番茄果胶和半纤维素抗氧化活性分析

Analysis of antioxidant activity of pectin and hemicellulose extracted from tomato fruit

为了探究番茄细胞壁中不同类型果胶和半纤维素的抗氧化活性,利用水、EDTA、Na2CO3、4%KOH和24%KOH溶液分步提取,得到水溶性果胶(WSP)、离子结合型果胶(CSP)、共价结合型果胶(SSP)、松散结合型半纤维素(LH)和紧密结合型半纤维素(TH)五种组分,对各组分进行了氧自由基吸收能力(ORAC)、DPPH自由基(DPPH·)清除能力、ABTS自由基(ABTS+·)清除能力和铁离子还原能力(FRAP)的分析。结果表明,番茄WSP含量显著高于CSP和SSP,为1.05 mg Gal UA/g FW,TH含量显著高于LH(p<0.05),为0.09 mg Glu/g FW。番茄不同类型果胶和半纤维素均具有一定的抗氧化活性。其中,CSP的ORAC、DPPH·清除能力和ABTS+·清除能力较强,综合抗氧化活性较高。在5 mg/m L时,CSP的ORAC值相当于76.4μmol/L Trolox,DPPH·和ABTS+·的清除率分别达到61.0%和99.8%。而SSP、LH和TH具有较强的FRAP。相关性分析表明各组分与抗氧化活性密切相关。研究结果为番茄的综合加工利用和作为功能性食品添加成分的开发提供了理论根据。

Water- soluble pectin （ WSP ）, chelate - soluble pectin （ CSP ）, sodium carbonate - soluble pectin （ SSP ）, loose - bonding hemicellulose （LH）and tight-bonding hemicellulose （TH）were extracted from tomato fruit cell wall with water, EDTA, Na2CO3,4% and 24% KOH. The antioxidant activity of different pectins and hemicellulose were studied, including oxygen radical absorbance capacity （ ORAC ）, DPPH radical （ DPPH - ） scavenging capacity, ABTS radical （ ABTS^＋·） scavenging capacity and ferric reducing antioxidant power（ FRAP）.It was suggested that the content of WSP（ 1.05 mg GalUA/g FW） was significantly higher than CSP and SSP in tomato fruit, and the content of TH （0.09 mg Glu/g FW）was significantly higher than LH（p 〈 0.05 ）.And different pectins and hemicellulose from tomato fruit all showed antioxidant activity in different degree, CSP＇ s total antioxidant activity was higher than other cell wall components with higher ORAC, DPPH- scavenging capacity and ABTS^＋ · scavenging capacity, when the concentration was 5 mg/mL, its ORAC value was 76.4μmol/L Trolox equivalent, and the DPPH. scavenging rate and ABTS^＋· scavenging rate was 61.0% and 99.8% ,respectively.But SSP,LH and TH possessed higher FRAP.Correlation analysis suggested each cell wall component was closely related with antioxidant activity.This result made a reference to comprehensive utilization of tomato fruit and the application of functional additive in food.