Water‐Holding Capacity in Hard‐to‐Cook Beans (Phaseolus vulgaris): Effect of pH and Ionic Strength

The effect of pH and ionic strength (IS) of soaking solution on the water holding capacity (WHC) of hard‐to‐cook (HTC) and control black beans ( Phaseolus vulgaris ) was evaluated. Beans were soaked 18 hr in solutions covering the pH range 1–7 at constant IS (1.0 M) or in solutions ranging in IS from 0.01 to 1.3M (prepared with either NaCl or CaCl 2 ) at pH 7. WHC was significantly reduced in the pH range 3.5 to 5.1 in control beans but the effect was not as pronounced with HTC samples which had a lower WHC at each pH. Solutions prepared with NaCl produced significantly lower WHC values than CaCl 2 solutions in the control but not in the HTC beans. WHC values in control beans tended to increase with higher IS, although this effect was not as apparent for HTC beans.