Shelf-life studies of vegetable-based millet soup mix.

The vegetable-based millet soup mix was prepared using millet in combination
with vegetables and a standardized spice formulation. The prepared product was packed and
shelf-life studies was conducted at ambient (27℃ at 65% RH) and accelerated (38℃ at 90%
RH) conditions. The soup mix was withdrawn at periodic intervals of 0, 30, 60, and 90 days
and subjected to physicochemical, biochemical, and microbiological analysis. Proximate
composition of the freshly prepared soup revealed the reducing sugar and total sugar content
of the soup mix as 2.12 % and 4.62%, respectively. The ash content, protein content, and
mineral content (Ca, Zn, K, Fe, and Mg) were found to be 10%, 2.07%, 154 mg/100g, 0.16
mg/100g, 293 mg/100g, 4.18 mg/100g and 9.63 mg/100 g, respectively. The viscosity of the
soup mix was found to be 272 cP at 65℃ and 420 cP at 30℃. During storage, water activity,
moisture content, free fatty acid value, colour (CIE L*, a*, b*), and microbiological parameters
were monitored in monthly intervals. The moisture content ranged from 2.95 ± 0.21% to 5.22
± 0.09% in ambient conditions and 10.19 ± 0.15% in accelerated conditions during the interval
from 0th day to 90th day. Water activity varied between 0.068 and 0.295 under ambient
conditions and 0.577 under accelerated conditions during storage from 0th day to 90th day.
Colour analysis revealed an increase in ΔE value ranging from 32.66 ± 0.01 to 34.04 ± 0.12
under ambient conditions and 34.68 ± 0.09 under accelerated conditions from 0th day to 90th
day. Free fatty acid values from 0th day to 90th day showed an increase from 0.086% to 0.62%
under ambient conditions and 1.17% under accelerated storage conditions. Microbiological
evaluation revealed that the soup mix was found to be microbiologically safe under the given
storage period of 90 days based on the TPC, TFC, Enterobacteriaceae and S.Aureus counts.