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Nutritional evaluation of kidney beans ( phaseolus vulgaris ): The isolation and partial Characterisation of Toxic Constituents
Author(s) -
Pusztai Arpad,
Grant George,
Palmer Robert
Publication year - 1975
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740260205
Subject(s) - phaseolus , globulin , fractionation , toxicity , albumin , casein , carbohydrate , trypsin , biology , trypsin inhibitor , storage protein , kidney , food science , biochemistry , chemistry , chromatography , botany , enzyme , endocrinology , organic chemistry , gene
Abstract Comprehensive fractionation studies on the contents of the seeds of two varieties of kidney bean ( Phaseolus vulgaris ) were carried out. The extent of toxicity of the fractions obtained was assessed from the depression of the growth of rats fed on a mixed diet containing 5% casein protein and 5% unfractionated bean proteins or proportional amounts of fractionated materials. The low molecular weight diffusible materials and the structural water‐insoluble carbohydrate‐protein complexes (10 and 73% of the seeds, respectively) were found to have had little deleterious effects on rat growth performance. However, both protein fractions, the albumins (6.3% of the seeds) and the globulins (11% of the seeds), were found to be toxic. Further fractionation with continuous high‐voltage electrophoresis indicated that most of the toxicity of the albumin fraction might be related to the presence of a range of isolectins. A similar, but not identical, isolectin might also be implicated in the toxicity of the globulin fraction. In addition, these results also demonstrated that the three major storage proteins, glycoprotein I and II and the trypsin inhibitors, which altogether made up about three quarters of the total protein content, could have made a small contribution only to the toxicity of kidney beans.