Abstract Hot-air assisted continuous radio frequency (HARF) heating was utilized to dry inshell hazelnuts with high initial moisture content (25.5%, MCwb) for achieving higher drying efficiency and lower shell cracks. Effect of electrode gap and hot-air (HA) velocity at 40 °C on drying efficiency, heating uniformity, and shell cracking ratio were investigated. The ideal electrode gap and hot-air (HA) velocity were identified as 14 cm and 2.0 m/s, respectively, to provide shorter drying time (3.5 h) compared to HA drying (22 h), and less (36%) level 3 cracked nuts (cracks with width > 0.3 mm and length > 10 mm, CR3). The two-step HA-HARF drying using 19% MCwb as an intermediate MCwb resulted in dried nuts with lower CR3 (27%). Shell cracking ratio highly correlated with the size and weight of inshell nuts and kernels, kernel weight percentage, and air-gap volume between shell and kernel. Unexpectedly, shell cracks to level 3 influenced kernel color, but not lipid oxidation. Level 3 cracked nuts dried by the two-step HA-HARF exhibited much less lipid oxidation than that of HA dried non-cracked nuts during accelerated storage at 35 °C, indicating that two-step HA-HARF has great potential for drying hazelnuts with high quality and storability.

中文翻译：

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热风辅助连续射频干燥提高干燥效率和减少带壳榛子壳裂的研究：开裂程度与坚果品质的关系

摘要 利用热风辅助连续射频（HARF）加热对初始含水量高（25.5%，MCwb）的带壳榛子进行干燥，以获得更高的干燥效率和更少的壳裂。研究了电极间隙和 40 °C 下的热空气 (HA) 速度对干燥效率、加热均匀性和壳裂率的影响。理想的电极间隙和热空气 (HA) 速度分别为 14 cm 和 2.0 m/s，与 HA 干燥 (22 小时) 相比，可提供更短的干燥时间 (3.5 小时) 和更少 (36%) 的水平3 个有裂纹的螺母（裂纹宽度 > 0.3 毫米，长度 > 10 毫米，CR3）。使用 19% MCwb 作为中间 MCwb 的两步 HA-HARF 干燥导致干燥坚果具有较低的 CR3 (27%)。壳裂率与带壳坚果和仁的大小和重量、仁重量百分比、以及壳和内核之间的气隙体积。出乎意料的是，外壳破裂到 3 级会影响内核颜色，但不会影响脂质氧化。在 35 °C 下加速储存期间，两步 HA-HARF 干燥的 3 级裂果比 HA 干燥的非裂果表现出更少的脂质氧化，表明两步 HA-HARF 具有很大的干燥榛子的潜力高品质和可储存性。