摘要
在前期干果品质分析时,发现部分干果的抗氧化能力异常,推测可能与二氧化硫有关。因此,该文采用了二苯代苦味酰基自由基(1,1-Diphenyl-2-picrylhydrazyl,DPPH)、2,2-联氮-(3-乙基苯并噻唑啉-6-磺酸)二氨盐自由基[2,2-diamine-(3-ethyl benzothiazolin-6-sulfonic acid)diammonate,ABTS]、铁离子还原能力(ferric reducing antioxidant power,FRAP)和氧自由基清除能力(oxygen radical absorbance capacity,ORAC)4种方法分析二氧化硫的抗氧化能力,同时测定8种新疆常见干果的二氧化硫含量。试验结果:在试验浓度范围内,二氧化硫具有一定抗氧化能力,1 mg二氧化硫相当于1μmol~2μmol 6-羟基-2,5,7,8-四甲基色烷-2-羧酸(6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid,Trolox)的抗氧化能力。此外,二氧化硫浓度与抗氧化能力呈线性相关,其中ORAC法的抗氧化能力最好(R~2=0.998 4);在8种干果中,黄提、枸杞、吊干杏、大无花果和小无花果中检出二氧化硫,其中,黄提(1.45 g/kg DW)和枸杞(0.18 g/kg)二氧化硫超过国家限量标准。这说明二氧化硫可能是导致部分干果抗氧化能力异常高的主要原因,因此在样品分析时,应考虑二氧化硫对样品指标的影响。
The antioxidant activities of dried fruits are abnormal in previous experiments,which might be due to the existence of sulfur dioxide. Therefore,the antioxidant activities of sulfur dioxide were analyzed by using1,1-Diphenyl-2-picrylhydrazyl(DPPH),ferric reducing antioxidant power(FARP),2,2-diamine-(3-ethyl benzothiazolin-6-sulfonic acid) diammonate(ABTS) and oxygen radical absorbance capacity(ORAC)assays,and the sulfur dioxide contents of 8 kinds of dried fruits were analyzed in this paper. The experiment results showed that sulfur dioxide exhibits some antioxidant ability,and the antioxidant ability of1 mg sulfur dioxide is equal to that of 1 μmol Trolox-2 μmol Trolox. Additionally,there a linear correlation between sulfur dioxide concentration and antioxidant activity,and the ORAC showed the best results of antioxidant activity(R~2=0.998 4).Among the eight kinds of dried fruits,sulfur dioxide was detected in yellow raisin,wolfberry,apricot,big fig and small fig. The sulfur dioxide contents of yellow raisin and wolfberry are1.45 g/kg DW and 0.18 g/kg DW,respectively,which are out of the national standard limit of sulfur dioxide in dried fruit. This suggests that sulfur dioxide might be one of reasons for resulted in abnormalities of antioxidant activities of some dried fruits. Therefore,the effects of sulfur dioxide should be taken into account,when samples are analyzed.
引文
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