TITLE:
Mathematical Modeling and Determination of Effective Diffusivity of Mesquite during Convective Drying
AUTHORS:
Rennan Pereira de Gusmão, Thaisa Abrantes Souza Gusmão, Mário Eduardo Rangel, Moreira Cavalcanti-Mata, Maria Elita Martins Duarte
KEYWORDS:
Diffusion Coefficient, Prosopis juliflora, Subproduct
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.7 No.6,
April
21,
2016
ABSTRACT: The mesquite pods have a high nutritional value, being a rich source of
sugars, proteins, minerals and fibers that can be used as a raw material for
the development of a number of food products and technological innovations. The
objective of this work was to study the drying kinetics of mesquite pods in a
thin layer, 20 mm length and determine the effective diffusion coefficient by adjusting
mathematical models that were based on heat transfer and mass fundamentals. For
the experiments, we used mature mesquite, with 20% water content (b.u). Drying
experiments were performed using temperatures of 50°C, 60°C, 70°C and 80°C with
drying air speed of 2 m•s-1. It was used a convective dryer with
fixed bed and upflow air. Mathematical models of Fick, Page, Cavalcanti-Mata,
Two Exponential Terms and Henderson & Pabis were used to adjust the
experimental data. To calculate the effective diffusivity, flat plate geometry
with sample thickness of 6.5 mm was used. Based on the results obtained, it was
concluded that the loss of water from mesquite occurred during the drying period in decreasing rate; and with increasing
drying temperature, total process time was reduced. The diffusion coefficient
increased by increasing drying temperature. Mathematical models including
theoretical (Fick), semi-theoretical (Page and Cavalcanti-Mata) and empirical
(Two Exponential Terms) models satisfactorily explain the experimental data of
drying mesquite.