Noodles, as the low-cost, convenience staple foods, are prepared mostly from wheat flour. Nowadays, consumers pay more attention to nutritional and healthy noodle products and require the noodles with ready-to-eat convenience and superior flavor and taste.Fermentation can convert wheat flour dough into inviting, toothsome and digestible products, and this technology is mainly used in the production of bread and steamed bread. However, in order to improve the nutrition, functional, sensory, and technological characteristics of noodle products, fermentation step as an innovative strategy was applied to pasta making (Montemurro et al., 2019).

Wheat-based noodle, an important part of staple food, has been consumed in numerous Asian countries ever since ancient days. However, limited amounts of nutrients (e.g., dietary fiber, vitamins) could be detected in products made from wheat flour (Rani et al., 2019). Recently, chronic diseases frequently occur in the world, such as diabetes, which is associated with metabolic disorder caused by high energy intake and nutrition imbalance (Reshmi et al., 2020). As a consequence, producing noodles using sole wheat flour could not meet the requirements for health any more, and it is crucial to incorporate functional ingredients.

Noodles, as one of the traditional Chinese staple foods, are usually divided into dried noodles and wet noodles according to the state of the noodles during storage. Compared to dry noodles, fresh noodles retain the original flavor and nutritional value of noodles, which conforms to the consumption philosophy of nutrition, health, and safety (Fu, 2008;Ma et al., 2019).However, when fresh noodles are placed at room temperature, especially in the high-temperature environment in summer, it is easy to cause the growth and reproduction of microorganisms for high water content and activity of fresh noodles, resulting in the noodles becoming sour and moldy, and then a series of quality deterioration reactions are triggered (Fuerst et al., 2006; Huis in't Veld, 1996;Ray & Bhunia, 2007). Ray and Bhunia (2007) pointed out that the main microorganisms that caused the spoilage of fresh noodles were bacteria, followed by mold and yeast. In addition, fresh noodles were prone to browning during storage and polyphenol oxidase was generally recognized as the main cause (Fuerst et al., 2006;Martin et al., 2005). The increase in the fat acidity content of noodle products during storage would lead to the sour and bitter taste of fresh noodles. The high-water activity would accelerate the growth and metabolism of microorganisms in noodles (Li et al., 2016). Therefore, by understanding the changes in the total plate count, water activity,

Liquid pre-fermentation technology was innovatively applied to the development of dried fermented noodles. The effects of fermentation time (1, 3 and 6 h) and yeast addition (0.2, 0.5 and 1.0 g/100 g of flour) on the quality, microstructure and flavor of dried noodles were also investigated in this study. Conspicuous porous structures and greater thickness of dried noodles were found when the fermentation time was ≤ 3 h and the yeast addition was ≥ 0.5 g/100 g of flour, which contributed to the increase in the breaking strength, cooking time and water absorption. However, when the fermentation time increased to 6 h, finer microporous structures, little change related to thickness and richer flavor levels were detected. Additionally, the total titratable acidity of dried fermented noodles was increased to 3.38–4.43 mL compared with the unfermented noodles (2.15 mL). Weaker gluten network structures caused by long-time fermentation and acidic environment led to lower hardness, chewiness, tensile force and tensile distance of cooked fermented noodles.

BACKGROUNDThis study developed an intelligent, pH‐sensitive and amine‐responsive colorimetric label based on chitosan, whey protein and thymol blue by controlling the pH value of the film‐forming solution. The obtained label was used to monitor shrimp freshness in real time. The results of this study offer a new approach for developing highly intelligent biogenic labels for freshness monitoring during seafood preservation and processing.RESULTSThe pH 2.0 chitosan–whey protein–thymol blue (CWT‐pH 2.0) label exhibited remarkable properties, including the highest tensile strength (5.90 MPa), excellent thermal stability, low water solubility (27.80%) and highly sensitive color responsiveness. The characterization techniques of scanning electron microscopy, X‐ray diffraction and Fourier transform infrared spectroscopy confirmed the effective immobilization of thymol blue within the film‐forming matrix through hydrogen bonding. Furthermore, the CWT‐pH 2.0 label demonstrated visible color changes in the presence of volatile ammonia concentrations ranging from 25 to 25 000 ppm. Consequently, the label successfully facilitated real‐time monitoring of shrimp freshness during storage at 4 °C. Importantly, the release rate of thymol blue from the label in food simulants was minimal, measuring only 2.53%.CONCLUSIONThe CWT‐pH 2.0 label exhibits significant potential as a highly intelligent biogenic label for freshness monitoring in seafood preservation and processing. © 2023 Society of Chemical Industry.