Semester of Graduation

Summer 2023


Master of Science (MS)


School of Plant, Environmental and Soil Sciences

Document Type




The leaf and root composition of different cultivars of ornamental sweetpotatoes (‘Blackie’, ‘Kakura’, ‘Manihi’, ‘Makatea’, ‘Tahiti’ and ‘Tatakoto’) were analyzed, and the impact of various factors on the levels of nutrients, vitamins, antioxidants, phenolic compounds, sugars, and organic acids in these sweetpotato cultivars were determined. The principal macronutrients found in sweetpotato foliage and roots were nitrogen (N), potassium (K), phosphorus (P), magnesium (Mg), calcium (Ca), and sulfur (S). Nitrogen was the most abundant macronutrient among all cultivars in sweetpotato foliage, whereas potassium was the most abundant macronutrient in sweetpotato roots. The principal micronutrients found in foliage and roots were iron (Fe), zinc (Zn), manganese (Mn), boron (B), and copper (Cu). Manganese was the most abundant micronutrient in the foliage, whereas iron was the most abundant micronutrient in the roots. Gallic acid, chlorogenic acid, caffeic acid, p-coumaric acid, and ferulic acid were the principal phenolic acids found in the in the foliage and roots. Rutin was also detected in the leaf tissue, but not in the roots. Unopened leaf tips exhibited the highest concentration of phenolics and antioxidant activity. Chlorogenic acid was the most abundant phenolic in fully opened young leaves, whereas caffeic acid was most abundant in unopened leaf tips. Chlorogenic acid was the most abundant phenolic acid in the roots. Low-temperature storage initially increased the total phenolic content, antioxidant activity, and individual phenolic acids in the leaves, but after 10 days, phenolic compound levels decreased and reached similar levels to those observed at harvest. However, the concentration of these compounds remained stable for one week when leaves were stored at ambient temperature. A significant increase in phenolic acids and antioxidants was observed in root tissue after 4 months of storage. On the other hand, storage decreased ascorbic acid content in both leaf tissues, with higher levels found in leaf tips than in young leaves. Baking significantly affected sugars and organic acids levels in sweetpotato roots. Baking increased glucose, fructose, and maltose levels, improving the overall flavor. Baking also enhanced malic and citric acid levels in the sweetpotato roots.



Committee Chair

David H. Picha

Available for download on Saturday, July 11, 2026

Included in

Horticulture Commons