Moisture Sorbsi Isotherm (MSI) Model for Drying Bread Fruit (Artocarpus Altilis) Chips using a Tray Dryer

The increase in breadfruit's water content and water activity causes the fruit to be susceptible to damage. Therefore, it is necessary to understand the absorption pattern of breadfruit's water content. The Water Sorption Isotherm (ISA) curve can be used to determine the pattern of water absorption. Therefore, it is necessary to know the knowledge of the sorption is other mic characteristics of water on breadfruit drying to predict the properties of these materials under conditions of relative humidity and air temperature in the storage area. This research investigates the effect of storage temperature on the sorption isotherm characteristic of water of breadfruit chips. Dried breadfruit chips were conditioned at various water activity levels (aw) 0.1 - 0.8 using several types of saturated salt solution at 30ᵒC and 40ᵒC by gravimetric method. Furthermore, the obtained equilibrium moisture content and water activity data were plotted into a graph using several mathematical equation models, i.e., the BET, GAB, Oswin, Caurie, Halsey and Henderson models. The curves were created using Microsoft Excel 2016 software. The exact model of the isothermic sorption equation of water for drying breadfruit was determined based on the equation model developed from the literature and adapted to the experimental data. The results show that the isothermic sorption curve of water of breadfruit drying followed the sigmoid type 2 pattern. Four models were appropriate to describe the isothermic sorption pattern of the water of breadfruit drying at a storage temperature of 30ᵒC, i.e., The GAB, Oswin, Caurie, and Halsey models. The correct model suitability is indicated by the coefficient of determination constant (R2 ) being high, the value of E is 5% < E < 10%, the value of the mean deviation (eave), and the value of the square root of the mean deviation (RMSE) is low. The relative mean deviation value (%E) of 30ᵒC storage temperature that can describe the isothermic sorption pattern is the CAB, Oswin,, Caurieand Halsey models (GAB= 6.713; Oswin=6.008; Caurie = 6.157; Halsey=6.189). The coefficient of determination(GAB=0.9544;Oswin= 0.7848; Caurie = 0.7705; Halsey = 0.8268), the average deviation value (eave GAB = 0.034; Oswin = 0.036; Caurie = 0.835; Halsey = 0.032) and the RMSE (GAB value. =0.183; Oswin=0.195;Caurie=0.416; Halsey=0.180). Four models can describe the isothermic pattern of water absorption for a storage room temperature of 40ᵒC, i.e., the GAB, Oswin, Caurie, and Halsey models. The relative mean deviation (%E) of the model is (GAB=2.130; Oswin=5.509; Caurie = 5.928; Halsey=7.804). Coefficient of determination (GAB = 0.9928; Oswin = 0.8869; Caurie = 0.8654; Halsey=0.8336), mean deviation value (eave GAB = 0.001; Oswin=0.001; Caurie= 0.009; Halsey = 0.001 ) and RMSE values (GAB = 0.004; Oswin = 0.008; Caurie = 0.097; Halsey = 0.011)