苦荞芽苗黄酮微胶囊的制备及其性质分析

Preparation and Property Analysis of Flavonoids Microcapsules from Tartary Buckwheat Sprout

为提高苦荞芽苗黄酮的稳定性及生物利用率,以卡拉胶+变性淀粉、阿拉伯胶(gum arabic,GA)+变性淀粉、麦芽糊精(maltodextrin,MD)+变性淀粉+明胶为壁材,采用喷雾干燥法制备三种苦荞芽苗黄酮微胶囊,并对微胶囊的水分含量、休止角、吸湿性和抗氧化特性等理化指标及微观形态、粒径等性能进行综合分析。结果表明,卡拉胶+变性淀粉制备的微胶囊水分含量(6.58%)较低,堆积密度较大,休止角较小(13.20°),流动性较好,吸湿性变化慢,DPPH自由基和ABTS阳离子自由基的清除能力高,抗氧化能力更强,表面形态饱满,呈球形,粒径均一度较高。GA+变性淀粉、MD+变性淀粉+明胶制备的微胶囊包埋率较高依次为82.21%、82.72%,相较于卡拉胶+变性淀粉,这两种微胶囊抗氧化能力较低,吸湿稳定性较差,颗粒表面有较大孔洞且粒径均一度低。傅里叶变换红外光谱分析表明三种微胶囊都含有黄酮的特征吸收峰。三种微胶囊在模拟肠液中释放性能优于在模拟胃液中,这有利于芯材在肠道中释放并发挥抗氧化作用。综合分析可知,卡拉胶+变性淀粉是制备苦荞芽苗提取物微胶囊较为理想的壁材。该研究有助于促进苦荞芽苗提取物的微胶囊化及在功能性食品领域的应用。

To improve the stability and bioavailability of tartary buckwheat sprout flavanoids,microcapsules containing tartary buckwheat sprout flavanoids(TBSF)were prepared according to spray drying process using carrageenan+modified starch,gum arabic(GA)+modified starch,maltodextrin(MD)+modified starch+gelatin as the wall materials.The structure and antioxidant activity of TBSF microcapsules were analyzed by measuring the water content,repose angle,hygroscopicity,DPPH and ABTS+free radical scavenging capacity of microcapsules.The results indicated that the microcapsule prepared from carrageenan+modified starch showed best performance,which possessed lowest water content(6.58%),largest bulk density and smallest repose angle(13.20°),best fluidity,slowest hygroscopicity change,highest scavenging capacity of DPPH and ABTS+free radicals,as well as highest uniformity with full and spherical surface.The embedding rate of GA+modified starch and MD+modified starch+gelatin microcapsules were 82.21%and 82.72%,respectively.Compared to carrageenan+modified starch,these two kinds of microcapsules displayed relative low antioxidant capacity,poor moisture absorption stability,large pores on the particle surface and worse uniformity.The fourier transform infrared spectroscopy analysis showed that three kinds of microcapsules contained characteristic absorption peaks of flavonoids.The release performance of three kinds of microcapsules in simulated intestinal fluid were all better than in simulated gastric juice,implied that the core materials(flavanoids)in microcapsules were mainly conducive to be released in the intestine and functioned as antioxidants.Totally,carrageenan+modified starch was an ideal wall material for production of TBSF microcapsules.Results would be helpful to promote the microencapsulation of tartary buckwheat sprout flavanoids and its application in the field of functional food.