Structural and textural quality of Kinu-Tofu frozen-then-thawed at high-pressure

To determine effects of high-pressure thawing on quality of high-pressure f rozen tofu, kinu-tofu (soybean curd) was frozen 90 min at ca -20 degrees C at 100 MPa (ice I), 200 MPa (liquid phase), 340 MPa (ice III), 400, 500 or 600 MPa (ice V), then thawed at the same pressure. Texture and structure of this tofu (D) were compared with high-pressure-frozen tofu thawed at atmos pheric pressure (A: 90 min frozen; B: 90 min frozen then 2 days at -30 degr ees C; C: 160 min frozen), When tofu was frozen at 200- 500 MPa, ice crysta ls were largest to smallest in B > A and C > D; pore size of D was the same as untreated tofu, Results indicated ice crystals never grew when frozen a t 200-500 MPa, Growth occurred during reduction of pressure at ca -20 degre es C, frozen storage or while thawing at atmospheric pressure due to phase transition.