Effects of different drying techniques on the quality and bioactive compounds of plant-based products: a critical review on current trends

Abstract

Drying is one of the foremost and important steps during the processing of agricultural crops, medicinal plants and herbs to preserve their properties. The present review provides a detailed overview regarding the effect of drying techniques on the physio-chemical properties (microstructure, color, aroma composition) and bioactive compounds (phenolic compounds, carotenoids, essential oils, etc.) of plant materials. Factors affecting different drying processes and their optimization strategies have also been discussed. Furthermore, current trends in the development of drying techniques for plant materials in terms of the retention of their bioactive compounds are critically analyzed. Based on the published research articles, oven drying, and microwave drying are the preferable techniques for most plant parts; while for drying the plant extract, freeze/spray drying methods have gained higher interest. Finally, recommendations are made considering the better use of drying techniques for both plant materials and retention of their bioactive compounds.

Keywords:

• Bioactive compounds
• freeze-drying
• spray drying
• oven drying
• microwave drying
• functional properties

Disclosure of interest statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

The research was financially supported by the Ministry of Science and Higher Education of the Russian Federation (World-Class Research Centers agreement № 075-15-2020-926). The research leading to these results was supported by MICINN supporting the Ramón y Cajal grant for M.A. Prieto (RYC-2017-22891) and by Xunta de Galicia for supporting the program EXCELENCIA-ED431F 2020/12. This work was funded by Федеральная целевая программа.