Quality changes and spoilage microbial community succession of steamed cold noodles (Liangpi) at different temperatures

Abstract

Steamed cold noodles (Liangpi) are traditional high-moisture starchy foods that are widely consumed in China for their refreshing taste. However, the relationships between the microbial community and the changes in the quality and flavor of Liangpi during storage have not been elucidated. Low-temperature storage (11 °C) effectively inhibited the growth of microorganisms and maintained the moisture and color of Liangpi, but as the hardness increased, the springiness and chewiness decreased rapidly. Short-term storage at 25 °C and 37 °C did not significantly change the color or texture, but the number of microorganisms increased immediately. After 12 h at 37 °C, the total plate count increased by 5.3 log CFU/g. Volatile organic compound (VOC) analysis revealed that after 1 day of storage at 11 °C, 25 °C, and 37 °C, 2-pentylfuran disappeared, and the contents of alcohols, ketones, esters, and olefins increased significantly. The microbial diversity results revealed that Bacillus was the absolute dominant bacterial genus at 25 °C and 37 °C, Acinetobacter was the dominant genus at 11 °C, and Byssochlamys and Sporidiobolus were the dominant fungal groups causing spoilage, which may contribute to the production of VOCs associated with their off-flavor nature during storage. These results provide a reference for optimizing storage conditions to extend the shelf-life of Liangpi.