Physicochemical characterization, and carbohydrate composition of pectin from sweet potato (Ipomoea batatas) and Irish potato (Solanum tuberosum) peels

Introduction: Pectin is a naturally occurring polysaccharide widely used in the food and pharmaceutical industries because of its excellent gelling, stabilizing, and thickening properties. Commercial pectin is primarily obtained from citrus peels and apple pomace, however, the search for alternative, low-cost, and sustainable sources has increased due to the abundance of agricultural wastes. Therefore, this study evaluated the extraction, physicochemical characteristics, and carbohydrate composition of pectin isolated from sweet potato (Ipomoea batatas) and Irish potato (Solanum tuberosum) peels.
Methods: Pectin was extracted from dried sweet potato and Irish potato peels using hydrochloric acid under acidic condition. The extracts were evaluated for percentage yield, equivalent weight, moisture, ash, crude protein, and carbohydrate composition using standard analytical procedures and high-performance liquid chromatography (HPLC).
Results: Sweet potato peel produced a higher pectin yield (13.75%) than Irish potato peel (9.86%). The equivalent weight ranged from 3,333.33 to 5,000.00 mg/mol. Moisture, ash, and crude protein contents ranged from 12.79-13.24%, 3.47-4.13%, and 6.79-9.27%, respectively. Carbohydrate analysis showed glucose contents of 151.51–323.44 mg/g, sucrose 196.38-215.51 mg/g, fructose 118.84-137.96 mg/g, and maltose 95.99-114.08 mg/g. Raffinose (183.72 mg/g) was detected only in sweet potato pectin. Therefore, sweet potato pectin exhibited superior extraction yield, while both pectin extracts possessed acceptable physicochemical characteristics and distinct carbohydrate values that may influence their functional properties.
Conclusion: Sweet potato and Irish potato peels are promising alternative sources of pectin with acceptable physicochemical and carbohydrate composition. Their utilization for pectin production provides a sustainable approach to agricultural waste valorization, environmental protection, and the development of locally sourced pectin for food and pharmaceutical applications.