Solar Drying Methods for Nutritional and Physicochemical Property Preservation of Huitlacoche (Ustilago maydis)

Abstract

Ustilago maydis, commonly known as huitlacoche, was dried under various conditions to study its physicochemical and bromatological properties. The goal was to evaluate its preservation after the drying processes, focusing on using environmentally friendly, cost-effective, and user-friendly technology, such as solar energy. For this research, a mixed-type solar dryer and an electric stove utilizing both natural and forced convection were employed. The initial moisture content of huitlacoche was reduced from 89.05% to 2.8% using the mixed-type solar dryer with forced convection and 2.39% with natural convection. In contrast, the final moisture content in the electric stove measured 6.4% under forced convection and 7.6% under natural convection. The proximal composition of huitlacoche revealed that it contained 2.54% protein, 0.113% fat, 4.08% fiber, 0.61% ash, and 3.58% carbohydrates. Notable increases in some properties of huitlacoche were observed following the drying processes: protein content rose from 11.16% to 12.09%, ash content increased from 3.19% to 4.74%, and total soluble solids rose from 21.5% to 30%. Additionally, fiber and fat content grew from 1.03% to 1.47%. The drying efficiency was measured at 30.72% using the mixed-type solar dryer with natural convection and 14.13% with forced convection. While raw huitlacoche exhibited a dominant black color, it turned brown during the drying process across all conditions, with the most pronounced change occurring in the stove using natural convection. This study demonstrates that solar technology is an excellent alternative for dehydrating huitlacoche and mushrooms by harnessing solar energy and utilizing low-cost equipment.