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THERMODYNAMIC ANALYSIS OF MOISTURE ADSORPTION ISOTHERMS OF RAW AND BLANCHED ALMONDS
Author(s) -
TAITANO L.Z.,
SINGH R.P.,
LEE J.H.,
KONG F.
Publication year - 2012
Publication title -
journal of food process engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 45
eISSN - 1745-4530
pISSN - 0145-8876
DOI - 10.1111/j.1745-4530.2010.00632.x
Subject(s) - sorption , gravimetric analysis , adsorption , equilibrium moisture content , enthalpy , moisture , thermodynamics , chemistry , mathematics , physics , organic chemistry
The equilibrium moisture content of raw and blanched almonds of California grown “Carmel” variety was determined by using static gravimetric method at 25, 35 and 45C over a range of water activities ( A w ) from 0.11 to 0.97. The sorption data were fitted to the Guggenheim–Anderson–de Boer (GAB) model. The goodness of fit of the model was evaluated by standard error of estimate, mean relative percentage deviation modulus and randomness of residual, which showed good fit of the GAB equation to the experimental data. The moisture adsorption isotherms of almonds exhibited type II sigmoid shape. Thermodynamic properties such as differential enthalpy and entropy were determined from moisture adsorption data by using the Clausius–Clapeyron equation. The results showed that enthalpy–entropy compensation theory was applicable for the moisture adsorption phenomena of raw and blanched almonds. The adsorption process of almond was enthalpy‐controlled. PRACTICAL APPLICATIONS Over 80% of the world almond production is grown in California and shipped to over 90 countries around the world. When exported to distant markets in the tropical regions, the physical, chemical and microbiological changes in almonds could cause the deterioration of food products due to environmental factors. Despite the large‐scale production and export of almonds, very little information on the sorption characteristics of almond varieties grown in California can be found in the literature. Reliable information on sorption isotherms is critical to designing optimum storage and shipping conditions to ensure desired levels of almond quality at consumption. This paper presents results from a comprehensive study of the sorption characteristics of one of the most important almond varieties grown in California, namely “Carmel.”