Development of shelf stable tomato rasam paste using hurdle technology.
The objectives of this work were to develop ready-to-use tomato rasam paste using hurdle technology involving water activity (a w ), temperature, pH and preservative as hurdles and evaluation of shelf stability of the developed product. Physico-chemical characteristics such as pH, titratable acidity (TA), colour changes, and microbiological profiles were evaluated during storage of 4 months at ambient temperature (AT, 28 ± 4oC) and 37oC. Hunter color analysis showed significant (P<0.05) decrease in the lightness (L * ) and redness (a * ) while yellowness (b * ) of paste increased during storage at both the storage temperatures. The L * value decreased from 27.23 to 20.78 and 18.23 in samples stored at AT and 37oC, respectively while a * values decreased from 34.29 to 30.02 and 31.21 in samples stored at AT and 37oC, respectively. The paste was found to be acceptable on sensory scale after 4 months of storage at ambient temperature. The quality of paste in terms of sensory colour attribute was found to be deteriorated in sample stored at higher (37oC) temperature.