A Comparison of Lime and Orange Pectin Which Were Rapidly Extracted From Albedo

Pectin was acid extracted from lime albedo by microwave heating under pressure. Extraction times ranged from 1 to 10 minutes. Solubilized pectin was characterized for molar mass (M), rms (root mean square) radius of gyration (Rg) and intrinsic viscosity (o) by HPSEC with online light scattering and viscosity detection. M, Rg and 0 were relatively constant up to an extraction time of 3 minutes, but decreased rapidly thereafter. At heating times of 3.0 minutes or less, M, Rg and 0 were significantly higher than for a commercial citrus pectin. At a heating time of 2.5 minutes, weight average molar mass (Mw) was 335 H 103, Z-average rms radius of gyration (Rgz) was 42 nm and weight average intrinsic viscosity (Ow) was 10.5 dL/g. These values were comparable to values for orange albedo pectin which were obtained previously by microwave heating under pressure (Fishman et al., Carbohydr. Res. 323, 126, 2000). Furthermore gel strength measurements revealed that the gel strength order was lime > orange > commercial citrus pectin.