Inactivation of Trypsin Inhibitor Activity from Brazilian Varieties of Beans (Phaseolus vulgaris L.)

Abstract

The trypsin inhibitor activity (TIA) of five varieties of beans ( Phaseolus vulgaris L.) namely, Carioca, Branco, Vermelho, Preto and Jalo, was investigated. No significant differences of TIA among varieties of raw beans were observed (P > 0.05). Pressure-cooking (121°C and 141 kPa) for 15 min resulted in complete inactivation of TIA. On cooking beans in water bath (90°C, 15 min), the TIA was inactivated between 80% and 95%, while total inactivation was achieved after 40 min suggesting the possibility of two-step inactivation kinetics. Microwave treatment was very effective for inactivation of this antinutritional factor (97% to 100% of inactivation) in the first 15 min of treatment. A 22 factorial design was developed to evaluate the effect of temperature and duration of thermal treatment for loss of TIA. As interdependence between temperature and time was evident, it is envisaged that both are important to process the beans to knock off TIA.