Obtaining the coefficient of mass diffusivity for jackfruit (Artocarpus integrifolia L.) using the CMC model

Jackfuit (Artocarpus integrifolia L.) is an exotic fruit, native to India, well adapted to the transition environment between the Atlantic Forest and the Northeastern Semi-arid. Although it is a very perishable fruit, jackfruit provides a large amount of pulp, and it is necessary to find alternatives to store this material without nutritional losses. One of the alternatives is the osmotic dehydration process, which consists of immersing the fruit samples in hypertonic solution of sucrose. However, osmotic dehydration alters the texture of the fruit, especially due to the dissolution of pectin and the breakdown of the cellular tissue, so it is necessary to evaluate the kinetics of osmotic dehydration. The kinetics of this process is generally evaluated in terms of water loss (WL) and solids gain (SG) and depends mainly on raw material characteristics and operating conditions, such as concentration, temperature and time of solution exposure and pressure. The objective of this work was to study the mass transfer process during the osmotic dehydration of the hardwood jaca (Artocarpus integrifolia L.), using the Castro-Mattedi-Chaves model (CMC) (Castro et.al., 2015). The samples were cut in the form of a semi-infinity solid. Sucrose solutions with concentrations ranging from 30% to 60% and temperatures ranging from 303 K to 333 K, in the time from 0 to 10 hours were used. The rotational central composite design (RCCD) was used to perform the treatments on the jaca (Artocarpus integrifolia L.) samples. WL and SG were evaluated. The mass diffusion coefficients for WL and SG were obtained by fitting the CMC model. The mass diffusion coefficients for WL varied from 1.95e-10m2 .s -1 to 4.10e-10 m2 .s -1 . The mass diffusion coefficients for GS varied from 1.5e-9 m2 .s -1 to 2.5e-11 m2 .s -1 . A mass balance was obtained and a parabolic Partial Differential Equation (PDE) model was obtained, discretized by the method of finite centered differences and finite progressive differences, with the Neumann contour conditions. The explicit method was used to obtain WL and SG kinetics. The results obtained through the simulation showed a good fit with the experimental data with a RMSE ranging from 0.14 to 0.54.