Performance evaluation of an automated hybrid solar system dryer for drying some aromatic herbs

Abstract

The hybrid solar smart dryer (HSSD) was established to dry medicinal and aromatic herbs that are sensitive to direct sunlight. This study explores the effectiveness of the HSSD as an indirect solar drying technique in drying lemongrass, thyme, marjoram, and lavender at different temperatures (30, 40, and 50 ± 2 °C), focusing on its ability to retain quality features. The total energy consumption was estimated by values of 27.72 kWh for lemongrass and 43.02 kWh for lavender using HSSD at 50 ± 2 °C. Generally, HSSD showed an improvement in the studied physicochemical quality parameters. The green color retention was with the parameters of 15.60 ± 0.89, −5.28 ± 1.92, −3.89 ± 1.86, and −5.89 ± 2.40 for lemongrass, thyme, marjoram, and lavender samples, respectively. The highest values of the lemon grass, thyme, marjoram, and lavender oil content (1.96, 1.73, 3.40, and 2.76%, respectively) were obtained when the aromatic herbs were dried using the HSSD at 40 °C. This study showcased the effectiveness of solar dryers in preserving the physicochemical properties of lemongrass, thyme, marjoram, and lavender during drying, which could be applied to other food products. HSSD is a promising energy-efficient method that can save 19–36% of energy consumption, reducing the carbon footprint of drying processes and delivering high-quality products.

Keywords:

• Aromatic herbs
• hybrid solar drying
• color analysis
• essential oil
• antioxidant
• microbial load

Acknowledgment

The authors are grateful to the Agricultural Engineering Research Institute (AEnRI), and Horticulture Research Institute, the Agricultural Research Center (ARC), Egypt, and the Science, Technology & Innovation Funding Authority (STDF) for supporting the project team.

Author contributions

Alia Amer, Ayman Ibrahim, Islam Elsebaee: Conceptualization; Data curation; Formal, analysis; Investigation; Methodology; Project administration; Writing-original draft; Writing-review and editing. Aml Shahin, Rasha Saad, Zeinab Hassan, Mohamed Fathi: Data curation; Investigation; Methodology.

Disclosure statement

The authors have declared no conflicts of interest for this article.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article. Also, fully prepared to cooperate by making the data available at reasonable request.

Additional information

Funding

This paper is based upon work supported by the Science, Technology & Innovation Funding Authority (STDF) under Call 10/Young Researchers Grant (STDF-YRG)/STDF-Youth, entitled “Towards Innovative Processing and PIONEER in Sustainable Medicinal and Aromatic Plants Industry” (Project ID 43259).