贮藏温度对葡萄果实采后抗氧化活性的影响及动力学分析

以"甬优1号"葡萄果实为原料,探讨贮藏温度(273.15、283.15、293.15K)对果肉和果皮总酚、花色苷和抗氧化活性的影响,并应用Gomportz函数模型,对不同温度下葡萄果实贮藏期间抗氧化活性变化的动力学模型进行研究。结果表明,葡萄果实贮藏过程中果肉和果皮中的总酚含量下降,果皮中花色苷含量也呈下降趋势。0℃贮藏可显著抑制果肉和果皮中总酚含量及果皮中花色苷含量下降,保持葡萄果实较高的DPPH自由基清除能力。在Arrhenius动力学方程基础上得出葡萄果实贮藏期间果肉和果皮总酚、花色苷和抗氧化活性变化的速率常数随着贮藏温度的提高而增大,拟合所得总酚、花色苷含量和DPPH自由基清除能力一级动力学模型回归方程的决定系数均大于0.91。由果肉和果皮总酚、花色苷和抗氧化活性预测模型所得各抗氧化指标预测值与实测值之间的平均相对误差均小于10%,表明在贮藏温度273.15～293.15K(0～20℃)范围,可预测葡萄果实采后抗氧化物质含量及抗氧化能力的变化。

Kinetic Analysis and Antioxidant Activity of Postharvest Grape Fruit at Different Storage Temperatures

The effect of storage temperature on total phenolics,anthocyanin contents and antioxidant activity of grape fruit stored at 0～20 ℃ was investigated.The change curve of these antioxidant parameters during storage was analyzed and fitted with Gompertz model.Results showed that there was a decline of total phenolic content both in flesh and peel tissue and total anthocayanin content in fruit peel during the whole storage period.Low temperature storage(0 ℃) inhibited the decline of total phenolic content in both flesh and peel tissue and total anthocayanin content in fruit peel,and maintained higher DPPH radical scavenging activities during storage.The high regression coefficients(R2>0.91) indicated the acceptability of Gomportz model for predicting the changes of antioxidant contents and activity of postharvest grape fruit.Rate constant,which were obtained based on the Arrhenius equation,increased with the storage temperature elevated.It shows from the reliability assessment between predicted and observed total phenolics,anthocyanin contents and antioxidant activity that average relative error all below 10% calculated by the prediction models.These results suggest that,total phenolics,anthocyanin contents and antioxidant activity of postharvest grape fruit can be predicted at the storage temperature from 273.15 K to 293.15 K.