Mathematical models of pretreatment processes to utilize purple-fleshed potato (Solanum tuberosum L.) peels for anthocyanin extraction.

The effect of particle size on the extraction rate of anthocyanin from Solanum tuberosum L. (purple-fleshed potato) peels (PFPPs) using the stagnant single-stage batch extraction system was investigated. Core pretreatment processes such as drying and grinding were quantitatively evaluated using mathematical models. The drying behavior of PFPP was successfully described using thin layer models (Page model and Midilli-Kucuk model). The effective diffusion coefficient of drying temperature at 40°C was determined to be 1.67x10-12 m2/s. The grinding time to obtain particles of a specific size was accurately estimated using the grinding kinetic model (R 2=0.97). The extraction rate of anthocyanin increased as the particle size decreased; however, when the particle size was 0.15mm, the anthocyanin content decreased. Our study demonstrated that the grinding kinetic model is useful to estimate the grinding time to produce an optimum particle size for anthocyanin extraction from PFPP.