Physicochemical and rheological characterization of pectin-rich fraction from blueberry (Vaccinium ashei) wine pomace

Blueberry wine pomace is rich in pectin, which has been extensively used as a functional dietary fiber and a rheological modifier in the food industry. This paper reports a method to extract the pectin-rich fraction (PF) with a mediate degree of esterification of 51.66% from blueberry wine pomace and provides insight into its relationship between the structure and rheological properties. The impacts of related extrinsic factors, such as sucrose, ions and pH, were also studied in view of food applications. The viscosity of PF aqueous dispersion gradually increased with its concentration. The addition of sucrose, CaCl2 or NaCl to the solution resulted in increased viscosity. Flow ever, the elevations in temperature and pH led to decrease in solution viscosity. The viscoelastic property of PF dispersion displayed strong temperature dependence but weak frequency dependence. This was largely due to PF concentration, sucrose, CaCl2 and solution pH. The present study revealed the unique characteristic of medium-methoxylated pectin fraction and the obtained results are helpful in value-added utilization of blueberry wine pomace. (C) 2019 Elsevier B.V. All rights reserved.