Moisture Adsorption Isotherms Of Dried Mangoes At A Temperature Range Of 25 To 45&deg;C

Lemuel  M. Diamante,; Ken-ichi  Ishibashi,; Kazunori  Hironaka,

Moisture Adsorption Isotherms Of Dried Mangoes At A Temperature Range Of 25 To 45°C

Lemuel M. Diamante | Ken-ichi Ishibashi | Kazunori Hironaka

Abstract:

A study was conducted to determine the adsorption isotherms of diied mangoes at different temperatures. Th results showed that the adsorption isothenns of dried mangoes at different temperatures were type Ill according to the BET classification. At a water acti ity <0.50,the equilibrium moisture content of samples at a given water activity increased a the temperature decreased. But at a water activity >0.50 the equilibrium moisture content of the samples increased as the temperatme increased. The adsorption isotherms were fitted with 8 two-parameter equations (Bradley, Caurie,Halsey, Henderson Kuhn Linear, Oswin and Smith). The Caurie, Henderson and Oswin equations gave consistently high coefficients of determination when fitted to the ad orption isotherms of dried mangoes at different temp ratures. However, fu1ther evaluation of the equations using the mean relative percentage deviations showed that the Caurie equation gave the best fit for describing the sorption data. A fem-parameter modified Caurie equation was de1ived for predicting the equilibrium moisture content of dried mangoes as a function of water activity and temperature. Using the derived equation, the water activities of dried mangoes at different temperatures and constant moisture content were determined and used for obtaining the net heat sorption. The net heat sorption for dried mango decreased with increasing moisture content and can be expressed using linear equations for moisture ranges below 15% dry basis and above 15% dry basis.

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