Effects of Two-Bacteria Fermentation on Physical, Chemical Properties and Flavor of Danpness-eliminating Decoction

Danpness-eliminating decoction was fermented by Bacillus sp. DU-106 and Lactobacillus plantarum. The effects of fermentation on physical and chemical properties and flavor substances of Danpness-eliminating decoction were compared, and sensory evaluation was conducted. Physical and chemical properties included pH, reducing sugars, total acids, polysaccharides, proteins, polyphenols, flavonoids, essential amino acids and organic acids. The results showed that after 4 days of fermentation, the pH of Danpness-eliminating decoction decreased to below 3.0, and the total acid content was increased by consuming reducing sugar, up to 11.00 g/kg. The contents of polysaccharides, proteins, polyphenols and flavonoids in Danpness-eliminating decoction increased by probiotic fermentation, and the maximum values were 20.95, 1.66 mg/mL, 52.45 and 53.26 μg/mL respectively on the 7th day. Probiotic fermentation also significantly (P<0.05) increased the content of essential amino acids and organic acids. In addition, fermentation also endowed Danpness-eliminating decoction with special fermentation flavor. The relative contents of esters and alcohols in Danpness-eliminating decoction increased after fermentation by headspace solid phase microextraction and GC. Sensory evaluation results showed that the probiotic fermentation improved the aroma and taste of Danpness-eliminating decoction, and the overall sensory quality of Danpness-eliminating decoction on the seventh day of fermentation was the best. In conclusion, the fermentation of Danpness-eliminating decoction with DU-106 and L. plantarum were beneficial to improve the quality of Danpness-eliminating decoction. This study would provide a theoretical basis for the production of compound decoction of medicine-food homologous material fermented by compound strains.