Babaei Rad Shima, Mumivand Hasan, Mollaei Saeed, Khadivi Ali
Department of Horticultural Science, Faculty of Agriculture, Lorestan University, PO Box 465, Khorramabad, Iran.
Department of Chemistry, Faculty of Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran.
BMC Plant Biol. 2025 Jan 31;25(1):133. doi: 10.1186/s12870-025-06110-y.
Drying is a critical post-harvest process for medicinal plants, which are typically high in moisture and microorganisms. To prevent spoilage and quality loss, it is essential to dry these plants promptly. The drying method significantly impacts the levels of secondary metabolites and the organoleptic characteristics of medicinal plants. This study aimed to investigate the effects of various drying methods on the total phenolics, flavonoids, anthocyanins, antioxidant activity, and phenolic acids in caper (Capparis spinosa L.) fruits. The experiment was performed using a completely randomized design with three replications and included 11 treatments: shade drying, sun drying, oven drying (at 50 °C, 60 °C, and 70 °C), microwave drying (at 300 W, 600 W, and 900 W), freeze-drying, salt-drying, and a fresh plant sample as a control.
Among the drying methods tested, microwave drying consistently produced the highest levels of flavonoids, anthocyanins, and antioxidant activity, regardless of wattage. Specifically, the highest total phenol content was observed in samples dried at 900 W microwave, 600 W microwave, and 70 °C in the oven (5.3, 5.37, and 5.31 mg GAE/g DW, respectively). Drying at 600 W microwave yielded the highest levels of caffeic, cinnamic, ferulic, vanillic, and protocatechuic acids (13.03, 3.85, 4.28, 9.73, and 5.6 µg/g, respectively) while drying at 900 W microwave also resulted in elevated levels of caffeic, ferulic, protocatechuic, and p-coumaric acids. The 70 °C oven drying method also showed high levels of caffeic, cinnamic, ferulic, vanillic, and protocatechuic acids. Freeze-drying achieved the highest levels of rosmarinic, gallic, and m-coumaric acids (320.17, 175.3, and 12.99 µg/g, respectively), while shade drying produced high levels of p-hydroxybenzoic, cinnamic, ferulic, m-coumaric, protocatechuic, and p-coumaric acids.
Overall, microwave drying (especially at 600 W), oven drying at 70 °C, and freeze-drying emerged as effective alternatives to traditional drying methods. These methods not only preserved the color, texture, and taste of the fruits but also enhanced their bioactive compound levels.
干燥是药用植物收获后的关键处理过程，这些植物通常含水量高且微生物含量高。为防止变质和品质损失，及时干燥这些植物至关重要。干燥方法对药用植物次生代谢产物水平和感官特性有显著影响。本研究旨在探讨不同干燥方法对刺山柑（Capparis spinosa L.）果实中总酚、黄酮、花青素、抗氧化活性和酚酸的影响。实验采用完全随机设计，重复三次，包括11种处理：阴干、晒干、烘干（50℃、60℃和70℃）、微波干燥（300W、600W和900W）、冷冻干燥、盐渍干燥以及新鲜植物样品作为对照。
在所测试的干燥方法中，无论功率如何，微波干燥始终产生最高水平的黄酮、花青素和抗氧化活性。具体而言，在900W微波干燥、600W微波干燥和70℃烘干的样品中观察到最高的总酚含量（分别为5.3、5.37和5.31mg GAE/g DW）。600W微波干燥产生的咖啡酸、肉桂酸、阿魏酸、香草酸和原儿茶酸水平最高（分别为13.03、3.85、4.28、9.73和5.6μg/g），而900W微波干燥也导致咖啡酸、阿魏酸、原儿茶酸和对香豆酸水平升高。70℃烘干方法也显示出较高水平的咖啡酸、肉桂酸、阿魏酸、香草酸和原儿茶酸。冷冻干燥获得了最高水平的迷迭香酸、没食子酸和间香豆酸（分别为320.17、175.3和12.99μg/g），而阴干产生了高水平的对羟基苯甲酸、肉桂酸、阿魏酸、间香豆酸、原儿茶酸和对香豆酸。
总体而言，微波干燥（尤其是600W）、70℃烘干和冷冻干燥是传统干燥方法的有效替代方法。这些方法不仅保留了果实的颜色、质地和味道，还提高了其生物活性化合物水平。
