Physicochemical characterization and modeling of water sorption isotherms for sugarcane samples (Saccharum officinarum L.)

Abstract

Sugarcane juice is a refreshing, energetic and highly nutritious beverage. Due to its composition, fresh sugarcane juice is prone to microbial deterioration. Therefore, the application of methods that extend its shelf life can be useful to obtain a product with desirable properties. The aim of this study was to perform physicochemical characterization of freeze-dried sugarcane samples and evaluate the capability of six different mathematical models to describe their water sorption isotherms at three temperatures. Higher mineral content and phenolic compounds were found in the freeze-dried sugarcane sample compared to in natura sugarcane sample. Several statistical indices were adopted to assess the mathematical models performances used for the isotherm studies. The Henderson model provided the best goodness-of-fit for the observed type-III experimental isotherms. The net sorption isosteric heat was negative, indicating the occurrence of exothermic reactions during the water absorption in sugarcane samples. An empirical equation for calculating the energy required for drying sugarcane samples by freeze-drying between two given moisture contents was obtained. The results described in this work could be used for designing and optimizing drying processes of sugarcane samples in real-world applications.