Moisture sorption studies on vacuum dried coconut presscake.

Area of Science:

• Food science and technology
• Material science

Background:

• Coconut presscake is a byproduct of coconut processing, often rich in residual oil and protein.
• Understanding its moisture sorption properties is crucial for storage stability, shelf-life prediction, and processing optimization.
• Hygroscopicity influences microbial growth, enzymatic activity, and physical changes in food materials.

Purpose of the Study:

• To determine the moisture sorption isotherms of vacuum-dried coconut presscake at different temperatures.
• To evaluate the suitability of GAB, BET, and Halsey models for describing the sorption behavior.
• To calculate and analyze the isosteric heat of sorption.

Main Methods:

• Gravimetric technique used to measure equilibrium moisture content at 25°C, 30°C, and 38°C.
• Fitting of GAB, BET, and Halsey thermodynamic models to the experimental sorption data.
• Application of the Clausius-Clapeyron equation to determine the net isosteric heat of sorption.

Main Results:

• Sorption isotherms exhibited a Type II behavior, characteristic of many food materials.
• Temperature had no significant effect on the equilibrium moisture content (p > 0.05).
• The Halsey model provided the best fit to the experimental data, with a relative deviation below 10%.
• Net isosteric heat of sorption decreased exponentially with increasing moisture content.

Conclusions:

• The Halsey model is suitable for predicting the moisture sorption behavior of coconut presscake.
• Coconut presscake exhibits typical hygroscopic characteristics, with decreasing sorption energy at higher moisture levels.
• These findings are vital for designing appropriate drying, storage, and packaging strategies for coconut presscake to ensure quality and stability.