Method for reducing content of diacetyl in solidifying type yoghourt

The invention relates to a method for reducing content of diacetyl in solidifying type yoghourt, and belongs to the technical field of dairy product processing. The method comprises the following steps of (1) taking fresh milk raw materials, and performing microfiltration treatment; (2) performing pasteurization; (3) adding ingredients of white granulated sugar and casein composite powder; (4) performing preheating for warming, and performing homogenizing; (5) performing heating for the second time for sterilization treatment; (6) inoculating the fresh milk treated in the step (5) with lactobacillus bulgaricus and streptococcus thermophilus, then performing inoculation with lactobacillus delbrueckii, and after inoculation is completed, performing mixing and stirring; (7) performing quick cooling to 20-25 DEG C, and performing filling treatment; (8) performing static fermentation so as to obtain yoghourt; and (9) immediately placing the yoghourt obtained in the step (8) in a cooling chamber of 2-6 DEG C for co