Sugar-free fermented red bean milk and preparation method thereof

The invention relates to sugar-free fermented red bean milk and a preparation method thereof. Red bean milk, the concentration of which is 2 to 6 percent, is first sterilized; strain NM-6 is then inoculated with the inoculation amount of 1 to 5 percent, moreover, 0.5 to 2.5 percent of erythritol is added, and after 8 to 40 hours of fermentation under a constant temperature of 35DEG C to 43DEG C, the sugar-free fermented red bean milk is prepared. The sugar-free fermented red bean milk disclosed by the invention has high free amino nitrogen content, high protein decomposition capability and good stable effect, furthermore, the color and texture of a finished product are more uniform, and the sugar-free fermented red bean milk has fragrant, pure lactic acid flavor and the specific bean fragrance of red beans, and is sour, sweet and palatable. An experiment proves that the free amino nitrogen content in the sugar-free fermented red bean milk product prepared by the invention is up to 1.524mmol/L, and the stable effect is best.