Abstract
A prototype solar tunnel dryer having base area 4.59 m(2) (2700 x 1700 mm) each of collector region and dryer region, respectively, was designed and fabricated as a single unit. The drying temperature can be easily raised by some 6-10 degrees C above the ambient temperature inside the tunnel with an air velocity of approximately 2-2.5 m/sec. The moisture content of 12.5 kg freshly harvested mushroom was reduced from 91.7% to 10% (wet-basis) within two days (10 hours/day). The drying was faster in solar tunnel dryer than the natural open air drying. The improvement in the quality of ear-lobe mushroom in terms of color, flavor and taste and food value was distinctly recognized.