A fat-free or low-fat yoghurt having a rich and creamy texture like yoghurts produced using whole-fat milk may be produced by adding a proper amount of a milk protein, such as a defatted milk powder, that has been deamidated with a protein deamidating enzyme to a fat-free or low-fat raw material milk. Alternatively, a proper amount of a milk protein, such as a defatted milk powder, is added to a fat-free or low-fat raw material milk, and the resulting mixture is subjected to a deamidation treatment with a protein deamidating enzyme so that the deamidation ratio reaches a proper level. In this manner, a fat-free or low-fat milk raw material having a milk protein mass and a deamidation ratio both falling within proper ranges can be prepared, and yoghurt may be produced using the milk raw material.
