Characterization of hawthorn pectin gained via different ethanol concentrations

Abstract

Pectin is identified as an effective delivery material due to its excellent gel-forming ability, low immunogenic properties, biocompatibility, and biodegradability. These excellent properties depend on the preparation method of pectin. In the study, four pectin fractions (named: CAHP30, CAHP40, CAHP50, and CAHP60, respectively) were obtained by different ethanol precipitations (30%, 40%, 50%, and 60%). Physicochemical properties, antioxidant activity, and emulsifying ability of HP were investigated and analyzed. Results showed that the surface structure of pectin was changed by ethanol fractional precipitation, and four fractions were low methoxy pectin. They had different monosaccharide compositions, but all rich in GalA. The Mw/Mn of CAHP30, CAHP40, CAHP50, and CAHP60 were 3.29, 2.57, 2.66, and 2.77, respectively. CAHP30 and CAHP60 had excellent emulsifying ability; moreover, CAHP60 was endowed with additional lipid antioxidant capacity and had the best thermal stability. E-CAHP40 exhibited a property between the entangled network structure. Overall, pectin with specific properties could be obtained by different ethanol concentrations.

Keywords: characterization; ethanol precipitation; hawthorn; pectin.

FIGURE 1

The UV spectrum of four pectin fractions (a), FTIR spectra in the range of 4000–400 cm⁻¹ of four pectin fractions (b), and changes in absorption wavelength maximum of mixture of Congo red and four pectin fractions (c).

FIGURE 2

Scanning electron microphotographs (SEM) of CAHP30 (a), CAHP40 (b), CAHP50 (c), and CAHP60 (d). The magnification of (a–d) is ×150.

FIGURE 3

DSC thermograms (a), thermogravimetric (TG, b), and thermogravimetric (DTG, c) of four pectin fractions.

FIGURE 4

Digital photos during storage with CAHP30, CAHP40, CAHP50, and CAHP60 stabilized oil‐in‐water emulsions (a) and optical micrographs preserved for 30 days (b).

FIGURE 5

The particle size distribution of emulsion after storage for 30 days (a), creaming index (CI) of emulsion prepared with different pectin fractions (b), and emulsifying capacity (EC) and emulsifying stability (ES) of emulsion prepared with different pectin fractions (c).

FIGURE 6

Viscosity of emulsion prepared with four pectin fractions (a), the frequency dependence of storage modulus and loss modulus (b), and damping factor (c) of emulsion prepared with four fractions.

FIGURE 7

Effect of ethanol fractionation on hydroxyl radical scavenging capacity (a), ABTS radical scavenging capacity (b), and reducing power (c) of pectin fractions.