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 ext ruded under different conditions of screw speed, 250-350 rpm; feed rat e, 30-40 kg/h; moisture, 20-30%, The yield of water soluble polysaccha rides (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 dimensionl ess term, product yield x intrinsic viscosity ([eta]), was an objectiv e function for optimizing conditions for the solubilization of Up poly saccharides. 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] compa rable to acid extraction was obtained in the SME ranges of 110-170 kWh /h.