Effects of isolation conditions on structural and functional properties of the seed gum from Chinese quince (Chaenomeles sinensis).

Chinese quince seed gum (CQSG) extracted under water-, alkali- and acid- conditions at 25, 50, and 80 °C, were evaluated in terms of yield, monosaccharide composition, molecular distribution, thermal gravimetry, emulsifying stability, rheological properties, and free radical scavenging ability. The results showed that the yield of CQSG increased to 3.9% after water extraction at 80 °C. Alkali and acid treatments promoted the conversion of neutral sugars to the uronic acid branch. Regardless of the extraction temperature, the xylose chain was the main component (35%-40%); however, a reduction was observed as the extraction temperature increased to 80 °C. All CQSG solutions extracted under these isolation conditions exhibited non-Newtonian rheological behavior. Compared to water-extracted samples, the alkali-extracted samples showed the worst thermal stability, while the acid-treated samples showed the worst emulsifying stability. This study provides theoretical support for the potential application of CQSG polysaccharides in the food and pharmaceutical industries.