Ultrasonication of mayonnaise formulated with xanthan and guar gums: Rheological modeling, effects on optical properties and emulsion stability

The present research explored the potential of probe ultrasound homogenizer and hydrocolloids in formulating and stabilizing mayonnaise. The effect of ultrasonic (US) treatment (12 min at 20%, 30%, 40% amplitude) and stabilizers xanthan gum (XG; 0.5% w/w), guar gum (GG; 0.5% w/w), and XG/GG (1:1) on emulsion storage stability (ESS), physicochemical and rheological properties of mayonnaise were studied. Rheological data comprising of shear rate (gamma) and shear stress (tau) was analysed through four different rheological models (Herschel-Bulkley, Casson, Power Law, and Carreau-Yasuda models), and their fitness was evaluated. The samples exhibited non-Newtonian, pseudoplastic behaviour with flow behaviour index (n) < 1 and consistency index (K) 43.58-72.38 Pa sn. The apparent viscosity measured at a shear rate of 0-20/sec, was decreased steeply, by the application of 40% amplitude, most prominent in GG samples (1007 Pa s to 608 Pa s) while compared with XG (1625 Pa s to 1304 Pa s). The increase in US amplitude caused a linear increase in the refractive index (ranging from 1.3681 to 1.3791) and decreased pH (ranging from 3.686 to 3.523). A significant reduction in whiteness (L* value) from 78.300 to 73.860 was noted for XG/GG (1:1) samples. The ESS decreased with an increase in US amplitude, and 40% US amplitude-modulated GG sample had the least ESS (90.14%) among all treated and control samples. However, treated samples had higher ESS than the market sample (86.50%).