COMPARATIVE EXTRACTION AND PHYSICOCHEMICAL CHARACTERIZATION OF PECTIN FROM Citrus sinensis AND Citrus limon PEELS BY ACID ASSISTED EXTRACTION

Citrus peel residues are promising renewable feedstocks for the recovery of pectin and other value-added biopolymers. This study comparatively evaluated pectin extracted from orange (Citrus sinensis) and lemon (Citrus limon) peels using conventional hydrochloric acid assisted extraction. Dried peel powders were extracted at pH 2.0 and 80 °C for 60 min, followed by filtration, ethanol precipitation, washing, drying, and physicochemical characterization. Pectin yield, moisture content, ash content, equivalent weight, methoxyl content, anhydrouronic acid (AUA) content, and degree of esterification (DE) were determined using conventional gravimetric and titrimetric procedures. Based on the results, orange peel produced a higher pectin yield (18.60 ± 0.17%) than lemon peel (16.80 ± 0.20%). Moisture contents were 8.20 ± 0.20% and 7.60 ± 0.20%, while ash contents were 2.90 ± 0.10% and 2.50 ± 0.10% for orange and lemon pectins, respectively. Equivalent weights were 945.33 ± 5.51 and 980.67 ± 5.51, respectively, whereas methoxyl contents were 7.10 ± 0.20% and 6.80 ± 0.20%. The AUA contents were 72.40 ± 0.60% for orange pectin and 74.10 ± 0.60% for lemon pectin. Statistical analysis indicated significant differences between the two sources in yield, moisture, ash, equivalent weight, AUA and DE, whereas methoxyl content did not differ significantly (p > 0.05). However, DE gives approximately 55.7% and 52.1% for orange and lemon pectins, respectively. Overall, the findings demonstrate the potential of locally available citrus peels as feedstocks for pectin recovery and agro residue valorization.