Abstract:
Common beans are highly nutritious and widely consumed in Kenya. Storage of common beans under adverse
conditions of high temperature (≥25°C) and high humidity (≥ 65%) renders them susceptible to the hard-tocook
(HTC) defect. This results in increased cooking time, fuel and water use. This has a negative effect on
acceptability and utilization of beans. The objective of this study was to determine effects of storage
temperature and relative humidity on development of the HTC defect in common beans and subsequent
physical and nutritional quality changes. Rose coco and Red kidney bean varieties were obtained from
Kenya Agricultural Research Institute (K ARI) - Thika. The beans were subjected to combination of varying
temperature (35˚ C and 45˚ C) and relative humidity (75% and85% RH). Beans from each treatment condition
were sampled at an interval of zero, two, four and six months followed by analysis of physical, cooking and
nutritional properties. There w a s a significant i n c r e a se i n conductivity and leached solutes. Significant
decrease was observed in hydration and swelling coefficients of beans under each storage condition.
Characteristic dimensions and one hundred seed weight were not significantly different among the various
storage conditions. Based on the results of this study, it was concluded that adverse storage conditions of
temperature (35˚ C and 45˚ C) and relative humidity (75% and85% RH) cause development of the HTC defect
which in turn affects physical properties and cooking quality of common beans.
