富硒香菇多糖发酵工艺的优化及其抗氧化活性

Optimization of Fermentation Process and Antioxidant Activity of Polysaccharide from Se-enriched Lentinula edodes

本试验利用香菇作为载体,Na2Se O3为添加的硒源,优化富硒香菇多糖的发酵条件并研究其抗氧化活性。采用单因素试验考察了培养基p H、硒灭菌方式、硒添加时间、硒添加量和发酵时间对富硒香菇多糖的影响,并通过BoxBenhnken实验设计和响应面分析法确定最优发酵条件。在优化条件下得到富硒香菇多糖,并利用DPPH自由基清除能力研究其抗氧活性。结果表明:当培养基p H调至4.16,发酵至第162 h时,向发酵液中添加7.97 mg/L过滤除菌的Na2Se O3溶液,发酵11 d,富硒香菇胞内多糖提取量可达到71.54 mg/100 m L;当培养基p H调至4.01,发酵至第191.5 h时,向培养基中添加6.68 mg/L过滤除菌的Na2Se O3溶液,发酵11 d,富硒香菇胞外多糖提取量可达到853.96 mg/100 m L。DPPH自由基清除实验结果表明,抗氧化活性大小依次为富硒香菇胞内多糖>香菇胞内多糖>富硒香菇胞外多糖>香菇胞外多糖。硒的添加不仅促进香菇菌丝的生长及多糖的累积,同时也提高了其抗氧化活性,对DPPH有较好的清除作用。

In this experiment, Lentinula edods （L.edodes） was used as carrier, with Na2 SeO3 as the selenium source, to optimize the fermentation conditions of polysaccharide from Se-enriched L.edodes ant its antioxidant activity was studied.The effects of culture medium pH, sterling condition of selenium, selenium relenishing time, selenium concentration and incubation duration to polysaccharide form Se-enriched L.edodes were investigated by single factor experiment.The process parameters were optimized using a Box-Behnken experimental design coupled with response surface methodology. Polysaccharide from Se-enriched L. edodes was obtained under optimized conditions and its antioxidant activity was discussed by DPPH free radical scavening ability.The results showed that when the culture medium was pH4.16,7.97 mg/L Na2SeO3 was added to the fermentation broth at 162 h, Na：SeO3 solution was sterilized by filtration, the incubation duration was 11 d, the yield of crude intracelluar polysaccharide in Se-enriched L. edodes reached 71.54 mg/100 mL; when the culture medimn pH was 4.01,6.68 mg/L Na2SeO3 was added to the fermentation broth at 191.5 h, Na2SeO3 solution was sterilized by filtration,the incubation duration was 11 d, the yield of crude extracellular polysaccharide in Se-enriched L.edodes reached 853.96 mg/100 mL. The results of DPPH free ladical scavening experiment showed that the antioxidative activities were as follows：intracellular polysaccharides in Se-enriched L. edodes 〉 intracellular polysaccharides in L. edodes 〉 extracellular polysaccharide in Se-enriched L. edodes 〉 extracellular polysaccharide in L.edodes. Se-enriched not only increased the yield of polysaccharide form L.edodes, but also improved the antioxidant activity, better scavenging of the DPPH.