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Drying kinetics and effective diffusion of buckwheat grains

Authors :
Valdiney Cambuy Siqueira
Rafael Araújo Leite
Geraldo Acácio Mabasso
Elton Aparecido Siqueira Martins
Wellytton Darci Quequeto
Eder Pedroza Isquierdo
Source :
Ciência e Agrotecnologia
Publisher :
Universidade Federal de Lavras.

Abstract

ABSTRACT Buckwheat has become important in the food sector as its flour does not contain gluten. Since buckwheat is a relatively new crop in the agricultural environment, there is little information available regarding its processing. Drying is one of the most important post-harvest stages of buckwheat. The aim of the present study was to describe the drying process of buckwheat grains. Buckwheat grains with a moisture content of 0.41 ± 0.01 (dry basis, d.b.) were harvested, followed by drying in an experimental dryer at the temperatures of 40, 50, 60, 70, and 80 °C, at an air speed of 0.8 m s-1. The drying rate was determined, and the mathematical models generally employed to describe the drying process of several agricultural products were fitted to the experimentally obtained data. Model selection was based on the Gauss-Newton non-linear regression method and was complemented by Akaike Information Criterion and Schwarz’s Bayesian Information Criterion. It was concluded that the drying rate increased with an increase in temperature and decreased with an increase in drying time. It is recommended to use the Midilli model to represent the drying kinetics of buckwheat grains at the temperatures of 40, 60, and 70 °C, while the Approximation of diffusion model is recommended for the temperatures of 50 and 80 °C. The magnitudes of effective diffusion coefficients ranged from 1.8990 × 10-11 m2 s-1 to 17.8831 × 10-11 m2 s-1. The activation energy required to initiate the drying process was determined to be 49.75 kJ mol-1.

Details

Language :
English, Spanish; Castilian, Portuguese
ISSN :
19811829 and 14137054
Database :
Directory of Open Access Journals
Journal :
Ciência e Agrotecnologia
Publication Type :
Academic Journal
Accession number :
edsdoj.66d44ea2444414381b2fbe910f91fa5
Document Type :
article
Full Text :
https://doi.org/10.1590/1413-7054202044011320