[Effect of high hydrostatic pressure on water imbibition, cooking times and microstructure of Phaseolus vulgaris]

The effect of high hydrostatic pressure (HHP) on water imbibition, cooking times, and microstructure of cotyledons and seed coats of black beans was evaluated. High pressure treatments at 275, 410, 550 or 690 MPa and 25 degrees C for 5 min increased the rate of water imbibition of black beans. The saturation degree of HHP treated black beans was reached 50% faster than the saturation degree of untreated black beans. High hydrostatic pressure treatments reduced the cooking times (CT) of unsoaked black beans by 25% to 39%, similar to black beans soaked for 3 h. The microstructure of HHP treated beans exhibited protein aggregation in cell protoplasm and swelling of cell walls and starch granules. Seed coats of HHP treated black beans were less smooth than seed coats of untreated black beans. The swelling of palisade, hourglass, and parenchyma cells was also observed in HHP treated black beans such as soaked beans. High hydrostatic treatment is an alternative for reducing the preparation long times of Phaseolus vulgaris.