Abstract:Pomelo peels are abundant in pectin. This study investigated molecular structure and rheological properties of pectin extracted from various parts of the pomelo fruit using high-performance liquid chromatography (HPLC), fourier transform infrared spectroscopy (FTIR), and rheometry to facilitate personalized applications and resource utilization of pomelo byproducts. Results showed that the galacturonic acid content of pectin from pomelo endocarp and peel was 75.13% and 87.33%, respectively, while degree of esterification was 65.69% and 64.04%, respectively. Both endocarp and peel pectin were classified as high methoxyl pectin. The endocarp pectin exhibited the highest peak molecular weight (2.02×105 Da) when compared to citrus and peel pectin. The main neutral sugars present in endocarp and peel pectin comprised GalA, rhamnose, arabinose, and galactose. Pectins from endocarp and peel had flow behavior indices of 0.508 and 0.635, respectively, both lower than 1, indicating that they belonged to pseudoplastic fluids with shear-thinning behavior. The pectin from pomelo endocarp showed higher apparent viscosity, storage and loss modulus compared to other pectins, suggesting better thickening and gelling properties compared to both pomelo peel and commercial citrus pectin. This research may establish a theoretical foundation for the exploitation and utilization of pomelo peel resources.
