ESTUDO DO COMPORTAMENTO HIGROSCÓPICO DA AMORA PRETA (Rubus ssp) LIOFILIZADA PARA APLICAÇÃO COMO ALIMENTO NUTRACÊUTICO

Abstract

Hygroscopic behavior of lyophilized products can be visualized starting from the construction of Moisture Sorption Isotherms (MSI). Such curves show the relationship between the maximum amount of absorbed water for a substance, with the equilibrium vapor pressure or water activity, at a given constant temperature. Aimed to study later the application in encapsulation and use as a nutraceutical food, it was plot adsorption curves of lyophilized blackberry, at temperatures of 15 and 25ºC by static gravimetric method, using saturated solutions of different salts in vacuum desiccators. The results showed MSI type II, according BET classification, typical reaction of hydrophilic surfaces with monolayer and multilayer formation. The mathematical models of BET and GABfitted well the experimental data and allowed the water monolayer calculation; estimate the critical level of residual moisture that assures more stability to the product.

Key words - Blackberry, hygroscopic behavior, lyophilization, moisture sorption isotherms.