Information about qualitative changes of walnut properties is very important for processing units of walnuts. In the present study, the physical and biochemical characteristics of fresh walnut kernels from four cultivars (Hartley, Ronde de Montignac, Damavand, and Pedro) were evaluated for 2 years. Also, biochemical and physical characteristics of kernels dried at 20 ± 1 °C, 30 ± 1 °C, and via sun drying were compared with fresh kernels for 2 consecutive years. The results showed significant variability among the studied cultivars regarding nut weight, kernel percentage (the ratio of kernel weight to nut weight × 100), fill, plumpness, weight, color, and shrivel of kernels. The oil content in fresh walnut kernels ranged from 51.11% to 45.62%, while the protein content of the kernel was 15.42–10.51 mg/g kernel. The peroxide value of the extracted oil from fresh walnut kernels varied between 0.37 meq/kg and 0.22 meq/kg oil. Kernels dried at temperatures of 20 ± 1 °C and 30 ± 1 °C as well as those that were sun dried showed significant deterioration in physical and chemical properties in comparison with fresh kernels. Damavand, a commercial Iranian cultivar, was superior with regard to most of the studied characteristics. Fresh kernels showed higher quality compared with dried ones; however, kernels dried at 20 ± 1 °C were better than those exposed to two other drying methods in terms of maintaining kernel quality. Therefore, it is recommended to do kernel drying at lower temperatures.

核桃性质的质变信息对于核桃加工单位非常重要。在本研究中，对来自四个品种（Hartley、Ronde de Montignac、Damavand 和 Pedro）的新鲜核桃仁的物理和生化特性进行了为期 2 年的评估。此外，连续 2 年将在 20 ± 1 °C、30 ± 1 °C 和晒干下干燥的籽粒的生化和物理特性与新鲜籽粒进行比较。结果表明，所研究的品种在坚果重量、籽粒百分比（籽粒重量与坚果重量之比×100）、填充、丰满度、重量、颜色和籽粒皱缩方面存在显着差异。新鲜核桃仁含油量为51.11%～45.62%，蛋白质含量为15.42～10.51 mg/g仁。从新鲜核桃仁中提取的油的过氧化值在 0.37 meq/kg 和 0.22 meq/kg 油之间变化。在 20 ± 1 °C 和 30 ± 1 °C 温度下干燥的籽粒以及晒干的籽粒与新鲜籽粒相比物理和化学性质显着恶化。Damavand 是一种商业化的伊朗品种，在大多数研究特征方面都表现出色。鲜果仁比干果仁质量高；然而，在保持籽粒质量方面，在 20 ± 1 °C 下干燥的籽粒优于采用其他两种干燥方法的籽粒。因此，建议在较低温度下进行籽粒干燥。在 20 ± 1 °C 和 30 ± 1 °C 温度下干燥的籽粒以及晒干的籽粒与新鲜籽粒相比物理和化学性质显着恶化。Damavand 是一种商业化的伊朗品种，在大多数研究特征方面都表现出色。鲜果仁比干果仁质量高；然而，在保持籽粒质量方面，在 20 ± 1 °C 下干燥的籽粒优于采用其他两种干燥方法的籽粒。因此，建议在较低温度下进行籽粒干燥。在 20 ± 1 °C 和 30 ± 1 °C 温度下干燥的籽粒以及晒干的籽粒与新鲜籽粒相比物理和化学性质显着恶化。Damavand 是一种商业化的伊朗品种，在大多数研究特征方面都表现出色。鲜果仁比干果仁质量高；然而，在保持籽粒质量方面，在 20 ± 1 °C 下干燥的籽粒优于采用其他两种干燥方法的籽粒。因此，建议在较低温度下进行籽粒干燥。在保持内核质量方面，在 20 ± 1 °C 下干燥的籽粒优于采用其他两种干燥方法的籽粒。因此，建议在较低温度下进行籽粒干燥。在保持内核质量方面，在 20 ± 1 °C 下干燥的籽粒优于采用其他两种干燥方法的籽粒。因此，建议在较低温度下进行籽粒干燥。