Influence of Citric Acid and Hydrochloric Acid with High-Pressure Processing on Characteristics of Pectic Polysaccharide from Choerospondias axillaris Fruit Peel

The aim of this study was to investigate the influence of citric acid combined with high-pressure processing (HPP) on the characteristics of pectic polysaccharide of Choerospondias axillaris fruit peel (CPP). Therefore, the physicochemical, structural, and emulsifying properties of CPP extracted by hydrochloric acid (HEP), HPP-assisted hydrochloric acid (HEP + HPP), citric acid (CEP), and HPP-assisted citric acid (CEP + HPP) were analyzed. Results showed that citric acid and HPP had a synergetic impact on extraction yield, weight-average molecular weight (Mw), emulsion ability (EA), and apparent viscosity of CPP; hence, the highest extraction yield (48.49%) and EA (70.25%) coupled with the lowest Mw (263.80 kDa) and apparent viscosity were observed in CEP + HPP. However, the effects of citric acid and HPP on DA, DM, and GalA of CPP were opposite. The lowest DA and DM were found in HEP + HPP. Moreover, both citric acid and HPP had great influences on the structure of CPP. The CPP extracted by citric acid had a lower crystallinity, and the microstructure of CPP extracted with HPP assistance was rougher. In summary, HPP-assisted citric acid extraction could improve the extraction yield and emulsion property of CPP.