Evaluation of the Consistency of Low-Fat Mayonnaise by Squeezing Flow Viscometry

Abstract

Lubricated squeezing flow viscometry was applied for the evaluation of the consistency of mayonnaise samples of 50% w/w oil content. Mayonnaise samples were prepared with the addition of four stabilizers: sodium alginate, xanthan gum, guar gum and carboxymethyl cellulose (CMC). Each stabilizer was added individually at concentrations from 0.5 to 2% w/w. In addition, a series of nine mayonnaise samples was prepared with mixtures of xanthan gum and guar gum in various ratios, at 1.5% w/w total concentration, aiming to determine synergistic effects between the two stabilizers. All samples were characterized as pseudoplastic since flow behavior index was shown to be lower than unity. Biaxial elongational viscosity, expressed as stress growth coefficient, was determined at specimen's compressive deformation 50%, because larger deformations lead to structural breakdown of highly viscous samples. Using the present method, the determination of stress growth coefficient was possible in the range from 40 to 300kPa·s. In all samples, stress growth coefficient was shown to increase with increasing concentrations of stabilizers. At concentrations ranging from 1.0 to 1.5%, CMC provided the most viscous emulsions, followed by those with xanthan gum and sodium alginate, while those with guar gum appeared as the least viscous. Conversely, at concentration of 0.75%, CMC was shown to be unable to form a sufficient network, thus providing a less viscous emulsion than the one by xanthan gum. All mixtures of xanthan gum and guar gum revealed synergistic action, where the highest stress growth coefficient values were observed in samples with xanthan gum/guar gum ratios of 30:70 and 40:60. The above mentioned values were higher by two or threefold (p<0.05) compared to those of samples of equal concentration (1.5%) prepared with the addition of xanthan gum or guar gum alone, respectively.