【作者】 张颖；

【导师】 姚卫蓉；

【作者基本信息】 江南大学 ， 营养与食品卫生学， 2015， 硕士

【摘要】 抗性糊精作为水溶性膳食纤维产品一种,主要应用在饮料、酸奶等领域。国家标准规定抗性糊精纯度为82%以上,但是将这个纯度的产品应用到透明清亮型饮料中就会影响品质;针对糖尿病人群时,其残存的葡萄糖也是一个主要限制因素。因此,本论文针对抗性糊精的生产,研究其进一步纯化工艺,并拓展应用在黄酒和葡萄酒中,初步探索其提高黏度和降低表面张力的原因,为其推广应用提供基础支撑。首先,以玉米淀粉为原料经过高温酸解干燥得到焦糊精,再用淀粉内切和外切酶酶解,得到焦糊精酶解液(葡萄糖含量456.28g/L)。研究了酵母发酵对焦糊精酶解液的进一步纯化效果,通过筛选酵母品种,发现国光高活性干酵母具有较好的葡萄糖利用能力,发酵24h可将葡萄糖含量降至50.77g/L,再选用低糖型酵母进行二次发酵,葡萄糖含量仅下降到39.18 g/L,而采用78%酒精沉淀法,剩余葡萄糖的去除效果更好;接着详细研究了全程采用溶剂沉淀法的纯化效果,发现酒精的沉淀效果优于丙酮;纯化前将焦糊精酶解液浓缩(控制比重在1.16 g/ml左右),先用4倍体积比的95%酒精沉淀,沉淀物再用1倍体积比的78%酒精连续沉淀洗涤6次,可得到纯度为95.30%的抗性糊精,得率为40.32%。其次,通过排阻液相色谱测定得到该抗性糊精重均分子量为8607Da,差示扫描量热仪(DSC)研究表明该产品中淀粉结构已不复存在,其热稳定性高;红外光谱显示该物质主要由糖类官能团组成;溶解在纯水中能显著降低其表面张力,并保持纯水原有流变性能;添加到黄酒和红葡萄酒中,能显著降低表面张力,提高溶液的稳定性;与同类产品聚葡萄糖相比,在改善黄酒和红葡萄酒的表面张力、流变性能方面,均没有显著性差异(p<0.05);以模糊综合评判法进行感官评定,发现加入5%(w/v)抗性糊精的黄酒和红葡萄酒感官品质均明显提高;进一步分析添加该抗性糊精的黄酒和红葡萄酒的溶液体系,其黏度和表面张力数值之间具有显著的负相关。但将该抗性糊精添加到白葡萄酒中时,其表面张力并没有显著下降;与黄酒、红葡萄酒相比,白葡萄酒中的多酚化合物含量明显偏低;本研究特别地将多酚化合物结合到抗性糊精上,形成了抗性糊精-多酚化合物混合物;再将该混合物添加到黄酒、红葡萄酒中,发现酒液黏度和表面张力不再显著变化(p<0.05),说明该混合物不再具有改善酒液品质的功能,猜测抗性糊精可能是通过结合多酚而使酒液的表面张力下降、黏度升高。本研究结果不仅为抗性糊精的进一步纯化提供了一个可借鉴的工艺,并为进一步拓展其应用提供了新的思路。更多还原

【Abstract】 The resistant dextrin is a kind of soluble dietary fiber products, mainly applied in beverage and yoghurt. The purity of resistant dextrin should reach 82% in accordance with the national standards, but its application in clear drinks is restricted. In addition, the remaining glucose is also a major limiting factor for the food of the diabetic population.This paper mainly studied the preparation of resistant dextrin with high purity,analyzedits characteristics,and then applied it in Rice Wine and Wine, which was expected to provide the foundation for its popularization and application.Firstly,the corn starch was acidhydrolyzed and enzymolyzed by amylase and glucoamylase to get enzymatic hydrolysate(glucose content was 456.28g/L).The yeast fermentation on enzymatic hydrolysate was studied to further purification, it was found that Guoguang high active dry yeast has good capability of glucose utilization through screening yeast species. Fermentation for 24 h, the glucose content was reduced to 50.77g/L, then another low sugar yeast was used to second fermentation, the glucose content was only decreased to 39.18g/L, while the removal effect of residual glucose was better by 78% alcohol precipitation method. The purification effect of solvent precipitation method was studied, it was revealed that the precipitation effect of alcohol was better than that of acetone. The enzymatic hydrolysate should be concentrated before purification(control proportion of about 1.16g/m L), then precipitated with 95% ethanol of 4 times volume ratio, and washed with 78% ethanol for 6 times, and the production of resistant dextrinwith the purity of95.30%was obtained and the yield was 40.32%.Secondly,the conventional ingrediants,molecular weight distribution and thermal properties was studied,the results showed the high thermal stability and the heavy molecular weight was 8607 Da,the structure of corn starch was not exist. Infrared spectroscopyshowed it was polysaccharide. The surface tension of pure water,rice wine and red winecould be decreased by adding the resistant dextrin and the rheological property keep constant. Compared with the other soluble dietary fiber products–polydextrose, the resistant dextrin showed no significant difference both in decreasing the surface tension and keeping the rheological property(p<0.05). And the result of sensory evaluation showed that the organoleptic quality of new rice wine and red wine by adding 5%(w/v)resistant dextrin wereimproved by fuzzy comprehensive evaluation method. There was significant negative correlation between viscosity and surface tension in rice wine and red wine.The surface tension was not decreased significantly when the resistant dextrin was added to white wine. By compared the contents of polyphenol compound in rice wine, red wine and white wine, it was revealed that the level of polyphenol compounds in white wine was very low. Designing the experiment of resistant dextrin combined with polyphenol compounds, then compared the antioxidant capacity of resistant dextrin before and after combined with polyphenol compounds. It was confirmed that the polyphenol compounds was indeed bound to resistant dextrin to formed resistant dextrin-polyphenol compounds mixture; further, the mixture was added to rice wine and red wine, the viscosity and surface tension did not changemarkedly(p<0.05).It was explained that the mixture was no longer improving the quality of wine. Therefore, it can be guessed that resistant dextrin may be combined with polyphenol compounds to decrease the surface tension and increase the viscosity.These results not only apply a new technology for production of high purity resistant dextrin, but also give some idea for its application.更多还原