Comparative analysis of drying methods for fresh in-hull walnuts: Impact on sensory quality, physical and chemical properties and flavor characteristics

作者：Yuxue Yuan, Xiaoli Liu, Jiashun Jiang, Shutong Liu, Deying Men, Jun Sheng, Yang Tian, Liang Tao, Jiahe Dai · 发表于：LWT · 年份：2025 · DOI：10.1016/j.lwt.2025.117675 · 被引用次数：15 · 研究领域：Nuts composition and effects、Food Quality and Safety Studies、Nutrition, Health and Food Behavior

The quality of dehydrated products, including physical, nutritional, and sensory attributes, is influenced by the drying method used. However, the effects of different drying methods on walnuts are not yet clear. To investigate a better drying method for fresh in-shell walnuts, five drying methods (natural drying, hot air drying, vacuum freeze-drying, vacuum drying, and microwave drying) were analyzed and compared for their effects on the sensory quality, physicochemical properties, and flavor characteristics of walnuts. The results indicated that, at the sensory level, the microwave drying group and the vacuum freeze-drying group were closer to fresh samples. In terms of physicochemical properties, vacuum freeze-drying had the highest protein content (21.41 ± 0.73 mg/g) and total phenolic content (212.08 ± 2.06 mg/g), with better antioxidant activity (84.11 ± 0.88 %) and optimal rehydration performance (90.61 %). Samples dried with hot air and microwave drying had more volatile compounds, resulting in better overall flavor quality of the walnuts. Compared to the microwave drying group, the hot airdrying group had the highest content of amino acids and fatty acids, emitting a pleasant baked aroma. A total of 47 volatile compounds were identified by gas chromatography-ion mobility spectrometry (GC-IMS), including 16 alcohols, 12 aldehydes, 8 ketones, 7 esters, 1 furan, 1 ether, 1 acid, and 1 aromatic hydrocarbon. OPLS-DA analysis identified 15 volatile flavor compounds, includ...