西兰花酵素在发酵过程中生化指标变化及其抗氧化活性研究

Study on Changes in the Biochemical Indicators and Antioxidant Activity of Broccoli Enzyme during Fermentation

以西兰花作为发酵原料,通过加入酵母菌、乳酸菌、醋酸杆菌复合发酵,研究西兰花酵素发酵过程中生化指标以及抗氧化性变化。其中,以p H值、菌落总数、总糖、乙醇、乳酸和乙酸作为生化指标考察西兰花酵素发酵过程中的变化;通过测定总酚、DPPH自由基清除率、超氧化物歧化酶(SOD)、氧自由基吸收能力(ORAC)作为抗氧化性变化指标。研究表明:在发酵过程中,p H值不断降低,由最初的4.49±0.02降低到3.51±0.03;菌落总数在第3 d最高,为9.03(±0.45)×10~7 CFU/m L;总糖被微生物利用消耗,由213.20±0.12 mg/m L降低到79.24±0.07 mg/m L;最终乙醇、乳酸和乙酸含量分别为28.23±0.06 mg/m L、7.89±0.05 mg/m L和11.66±0.05mg/m L;而抗氧化性指标总酚、DPPH自由基清除率、SOD和ORAC在前7 d处于上升趋势,7 d后趋于稳定。其中,DPPH自由基清除率、ORAC与总酚有正相关性(p<0.01)。相对于实验室自制桑葚酵素,DPPH自由基清除率较高,抗氧化性较好。

Broccoli was used as the raw material for fermentation, and yeast, lactic acid bacteria, and acetic acid bacteria were added to carry out mixed fermentation to study the changes of biochemical indicators and antioxidant activity in broccoli Jiaosu during fermentation. In this study, the changes of biochemical indicators were investigated by monitoring the changes in the p H value, total number of colonies, total amounts of carbohydrate, ethanol, lactic acid, and acetic acid. Further, the antioxidant activity was studied by measuring the total phenol, 2,2-diphenyl-1-picrylhydrazyl（DPPH） radical scavenging rate, superoxide dismutase（SOD） activity, and oxygen radical absorbance capacity（ORAC）. The results showed that during fermentation, the p H value decreased constantly from the original 4.49±0.02 to 3.51±0.03. The highest total number of colonies was observed on the third day, which was 9.03（±0.45）×10~7 CFU/m L. Carbohydrate present in the medium was consumed by the microbes resulting in the reduction of its total concentration from 213.20±0.12 mg/m L to 79.24±0.07 mg/m L. Finally, the contents of ethanol, lactic acid, and acetic acid were 28.23±0.06 mg/m L, 7.89±0.05 mg/m L, and 11.66±0.05 mg/m L, respectively. The total phenolic content, DPPH radical scavenging ability, SOD activity, and ORAC showed an increasing trend during the first seven days and tended to remain stable after day seven. The total phenolic content showed positive correlations with DPPH radical scavenging rate and ORAC（p〈0.01）. Compared with the mulberry enzyme prepared by the laboratory, broccoli enzyme had a higher DPPH radical scavenging rate and better antioxidant activity.