Kothakota et al.

Livestock sector plays a multi-faceted role in socio-

dairy product in a shelf stable powder form of high

economic development of rural households and

quality without refrigeration. Removal of moisture

contributes about 4.2% to the Gross Domestic

from dahi and conversion into powder will not only

Product and 25.6% to the Agricultural Gross

increase its shelf life but also result in reduction of

Domestic Product in the country. Over the last three

packaging, transportation and storage costs because

decades, livestock sector has grown at an annual

of reduction in bulk. The dahi powder can be used

rate of 7%, which is more than double the growth of

as a base for the formulation of health drinks, energy

the agricultural sector. Empirical evidences indicate

drinks, food fortification and nutraceuticals. In order

that livestock is an important component of the

to have health claims for such products, the survival

agriculture system, providing an additional source

of beneficial lactic acid bacteria is an important

of income and nutritional cover to a large section of

criterion.

the rural population, particularly the disadvantaged

and poor households (Singh et al., 2007). Dahi or

The spray drying is a continuous operation in which

curd is the most popular indigenous fermented dairy

almost any pumpable liquid can be converted into

product of Indie, which is made from buffalo milk. It

a free flowing powder. This type of drying process

has a firm body and white glossy appearance, with

is commercialized for the large-scale industrial

a cream layer on top. Mixed mesophillic cultures

productionofmilkpowders,instantaneouscoffeeand

of Lactobacillus lactis sub sp. lactis, Lactobacillus

fruit juice powders, as well as for the encapsulation

lactis sub sps. Cremorosis, Lactobacillus lactis sub

of functional active components (Barbosa et al.,

sp. diacetylactis species are grown together for

2005; Masters, 1991). Spray drying revolutionized

production of dahi. Dahi has a short shelf life, i.e.,

the production of good quality fruit juice powders

about one or two days under ambient conditions

with low water activity feasible for easier transport

and not more than a week under refrigerated

and storage. Some researchers claimed that drying

conditions (Kamruzzaman et al., 2002). Besides the

of fruit juice could produce the fruit powder that

limited keeping quality of dahi, the maintenance and

reconstituted rapidly to a fine product resembling

propagation of dahi culture, packaging and transport

the original juice (Gabas et al., 2007). However

of dahi in semi solid form are other challenges faced

Spray dried fruit juice powder has some inherent

by the dairy industry. Fermented dairy products

problems such as stickiness, hygroscopicity and

like dahi can only be presented by keeping it at low

solubility because of presence of low molecular

temperature as no other method of preservation

weight sugars and acids having low glass transition

seems suitable for it. However dehydration or

temperature (Bhandari et al., 1993). However most

drying of dahi may be other potential techniques

of aroma compounds and rheological characteristics

to preserve it. Among the various methods of

of product are lost during this process. it is known

preservation drying of food products is the most

that complex changes in the morphologies (size,

widely used process in dairy industry. The selection

shape, and appearance) of drops occurs during this

of drying process should be based on the important

process and that of retention of volatile compounds

criteria of starter culture survival and sensory quality

and protection of these materials are related to the

of final product in terms of colour, flavour and

porosity integrity of the microcapsules (perez silva

overall acceptability. The versatility of spray drying

et al., 1997) Thus powder can stick on the walls of

process and the considerable progress made through

chamber during drying process leading to lower

technical innovation have lead to greater flexibility

yield and certain operational problems. These

to meet bio technical requirements, especially low

problems can be resolved by addition of some carrier

heat treatment to avoid loss of activity (fu and chin,

agents, like polymers and gums to the product before

2011; Silva, Freixo, Gibbs and Teixeira, 2011). The

atomization, (Figueroa et al., 2002) reported the

primary objective of spray drying is to preserve

effect of hydrocolloids on reconstitution properties

850