Abstract
The physico-mechanical properties of date fruit varieties can indicate their quality and freshness. These properties, which include firmness, moisture content, and mechanical resistance, are closely linked to the fruit's overall quality and can be used to assess its ripeness and suitability for consumption. Therefore, the current study evaluated the physico-mechanical properties of three date varieties-Sukkari, Khalas, and Saqie-across different ripening stages to enhance food quality and optimize postharvest handling. The study uniquely focused on how ripening stages affect the stress-strain behavior of dates, offering new insights into their mechanical resistance, deformability, and structural stability, all of which are critical parameters for maintaining food quality during storage, transportation, and processing. Significant changes in physical characteristics, including size, mass, moisture content, and density, were observed as the fruit progressed through ripening stages. Sukkari showed the most notable decrease in moisture content, from 61.8% at the Khalal stage to 17.3% at the Tamar stage, resulting in softening and reduced mechanical resistance, potentially impacting shelf life and consumer acceptance. Khalas exhibited a more gradual decline in mechanical properties, with moisture content dropping to 24.6%. At the same time, Saqie demonstrated minimal changes in mechanical properties and moisture content, suggesting better structural and nutritional quality retention. Additionally, the dynamic coefficient of friction increased with temperature and pressure at the Tamr stage, with Sukkari showing the highest values (up to 0.496), followed by Khalas (up to 0.451) and Saqie (up to 0.406). This study introduced the concept of variety-specific differences in frictional behavior, providing valuable insights for improving mechanical processing, reducing physical damage, and preserving date fruits' nutritional and sensory quality. In conclusion, findings highlight the importance of variety-specific mechanical profiling in improving processing protocols, reducing postharvest losses, and maintaining the nutritional and sensory quality of date fruits for industrial-scale operations.