Effect of water activity (aw) and irradiation on the shelf-life of fresh noodles

Abstract

In this work, the effect of water activity (aw), irradiation and their combination on the preservation of fresh noodles was studied. Microbial growth, pH and sensory characteristics were investigated during 16 days' storage time under 37 °C. The combination of glycerol (3%), propylene glycol (2%), compound phosphate (0.4%) and salt (3%) was proved to be the most effective group which could reduce aw from 0.979 (control) to 0.900. Under this condition, the shelf-life of fresh noodles could be extended for more than 7 times. Moreover, a synergism between humectants and irradiation treatment was observed in relation to microorganism inhibition and shelf-life extension. For all the irradiated noodles, TPC (total plate count) did never exceed the selected deterioration threshold limit (106 CFU/g) during the entire observation period. When the irradiation dose was 4 kGy or higher, scarcely any bacteria proliferation was observed. Noodle samples irradiated at 4 kGy showed the best pH and sensory stability as the storage time increased. This paper presents an effective and low-cost method to prolong the shelf-life of fresh noodles, which can largely extend the store time of fresh noodles at room temperature, and does not produce any negative changes in sensory attributes. This method will be a new system for food preservation with lots of possible industrial applications. The results of this research also have implications for dumpling skins and other noodle types.