مرکز منطقه ای اطلاع رساني علوم و فناوري - Modeling of extraction of total polyphenols from Zingiber officinale

Abstract :

In this paper, kinetics of extraction of total polyphenols from Zingiber officinale was investigated. Samples were extracted using water at different temperatures and the extraction was realized under mixed and unmixed medium to observe the changes in the kinetics. Four different models, namely Peleg, Mass Transfer, Logarithmic and Page’s Models, were used for mathematically describing the physical behavior of the extraction. The yields of polyphenols determined as gallic acid equivalents ranged between 2.29-5.23 mg/g depending on the temperature and mixing conditions. Peleg’s model, having the highest regression coefficients at all conditions investigated for steady-state conditions, and Mass transfer model for unsteady-state conditions were found as the best fit to the experimental data. Also, molecular and convective diffusivities and activation energy of extraction were evaluated in this study. It was found that increase in temperature and mixing rate increased the diffusion coefficients because they decreased the activation energy of extraction. It has been found that temperature was much more effective than mixing rate, on the process.