Kelly Guthrie

Date of Award


Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)


Food Science and Human Nutrition


L. Brian Perkins

Second Committee Member

Rodney Bushway

Third Committee Member

Lawrence LeBlanc


A study was conducted to examine the vitamin C and total glycoalkaloid (TGA) content of organically grown tubers from eight novel varieties. Potatoes were sampled at harvest and also after two and four months in storage. Organic growing conditions did not appear to have any major effect on either vitamin C or TGA concentrations in the potatoes. Variation between tubers was great enough to eclipse any effects of cultivation system, had they existed. There was not only high variability in vitamin C and TGA content between varieties, but high variability was also seen between individual tubers. Among varieties, significant differences (p≤0.05) were noted over time for all varieties in regard to vitamin C content and for most varieties in regard to TGA content. Vitamin C levels decreased with time in all varieties except Yellow Banana, which actually showed a significant increase during storage. Trends in TGA were not as apparent and varied by cultivar. Some increased or decreased steadily during storage, some changed only during a certain period of storage and some did not change significantly at any time point. The most notable change in TGA content occurred in Cranberry Red, which showed a decrease from a very high initial concentration of 19.70 mg/100g to a much lower level of 9.73 mg/100g after four months.