Quality of beans (Phaseolus vulgaris L.) after postharvest microwave treatments

Abstract

ABSTRACTThe potential of microwave heating (2450 MHz) was studied as a postharvest treatment on the quality of beans (Phaseolus vulgaris L.). Two of the most consumed bean varieties in Mexico were considered: ‘Bayo’ and ‘Negro’, with 11.3% and 10.7% (w.b.) of moisture content, respectively. Different power levels – 370, 510 and 950 W – were evaluated. The different treatment times were determined as the time needed to reach 48.9 °C at the centre of the beans, this target temperature is recommended to control bean weevil. Then, the beans were cooled with air flowing at 2.8 m/s at a temperature of 24 °C (60% RH). Several quality parameters were evaluated after treatment (moisture content, water activity, germination ability, hardness and cooking time). Cooking time was well modelled by Fermi equation. The treatment that showed the best results was 370 W for 72 s in ‘Bayo’ variety and 54 s in ‘Negro’ variety.