不同处理对糙米发芽后酚类含量及其抗氧化活性影响

Effects of Different Treatments on Phenolic Content and Antioxidant Activities of Brown Rice by Germination

为研究糙米发芽后不同处理方式对其中酚类物质及体外抗氧化活性的影响,在对同一稻谷品种的精米、糙米、发芽糙米3个样品中游离酚、结合酚及其1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力、亚铁还原能力(ferric ion reducing antioxidant power,FRAP)和氧化自由基吸收能力(oxygen radical absorbance capacity,ORAC)分析基础上,以常温25℃匀浆处理方式为对照分别考察热风干燥、真空干燥对样品中游离酚、结合酚及其DPPH自由基清除能力、FRAP和ORAC变化情况。结果表明,精米、糙米、发芽糙米中游离酚、结合酚及DPPH自由基清除能力、FRAP、ORAC均有显著性差异(P<0.05),其中经过热风干燥后的发芽糙米相较糙米的游离酚、结合酚增加了27.28、10.24 mg GAE/100 g DW,游离酚和结合酚的DPPH自由基清除能力、FRAP、ORAC也显著增加(P<0.05);而热风干燥、真空干燥组之间的游离酚、结合酚及其对应的DPPH自由基清除能力、FRAP、ORAC之间无显著性差异(P>0.05),但相较于常温25℃匀浆处理方式,热风干燥、真空干燥组中的游离酚、结合酚及其对应的DPPH自由基清除能力、FRAP、ORAC显著降低(P<0.05)。

The effects of different treatments on the phenolic and their antioxidants activities in vitro were stud-ied in the germinant brown rice.Using room temperature(25℃)homogenized samples as controls,the effects of hot air drying and vacuum drying on the content of free or bound phenolic,and their 1,1-diphenyl-2-nitro-phenylhydrazine(DPPH)free radical scavenging capacity,ferrous iron reduction capacity(FRAP)and oxida-tive free radical absorption capacity(ORAC)were investigated,relative to the DPPH,FRAP and ORAC activ-ities of untreated white rice,brown rice,or geminated brown rice obtained from the same rice variants as the treated samples.The results showed that there were significant differences in free and bound phenolic content,DPPH,FRAP,and ORAC in white rice,brown rice,and germinated brown rice(P<0.05),and the amount of free and bound phenolic in germinated brown rice was increased by hot air drying by 27.28,10.24 mg GAE/100 g DW.Compared to brown rice,the DPPH,FRAP and ORAC of free and bound phenolic were also significantly increased by germination(P<0.05).There were no significant difference in free and bound pheno-lic and their DPPH,FRAP and ORAC between hot air dried and vacuum dried groups(P>0.05).Nevertheless,free and bound phenolic and their DPPH,FRAP and ORAC were significantly reduced by hot air drying and vacuum drying compared to samples homogenized at room temperature(25℃)(P<0.05).