Effect of heat treatment and salt addition on the physicochemical properties and quality of fresh noodles

Identification and control of gas-producing bacteria isolated from the swollen bagged soy sauce

The swelling of soy sauce bags seriously affects product quality and causes food safety problems, which has become an urgent problem to solve in the condiment industry. Here, gas-producing bacteria in the swollen bagged soy sauce were isolated and identified to provide an effective control method for inhibiting their growth and solving the swelling of soy sauce bags. It was found that three gas-producing bacteria isolated from the swollen bagged soy sauce were confirmed as Bacillus amyloliquefaciens (G1), Bacillus sp. (G2) and Bacillus subtilis (P3) using 16S rDNA analysis. The strains' morphologies, growth rates, and physiological and biochemical characteristics were also compared. Further studies yielded the optimal growth time, temperature and pH for the three gas-producing bacteria (B. amyloliquefacien: 24 h, 37 °C, and pH 7; Bacillus sp.: 18 h, 30 °C, and pH 6.5-7.5; B. subtilis: 36 h, 30 °C, and pH 8). Bacillus sp. was more salt tolerant than the other two. Then the antibacterial effect of the combination was tested by the physicochemical index. The results showed that filtering through a 0.22 μm inorganic micro-filtration membrane, sterilizing at 121 °C for 2 min, and adding 1 g/kg potassium sorbate was effective methods to inhibit three gas-producing bacteria and control the swelling of soy sauce.

Recent advances in extending the shelf life of fresh wet noodles: Influencing factors and preservation technologies

Fresh wet noodles (FWNs) are popular among people and have attracted increasing attention because of their characteristics of freshness, chewiness, good taste, and better maintenance of noodle flavor. However, due to the high moisture content and abundance of nutrients in FWN, they are prone to spoilage, which shortens their shelf life and reduces their quality, greatly restricting their large-scale production. Therefore, seeking effective preservation methods to prolong the shelf life is a major breakthrough for the industrialization of FWN. The present review provides a comprehensive overview of the main factors that contribute to the spoilage and degradation of FWN. These factors encompass microorganisms, moisture content, nutritional composition, enzymes, and storage temperature. Moreover, the recent developments in novel shelf-life extension technology applied to FWN, such as chemical preservatives, natural preservatives, physical treatment technologies, and composite preservation technology, are presented and discussed. From the literature reviewed, the application of technologies, such as adding preservatives, modified atmosphere packaging, microwave, cold plasma, ozone, and other technologies, has a certain effect on improving the shelf life of FWN, but the single preservation technology still has some deficiencies. In order to further improve the preservation efficiency, using two or more preservation methods is an important direction for future research on the preservation technology of FWN.