Abstract
This study employed response surface methodology to optimize the conditions for ultrahigh-pressure-assisted enzymatic extraction (UHPEE) of pectin from hawthorn using cellulase. The effects of this method on the characteristics of the extracted pectin were investigated. The optimal extraction parameters were determined to be a solid-to-liquid ratio of 1:70 g/mL, an extraction pressure of approximately 300 MPa, and a holding time of roughly 600 s, yielding a pectin recovery of 4.02%. The optimized UHPEE process resulted in reductions in both the degree of esterification and molecular weight of the pectin, while concurrently increasing the content of total galacturonic acid and total polyphenols. Ion chromatography analysis identified five monosaccharides in the hawthorn pectin, with galacturonic acid being the most predominant. Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) analyses revealed the presence of characteristic absorption peaks of pectin and a rough surface topology with a loose, flaky structure, respectively. Rheological measurements demonstrated that the hawthorn pectin exhibited shear-thinning behavior, characteristic of a pseudoplastic fluid. In vitro antioxidant assays showed that hawthorn pectin scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals with a rate of 92.72%, comparably to vitamin C at the same concentration (96.30%). These results indicate that the optimized UHPEE method is a more efficient technique for extracting hawthorn pectin and effectively enhances its antioxidant activity, suggesting its potential application in the food industry.