Characterization of dietary fiber from coffee silverskin: An optimization study using response surface methodology

•Coffee silverskin dietary fiber (DF) isolated by alkaline hydrogen peroxide method.•DF's loss, protein, cellulose, color, water and oil holding capacity were assessed.•The extraction procedure optimized using response surface methodology.•The desirability function approach which used for multiple optimizations was 0.89.

Coffee silverskin dietary fiber (DF) was obtained by alkaline hydrogen peroxide (AHP) extraction procedure. Response surface methodology was used to study the effect of temperature (25, 40, & 55 °С), hydrogen peroxide (HP) concentration (2, 6, & 10% v/v), pH (9, 10, 11,& 12), and time (1, 6, 12, 18, & 24 h) of AHP treatment on loss, protein removal (PR), cellulose content, whiteness index (WI), water holding capacity (WHC) and oil holding capacity (OHC). AHP treatment (extraction time 18 h, extraction temperature 25 °С, HP concentration 6%v/v, & pH 12) enhanced the cellulose content of CS from 34-67.4%. The desirability function approach which used to perform multiple optimizations was 0.89, indicating the distance of the lower and upper limits relative to the actual optimum was highly suitable. The optimum isolation conditions were: extraction time 9.25 h, extraction temperature 37.34 °C, HP concentration 10%v/v, & pH 10.54. At optimum condition, WI, WHC, OHC, loss, & PR of DF were 80.30, 8.18 & 5.27, 40.05, 89.04%, respectively. The results suggested CS could be used as a source of insoluble DF especially cellulose in food formulations.

Graphical abstractThe desirability function values of target responses in optimized extraction process of dietary fiber from silver skin.Download full-size image