3.2. Effect of HPP and Stevia concentration on physicochemical properties
of the beverages
The results obtained for turbidity index (TI), browning index (BI)
and color parameters (a*, b* and L*) in the untreated and HPP samples
are shown in Tables 2–3 and Fig. 4. As can be expected, among
the studied parameters, Stevia percentage had the greatest effect on
the quality parameters of the beverages. Compared to the untreated
samples, lower browning index values were obtained for the HPP
samples when 0 and 1.25% (w/v) Stevia percentages were used, however
a significant increase in BI was observed after applying HPP in
the samples with 2.5% (w/v) Stevia. The regression model was accurate
enough (R2=0.962, pb0.05, standard error=0.181). The regression
equation describes the following model (Eq. (6)):