Characteristics of spray dried dahi powder

Bulk density

were vigorously mixed in a 50 ml centrifuge tube,

The procedure described by (Al-Kahtani and

incubated at 37 °C water bath for 30 min and then

Hassan, 1990) was used. Twenty grams of powder

centrifuged for 20 min at 10,000 rpm in a centrifuge.

were transferred to a 100 mL graduated cylinder

The supernatant was carefully collected in a pre-

which was mounted on a shaker compartment of the

weighed beaker and oven dried at a temperature of

“STUART SCIENTIFIC” water bath model SBS 30

103 ± 2 °C. The solubility index (%) was calculated as

(produced by Bibby Scientific Ltd., StaffordshireST15

the percentage of dried supernatant with respect to

OSA, UK). The shaker was set at position 100 rpm

the amount of the original 2.5 g dahi powder.

and operated for 5 minutes. The bulk density was

Dispersibility

calculated by dividing the weight of the powder by

the volume occupied in the cylinder.

Dispersibility of powder in water is the amount

of dry matter, which after stirring for 15 seconds

Solubility

with a spoon can pass through a 210 microns sieve

To determine the solubility index, the methods of

(Haugaard et al., 1978). The 13 g dahi powder was

(Anderson et al., 1969) was applied. Spray-dried

stirred with 100 ml water at 50 o C in a beaker for 15

dahi powder (2.5 g) and distilled water (30 ml)

s. The reconstituted dahi was then filtered through a

210 micron sieve. The dry matter of filtered dahi was

Figure 2. A schematic diagram of the spray dryer.

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