Abstract:

Anti-nutritional factors such as lectins，saponin，trypsin inhibitor and phytic acid are
endogenous substances in kidney bean（Phaseolus vulgaris L.）. In this study，the contents or activities of
these four anti-nutritional factors in fresh pods were detected in 56 selected cultivars. The results revealed
significant difference of each factor in the tested cultivar population. The mean value of lectin content and
the activity of trypsin inhibitor was 1.743 mg · g-1 and 1.680 mg · g-1 respectively. Their coefficients of
variation（CV）were both more than 100% and each of the cultivar frequency distribution curve showed a
main peak，but the discontinuous distributions in the extremely high and low areas indicate hierarchic
cultivars. However，the content of saponin（mean value 3.730 mg · g-1）and phytic acid（mean value 3.102
mg · g-1）were with CV less than 41%. Each showed a main peak in its normal distribution curve and low
frequency continuous distribution in dual tails. Meanwhile，statistic analysis demonstrated a positivecorrelation between the lectin content and trypsin inhibitor activity in fresh pods. Furthermore，all tested 56
cultivars clustered into three groups based on their level of four anti-nutritional factors，80% of them into
medium level group，12% of them into low level group. The endogenous edible toxic compounds，such as
lectin and trypsin inhibitor，are closely related to the insect resistance in field. This study suggested that it
is possible to screen the cultivars contain less lectin and other factors but with reduced the pest resistance
in field.

Key words: kidney bean, Phaseolus vulgaris, lectin, saponin, trypsin inhibitor, phytic acid, genetic
variation