Physicochemical characteristics, rheology, and emulsifying properties of ultrasound-extracted pectin from 'saba' banana peel

Banana peel is an abundant agricultural waste in the Philippines. Valorization of the waste was done by extracting pectin from the 'saba' banana peel using ultrasound technology. The ultrasound-extracted pectin (UEP) was characterized physicochemically. UEP was also compared with commercial low-methoxy pectin (LMP) in terms of rheology and emulsification ability. Results showed that UEP has higher protein and ash content, and lower methoxyl, total pectic content, and interfacial tension. During the emulsion preparation, increasing the concentration of both UEP and LMP resulted in an increased production of stable emulsion droplets. Also, UEP-stabilized emulsion had improved stability when higher oil fraction and ionic strength were used. In terms of pH, higher volumes of stable emulsion were produced by UEP and LMP at conditions close to pectin's isoelectric pH. Lastly, UEP and LMP produced emulsions that were stable in all stages of in vitro digestion.