Mathematical Models to Describe the Foam Mat Drying Process of Cumbeba Pulp (Tacinga inamoena) and Product Quality

Abstract

The present study investigated the mathematical modeling foam-mat drying kinetics of cumbeba pulp and the effect of drying conditions on the color and contents of ascorbic acid, flavonoids, and phenolic compounds of the powder pulps obtained. Foam-mat drying was carried out in a forced air circulation oven at temperatures of 50, 60, and 70 °C, testing foam-mat thicknesses of 0.5, 1.0, and 1.5 cm. The increase in the water removal rate is a result of the increase in air temperature and the decrease in the thickness of the foam layer. Among the empirical and semi-empirical mathematical models, the Midilli model was the one that best represented the drying curves in all conditions evaluated. Effective water diffusivity ranged from 1.037 × 10−9 to 6.103 × 10−9 m2 s−1, with activation energy of 25.212, 33.397, and 36.609 kJ mol−1 for foam thicknesses of 0.5, 1.0, and 1.5 cm, respectively. Cumbeba powders showed light orangish colors and, as the drying temperature increased from 50 to 70 °C, for all thicknesses, the lightness value (L*) decreased and the values of redness (+a*) and yellowness (+b*) increased. Foam-mat drying at higher temperatures (60 and 70 °C) improved the retention of ascorbic acid and flavonoids, but reduced the content of phenolic compounds, while the increase in thickness, especially for flavonoids and phenolic compounds, caused reduction in their contents. The foam-mat drying method allowed obtaining a good-quality cumbeba pulp powder.

Effects of foam‐mat drying temperature on thermodynamic properties, microstructural properties, and X‐ray diffraction of Biribá (Rollinia mucosa [Jacq.] Baill) pulp

“…Figure 3 presents the drying rates of “biribá” pulp foam at temperatures ranging from 30°C to 60°C, calculated by derivation of the Midilli empirical model, which is considered the best model for describing the experimental drying kinetics (Section 3.2). In previous studies, the drying rate was also calculated from the derivative of the best model for the drying kinetics (Diógenes et al, 2022; Santos et al, 2020; Silva et al, 2014). It was found that the relationship between the drying rate and time was not linear, and the drying of the ‘biribá’ pulp foam decreased over time, a phenomenon also reported by Santos et al (2019) in “acuri” ( Scheelea phalerata ) pulp.…”

Impact of pretreatments with ethanol and freezing on drying slice papaya: drying performance and kinetic of ultrasound‐assisted extraction of phenolics compounds

“…Naturally, during the drying process, especially in the initial moments, the temperature of the product and the drying air are different, but when the water removal process progresses, the temperature of the product gradually increases until a state of thermal equilibrium is reached 39 . In fact, in this study we focused our attention only on the mass (water) transfer mechanisms; thus, we consider that in each experiment the drying process occurs isothermally.…”

Smelling Peppers and Pout Submitted to Convective Drying: Mathematical Modeling, Thermodynamic Properties and Proximal Composition

“…Peppers have abundant production; on the other hand, their fruits are perishable, deteriorating within a few days after harvesting. Therefore, they need adequate conservation methods to increase their shelf life, minimizing loss or damage to their bioactive and nutritional compounds [8].…”

“…Conventional hot air drying has become a popular method due to its relatively short time and uniform heating. Studies of drying kinetics combined with mathematical modeling and the evaluation of thermodynamic properties deserve the interest of researchers in the area of the most diverse products, considering the diversity of biological structures involved in heating and mass transfer and the effects observed in each material [8].…”