Ultrasonic-assisted extraction of dietary fibers from fenugreek seeds

In this study, soluble and insoluble dietary fibers were extracted from fenugreek ( Trigonella-foenum graecum L. ) seeds using the ultrasonic-assisted extraction method and the fibers were characterized. The effects of the solid-solvent ratio, ultrasonic amplitude and extraction time were investigated using the response surface methodology to obtain the highest total dietary fiber yield. In addition, functional and physicochemical properties of soluble and insoluble dietary fibers such as water holding capacity, oil holding capacity, swelling capacity, glucose adsorption index and alpha-amylase inhibition capacity were determined. The optimum process conditions were determined as follows: the solid-solvent ratio of 52.83 g/L, ultrasonic amplitude of 57.86 % and extraction time of 24.68 min. At these conditions, insoluble dietary fiber yield was 50.73 % and soluble dietary fiber yield was 28.67 %. According to the characterization results, insoluble dietary fiber achieved better physicochemical and functional properties compared to soluble dietary fiber.