STUDY ON THE EFFECTS OF MOISTURE CONTENT ON THE COMPRESSIVE MECHANICAL PROPERTIES OF SWEET POTATO ROOTS

Abstract

To investigate the effects of moisture content on the compressive mechanical properties of sweet potato roots, this study used three sweet potato varieties (Zishu, Hongyao, and Xiguahong) cultivated in the Tianjin region as experimental materials. Experiments were conducted between October 8, 2025, and January 8, 2026, in a laboratory environment maintained at 20°C ± 2°C and 50% ± 5% relative humidity. The test employed a moisture content measurement method based on storage duration, measuring moisture content every 10 days. Simultaneously, compressive mechanical property tests were performed using an INSTRON 3344 series universal material testing machine under conditions of a 10 mm/min loading speed and a maximum pressure of 1500 N. The maximum rupture force, maximum deformation, and elastic modulus of sweet potatoes at different moisture contents were determined. Data analysis was conducted using Design-Expert 13 software. The results indicated that the variation patterns of moisture content were similar across the different sweet potato varieties. The moisture content decreased rapidly during the initial storage period, showed a brief increase in the middle stage, and then continued to decline at a slower rate in the later stage. Moisture content significantly affected the compressive mechanical properties of sweet potatoes. As the moisture content decreased, the elastic modulus and maximum rupture force increased, while the maximum deformation decreased.