Optimization and characterization of walnut beverage emulsions in relation to their composition and structure.
A central composite rotatable design (CCRD) was used to evaluate the effects of walnut oil (WO, 3-6%, w/w) and gum arabic (GA, 5-10%, w/w) on the average droplet size (D(32)), specific surface area (SSA), polydispersity index (span), apparent viscosity, interfacial tension and opacity of walnut-beverage emulsions. The response surface methodology (RSM) showed that the significant second-order polynomial regression equations with high R(2) (>0.95) were successfully fitted for all responses as function of independent variables. The linear effect of WO had a significant term in all reduced models. The overall optimum region was found to be at the combined level of 10% (w/w) GA content and 5.84% (w/w) WO concentration. At this optimum point, D(32), SSA, span, apparent viscosity, interfacial tension and opacity of emulsions were 0.609 μm, 8.236 m(2)/ml, 0.886, 1.336 Pa s, 51.37 mN/m and 0.810, respectively. No significant (p>0.05) difference was found between the actual values and predicted values. Moreover, principal component analysis (PCA), conducted via PCA variable loadings and cluster dendrogram was able to discriminate the emulsions with different formulations into separate classes.
Department of Food Science, Engineering and Technology, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran.
Seyed Mohammad Taghi
SM
Gharibzahedi
Seyed Mohammad
SM
Mousavi
Faramarz
F
Khodaiyan
Manouchehr
M
Hamedi
D001628:Beverages; D004655:Emulsions; D061353:Food Storage; D006170:Gum Arabic / Q000737:chemistry; D031324:Juglans / Q000737:chemistry*; D010938:Plant Oils / Q000737:chemistry; D013500:Surface Tension; D014783:Viscosity
D004655:Emulsions; D010938:Plant Oils; D006170:Gum Arabic