Effect of Ultrasound Time and Acid Type on the Qualitative Properties of Extracted High Methoxyl Pectin from Quince Fruit

Background and Objectives: Pectin is a complex mixture of polysaccharides that is widely used in the food industry as a gelling agent, stabilizer and emulsifier. The aim of this study was to investigate the efficiency and physicochemical properties of extracted pectin from quince fruit using ultrasound.  Materials & Methods: Pectin was extracted by ultrasound under the power of 320 W, two types of acids (HCL and citric acid), pH=2, time=30, 60 and 90 min, and temperature=60 °C. Then the physicochemical properties of pectin such as content of galactoronic acid, esterification degree, emulsifier properties, extraction efficiency, and rheological properties were investigated. Results: The results showed that pectin had an efficiency of 9.28% and a reasonable purity (with galacturonic acid content of 74.95%). The study of degree of extraction revealed that the pectin derived from quince fruit at 60 and 90 min of ultrasound and extraction with HCL was high methoxyl (HM) pectin. The pectin’s emulsifying activity was high. The viscosity results illustrated that the pectin solutions obtained from quince fruit by HCL at 30 min had a pseudo-plastic behavior, and at 60 and 90 min of ultra sonication and at higher shear rate, they had Newtonian behavior. Conclusion: Good degree of purity and acceptable physicochemical properties of the obtained pectin show that this agricultural product can be used as a promising source for pectin production.