Study of changes in functional properties of fermented Idli batter during storage under different temperature conditions

Abstract

The comprehensive analysis of multiple quality parameters in Idli batter (IB) was estimated quantitatively for 16 days of storage at 5 and 30 ℃. A modified Baranyi model was proposed for fitting microbial growth during storage conditions in IB with the inclusion of the death rate (kd) constant in the original model equation. The kd observed for lactic acid bacteria, total bacteria, and yeast counts were − 0.059, − 0.103, − 0.074 at 30 °C and − 0.019, − 0.040, − 4.97 (log CFU/g/d) at 5 °C during storage of IB. Peleg’s model was used to estimate the phenolic content during the storage of IB. The correlation coefficients (R2) were above 0.90 for these models. The acidity and pH content marginally increased in the IB stored at 5 °C. The total and reducing sugar levels increased in IB from 67 to 122 and 96 to 226 µg/mL, respectively, after storage. The antioxidant activity and total flavonoid content in batter increased significantly during storage. The biogenic amine content varied from 10- 256 µg/g during storage. In the product prepared from batter stored at 5 °C, hardness was not observed until the 9th day, whereas for 30 ℃ stored batter, the hardness was seen from the 2nd day onwards, as determined by texture profile analysis. Based on Pearson’s coefficient correlation between parameters significantly varied when the batter was stored at 5 and 30 ℃. Based on our study, it was observed that the IB stored at 5 ℃ can retain its properties for consumption until 9 days, whereas IB stored at 30 ℃ loses its properties after just 48 h of storage. Thus the above models were useful in predicting the food quality and shelf-life of the product.