Drying kinetics and water adsorption properties of jalapeño pepper seeds (Capsicum annuum L.): A study aiming at their recovery and integral exploitation

Abstract

Drying kinetics (DK) and water adsorption isotherms (WAI) of Jalapeño pepper seeds (JPS) were evaluated and modeled at different temperatures. The proximate composition, flavonoid content (FC), and total phenolic compounds (TPC) of JPS were determined. Furthermore, JPS oil was extracted and characterized. Five mathematical models were tested to describe the JPS drying kinetics at five temperatures (40–80 °C) as well as the effective diffusion coefficient (Deff) and activation energy (Ea) were calculated. The WAI of the JPS was determined at nine temperatures (8–72 °C) and five mathematical models were fitted to JPS adsorption data. Thermodynamic properties were also estimated. The JPS presented TPC (30.9 mg GAE/g), FC (17.4 mg catechin equivalents/g), fibers (54.8 g/100 d.b.), lipids (22.2 g/100 d.b.), and proteins (15.5 g/100 d.b.). The study on drying kinetics pointed out that the Weibull model best fitted to drying kinetics data, Deff increased directly to temperature, and the Ea = 30.302 kJ/mol. The GAB model presented good accuracy in describing the WAIs that were classified as BET Type II. The net isosteric heat of adsorption and differential entropy decreased with increasing EMC. Enthalpy-entropy compensation theory was corroborated and characterized the adsorption of JPS as enthalpy-driven and spontaneous.