Community Solar Food Drying in Afghanistan
Abstract
Solar food drying is a thousands years old technique used for food preservation. Bacteria, yeast, and mold are prevented from spoiling the food due to a low moisture content. Dried food takes up less room and is light and easier to transport. Afghanistan is a leading exporter of dried foods, but often still using inefficient traditional outdoor direct drying methods with longer drying times. Traditional outdoor drying is also less hygienic and subject to contamination from dust, insects, birds, and animals. New Mexico State University (NMSU) introduced more efficient active and enclosed passive solar food drying techniques to Afghanistan in 2009 with faster drying times, better hygiene, and improved quality of dried foods. Food is normally dried between 50 to 80°C, which is a desirable range for drying and pasteurization. Solar drying reduces moisture content typically from about 10 to 20 percent. There are now over a dozen Afghan vendors supplying solar dryers. Many farmers also rent out their food dryers to after they have dried their own crops. This paper discusses solar dryer theory, operation, drying results, vitamin and color retention, business development, and applications in Afghanistan. Keywords: solar energy, food drying, Afghanistan