State Key Laboratory of Food Science & Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China.
State Key Laboratory of Food Science & Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, Jiangsu 214122, China.
Food Chem. 2023 Jan 1;398:133849. doi: 10.1016/j.foodchem.2022.133849. Epub 2022 Aug 4.
A promising drying technology, namely combined freeze-drying and far-infrared drying (FD-FIRD) was employed to dehydrate seed-used pumpkin (SUP) and its effects on physical characteristics (color, microstructure, texture, shrinkage), bioactive components (phenolics and carotenoids) of SUP were evaluated. The low-field nuclear magnetic resonance (LF-NMR) was used to analyze moisture state and distribution during FD process, which is beneficial for choosing appropriate moisture transfer point. Results showed that most free water (87.29 %) was removed when drying time reached 25 h, thus retaining original tissue structure of sample with almost no deformation during later FIRD process. Therefore, FD for 25 h followed by FIRD for 2 h (FD25-FIRD2) sample exhibited similar appearance with FD sample. The free phenolics content of FD-FIRD samples was 14.97 %-26.60 % higher than that of FD depending on FIRD duration. Especially, p-coumaric acid content of FD25-FIRD2 sample increased of 32.23 %. Besides, FD-FIRD performed higher retention for carotenoids showing 3.00-3.39 folds than FIRD.
一种有前途的干燥技术，即联合冷冻干燥和远红外干燥（FD-FIRD），被用于脱水种子南瓜（SUP），并评估其对 SUP 的物理特性（颜色、微观结构、质地、收缩）和生物活性成分（酚类和类胡萝卜素）的影响。低场核磁共振（LF-NMR）用于分析 FD 过程中的水分状态和分布，这有利于选择合适的水分传递点。结果表明，当干燥时间达到 25 小时时，大部分游离水（87.29%）被去除，因此在随后的 FIRD 过程中，样品几乎没有变形，保留了原始的组织结构。因此，FD25-FIRD2 样品（FD 干燥 25 小时后再进行 FIRD 干燥 2 小时）的外观与 FD 样品相似。FD-FIRD 样品的游离酚含量比 FD 样品高 14.97%-26.60%，这取决于 FIRD 的持续时间。特别是 FD25-FIRD2 样品的对香豆酸含量增加了 32.23%。此外，FD-FIRD 对类胡萝卜素的保留率更高，为 FIRD 的 3.00-3.39 倍。
