Application of a response surface Model for solar and indirect drying of muscat of alexandria grapes (Vitis vinífera)

Pezantes D.V.; Navarro H.R.; Jara R.S.; Romero D.C. · Granja (2026) · DOI: 10.17163/lgr.n44.2026.07

Resumen

By applying the response surface methodology, we optimized the sun and indirect solar drying of Muscat of Alexandria grapes. Initial moisture was measured and then the grapes were pretreated by thermochemical treatment with sodium hydroxide. Employing a centralized planning of rotating compounds, the pretreatment conditions were established, considering: temperatures, concentrations and times between 55-95°C, 0.5-3.0% and 2-30 seconds, respectively. For each drying process, drying times were determined, considering the final moisture content of 20% on a wet basis, as well as the overall acceptance of the product. Using quadratic order polynomial equations, response surfaces were generated to obtain a shorter drying time and a maximum value of product acceptability, obtaining high values of coefficient of determination (R2>0.97) and significant interactions of the independent variables (p<0.001). Solar and indirect drying were optimized at 80 °C, 1.75% and 16s, for the temperature and concentration of the sodium hydroxide solution and immersion time, to obtain drying times of 75 h and 50 h, respectively, with a high degree of overall product acceptability and a score above 8 points on the established hedonic scale. Effective water diffusivity values of 8.57∙10-11 and 1.90∙10-10 m²/s were obtained for the sun-drying and indirect solar drying process, respectively. Under optimal conditions, the mathematical model of Midilli et al. (2002) best simulates the variation of moisture versus drying time of Muscat of Alexandria grapes.

Instituciones: Universidad Nacional de Trujillo; Universidad Nacional del Callao; Universidad Nacional de Educación Enrique Guzmán y Valle