BACKGROUND: Pectin is a heteropolysaccharide used in pharmaceutical formulations as a binding agent. Importation of pectin costs billions of Philippine pesos, but the local laboratory-scale production of this excipient from fruit peel wastes is estimated to be cheaper by 80%.

OBJECTIVE: To address economic and environment concerns associated with pectin production, this study aimed to optimize the isolation and purification of pharmaceutical grade pectin from pomelo (Citrus maxima Merr.) fruit peel as basis for commercial-scale production.

METHODS: Pectin was extracted from pomelo using different solvents: 6.2% w/w citric acid, 1N acetic acid, 3N hydrochloric acid, 3N nitric acid, and 3N sulfuric acid. Temperatures for extracting pectin were explored at 40°C, 60°C, and 90°C. Obtained pectin samples were characterized based on the following parameters: equivalent weight (EW), methoxyl content (MC), ash content (AC), anhydrouronic acid content (AUA), and degree of esterification (DE).

RESULTS: Highest pectin yield (9.25%) was obtained using 3N nitric acid and 3N sulfuric acid at 90°C.Based from the pharmacopeial standards (MC ? 6.7, AUA ? 74.0), all the samples did not pass the parameters, except the pectin extracted using 3N sulfuric acid at 90°C (MC = 6.76, AUA = 74.61).

CONCLUSION: Among the different solvents used for extraction, 3N sulfuric acid produced the highest percent yield of pharmaceutical grade pectin from pomelo fruit peel. Its optimum temperature for extraction was at 90°C. The sample passed the USP standards of MC values not less than 6.76 and AUA values not less than 74. Under the following conditions, pomelo fruit peel have the potential for commercial-scale production of pharmaceutical grade pectin.