Optimization extraction and functional properties of soluble dietary fiber from pineapple pomace obtained by shear...

Response surface methodology (RSM) was used to optimize the extraction conditions for shear homogenization-assisted extraction of soluble dietary fiber from pineapple pomace (s-SDF), and the absorption capacities and antioxidant activities of the obtained s-SDF were also investigated. The optimum extraction conditions consisted of a cutting speed of 9000 rpm, a cutting time of 20 min, a cellulase content of 5.0%, a hydrolysis time of 120 min, a pH value of 4.5, a hydrolysis temperature of 50 °C, and a raw material to water ratio of 1 : 45 g mL^-1. Under these conditions, the theoretical and actual extraction yields of s-SDF were 8.80% and 8.76%, respectively. An absorption capacity analysis indicated that s-SDF exhibited higher absorption abilities to sodium cholate, cholesterol and fat. In addition, s-SDF possessed higher antioxidant activities, showing a positive concentration effect relationship for DPPH˙, ABTS⁺, ·OH and O₂ ^-˙. The concentration of 1.0 mg mL^-1 scavenged 76.72% DPPH˙, 58.40% ABTS⁺, 23.47% ·OH and 48.47% O₂ ^-˙, respectively, and the reduction power was 0.70. These results indicated that pineapple pomace is a potential source of natural dietary fiber and a potential functional food ingredient.