Physicochemical Properties of Low-Molecular-Weight Homogalacturonan Pectin from Enzyme-Hydrolyzed Red Okra

Abstract

In this study, we focused on reducing the molecular weight of purified red okra pectin using various hydrolytic enzymes and evaluating its physicochemical properties or characterization. The enzyme treatments targeted both the main pectin chain and the side-chain sugars, resulting in a reduction in the molecular weight by approximately 10% (from 647 kDa) to 60% (down to 252 kDa). Both the purified red okra pectin and enzyme-treated pectins exhibited a homogalacturonan (HG)-type backbone. Fourier transform infrared (FT-IR) spectroscopy revealed a decrease in the absorbance peak for the pectin backbone (1200–1000 cm−1) in the low-molecular-weight (LMW) pectin. The most significant decrease was observed at 3300 cm−1 in pectin treated with both RGH+RGAE enzymes, indicating reduced sugar bonds. These results demonstrate the physicochemical changes in LMW red okra pectin following enzyme treatment and confirm its potential applications due to its unique characteristics.

Keywords

• polysaccharides
• enzymatic hydrolysis
• pectin modification
• red okra mucilage
• bioactive compounds