Characteristics and rheological properties of ammonium oxalate extracted rosehip pectin

Abstract

Abstract Rosehip fruits are an abundant source of bioactive compounds with enormous application in food technology, because of its nutritional and healthy properties. However, isolation and characterization of rosehip pectin remained challenges, because its properties depend on extraction procedure. Therefore, this study aims to evaluate the characteristics of ammonium oxalate-extracted rosehip pectin and its rheological behavior. Dried rosehip fruits (cultivar Plovdiv 1) were used for alcohol-insoluble solids (AIS) preparation. Rosehip pectin was extracted from AIS using 0.5% aqueous ammonium oxalate. The obtained polysaccharide was characterized with a degree of esterification 68%, degree of acetylation 1.0%, anhydrouronic acid content 87% and yield 13%. FTIR spectrum confirmed the pectin structure with typical bands, especially in finger print region showing the presence of α-(1→4)-bond between the galacturonic acid units. To the best of our knowledge, some physicochemical properties of rosehip pectin were evaluated for the first time. The rheological studies showed the non-Newtonian, shear-thinning and weak thixotropic behavior. The rosehip pectin demonstrated good swelling properties (22 ml/g), higher water holding capacity (6.04 g water/g sample), than oil-holding capacity (2.44 g oil/g sample). The obtained results highlighted that rosehips are rich in pectin with valuable rheological properties, revealing their potential use in food technology.