蓝莓多酚微胶囊的制备及体外消化特性研究

Preparation and in vitro digestibility of blueberry polyphenols microcapsules

【目的】旨在研究蓝莓多酚的提取纯化及微胶囊制备工艺,为研发具有缓释功能的蓝莓多酚微胶囊提供科学依据。【方法】以酶解渣汁分离后的蓝莓皮渣为试验材料,通过比较不同提取方法和不同大孔树脂在蓝莓多酚纯化上的作用,确定蓝莓多酚的提取纯化工艺,在此基础上通过均质和冷冻干燥的方法制备蓝莓多酚微胶囊,以包埋效率为主要指标,结合颜色和结构表征明确蓝莓多酚微胶囊的最佳制备工艺,并进一步分析微胶囊的体外胃肠消化特性。【结果】(1)分别比较园蓝、巴尔德温和寨选4号3个品种蓝莓果渣和果汁提取物,发现果渣提取物的总多酚含量均高于果汁提取物,寨选4号最高达2倍以上;(2)通过比较10种大孔树脂对蓝莓多酚吸附和解吸附的性能,优选出HPD-300、HPD-100B和HPD-1003种树脂,并比较不同乙醇体积分数对蓝莓多酚的解吸附效率,确定选用80%的乙醇溶液对蓝莓多酚进行解吸附;(3)选择HPD-100B大孔树脂进行提取和纯化的扩大试验,获得纯度达71.4%的蓝莓多酚提取物;(4)在此基础上比较麦芽糊精、大豆蛋白和乳清蛋白3种壁材对蓝莓多酚的包埋率,发现大豆蛋白的包埋率最高,并且复配阿拉伯胶能够进一步提高多酚的包埋率;(5)通过色差的比较发现,相比多酚提取物,微胶囊产品的L*降低,a*、b*升高,即微胶囊的明度降低,红色增强,蓝色减弱;(6)扫描电镜结果显示与片层结构的多酚提取物相比,微胶囊呈现交联状的圆球形;(7)体外消化试验发现,多酚提取物在胃液和肠液中的释放率均达到99.8%,而多酚微胶囊在胃液和肠液中的释放率分别为65.77%和74.31%。【结论】蓝莓多酚的最优制备工艺为蓝莓皮渣粗提物水液上样HPD-100B、HPD-300或HPD-100大孔树脂,5倍柱体积的水冲洗,80%的乙醇收集蓝莓多酚,且经减压浓缩和冷冻干燥制备得到蓝莓多酚提取物,纯度达71.4%。蓝莓多酚微胶囊的最优制备工艺为阿拉伯胶与大豆蛋白比例为3∶7,壁材溶液质量分数10%,芯壁比1∶5,芯壁混合液pH 2.0,4000 r/min均质10 min,冷冻干燥。所制备的蓝莓多酚大豆蛋白+阿拉伯胶微胶囊的包埋率97.6%,颜色为带有红、蓝色调的低明度粉末,结构为交联状的圆球形,具有一定的缓释特性。

[Objective]This study aims to study the extraction and purification of blueberry polyphenols and the preparation process of microcapsules,so as to provide scientific basis for the development of blueberry polyphenol microcapsules with sustained release function.[Method]The blueberry pomace separated from enzymolysis residue juice was used as the experimental material.The extraction and purification process of blueberry polyphenols was determined by comparing the effects of different extraction methods and different macroporous resins on the purification of blueberry polyphenols.On this basis,the blueberry polyphenols microcapsules were prepared by homogenization and freeze-drying.The embedding efficiency was taken as the main index,and the optimal preparation process of blueberry polyphenols microcapsules was determined by combining color and structure characterization,the in vitro gastrointestinal digestion characteristics of microcapsules were further analyzed.[Result](1)By comparing the fruit pomace and juice extracts of three blueberry cultivars,Gardenblue,Baldwin and Zhaixuan 4,the results showed that the total polyphenol contents of the fruit pomace extracts were higher than that of the juice extracts,with the highest being more than twice(Zhai Xuan 4).(2)The three macroporous resins HPD-300,HPD-100B and HPD-100 were selected by comparing adsorption and desorption capacities of 10 macroporous resins.(3)HPD-100B macroporous resin was selected to enlarge the extraction and purification experiment,and the blueberry polyphenol extract with purity of 71.4%was obtained.(4)On this basis,the embedment rate of blueberry polyphenols in the three wall materials of maltodextrin,soy protein and whey protein was investigated.It was found that the embedment rate of polyphenols in the soybean protein was the highest,and the compound of arabic gum could further improve the embedment rate of polyphenols.(5)Through the comparison of color differences,it was found that compared with the polyphenol extracts,the L*of microcapsule products decreased,while a*and b*increased,indicating a decrease in the brightness and blue color of microcapsules,and an increase in red color.(6)The results of scanning electron microscopy showed that compared with the polyphenol extract with lamellar structure,the microcapsules presented cross-linked spherical shape.In vitro digestion experiments showed that the release rate of polyphenol extract in gastric fluid and intestinal fluid was as high as 99.8%,while the release rate of polyphenol microcapsules in gastric fluid and intestinal fluid were 65.77%and 74.31 respectively.[Conclusion]The optimal preparation process of blueberry polyphenols is HPD-100B,HPD-300 or HPD-100 macroporous resin loaded with aqueous solution of the crude extract of blueberry residue,washed with 5 times bed volume of water to remove impurities such as sugars and acids,and then collected with 80%ethanol and concentrated under reduced pressure and freeze-drying to obtain blueberry polyphenols extract with the purity of 71.4%.The optimal preparation process of blueberry polyphenol microcapsules was using soybean protein and arabic gum as the optimal wall material whose solution concentration was 10%,and the soybean protein and arabic gum ratio was 3∶7.The core-wall ratio was 1∶5 and the pH of the core-wall mixture was 2.0.After homogenizing at 4000 r/min for 10min and freeze-drying,the embedding rate of the prepared microcapsule attained 97.6%.The color of the microcapsule was low brightness with red and blue tones,the structure is crosslinked spherical,and the microcapsule has certain slow-release characteristic.