Abstract: A proanthocyanidin, such as an extract of grape seeds or skin, is added to a protein food, so that the flavor of the protein food is improved.

Abstract: A process for producing packed tofu includes the steps of mixing soybean milk that has been heat-sterilized and cooled with (A) 0.01 to 0.3% by weight by volume of at least one coagulant selected from the group consisting of natural bittern, magnesium chloride, magnesium sulfate, calcium chloride, calcium primary phosphate, calcium sulfate, and calcium lactate and (B) 0.1 to 5 units, per gram of soybean milk protein, of transglutaminase either simultaneously or in the order (A) then (B), then packing and sealing the mixture in a container, then coagulating the mixture in the sealed container at a temperature of 70.degree. C. or lower by the action of the coagulant and transglutaminase, and thereafter heating the coagulated mixture to 75.degree. C. or higher in the sealed container to deactivate the transglutaminase and to complete the coagulation by the coagulant.