Application of gamma irradiation in combination with moderate dehydration to extend the shelf life of fresh rice noodles at ambient temperature

Gamma irradiation was applied to extend the shelf life of fresh rice noodles stored at ambient temperature. Doses of 2–8 kGy did not affect water absorption and cooking loss but increased the gel strength of cooked rice noodles. An increase in Thiobarbituric acid (TBA) was noticed at 4 kGy accompanied by changes in noodle color to darker and more yellow. Although gamma irradiation at 2 kGy could completely eliminate spoilage microorganisms, Escherichia coli, and Staphylococcus aureus, the dose of 4 kGy was recommended because it could ensure the safety of high contaminated fresh noodle. By moderate dehydration (60 °C) and adding Carboxymethyl Cellulose, aw of fresh rice noodle (0.960) was reduced to 0.673. This semi-dried rice noodle had more pasting viscosity, water absorption, cooking loss, and gel strength, whereas less TBA and microbial contamination was exhibited. Gamma irradiation probably had less effects on aw and color with unclear dose-dependent tendency. Fresh rice noodle irradiated at 4 kGy and semi-dried rice noodle treated with irradiation at 2 kGy and moderate dehydration were microbiologically safe throughout 30 days of ambient storage. While fresh rice noodle had shelf life less than 1 day at ambient temperature.