Modelado de las isotermas de adsorción de agua de harinas obtenidas a partir de residuos de coliflor (Brassica oleracea var. Botrytis L.) y brócoli (Brassica oleracea var. italica Plenck) sometidos a diferentes pretratamientos

Abstract

Nowadays, people seek to acquire a range of functional foods that provide nutrients and substances that produce beneficial physiological and metabolic effects, with cauliflower and broccoli being highly valued and consumed in the human diet. This research aims to construct water adsorption isotherms by valorizing and transforming cruciferous vegetable waste into flour and fitting their experimental data into mathematical models, evaluating the effect of pretreatments. Samples of both cauliflower and broccoli were precooked in water, steam, and microwaves, and convectively dried at 65 degrees Celsius for eight hours. They were placed in airtight containers with saturated saline solutions at controlled relative humidity until a constant weight of 0.0005 grams was achieved. The shelf life and stability of the flours were analyzed by constructing water adsorption isotherms, which presented type II sigmoidal curves due to their macroporous nature of active polar sites and hydrophobic character, representing an equilibrium moisture content of 0.15 to 0.35 kg water per-kg dry solids, at relative humidities above 60 percent. The experimental data were fitted to the GAB and BET models, corroborating a strong energy for the adhesion of water molecules in the monolayer. The coefficient of determination in the BET model presents a better fit due to its approximation values. Ultimately, both monolayer moisture and sorption constants are significantly affected by the treatments.