Extrusion of apple pomace facilitates pectin extraction

Twin-screw extruder was employed to disintegrate apple pomace (UP) to facilitate production of apple pectins by water extraction. UP was extruded under different conditions of screw speed, 250-350 rpm; feed rate, 30-40 kg/h; moisture, 20-30%, The yield of water soluble polysaccharides (WSP) increased with increasing specific mechanical energy (SME), but intrinsic viscosity decreased with in creasing SME. Considering both the WSP yield (g/dL) and intrinsic viscosity (dL/g), a dimensionless term, product yield x intrinsic viscosity ([eta]), was an objective function for optimizing conditions for the solubilization of Up polysaccharides. Y[eta] of pectins in extruded WSP ranged 0.59-1.34, while acid extracted WSP had Y[eta] Of 1.12. Extruded WSP with Y[eta] comparable to acid extraction was obtained in the SME ranges of 110-170 kWh/h.