Saponins are rich in the legumes which are known to provide many health benefits for human beings. Saponin B is the main component in the saponins group present in navy beans. The stability of saponin B during food processing is a key issue in evaluating the quality and nutrition of food products. The effects of different soaking and cooking methods and conditions on the stability of saponin B were investigated. The effects of the soaking process on saponin reduction followed a first order kinetic model. The soaking time and the seed-to-water ratio significantly affected the stability of saponin B during the soaking process. Short time soaking and lower seed-to-water ratio would keep more saponin B in the soaked beans. The cooking medium and methods greatly influenced saponin B degradation during cooking. Water-oil mixed cooking media enhanced saponins stability in the seeds during the cooking process, as compared to a water-only cooking medium. Combined soaking and ordinary cooking induced more saponin degradation in ordinary cooked seed samples. An autoclave cooking method eliminated most of the saponin B from the autoclaved beans. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.