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

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.

Automated summary

The study found that increasing Psyllium husk powder concentration in the PHP-soybean oil emulsions resulted in increased emulsion stability, viscosity, storage modulus, while decreased emulsion droplet size, surface tension, peroxide value. Furthermore, PHP formed a network structure around the oil droplets, contributing to the improved emulsion stability and oxidative stability.