In this study, rheological properties of several food hydrocolloids (guar gum, xanthan gum and arabic gum) and
sweeteners (aspartame and stevioside) were evaluated using a rotational viscometer at concentrations of (0.5% and
1.2g/L for hydrocolloids and sweeteners, respectively), Hydrocolloids and sweeteners concentrations were selected
depending on preliminary sensory evaluation. The rheological properties for nectar samples were measured at
four temperatures (5, 25, 50 and 75°C). The flow behavior of the nectars was characterized as non-Newtonian
(pseudoplastic with yield stress). The pseudoplasticity increased due to hydrocolloids addition, while it decreased
due to sweeteners addition. Herschel-Bulkley and Bingham rheological models were used to describe the flow
behavior of papaya–apricot nectars samples. Addition of aspartame and stevioside reduced the viscosity of nectar
samples compared to control nectar samples. Nectar sample contains hydrocolloids had a higher and best sensory
and rheological characteristic. Papaya-apricot nectar containing guar gum, xanthan gum or arabic gum had high
score in overall all acceptability. |
