Kothakota et al.

PH of the Reconstituted powder

property depends largely on particle size. Small

The results of color and pH determination for the

particles have a large value of specific area (i.e.,

solutions comparing to the fresh dahi are illustrated

the ratio of surface area to mass) and may not be

in Table 2. It showed that the pH of the solutions were

wetted individually; Increasing particle size and/or

significantly higher than those of the fresh sample.

agglomerating particles can reduce the incidence of

This result was unsurprising because the pH value of

clumping. The nature of the particle surface can also

maltodextrin applied in this study was 4.7 while the

affect wettability. For example, the presence of free

fresh dahi pH was 4.3. Furthermore, there were only

fat in the surface reduces wettability. The selective

slight differences in the pH among the reconstituted

use of surface-active agents, such as lecithin, can

specimens. If deeming the proportion total soluble

sometimes improve wettability in dried powders

solids and maltodextrin (based on dry weight), it

containing fat. Results shows that wettability of

is clear that maltodextrin contents were not very

sample without addition of maltodextrin was 178 s

difference between powder samples. Moreover,

and it increases as the maltodextrin concentration

these powders were reconstituted with distilled

increase may be due to difference in particle size.

water before measuring pH; as a result, the effects

Acidity

of different proportions of juice and maltodextrin

contents on the pH values were also diluted.

Acidityofreconstituted dahi powderwithoutaddition

of maltodextrin was 0.936% and the values for

Wettability

acidity decreases as the maltodextrin concentration

The term wettability refers to the ability of

increases beyond 7.5%.According to the (Narender

agglomerates to be penetrated by the liquid. Wetting

Raju and Dharam Pal, 2011) showed that there was

is a time controlling first step and it refers to a simple

increase in acidity of artificially sweetened misti dahi

solid wetting assisted by the capillary suction of

on maltodextrin addition as a bulking agent but in

the pores in the agglomerates (Pietsch, 1999). This

contrast in our study there was decrease in acidity

describes the capacity of the particles to absorb water

of reconstituted dahi as we added the maltodextrin

on their surface, thus initiating reconstitution. This

after incubation where as they added maltodextrin

before incubation. Acidity for the sample containing

5% maltodextrin remains same as that of the sample

Table2. The Dispersibility, Colour and pH values of the spray dried dahi powder

Outlet air temperature

MD content

Dispersibility

Colour characteristics

( o C)/blower speed

(%)

(%)

L* a* b*

(rpm)

pH

0

96.2 ±.1

93.6±.4

3.2±.3

15.3±.4

4.3±.1

5

97.4 ±.3

96.5±.4

0.57±.4

9.3±.2

4.3±.1

70 o C /2200

7.5

97.4± .2

97.4±.1

-0.02±.1

6.8±.3

4.35±.1

10

97.9±.1

97.6±.2

0.22±.3

7.1±.1

4.4±.2

12.5

98.4± .2

98.3±.1

-0.1±.1

6.3±.1

4.4±.1

Note: rpm = rotation per minute, MD= maltodextrin L*, a*, b* and pH values are mean ± standard deviation.

858