Sensory and rheological properties of artificially sweetened
papaya-apricot nectar (aspartame or stevioside) were improved with
some hydrocolloids (guar gum, xanthan gum or arabic gum).
Concentration of artificial sweeteners and hydrocolloids were 1.2 g/L
and 0.5% respectively. Using artificial sweeteners instead of sugar
leads to decrease the sensory properties of papaya-apricot nectar.
There was no significant difference (p>0.05) between aspartame and
stevioside. Using hydrocolloids leads to increase the sensory
properties of papaya-apricot nectar. There was no significant
difference (p>0.05) between the used hydrocolloids. Rheological
behaviour of nectar samples were studied using Brokfield rotational
viscometer applying Herschel-Bulkley and Bingham models at four
temperatures. Yield stress, consistency coefficient, flow behavior
index and apparent viscosity were obtained. They increased and
decreased at using hydrocolloids or artificial sweeteners, respectively.
Effect of temperature on viscosity of nectar was studied applying
Arhenious equation. Activation energy increased and decreased at
using hydrocolloids or artificial sweeteners, respectively. The
rheological properties confirmed the sensory properties that
consistency index (Herschel-Bulkley equation) or viscosity (Bingham
equation) was decreased by artificial sweeteners while there were
increased by hydrocolloids. The obtained results could be help in
establishing of quality control programs of such artificially sweetened
nectars.
Key words: Sweeteners; Hydrocolloids; papaya-apricot nectar; flow
behavior; rheological characteristics, sensory evaluation. |
