β-环糊精提高乳酸菌发酵大麦粉提取物的抗氧化及结构稳定性研究

李明松; 董英; 张家艳; 赵延胜

doi:10.13386/j.issn1002-0306.2017.10.020

β-环糊精提高乳酸菌发酵大麦粉提取物的抗氧化及结构稳定性研究

The improvement of antioxidant and structural stability of fermented barley extract with Lactobacillus plantarum with β-cyclodextrin

摘要

摘要: 本文研究β-环糊精（β-cyclodextrin,BC）对植物乳杆菌发酵大麦粉提取物（fermented barley extract of Lactobacillus plantarum,LFBE）的抗氧化及结构稳定性的增强作用,以期制备具有预期生物活性的较稳定LFBE。采用冷冻干燥法制备BC与LFBE包埋物（fermented barley extract of Lactobacillus plantarum embedding with BC,BLFBE）冻干粉,借助扫描电镜和X-射线衍射技术研究其微观结构。抗氧化活性实验结果表明,LFBE在常温贮藏12 h后,其多酚化合物含量由（0.30±0.11）mg/m L迅速降至（0.019±0.0023）mg/m L,其DPPH自由基清除率由67.95%±2.16%降至9.16%±0.65%,·OH自由基清除率由72.97%±3.01%下降至11.14%±3.16%;采用1.6%的BC对LFBE进行包埋处理后,BLFBE内多酚化合物含量由（0.25±0.015）mg/m L仅降至（0.21±0.01）mg/m L,其DPPH自由基清除率由52%±2.01%则仅降至45%±2.43%,·OH自由基清除率由67.16%±1.31%仅降至54.74%±2.53%。LFBE色度检测结果表明,BC包埋作用能显著抑制LFBE的L*值在常温24 h内的快速下降,使其在冷冻干燥前保持稳定色泽。扫描电镜图显示,LFBE冻干粉为不规则片状结构,而经BC包埋后变为易分散的类球状结构;X-射线衍射结果发现LFBE冻干粉为非晶型、不定型结构,经BC包埋的BLFBE冻干粉出现晶体结构。因此,采用BC直接包埋LFBE,可有效抑制LFBE抗氧化活性下降与褐变,并增加BLFBE冻干粉的结构稳定性。

Abstract: β-cyclodextrin ( BC) was used to improve the antioxidantand microstructure stability of fermented barley extract with Lactobacillus plantarum ( LFBE) in order to keep bioactivity of LFBE. LFBE was embedded with BC ( BLFBE) and dried with freed-dried method.X-ray diffraction and scanning electron microscope technologies were used to analyze microstructure of BLFBE.The results of antioxidant experiments showed that polyphenol content in LFBE decreased from ( 0.30 ± 0.11) mg/m L to ( 0.019 ± 0.0023) mg/m L, its DPPH clearance reduced from 67.95% ± 2.16% to 9.16% ± 0.65%, and its ·OH clearance decreased from 72.97% ± 3.01% to 11.14% ± 3.16% after storing 12 h at normal temperature. After LFBE embedded with1.6 mg/m L BC, polyphenol content of BLFBE merely decreased from ( 0.25 ± 0.015) mg/m L to ( 0.21 ± 0.01) mg/m L, its DPPH clearance only reduced from 52% ± 2.01% to 45% ± 2.43%, and its ·OH clearance only decreased from 67.16% ± 1.31% to54.74% ± 2.53%.The results of chroma experiments indicated that BC inhibited the browning of LFBE.The results of scanning electron microscope showed that LFBE was irregular sheet structure, but appeared near-spherical structure after embedded with BC.X-ray diffraction experiment indicated that LFBE powder was armorphous and shapeless structure, but BLFBE appeared crystal structure after embedded with BC.Therefore, BC significantly inhibited the descent on antioxidant activity of LFBE, and embedding function of BC also improved structural stability of BLFBE.