Hassan Ahmed M, Ibrahim Mohamed M, Ghonimy Mohamed, Fathy Maher
Department of Agricultural Engineering, Faculty of Agriculture, Cairo University, Giza, Egypt.
Department of Agricultural and Biosystems Engineering, College of Agriculture and Food, Qassim University, P.O. Box 6622, Buraydah, 51452, Saudi Arabia.
Sci Rep. 2025 Jan 9;15(1):1510. doi: 10.1038/s41598-024-81881-2.
This study aimed to predict the toughness of date palm fruit (Barhi, Saqie, and Khodry varieties) at different ripening stages (Khalal, Rutab, and Tamar) using Hertz Theory by evaluating the physical and mechanical characteristics of the fruits. Physical measurements revealed that high moisture content in the Khalal stage led to larger dimensions and mass across all varieties, with Barhi dates showing a moisture content of 63.31%, which decreased to 32.60% at Rutab as the fruit dehydrated. This moisture reduction also impacted other characteristics, such as bulk density, volume, and flesh thickness, resulting in a concentrated, denser structure in the Tamar stage. Mechanical analysis demonstrated significant softening in all varieties as they transitioned from Khalal to Rutab stages, with Barhi dates' modulus of elasticity dropping from 548.83 to 16.72 kPa. Similarly, bioyield and rupture stress decreased, highlighting the influence of moisture loss on textural characteristics. Saqie and Khodry varieties followed similar trends, with initial softening from Khalal to Rutab, and a slight firmness increase at Tamar due to dehydration. The force-deformation curves and toughness measurements confirmed these findings, showing significant reductions in toughness from Khalal to Rutab, with a slight increase in Tamar. These results underscore the pronounced textural and structural changes as dates ripen, influencing their suitability for different applications. Also, the measured toughness (τm) closely aligned with predicted toughness (τp), with significant textural differences observed across varieties and ripening stages. For all varieties, the τp is approximately 0.00-9.24% lower than the τm. Finally, the derived equation can be used with enough confidence to theoretically predict the toughness of date palm fruit.
本研究旨在通过评估椰枣果实的物理和机械特性，利用赫兹理论预测不同成熟阶段（哈勒尔、鲁塔卜和塔马尔）的椰枣果实（巴尔希、萨基和霍德里品种）的韧性。物理测量结果显示，哈勒尔阶段的高水分含量导致所有品种的果实尺寸和质量更大，巴尔希椰枣的水分含量为63.31%，随着果实脱水，在鲁塔卜阶段降至32.60%。这种水分减少也影响了其他特性，如堆积密度、体积和果肉厚度，导致在塔马尔阶段形成浓缩、致密的结构。力学分析表明，所有品种从哈勒尔阶段过渡到鲁塔卜阶段时均显著软化，巴尔希椰枣的弹性模量从548.83 kPa降至16.72 kPa。同样，生物屈服强度和破裂应力降低，突出了水分流失对质地特性的影响。萨基和霍德里品种遵循类似趋势，从哈勒尔到鲁塔卜最初软化，在塔马尔阶段由于脱水略有变硬。力-变形曲线和韧性测量结果证实了这些发现，表明从哈勒尔到鲁塔卜韧性显著降低，在塔马尔阶段略有增加。这些结果强调了椰枣成熟时明显的质地和结构变化，影响了它们对不同应用的适用性。此外，测得的韧性（τm）与预测的韧性（τp）密切相关，在不同品种和成熟阶段观察到显著的质地差异。对于所有品种，τp比τm低约0.00 - 9.24%。最后，导出的方程可以有足够的信心用于从理论上预测椰枣果实的韧性。
