A protein material having a novel texture is provided by imparting hardness and elasticity comparable to livestock meats to an animal protein material such as fish meat or chicken meat that is inferior in hardness and elasticity to livestock meats. Provided is a method for manufacturing a protein material having a livestock meat-like texture, said method being characterized by comprising adding an organic acid to a paste of fish meat or chicken meat and, at the same time, heating the mixture. It is preferred to perform the addition of the organic acid and heating by using an extruder or a silent cutter. Alternately, it is preferred to add an organic acid preparation, said organic acid preparation exerting the function of the organic acid upon heating, to the chicken meat or fish meant paste and, after cutting into pieces, heating the mixture. As the organic acid, any of acetic acid, citric acid, succinic acid or gluconic acid or a mixture thereof is preferable. Also, it is preferred that the organic acid is added in an amount of 0.1-1.0 wt% relative to the chicken or fish meat and the extruder is driven at a screw rotation speed of 50-250 rpm and at a barrel temperature of 80-200°C. The livestock meat-like protein material is in the form of grains having a hardness of 8-30 N, a pH value of 5-7, a moisture content of 70-85% and a grain size of 0.2-10 mm.
