Dewanto Veronica, Wu Xianzhong, Liu Rui Hai
Department of Food Science and Institute of Comparative and Environmental Toxicology, Stocking Hall, Cornell University, Ithaca, New York 14853, USA.
J Agric Food Chem. 2002 Aug 14;50(17):4959-64. doi: 10.1021/jf0255937.
Processed fruits and vegetables have been long considered to have lower nutritional value than the fresh produce due to the loss of vitamin C during processing. Vitamin C in apples has been found to contribute <0.4% of total antioxidant activity, indicating most of the activity comes from the natural combination of phytochemicals. This suggests that processed fruits and vegetables may retain their antioxidant activity despite the loss of vitamin C. Here it is shown that thermal processing at 115 degrees C for 25 min significantly elevated the total antioxidant activity of sweet corn by 44% and increased phytochemical content such as ferulic acid by 550% and total phenolics by 54%, although 25% vitamin C loss was observed. Processed sweet corn has increased antioxidant activity equivalent to 210 mg of vitamin C/100 g of corn compared to the remaining 3.2 mg of vitamin C in the sample that contributed only 1.5% of its total antioxidant activity. These findings do not support the notion that processed fruits and vegetables have lower nutritional value than fresh produce. This information may have a significant impact on consumers' food selection by increasing their consumption of fruits and vegetables to reduce the risk of chronic diseases.
长期以来，加工过的水果和蔬菜被认为营养价值低于新鲜农产品，因为加工过程中维生素C会流失。研究发现，苹果中的维生素C对总抗氧化活性的贡献不到0.4%，这表明大部分抗氧化活性来自植物化学物质的天然组合。这表明，尽管维生素C流失，但加工过的水果和蔬菜可能仍保留其抗氧化活性。研究表明，在115摄氏度下热处理25分钟可使甜玉米的总抗氧化活性显著提高44%，并使阿魏酸等植物化学物质的含量增加550%，总酚类物质增加54%，尽管观察到维生素C损失了25%。与样品中剩余的3.2毫克维生素C相比，加工后的甜玉米抗氧化活性增加，相当于每100克玉米含有210毫克维生素C，而样品中剩余的维生素C仅占其总抗氧化活性的1.5%。这些发现并不支持加工过的水果和蔬菜营养价值低于新鲜农产品这一观点。这些信息可能会对消费者的食物选择产生重大影响，促使他们增加水果和蔬菜的摄入量，以降低患慢性病的风险。
