Effects of different extraction methods on the structure and function of blackberry seed polysaccharides

The different extraction methods including hot-water extraction, ultrasound-assisted extraction, and microwave-assisted extraction, enzyme-assisted extraction, ultrasound and microwave-assisted extraction, and ultrasound and enzyme-assisted extraction (UEE) methods were carried out to extract blackberry seed polysaccharides (BSPs). The extraction yield, structure, antioxidant capacity, and glucometabolic enzyme inhibition activities of BSPs were determined in this work. Extraction methods have no influence on the monosaccharide composition of BSPs but affected the molar ratio of monosaccharides. Fourier transform infrared spectroscopy and X-ray diffraction results showed that the extraction method cannot effect on the functional groups and crystal forms of BSPs. The findings also revealed that UEE led to the highest BSP extraction yield (4.56%), highest antioxidant capacities, and highest alpha-amylase (48.49%) and alpha-glucosidase (67.33%) inhibitory rates, which may because of the dispersed molecular weight distribution and loose microstructure of BSPs. These results suggest that UEE may be used in the industry to obtain BSPs with high functional activities.