Dietary fiber from coconut residue: effects of different treatments and particle size on the hydration properties

Abstract

The present work is aimed at the production of dietary fiber from underutilized coconut residue left after the extraction of milk, by subjecting it to physical treatments such as water washing, hot water washing, boiling water washing and pressure cooking, as well as solvent extraction. The fat content was reduced from 62% to 45% and 41% by treatment with boiling water and pressure-cooking, respectively. Water-holding, water retention and swelling capacities increased with decreasing fat content. A marked increase was observed in hydration properties when the fat content decreased from 10 to 2%. The hydration properties were maximum for 550 μm particle size coconut fiber. For the higher particle size (1,127 μm), the oil was trapped inside the fiber matrix, resulting in decreased hydration properties, whereas for the lower particle size (390 μm) the rupture of the fiber matrix was responsible for low hydration properties. An attempt was made to compare the hydration properties of coconut dietary fiber with other commercially available dietary fibers.