Effect of Polysaccharide Compounds on the Stability of Oil-In-Water Emulsions during Storage

Abstract

Polysaccharides interact synergistically to form sedimentation-resistant emulsions. However, data on the effect of polysaccharide combinations on oxidative stability are scarce. Sedimentation and oxidative stability are equally important for fat emulsion products. In fact, emulsions owe their stability to various substances of polysaccharide nature. The research objective was to study the effect of polysaccharides and their combinations on the oxidative and sedimentation stability of direct emulsions during storage. The study involved direct emulsions of sunflower oil, stabilized polysaccharides, and their combinations. The dispersed phase of sunflower oil was gradually added to the continuous phase of dissolved polysaccharides with intensive stirring. The emulsions were stored at 60°C for eight days. The sedimentation stability was assessed by analyzing sedimentation rate, fractal dimension, lacunarity, and droplet size. The oxidative stability was studied using standard methods for determining the peroxide value and conjugated dienes. The emulsions had an average particle size from 6.78 ± 2.50 to 12.67 ± 6.53 µm. The samples based on xanthan gum and its combinations with other polysaccharides showed the highest sedimentation stability: exfoliated liquid proportion was 0–5.3%, highly esterified pectin being the only exception. The samples based on locust bean gum and its combination with low esterified pectin demonstrated the highest oxidative stability: peroxide value – 9.85 ± 0.45 mEq/kg. The lowest oxidative stability was found in the sample of locust bean gum with highly esterified pectin: peroxide value – 1.44 ± 0.85 mEq/kg. The combination of locust bean gum and xanthan gum provided satisfactory sedimentation (exfoliated liquid proportion – 2.2%) and oxidative (peroxide value – 11.8 ± 1.1 mEq/kg) stability of the emulsion. The experiment revealed weak correlation (r = – 0.096) between the sedimentary and oxidative stability parameters. Therefore, it was the nature of the polysaccharides themselves that affected these systems. The authors proposed such modes of action as metal chelating, free radical scavenging, and adding polysaccharide phenolic com-pounds. Combinations of different polysaccharides increased the sedimentation and oxidative stability of direct emulsions. The research results can help food producers to develop new types of stable emulsion-based fat products.