Antioxidant capacity and polyphenolic content of potato tubers are affected by cultivar and hormetic treatment.

摘要

This thesis involved an investigation of potato ( Solanum tuberosum L.) tuber antioxidant capacity, particularly the phytonutrients vitamin C and polyphenolics. Tubers of 12 Canadian-grown and 5 foreign cultivars were screened for antioxidants qualitatively and quantitatively following 1 and 7 months of storage (5+/-1 °C). Significant differences were seen in quality and quantity of tuber antioxidants (including vitamin C and polyphenolics) between cultivars, storage intervals, and tuber tissues (skin, cortex, and pith). A potato microtuber model system was developed to test the effects of hormesis on microtuber antioxidant capacity. Hydrogen peroxide sprays (2 and 4 mM) increased the antioxidant capacity of microtubers in 2 cultivars by 12-26 %, showing the potato microtuber model system to be sensitive and useful for manipulating phytonutrient composition via hormetic treatments. Information in this thesis may have future applications for better cultivar selection and cultivation practices for improved phytonutrient content of field-grown potato tubers.