Advances in Combined Drying Techniques for Enhancing Dried Fruits’ Quality, Drying Efficiency, and Energy Conservation: A Critical Review

Abstract

Fruits are widely consumed for their rich array of vitamins, minerals, and health-promoting compounds. However, their high perishability due to elevated moisture content often results in significant postharvest losses. To tackle this global challenge, drying represents one of the oldest preservation strategies. In the last decade, advances in drying strategies have led to the emergence of combined drying techniques. This critical review synthesises the existing literature on combined drying techniques for fruit preservation, focusing on publications from the Scopus database. The integration of bibliometric analysis with VOSviewer yielded 67 journal articles and an evaluation of global research trends, geographic contributions, and network visualisation. From a mechanistic perspective, combined drying techniques enhance fruit quality and drying performance while minimising energy consumption and production costs, thereby promoting global sustainability. However, various challenges hamper their broader acceptance, including the high upfront investment, a lack of legislative backing, and technical difficulties that prevent large-scale deployment. This dual approach (bibliometric and systematic review) highlights these challenges and proposes future research directions for combined drying techniques for fruits.