Screening of antifungal lactic acid bacteria from traditional sourdough and its application in the steamed cake

To isolate and identify lactic acid bacteria which could inhibit mainly molds from steamed cake. The antifungal activity was determined by oxford cup method firstly and then 96-microwells plates method, and analysis of the active components of bacteriostatic activity of lactic acid bacteria, and the molecular biology identification of lactic acid bacteria.The sourdough fermented flour was used to substitute for the cake flour ( 0, 25%, 50%, 75%) and studied the influence of it on the quality, structure, the senses and the shelf life of steamed cake. Results indicated that the culture supernatant of lactic acid bacteria treatmenting with different proteases had different effects on the antibacterial activity.It was very sensitive to p H, while three heat treatments did not hardly affect the inhibitory efficiency. Organic acid analysis showed that the content of phenyl lactic acid was 95.91 mg/L. The lactic acid bacteria was identified as L. plantarum. Adding sourdough fermented flour can significantly reduce the hardness and chewiness of steamed cake when replacement rate was 25% and 50%.With the increasing of replacement rate, bacteriostatic activity increased.Sensory results showed that when the replacement rate was 50%, it had no significant changes, which can be accepted by consumers.