Effects of psyllium husk powder on the emulsifying stability, rheological properties, microstructure, and oxidative stability of oil-in-water emulsions

Abstract

Psyllium husk powder (PHP) is a natural food hydrocolloid. This study was conducted to examine the changes of PHP-soybean oil emulsions affected by PHP concentrations. The emulsifying stability, rheological properties, microstructure and oxidative stability of four levels of PHP emulsions (0.3%, 0.4%, 0.5%, 0.6%, w/w) were determined. Results showed that the emulsion stability, the apparent viscosity, the storage modulus, and the loss modulus were increased with the incremental PHP concentration, whilst the emulsion droplet size, the surface tension, the peroxide value, and the thiobarbituric acid reactive substance value were decreased. The PHP formed a network structure around the oil droplets evidenced by cryo-scanning electron microscopy. The decreased oil droplet size and incremental viscosity might the reasons for the increase of emulsions stability and oxidative stability as the PHP concentration increased. The above results indicate that PHP could be an efficient emulsifier to form a stable oil-in-water emulsion and have a potential application for the food industry. • Psyllium husk powder (PHP) could be used as a potential edible stabilizer. • The emulsion stability was increased with the PHP concentrations. • Higher PHP concentrations led to the formation of smaller emulsion droplets. • Emulsions with high PHP concentrations showed higher oxidative stability.