Mathematical modeling of vacuum drying characteristics of chlorococcum infusionum

Certain strains of algae yield adequate amounts of protein, and the microalgae species, Chlorococcum infusionum, is reported to have 50% protein yield which could alleviate food shortage. However, limited studies about this strain restricts its potential for food production. Furthermore, in algal protein processing, the drying process consumes large amounts of energy. This study investigated the drying characteristics of C. infusionum to analyze its drying time and drying behavior. A definitive screening design of experiment used temperatures of 40°C, 55°C, and 70°C, absolute pressures of 20 kPa, 50 kPa, and 80 kPa, and microalgae thicknesses of 3 mm, 5 mm, and 7 mm. Thin-layer specimens are placed on petri dishes for vacuum drying, and data is automatically collected using an Arduino microcontroller. Page, Modified Page, Henderson-Pabis, Two-term, and Aghbashlo models are used, and a proposed model is constructed to improve the goodness of fit of the experimental data with the mathematical model. Newton-Rhapson method was used to fit the experimental data with the mathematical models, and the coefficient of determination (>0.989), root mean square error (<2.7%), and reduced chi-square (<0.001) are computed to analyze the goodness of fit of each model. All models exhibited good fit with the experimental data, and the proposed model was verified to best represent the drying characteristics of C. infusionum based on t-tests. The drying curves of C. infusionum is observed only in the falling-rate period and the degree of the effects of temperature, pressure, and thickness on drying time and drying rate are investigated.