改性处理对牛蒡根膳食纤维结构和功能特性的影响

Effects of Modification on the Structure and Functional Properties of Dietary Fiber in Burdock Root

本研究旨在通过超声联合过氧化氢改性处理牛蒡根膳食纤维,期望实现其水合特性及功能特性的双向提升。以牛蒡根膳食纤维为研究对象,分别采用超声、碱性过氧化氢、超声-碱性过氧化氢、碱性过氧化氢-超声的方式对其进行改性处理,探究不同改性方法对牛蒡根膳食纤维结构和功能特性的影响。结果表明,通过功率200 W、时间10 min的超声条件与pH11、5%体积分数的过氧化氢处理牛蒡根膳食纤维的膨胀力和持水力均显著(P<0.05)提高,其中碱性过氧化氢-超声处理后效果最佳;粒径分布、扫描电子显微镜分析结果表明,经过碱性过氧化氢-超声处理后的膳食纤维粒径最小,表面结构疏松多孔;X射线衍射、傅里叶变换红外光谱分析表明,碱性过氧化氢-超声的膳食纤维相对结晶度最低,部分纤维素组分重新分布,向可溶性膳食纤维转化;热重分析表明,碱性过氧化氢-超声处理的膳食纤维热稳定性得到改善;体外抗氧化、α-淀粉酶与α-葡萄糖苷酶抑制实验表明,改性前后的膳食纤维均具有较强的抗氧化能力和糖消化酶抑制能力,其中碱性过氧化氢-超声处理的膳食纤维对DPPH、ABTS+自由基清除能力最强,半数抑制浓度(Median Inhibition Concentration,IC_(50))分别为1.07和0.89 mg/mL;对α-淀粉酶与α-葡萄糖苷酶的抑制作用最佳,其IC_(50)分别为2.00和1.32 mg/mL。综上所述,碱性过氧化氢-超声改性是提升牛蒡根膳食纤维水合特性及功能特性的优良方法,可为牛蒡根膳食纤维理化特性的精准利用及功能食品研发提供理论依据。

To improve the hydration and functional properties of dietary fiber from burdock root by ultrasonic treatment combined with hydrogen peroxide modification.The dietary fiber from burdock root was modified by ultrasonic,alkaline hydrogen peroxide,ultrasound-alkaline hydrogen peroxide and alkaline hydrogen peroxide-ultrasonic methods,which was aim to explore the effects of different methods of modification on the structure and functional properties.The results showed that the expansibility and water-holding capacity of dietary fiber from burdock root were significantly(P<0.05)improved by ultrasonic condition associated with 200 W,10 min and 5%v/v of hydrogen peroxide with pH value of 11.Among them,the alkaline hydrogen peroxide-ultrasonic treatment had the best effect.The particle size data and scanning electron microscope showed that the particle size of dietary fiber was the smallest,and the surface structure was loose and porous after alkaline hydrogen peroxide-ultrasonic treatment.X-ray diffraction and fourier transform infrared spectroscopy showed that dietary fiber modified with alkaline hydrogen peroxidation-ultrasonic treatment had the lowest relative crystallinity,and components of cellulose were redistributed and converted to soluble dietary fiber.Thermogravimetric analysis showed that the thermal stability of dietary fiber treated with alkaline hydrogen peroxide and ultrasound was improved.In vitro antioxidant,α-amylase andα-glucosidase inhibition experiments showed that dietary fiber had strong antioxidant and glucose-digesting enzyme inhibition ability before and after modification,and dietary fiber with the alkaline hydrogen peroxidation-ultrasonic treatment had the strongest cationic free radical scavenging ability on DPPH and ABTS+.The half maximal inhibitory concentration of which were 1.07 and 0.89 mg/mL,respectively.The inhibition ofα-amylase andα-glucosidase was the best by it,and the half maximal inhibitory concentration was 2.00 and 1.32 mg/mL,respectively.In summary,alkaline hydrogen peroxide-ultrasonic treatment was an excellent method to improve the hydration and functional properties of burdock root dietary fiber,which would provide a theoretical basis for the precise utilization of physicochemical properties of dietary fiber from burdock root and the research of functional foods.