Water-based extraction of pectin from flavedo and albedo of orange peels

The extraction of pectin from orange peels has been studied at different sample to solvent ratios, different pHs and with different extraction techniques using water. The highest pectin and total nitrogen was produced by a sample to solvent ratio of 1: 12.5. The amount of pectin extracted reduces as the pH increased, while the extractability of crude protein is not affected so significantly. Previous workers have found similar results. Considerably more pectin was obtained by the Soxhlet method than by microwave extraction by a factor of two, with a longer extraction duration than the microwave extraction by a factor of 240, so microwave extraction showed a much higher extraction rate (per unit time) by a factor of 120. Pectin existed mainly in the albedo, but the flavedo still contained 27% of the amount of pectin in the total extract. The total pectin yield from the dried peel was 2.2%. The combination of hand-pressure and microwave on pectin yield from flavedo was 12% better than hand-pressure alone, which was also better than microwave extraction alone. (c) 2006 Elsevier B.V. All rights reserved.