Influence of Elevated Potassium Fertilization on Structural and Functional Properties of Sweet Potato Root Tuber Starch.

Nine sweet potato varieties with different flesh colors were cultivated under uniform environmental conditions with potassium (K) fertilizer treatments at levels of 0, 22.5, and 45 kg/ha. The structural and functional properties of the starches were subsequently analyzed. The soluble sugar content in the dry root tuber increased, with higher K levels in most varieties. Amylose content decreased in Sushu16 but increased in Ningzishu1, with no significant differences observed in other varieties across different K levels. Elevated K levels had no effect on starch protein content, crystalline type, or gelatinization enthalpy. The impact of K fertilizer on starch thermal and pasting properties varied among the varieties. PLSR and PLS-DA analyses revealed that genotype background was the primary factor influencing starch properties. This research will provide a reference for the improvement of sweet potato production quality and efficiency and a scientific basis for the cultivation and utilization of sweet potato root tubers.