Seed oils from six legume cultivars of Phaseolus
vulgaris, grown in the Kingdom of Lesotho, were extracted and
their physicochemical properties and FA compositions were determined
in order to compare their dietary lipids with those in P.
vulgaris cultivars grown in other parts of the world. The oil content
of the beans was very low, ranging from 1.5 to 2.0% (w/w).
The acid values ranged from 11.0 to 19.2 mg KOH/g, whereas a
combination of the PV and the p-anisidine values in Holm’s
equation gave oxidation values that ranged from 11.0 to 15.0.
Thus, considerable enzymatic hydrolysis and oxidation had
taken place in the beans during storage. Iodine values ranged
from 80.5 to 92.3 (Wijs method), indicating moderate unsaturation
in the oils. However, capillary GC analysis, supported by
proton NMR analysis of the FAME, gave a total unsaturation
range from 79.67 to 84.24%. The dominant FA were α-linolenic
acid (36.47–48.81%) and linoleic acid (20.96–36.10%), with appreciable
amounts of palmitic acid (14.33–18.23%). This FA
composition pattern is quite similar to the FA distribution reported
for low oil-bearing legume seeds. Thus, notwithstanding
the different climatic and soil conditions, the general properties
of lipids in the southern African legume cultivars were quite similar
to those of lipids in P. vulgaris cultivars grown in other parts
of the world. The high content of α-linolenic acid in the cultivars
of P. vulgaris could very likely play a beneficial role in reducing
the risk of coronary heart disease among the large populations
consuming them in the southern African region.