Time-dependent extraction of pectins from jabuticaba peel using hydrothermal, microwave, and ultrasound methods: Physicochemical and morphological characterization

This study evaluated the influence of extraction time and method, namely hydrothermal (HDE), microwave assisted (MAE) and ultrasound assisted (UAE), on the yield and characterization of pectin extracted from jabuticaba peel. Extractions were conducted at 1, 3 and 5 min for HDE (HDE1, HDE3 and HDE5) and MAE (MAE1, MAE3 and MAE5), and at 15, 25 and 35 min for UAE (UAE15, UAE25 and UAE35). Conventional extraction (CE) at 100°C for 35 min was used as a control. The highest yields were obtained by HDE (20.72–39.79%), particularly HDE3 (p < 0.05). CE produced pectin with greater structural integrity but lower yield (10.82%) (p < 0.05). UAE25 (20.25%) and MAE3 (29.17%) exhibited the lowest degree of esterification (DE), suggesting partial depolymerization under more intense conditions. MAE samples presented the highest galacturonic acid contents (71.53–76.36%), indicating high purity. Gel strength in UAE15 (52.82g) and UAE25 (49.15g) was comparable to CE (57.51g), showing cohesive gel formation even with lower DE. Color, structural and morphological analyses revealed changes dependent on extraction time and method. Overall, appropriate time control is crucial to preserve pectin quality, and intensified processes, particularly HDE1 and HDE3, are promising sustainable alternatives to CE for the valorization of agro industrial residues.