发酵对几种谷物提取物总酚及抗氧化活性的影响

目的：研究发酵对谷物提取物抗氧化活性的影响。方法：采用德氏乳杆菌和啤酒酵母菌分别对小米、燕麦、黑米、高粱米4 种谷物进行发酵，福林-酚法测定未发酵及发酵后谷物乙醇提取物总酚含量、1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-（2,4,6-trinitrophenyl）hydrazyl，DPPH）法测定清除自由基能力、铁还原抗氧化能力（ferric reducing-antioxidant power，FRAP）法测定还原能力、硫代巴比妥酸（thiobarbituric acid，TBA）法测定脂质过氧化抑制能力。结果：4 种谷物提取物具有显著的清除自由基能力、铁离子还原能力、抑制脂质过氧化能力和较高的总酚含量；经两种微生物发酵后谷物提取物总酚含量增加，具有更高抗氧化活性；其中德氏乳杆菌发酵对总酚含量及抗氧化能力影响均显著（P＜0.05）；啤酒酵母发酵对总酚含量影响显著（P＜0.05），但对抗氧化能力影响不显著（P＞0.05）。结论：微生物发酵可提高谷物的总酚含量及抗氧化活性，但提高的程度与发酵采用的微生物种类有关。

Effect of Fermentation on Total Polyphenol Content and Antioxidant Activity of Cereal Extract

The objective of this work was to assay the influence of different fermentation types (yeast fermentation and lactic
acid fermentation) on antioxidant activity and total polyphenol content in selected cereals. After fermented by Lactobacillus
delbrueckii, Saccharomyces cerevisiae or nothing, the cereals were extracted by ethanol. The content of total polyphenols
in extracts was determined by the Folin-Ciocalteu method, and the antioxidant activity was measured by 1,1-diphenyl-2-
picrylhydrazyl (DPPH) radical scavenging assay, ferric reducing-antioxidant power (FRAP) method and thiobarbituric acid
(TBA) test. This study indicated that four cereals used widely for human consumption exhibited significant levels of free
radical scavenging activity, ferric-reducing power, inhibitory activity against lipid peroxidation and total polyphenol content.
These factors suggested that cereal-based foods alone could contain important dietary antioxidants, but further research is
needed to determine whether or not these dietary antioxidants could be beneficial to human health. The total polyphenol
content (TPC) increased upon fermentation. The presence of these microorganisms was more or less important for enhanced
levels of antioxidant activity. Thus fermentation offers a tool to further increase the bioactive potential of cereal products.
In conclusion, it seems advantageous to select microorganism starter culture for the fermentation of cereals based on their
positive correlation with total antioxidant capacity.