Changes in the saponin content and composition of both chickpeas (Cicer arietinum) and lentils (Lens culinaris) were investigated after the seeds were soaked in distilled water, citric acid, and sodium bicarbonate solutions. The effect of cooking for 30, 60, 90, and 120 min after the seeds were presoaked in distilled water was also studied. Soaking did not modify the saponin content or composition of chickpeas and lentils regardless of the pH of the soaking solution. The native saponin, soyasaponin VI, was partially degraded during cooking into soyasaponin I, and both of these saponins leached into the cooking solution, 2-5% and 6-14% for chickpea and lentil, respectively. An overall loss of saponin content was found for lentil (15-31% loss), but none was observed for chickpea.

Myrosinase activity in partially purified extracts of 12 cruciferous vegetables and an acetone powder preparation of Sinapis alba L. (white mustard) was determined by the initial rate of glucose formation from glucosinolate hydrolysis using a coupled assay. Of the species studied Raphanus sativus L. (radish, 12.8+0.7pmol min-' g-' powdered tissue) had the greatest myrosinase activity, and Brassica campestris L. ssp. rapifera (turnip) and Nasturtium officinalis R.Br. (watercress) ( 0 . 6 f 0 . 1 and 0.8k0.03 pmol min-' g-' powdered tissue respectively) the least. The sub-species of Brassica oleracea studied all had similar myrosinase activity (ca 2.5-tO.2prnol min-'g-' powdered tissue) except B. oleracea L. var. gemmifera D.C. (Brussels sprouts) and B. oleracea L. var. capitata L. (white cabbage) which had higher activities (7.6f0.1 and 5.2+0.2pmol min-' g-' powdered tissue respectively). The effect of ascorbate concentration upon the myrosinase activity of six of the crucifers studied and the white mustard preparation, revealed that the ascorbate concentration necessary to promote maximal activity vaned with species. A concentration of 0 . 9 m~ ascorbate maximally activated radish and turnip myrosinase, while red cabbage, watercress, white mustard and Brussels sprouts were maximally activated at 2.0, 3.0, 5.0 and 0.7-1.0m~ ascorbate respectively. Two peaks of maximal myrosinase activity, occurring between 0.9 and 1.OmM and at 3 . 0 m~ ascorbate, were found for B. oleracea L. var. botrytis L. subvar. cauliflora D.C. (cauliflower).