Impacts of surfactin on the qualities and gluten network structure of fresh noodles during storage

Surfactin could improve the quality of fresh noodles (FNs) during storage. The impacts of different levels of surfactin (0.0%, 0.2%, 0.3%, and 0.4%) on the quality and gluten network structure of FNs after storage (0d, 1d, 2d, and 3d) at 25 °C were investigated. The results showed that the addition of surfactin inhibited the tendency of hardness and tensile strength to decrease in FNs and improved their cooking properties. Size exclusion (SE-HPLC) and electrophoresis were employed to evaluate the strength of the gluten network, which indicated that surfactin increased the cross-linking of the gluten network during storage by promoting more disulfide bonds (SS). Surfactin increased the total contents of SDS-soluble polymers (SDS-P) and SDS-insoluble polymers (SDS-I) from 24.66% (control samples) to 33.32% (FNs with 0.4% surfactin) after 3 days of storage. The secondary structure of gluten network was determined using Fourier transform infrared (FTIR) spectroscopy, suggesting that surfactin increased α-helices and decreased random coil during storage. Moreover, confocal laser scanning microscopy (CLSM) showed that surfactin additions delayed the depolymerization of the gluten network in FNs during storage. This research could provide a theoretical basis for using surfactin as improver for FNs.