The effect of addition of the optimized levels of selected
hydrocolloids (SA and CMC) on various physicochemical
parameters of litchi juice is presented in Table 1. Acidity,
ascorbic acid, total sugars, reducing sugars and tannin
values did not significantly differ among juice samples containing
selected hydrocolloids at their optimized concentrations
and control (Table 1). Incorporation of both the
hydrocolloids at selected levels had a significant effect on
raising pH of the juice. Addition of SA raised the pH of the
juice from 3.9 to 4.1 probably due to the presence of Na+ in
SA. Aggarwal and Sandhu (2004) also observed a rise in pH
of kinnow squash with the addition of SA.
Total solids and TSS at 19.42% and 16.10 °Brix, respectively,
were highest in samples containing 0.3% CMC followed
by the samples containing 0.2% SA and the control sample in this order (Table 1). There was a considerable difference
in the specific gravity of juice samples containing
hydrocolloids in comparison to control. The increase in specific
gravity can be attributed to the increase in total solids.
The specific gravity of juice sample containing 0.3% CMC
and 0.2% SA was the same (Table 1). A conspicuous change
in viscosity of litchi juice was observed with the addition of
hydrocolloids. Among the two hydrocolloids, the thickening
effect with addition of 0.3% CMC was most noticeable
which resulted in the juice with viscosity of 28 cps, while
that of juice containing 0.2% SA was 24 cps and that of
control was 18 cps. Ibrahim et al. (2011) also observed an
increase in viscosity of apple juice containing hydrocolloids.
Significant difference in turbidity of juice samples containing
0.3% CMC, 0.2% SA and control was observed. Juice
containing 0.3% CMC showed the highest turbidity followed
by 0.2% SA and control in that order (Table 1). Likewise,
Mirhosseini et al. (2008) found an increase in
cloudiness of orange flavor beverage emulsion when the
concentration of CMC was increased. The effect of addition
of hydrocolloids on turbidity and viscosity could primarily
be due to the interaction between the hydrocolloid and
protein as mentioned previously.