Using inverse numerical method in modeling of microwave-assisted extraction of galactomannans obtained from Trigonella foenum - graceum and Gleditsia caspica seeds: Measurement of mass transfer coefficients

Due to the increasing use of biopolymers in food formulations, introducing new hydrocolloid sources has become particularly important. Numerous researches have been done on aqueous extraction or new extraction methods such as extraction with microwave pretreatment, but in most cases, the engineering part of these processes has been neglected. In this study, the main purpose was to investigate the mass transfer in the process of microwave-assisted extraction of galactomannan from two plant seeds using a new method known as inverse numerical method. To achieve this goal, the concentration of galactomannan extracted from both plant seeds was obtained against time and the experimental data and the data predicted by the software (based on the simulation) were compared which indicated proper convergence between these data. Effective parameters in mass transfer including dispersion coefficient (E), diffusion coefficient (D) and total mass transfer coefficient (kc) were in the range of 1.12 – 1.63×10-12, 2.30 – 3.28×10-8 and 1.54 – 2.25×10-7  m2/s for fenugreek galactomannan and 1.27 – 1.76×10-12, 2.55 – 3.52×10-8 and 1.85 – 2.30×10-7m2/s for Gleditsia caspica galactomannan. The difference between the values obtained for the two galactomannans could be attributed to the seed type, hardness or softness of the seed wall and characteristics of the target component. According to the obtained results, inverse numerical method could be introduced as an acceptable and effective method for modeling of the extraction process of both galactomannans.