Influence of process variables on the green microwave-assisted low-methoxyl pectin extraction from Calamansi peels using citric acid
Year: 2026
Type: preprint
Abstract: The Philippines generates substantial amounts of Calamansi (Citrus microcarpa) residues from various industrial production and processing, making its peel an abundant yet underutilized agro-industrial pectin-rich waste resource. Conventional pectin extraction commonly relies on mineral acids and prolonged heating, increasing chemical and energy demands, which can be addressed using microwave-assisted extraction using a green solvent such as citric acid. This study investigated the effects and interactions of microwave and solvent treatment parameters in citric acid-assisted microwave extraction of pectin from Calamansi peel. Calamansi peel pectin (CPP) was extracted with varying CA concentration (5%, 10%, 15% w/v), extraction power (100 W, 200 W, 300 W), and extraction time (60 s, 120 s, 180 s) using a face-centered central composite design. Citric acid concentration and extraction time were shown to have a statistically significant effect on the pectin yield (p < 0.01). The highest yield was achieved at 15% citric acid concentration, 300 W extraction power, and 180 s extraction time. Validation was conducted with three replicates, resulting in a mean yield of 27.72 ± 4.17% and a relative standard error of 12.26%, indicating a statistically reliable model. The extracted pectin was also characterized based on its equivalent weight (483.77 ± 26.37 g/mol), methoxy content (3.95 ± 0.82%), degree of esterification (35.19 ± 3.14%), and anhydrouronic acid (57.63 ± 8.21%).
Source: Research Square
Institutions: De La Salle University, Sultan Kudarat State University
Language: English
Subfield: Food Science
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7214730944