Estudo higroscópico da polpa em pó do fruto da pitaya (Hylocereus costaricencis) em diferentes concentrações de maltodextrina

Pitaya is a nutritious fruit with low caloric value and high antioxidant power due to the presence of betalains, nitrogenous and water-soluble pigments similar to anthocyanins and flavonoids, with different chemical structures. This article presents a systematic Pitaya pulp powder dye study regarding its hygroscopic behavior. The experiments were conducted by adding maltodextrin in the proportions of 10, 20, 30, 40, 50 and 100%. The different percentages allowed a progressive incremental number of solids in Pitaya dye and a more thorough pure powder dye analysis. The bleaching process was carried out in all samples and, subsequently, the samples were lyophilized for 48 hours to increase stability through the reduction of water activity. This is done to minimize enzymatic chemical reactions, which occur during material storage, and to augment product lifespan. Therefore, by the construction of adsorption and moisture desorption isotherms at 25 °C in different concentrations of maltodextrin, the hygroscopicity of Pitaya dye was analyzed as well as the applicability of mathematical models in the prediction of product isotherms. The obtained isotherms were sigmoidal, classified as type II and the GAB model was proved more suitable to be used in the prediction of dye sorption isotherms.