Modeling Milk Heating Processes for the Production of Milk Shelf-stable without Refrigeration

Effect of Different Storage Conditions on Analytical and Sensory Quality of Thermally Processed, Milk-Based Germinated Foxtail Millet Porridge

Foxtail millet porridge was prepared using germinated grains and milk and was evaluated for its storage stability after thermal processing at ultra-high temperatures (UHT) of 142 °C for 5 s and retort processing temperatures of 121.5 °C for 15 min. Various physical, chemical, and microbial changes of the porridge were studied for a storage period of 180 days at 25 ± 1 °C. Using consumer perception and survival analysis, the predicted shelf life of the UHT treated and retort processed foxtail millet porridge samples stored at 25 ± 1 °C was found to be 186 ± 9 days and 245 ± 15 days, respectively. Also, data from consumer liking, profiling, physical, chemical, and microbial parameters showed significant changes (P < 0.05) in the thermally treated packaged porridge samples over time. As the consumer overall acceptability decreased, the detection of positive attributes (thick and uniformly colored texture and appearance; grainy mouth texture; caramel taste and aroma) in the porridge decreased, while the detection of negative attributes (uneven, decolored, and curdled texture and appearance; sticky mouth texture; cooked, sour and off smell; cooked, sour and off taste) increased. The present study could establish a significant difference (P < 0.05) in the storage induced properties of UHT and retort processed porridge samples. The analytical evaluation of foxtail millet porridge found that UHT treated porridge was better in quality, but consumers preferred retort processed porridge. PRACTICAL APPLICATION: The quality and sensory attributes, evaluated for UHT treated and retort processed porridge samples during the storage period of 180 days, were found to be contradictory. Based on the results of CATA sensory analysis, the shelf life of UHT treated and retort processed porridge samples was predicted to be more than 6 months. Therefore, both UHT treatment and retort processing can be effectively applied to prepare a ready to eat milk based porridge using germinated foxtail millet grains.