Stability, physical properties and acceptance of salad dressings containing saffron (Crocus sativus) or pomegranate juice powder as affected by high shear (HS) and ultrasonication (US) process

Abstract

The influence of preparation method, high shear (HS) or ultrasonic (US) homogenization on stability, physical and sensory attributes of salad dressings containing saffron and pomegranate juice has been investigated upon 6 months of ambient storage. Emulsified dressings were evaluated for stability, microstructure, viscoelastic properties, and acceptance. All samples processed by HS showed higher apparent viscosity, yield stress (τ0), storage and loss moduli (G′, G″), particle diameters, yellow-blue color (b values) and lower lightness (L) compared to their US counterparts. Ambiguous results depending on added constituents (saffron or pomegranate juice) were obtained regarding long term stability and red-green color (a), whereas total color change (TCD) of samples was unaffected. Pomegranate dressings prepared with HS exhibited enhanced viscoelastic character and high stability during storage (Back scattering variation, dBS ∼ 1%). US samples were equally accepted as their HS counterparts by panelists for most sensory attributes, but sonication clearly improved the color likeness of samples containing pomegranate by 51%. Saffron addition significantly improved the taste of the dressings.This study shows that ultrasonication may be used to ameliorate color attributes related to pomegranate juice addition homogenizating successfully these products without detrimental effects on their long-term stability i.e. product syneresis.