Comparison of ascorbic acid content of super-market versus roadside stand produce

Seven vegetables and one fruit from two roadside stands and two major local supermarkets were analyzed for their ascorbic acid content. Produce was sampled during a nine week period from late July through September of 1987. Significant differences at the 0.05 level for ascorbic acid were observed between supermarket and roadside stand produce for potato, cauliflower, cabbage and tomato while no significant differences were found between cantaloupe, broccoli, green peppers and spinach from either market. Cabbage was the only supermarket item that was significantly higher in ascorbic acid concentration. Very little dehydroascorbic acid was shown to be present in these vegetables and fruit making ascorbic acid an accurate indicator of total vitamin C activity for this study. The quality of freshness does not appear to be a major factor as to the amount of vitamin C present in these 8 products.