Antioxidant and phenolic contents in potatoes (Solanum tuberosum L.) and micropropagated potatoes

This work investigated the extraction efficacy of phenolic acids on the potato and its byproducts. Also, the compositions of bioactive compounds and antioxidants were evaluated in various parts of the potato, such as the tuber, microtuber, peel, and flesh. The chemical constituents were quantified by HPLC analysis, and the highest levels of phenolics (88.99mg/L) were obtained in acetone extracts from a micropropagated potato. The micropropagated potato demonstrated that notable phenolic compounds were mainly a bound form of phenolic acids including caffeic acid and vanillic acid. The micropropagated extracts using acetone showed the higher radical scavenging activity, 94.3% and 95.5% at 5mg/mL in 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azinobis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS(+)), respectively. In addition, the same extracts showed the highest (85.61%) -carotene bleaching inhibition activity. A positive relationship existed between DPPH and either ABTS(+) (r=0.58, p<0.05), -carotene bleaching (r=0.65, p<0.05), or total phenolics (r=0.63, p<0.05). However, ABTS(+) did not show a significant correlation between both total phenolics and -carotene bleaching. The effective phenolic compounds contributing to antioxidant activity were caffeic acid and vanillic acid, which could be extracted in high amounts by acetone from potato peels and micropropagated potatoes.