为1.56 A/mm。红外光谱证明不同OSCS/壳聚糖质量比的薄膜只是通过简单的物理混合,并无新化学键的产生,并且OSCS/壳聚糖的质量比为1:1时,热性能最佳,玻璃态转化温度最高为102.03 ℃。综合研究,OSCS/壳聚糖的质量比为1:1,整体性能较优,为辛烯基琥珀酸淀粉酯与多糖类复合提供理论基础。     

聚乳酸/聚丁二酸丁二醇酯共混物的研究

通过熔融共混制备了聚乳酸(PLA)/聚丁二酸丁二醇酯(PBS)共混物,采用扫描电子显微镜、差示扫描量热仪、旋转流变仪对其相容性、热性能和黏度等进行了研究,并研究了PBS的加入对PLA力学性能的影响。结果表明,PLA和PBS之间是部分相容的,PBS的少量添加并不影响PLA的拉伸强度,且其冲击强度随着PBS含量的增加呈先上升后下降的趋势,当PBS含量为10份时,共混物的冲击强度最好;与纯PLA相比,共混物的黏度有所增加,且随着PBS含量的增加,共混物的黏度逐渐增大;PBS的添加起到异相成核作用,促进了PLA的结晶。     

聚丁二酸丁二醇酯环状二聚物的纯化、表征及其开环聚合的研究

从聚丁二酸丁二醇酯(PBS)的环状低聚物中分离提纯出了PBS的环状二聚物〔cyclic dimer of poly(butylenesuccinate),CDBS〕,采用核磁、质谱对该环状二聚物进行了表征,研究表明,通过分离纯化得到了纯度高的PBS的环状二聚物。以纯化的CDBS为原料、十二醇为初始剂、辛酸锡作催化剂,采用开环聚合的方法合成了PBS,采用核磁、红外光谱对合成的PBS的结构进行了表征,并研究了开环聚合温度、聚合时间以及催化剂用量对PBS的分子量、单体转化率的影响,结果表明,开环反应温度220℃左右,反应3 h,PBS的相对分子质量(简称分子量,下同)可达到63 300,与直接酯化-缩聚法相比,采用开环聚合法能提高PBS的制备效率。     

PBS合成用催化剂的研究概况

选择良好的催化剂对聚丁二酸丁二醇酯(PBS)的合成至关重要.对PBS的各种催化剂进行了归纳和总结,并重点介绍了催化机理,为PBS的催化合成提供了重要的参考.