Pectin from sunflower by-product: Optimization of ultrasound-assisted extraction, characterization, and functional analysis

In the current study, sunflower by-product pectin (SFBP) was obtained using ultrasound-assisted extraction (UAE) technique. The UAE variables were successfully optimized, and the optimal condition (irradiation time 30 min, temperature 33 °C and ultrasound power 400 W) yielded 11.15%. Under this condition, SFBP was rich in low-esterified galacturonic acid content (72.94%), and had long side branches of galactan, arabinogalactan, and arabinan, with an average molecular weight of 175.353 kDa. The structural properties were characterized using FTIR, NMR, XRD spectroscopies. The thermal analysis by DSC and TGA suggested suitable thermal stability for SFBP. The solubility, water and oil holding capacities, emulsifying capacity, emulsifying stability (vs various conditions), foam capacity, foam stability, DPPH and ABTS inhibitions, and reducing power assay were measured to evaluate the potential of SFBP to be considered as a food ingredient.