Fig. 5

Reduction of proteinase inhibitor activity in potato tubers incubated in wet conditions. Three potato tuber cultivars were incubated in wet or dry conditions for one week. To measure the activity of the proteinase inhibitors, the potato extracts were incubated with three commercial proteinases, after which the proteinase activities were measured with the azocasein method. The percentages of protease inhibition were calculated by comparing the activities before and after incubation, with the negative control containing no potato extract, and calculated using the least significant difference test at P < 0.05 (p < 0001). The error bars represent the 95% confidence intervals for the estimated proportions representing four replicates of five tubers per protease assay