Abstract
Drying is one of the most commonly employed preservation techniques for medicinal plants, significantly influencing their physicochemical and functional properties. This review investigates the impact of various drying methods on the chemical composition, bioactive compounds, antioxidant activity, and overall quality of medicinal plants. These changes can diminish the therapeutic potential of the plants, thereby limiting their effectiveness in food applications and human health remedies. However, certain drying techniques are shown to better preserve these functional properties. The review discusses the integration of dried medicinal plants into functional foods, nutraceuticals, and supplements, showcasing their potential in promoting health and preventing diseases. The industrial significance of these approaches is in their capacity to prolong the period that a product can be stored, guarantee the safety of food, and satisfy consumers’ desires for items derived from nature. Nevertheless, there are still obstacles to achieving a harmonious equilibrium between cost-efficiency, scalability, and environmental sustainability. By understanding the effects of different drying methods, this review aims to guide future research and industrial applications for maximizing the health benefits of medicinal plants.
1. Introduction
Medicinal plants have been valued for centuries for their abundant bioactive compounds, which provide a wide range of health benefits, including antioxidant, anti-inflammatory, antimicrobial, and antiviral effects (Shahane et al., 2023; Kaveh et al., 2024). Often referred to as “nature’s pharmacy,” these plants are increasingly recognized for their dual role in traditional medicine and modern pharmacology. Recently, there has been a noticeable shift toward integrating medicinal plants into food systems as functional components to promote health and well-being (Tripathy et al., 2021a; Tripathy and Srivastav, 2023b). However, their high moisture content makes them prone to spoilage, leading to substantial wastage. Drying these plants offers a solution to reduce losses, significantly addressing global food shortages while maximizing resource utilization. Moreover, with evolving consumer preferences and a growing appetite for diverse food products, drying techniques have gained considerable attention as a vital food preservation strategy (Mahanti et al., 2021; Chen et al., 2023). Notably, the drying process can profoundly influence medicinal plants’ physicochemical and functional attributes, directly impacting their potential uses in food and healthcare applications (Siddiqui et al., 2024).
Drying is one of the oldest and most effective methods for preserving medicinal plants, primarily by lowering their moisture content to inhibit microbial activity and delay spoilage. This process offers several benefits, including extended shelf life, reduced weight and volume of the product, decreased transportation and storage costs, and the availability of medicinal plants, fruits, vegetables, and other seasonal crops throughout the year in high quality (Kaveh et al., 2024). As a critical step in the post-harvest handling of herbal plants, drying significantly influences the composition of volatile compounds and essential oils (Parhizi et al., 2022). By decreasing the water content of crops, drying is considered a vital technique for safeguarding agricultural produce, with notable effects on the quality of the dried materials (El-Mesery et al., 2022). Besides enhancing storage stability, drying inhibits enzymatic activity and microbial growth in herbal products (Kocyigit et al., 2023). However, the impact of drying on a plant’s therapeutic properties depends heavily on the drying methods and conditions used. Key attributes such as phenolic content, antioxidant activity, essential oil concentration, and color are particularly affected, which in turn influence the medicinal and functional value of the plants. Understanding these effects is essential for optimizing drying strategies and ensuring their suitability for applications in the food and health sectors (Nguyen et al., 2023; Cakmak et al., 2023).
Agricultural products exhibit low thermal conductivity, slowing heat transfer to their interior, making drying energy-intensive. Opting for an appropriate drying technique and reducing drying duration can cut energy costs and minimize adverse effects on properties such as texture, nutritional content, flavor, color, and aroma (Rybak et al., 2022). Various drying methods, including sun drying, oven drying, freeze drying, and air drying, influence the quality of medicinal plants differently (Karami et al., 2021; Bala et al., 2024; Bharali and Bhattacharyya, 2024). Freeze drying, for instance, is highly effective at preserving bioactive compounds but requires significant resources, whereas sun drying is a more economical option but can degrade heat-sensitive compounds (Jadhav et al., 2024). With the growing use of medicinal plants in functional foods and nutraceuticals, it is vital to understand how different drying techniques affect their properties (Ramachandran et al., 2024). Such knowledge facilitates the development of optimized drying processes that retain bioactive compounds, ensuring the plants’ full potential can be utilized to support human health.
Therefore, this review aims to provide a comprehensive examination of the effect of drying on the physicochemical and functional properties of medicinal plants. It will explore the impact of various drying methods on key parameters such as color, microstructure, water activity, bioactive compound stability, and antioxidant activity. Additionally, the review will discuss the implications of these changes on the application of dried medicinal plants in food products and their potential health benefits which will enhance the functionality in food systems and human health.
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Drying as a preservation strategy for medicinal plants: Physicochemical and functional outcomes for food and human health
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Sarthak Nakra, Soubhagya Tripathy, Prem Prakash Srivastav, Drying as a preservation strategy for medicinal plants: Physicochemical and functional outcomes for food and human health, Phytomedicine Plus, Volume 5, Issue 2, 2025, 100762, ISSN 2667-0313,
https://doi.org/10.1016/j.phyplu.2025.100762.
