Additive-free sweet fermented grain yoghourt and preparation method thereof

The invention relates to the field of preparation of yoghourt, and particularly provides zero-additive sweet fermented grain yoghourt and a preparation method thereof.In the preparation process, oat grains and broomcorn millet are used as sweet fermented grain fermentation raw materials, proportion control is conducted, and secondary fermentation is conducted on sweet fermented grains and raw milk; a stable system is formed by fully utilizing the interaction of the components of the raw materials and the processing technology to realize stable tissue state and clean label in the shelf life; on the other hand, sweet substances such as white granulated sugar and an artificial sweetening agent do not need to be additionally added into the yoghourt to neutralize the sour feeling of the product, the prepared yoghourt breaks through a traditional cereal yoghourt post-adding technology, a double-fermentation technology is adopted, and the yoghourt is good in texture and tissue state, rich and full in taste and flavo