Muscat  – Solar tunnel drying in greenhouses has emerged as the most efficient method for processing Oman’s traditional dried anchovies, known as ‘qasha’, according to a study by Sultan Qaboos University (SQU).

The research found that the solar tunnel dryer completed the drying process in six hours, compared to nine hours required for open sun drying and solar forced-convection drying. It also recorded the highest effective moisture diffusivity, indicating faster and more consistent moisture removal.

The study was conducted by Aisha bint Khamis Al Saadi from the College of Agricultural and Marine Sciences at SQU. It examined drying kinetics and colour changes in anchovies, assessing how different techniques affected product quality and moisture content.

A total of 20kg of anchovies were processed at the Agricultural Experimental Station using three methods: open sun drying, solar tunnel drying in greenhouses and solar forced-convection drying. The results showed a strong correlation between drying rate and moisture content, with solar tunnel drying delivering the best overall performance.

Anchovies are highly perishable and sensitive to humidity and temperature. Effective drying is essential to extend shelf life and reduce spoilage. The study found that solar drying techniques improved heat and mass transfer, shortened drying time and enabled better control of environmental conditions during processing.

Researchers also highlighted economic and environmental gains. Solar tunnel and forced-convection dryers reduced operational costs, lowered reliance on conventional energy sources and decreased carbon emissions.

With Oman’s 3,165km coastline, qasha remains a staple of coastal communities and a product traded inland. The study noted that rising demand for dried seafood products increases the need for efficient preservation methods that maintain nutritional value.

Although conducted on an experimental scale, the findings provide a basis for wider industrial application. The study recommended further research on cost-effectiveness and scalability to support fisheries and food-processing development in Oman.