Abstract:

【Objective】 In order to provide a theoretical basis for development and utilization of the pectin resources in sweetpotato residues, the characteristics of pectin and its emulsion properties were investigated. 【Method】 The pectin was extracted by using hydrochloric acid solution, in which, the galacturonic acid content, degree of esterification (DE) and molecular weight were determined by carbazole and sulphuric acid spectrophotometric determination method, titration method and HPLC, respectively. The effects of different pectin concentrations (0.5%-4.0%, w/v) and oil-phase volume fraction (5%-40%, v/v) on emulsion properties of sweetpotato pectin were studied. 【Result】 The galacturonic content, DE and molecular weight of sweetpotato pectin were 73.28%, 31.71% and 292 kD, respectively. With increasing the pectin concentration, the particle size (d4,3) of emulsion decreased, while adsorbed fraction of pectin onto emulsion droplets, apparent viscosity of emulsion, the emulsion activity (EA) and emulsion stability (ES) of emulsion increased (P＜0.05). Furthermore, with increasing the oil-phase volume fraction, d43, EA and the apparent viscosity of emulsion increased (P＜0.05), whereas the value of adsorbed fraction of pectin onto emulsion droplets and ES presented a trend of increasing firstly and then decreasing. 【Conclusion】 Sweetpotato starch residues is a kind of potential resource for pectin extraction, the pectin extracted by using acid solution belongs to low methoxy pectin, which has excellent emulsion ability and emulsion stability.

Key words: sweetpotato residues')">sweetpotato residues, sweetpotato pectin, degree of esterification, molecular weight, emulsion properties