微波改性对燕麦麸膳食纤维结构及功能性质的影响

Effects of Microwave Modification on the Structure and Functional Properties ofOat Bran Dietary Fiber

以燕麦麸皮为原材料,利用微波对燕麦麸膳食纤维(OBDF)进行改性处理。借助扫描电镜(SEM)、X-射线衍射(XRD)及傅里叶红外图谱(FT-IR)研究改性前、后OBDF的结构。测定吸附性能、溶解性能以及对DPPH·和羟自由基清除能力,研究改性前、后OBDF功能性质的变化。扫描电镜结果显示,改性OBDF呈现多孔隙网络结构,比表面积增大,微观结构发生明显改变。X-射线衍射结果显示,改性OBDF晶体结构仍保持原有纤维素Ⅰ型结构,结晶区域增大。红外图谱结果显示改性前、后OBDF红外图谱特征吸收峰的整体峰型、位置并未发生明显改变,而强度减弱。吸附性能测定结果显示,改性后OBDF及可溶性膳食纤维(SDF)对胆固醇(pH 7.0条件下)、亚硝酸钠、葡萄糖、油的吸附能力明显高于改性前(P<0.05)。溶解性能测定结果显示,温度和pH值对膳食纤维溶解度影响较大,其中改性OBDF在70℃、模拟人体胃中环境(pH 2.0)条件下,溶解度达(0.14±0.02)g/mL。改性后OBDF对DPPH·和羟自由基呈现较好的清除能力,其中改性OBDF和改性SDF对羟自由基的清除能力最高达49.8%,62.1%。

Oat bran was used as the raw material,the modified Oat bran dietary fiber(OBDF)was processed by microwave method.The structure of OBDF before and after modification was studied by scanning electron microscopy(SEM),X-ray diffraction(XRD)and fourier transform infrared spectra(FT-IR).The functional properties changes were measurement by adsorption,solution,as well as scavenging ability of DPPH·free radical and hydroxyl radical.The results of SEM showed that modified OBDF appeared porous network structure,specific surface increased and microstructure were obvious changed.X-ray diffraction results showed that the modified OBDF crystal structure retained the original cellulose typeⅠstructure,crystalline domain of OBDF after modification increased.FT-IR results showed that the characteristic absorption peak in the infrared spectrum was not changed significantly,but the intensity was decreased.The results of absorbent abilities showed that the modified OBDF and soluble dietary fiber(SDF)on cholesterol(under the condition of pH 7.0),sodium nitrite,glucose,and oil were significantly increased than before modification(P<0.05).The results of solubility showed that temperature and pH had great influence on the solubility of dietary fiber,under the condition of 70℃and simulated stomach environment of human(pH 2.0),the solubility of OBDF was reached to(0.14±0.02)g/mL.The modified OBDF showed better scavenging ability for DPPH·free radical and hydroxyl radical,and the scavenging ability of modified OBDF and SDF on hydroxyl radical reached up to 49.8%and 62.1%respectively.