Physicochemical and functional characterization of pectin extracted from Moroccan citrus peels

Three Moroccan citrus peels, such as orange, lemon, and bigarade, were chosen to extract the pectin using Box Behnken Design. At a temperature of 90 degrees C, pH = 1.5, and extraction time = 120 min, a high pectin yield was recorded with 28.57, 26.86, and 26.55% for lemon (LPP), bigarade (BPP), and orange (OPP) peel pectins respectively. The extracted pectins have a less branched linear structure with high GalA contents for BPP (86.0 mol%), LPP (82.0 mol%), and OPP (79.0 mol%), and a high degree of methyl esterification (> 74%), but a low degree of acetylation (< 4%). A narrow and homogeneous distribution was recorded with a higher average Mw for LPP (90.0 kDa) than OPP (88.0 kDa) and BPP (80.0 kDa). One gram of Moroccan citrus pectin could hold more than 23.0 g of water. The high emulsifying activity was recorded for the three citrus pectins (similar to 50%), with higher emulsion stability for BPP pectin at 4 degrees C (94.42%). Furthermore, all extracted pectins exhibit a significantly non-Newtonian pseudoplastic behavior when the concentration increases. At 3% concentration, the apparent viscosity of BPP was higher than that of OPP and LPP with 40.26, 13.45, and 6.85 Pa s, respectively.

Automated summary

In this study, pectin was extracted from lemon, bigarade, and orange peels using Box Behnken Design. The extracted pectins had a less branched linear structure, high GalA content, and high degree of methyl esterification. The pectins also exhibited high emulsifying activity and non-Newtonian pseudoplastic behavior.