Valorization of pectic polysaccharides from Gardenia jasminoides Ellis flower: Physicochemical, structural, rheological, and functional properties

Abstract

Gardenia jasminoides Ellis is a widely cultivated garden plant, but its flower resources are underutilized. In this study, three pectic polysaccharides extracted from Gardenia flowers (GFPPs) were obtained, including acid-extracted pectin (ACP), hot water-extracted pectin (HWP), and alkaline-extracted pectin (ALP). The physicochemical, structural, rheological, and functional properties of GFPPs were compared and analyzed. The results showed that the yield of all GFPPs exceeded 21%, and the proportion of the rhamnogalacturonan I (RG-I) regions ranged from 42.20% to 54.66%. The GFPPs were identified as low-methoxyl pectin with a semi-crystalline and amorphous structure. Among them, ACP had the highest molecular weight and neutral sugar content, while ALP had the highest content of galacturonic acid and protein. Rheologically, all three GFPPs exhibited pseudoplastic behavior with thixotropic properties, particularly ACP. Storage at low temperatures increased the apparent viscosity of ACP and HWP, while that of ALP was decreased. Importantly, emulsions prepared with 2% GFPPs and 10% medium-chain triglycerides remained stable at 4 °C and 25 °C for 21 days. Moreover, the ALP-based emulsion demonstrated excellent emulsifying capability, maintaining stability at 60 °C for 21 days with an emulsion appearance. These findings suggest that GFPPs hold promise as a pectin source for hydrocolloids and can be used in various food applications.