Agrofood Waste and By-Product Valorization, Extraction, and Characterization of Pectin from the Waste Biomass Fruit Peel of Aframomum angustifolium Using Response Surface Methodology as Alternative Sources of a Functional Pectin

Applications of pectin in the food industry are strongly influenced by their source, structures, and extraction methods, which affect their functionalities. This research aims to extract and assess pectin’s physicochemical and functional properties from waste biomass peels of Aframomum angustifolium as an alternate source using acid (AAE) and microwave extraction (MAE) methods. Pectin extracted from A. angustifolium was compared based on yield, color, moisture, equivalent weight, methoxyl content (MC), and degree of esterification (DegE). Response surface experimental design was used to study the effect of the extraction process pectin such as the yield and the DegE. MAE had a significantly higher % yield of 4.74 ± 0.1% and a lower equivalent weight of 852.49 ± 16.59 mg/ml than AAE with 3.09 ± 0.03% and 882.1 ± 9.04 mg/ml, respectively, with light brown color. The lower moisture contents of 6.5%, MC of 33.06%, and DegE of 67.96% were obtained by MAE compared to 6.9%, 31.85%, and 66.61%, respectively, for AAE. The time and temperature had a positive significant effect ( $p$ < 0.05) on % pectin yield for MAE and AAE, while time and pH squared had a negative. Temperature squared had a negative significance on % DE, and pH had a positive significance using AAE and MAE. Optimal conditions for MAE obtained were the power of 555.18W, pH of 2.79, and time of 40.69 min with optimum desirability of 0.829, while for acid extraction, the temperature of 72.95°C, pH of 2.31, and time of 142.55 min with the desirability of 0.88. A highly functionalized pectin can be extracted from the peels of A. angustifolium as an alternate source.