To investigate the effects of controlled moisture levels on the peach (Prunus persica) kernels: Dimensional, gravimetrical, frictional, optical, and mechanical properties

Moisture content markedly influences the physical and mechanical properties of peach (Prunus persica) kernels, thereby affecting the performance of post-harvest handling and processing equipment. This study examined the effect of five controlled moisture levels (5.83 %, 9.86 %, 14.56 %, 20.12 %, and 25.26 %, wet basis) on the dimensional, frictional, optical, and mechanical properties of peach kernels. Dimensional measurements showed significant (p ≤ 0.05) increases of 3.42 %, 5.84 %, and 15.88 % in the major, medium, and minor axes, respectively, with rising moisture content. Static and dynamic frictional analyses indicated reduced flowability and increased resistance to movement at higher moisture levels. Optical assessment revealed total colour differences (ΔE) of 1.68, 4.70, 5.45, and 7.60 between moisture treatments, indicating moisture-induced changes in surface reflectance. Mechanical testing demonstrated that rupture force, hardness, deformation at rupture, and toughness decreased significantly (p ≤ 0.05) with increasing moisture content, with the lowest rupture force (1.86 N) recorded under horizontal loading. These results provide critical engineering parameters for designing and optimizing moisture-specific storage systems, conveying equipment, and cracking processes, thereby improving energy efficiency and product quality in peach kernel processing.