大麦乳酸菌发酵液粉中多酚的提取及其抗氧化性研究

通过单因素和正交实验优化大麦乳酸菌发酵液粉（barley lactobacillus fermented solution,BLFS）中多酚的提取工艺条件,高效液相色谱分析鉴定多酚成分,并对其抗氧化活性进行测定。结果表明:在60%的乙醇浓度,1∶50 g/m L的料液比,60℃提取60 min的最优条件下,BLFS多酚的提取率为（18.09±0.25）mg/g;HPLC分析结果显示,经乳酸菌发酵后大麦多酚中没食子酸、香豆酸、阿魏酸和芦丁的含量显著增加（p<0.05）,香草酸和对香豆酸的含量显著减少（p<0.05）,BLFS多酚的主要成分为芦丁35.08μg/g,香草酸21.28μg/g,阿魏酸19.38μg/g,香豆酸11.36μg/g,没食子酸6.80μg/g,原儿茶酸2.99μg/g,对香豆酸0.83μg/g。BLFS多酚提取物和大麦多酚提取物清除羟自由基、1,1-二苯基-2-苦基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基和还原能力的半数有效质量浓度（EC50）分别为0.66和0.87、0.88和0.96、0.76和0.89 mg/m L,具有良好的体外抗氧化活性。BLFS多酚提取物的抗氧化活性均高于大麦多酚提取物,说明经乳酸菌发酵后大麦的抗氧化活性增加。 

Extraction and antioxidant activity of polyphenols from barley lactobacillus fermented solution

Single factor experiment and an orthogonal array design were used in combination to optimize the extraction conditions of polyphenols from barley Lactobacillus fermented solution ( BLFS) . High performance liquid chromatography ( HPLC) was employed to identify the chemical composition of polyphenols.Antioxidant activities of the extracted polyphenols were also measured in this study.The results showed that under the optimum conditions: ethanol concentration 60%, solid-toliquid ratio 1∶ 50 g/m L, extraction temperature 60 ℃, and extraction time 60 min, the extraction yield of BLFS polyphenols was ( 18.09 ± 0.25) mg/g.The results of chromatograph analysis with HPLC showed significant increase of gallic acid, coumaric acid, ferulic acid and rutin contents in barley after lactobacillus fermentation ( p < 0.05) . On the contray, vanillic acid and p-coumaric acid contents reduced dramatically ( p < 0.05) . In BLFS polyphenols, main components including rutin, vanillic acid, ferulic acid, coumaric acid, gallic acid, protocatechuic acid and p-coumaric acid, their contents were 35.08, 21.28, 19.38, 11.36, 6.80, 2.99 μg/g and 0.83 μg/g respectively. The polyphenols extraction from BLFS and barley displayed excellent antioxidant activities with half maximal effective concentration ( EC50) values of 0.66 and 0.87, 0.88 and 0.96, 0.76 and0.89 mg/m L for scavenging hydroxyl, DPPH radicals and reducing capacity, respectively. Antioxidant activities of BLFS polyphenols extraction were higher than these of barley polyphenols extraction, showed that barley increased antioxidant activity by Lactobacillus Fermentation.