The objective of the present study was to investigate the effect of gamma radiation
on phytochemical compounds in faba bean. Samples of faba bean seeds were exposed to gamma
radiation at doses of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 kGy. Then the contents of total phenolic and
flavonoid compounds in non-irradiated and irradiated samples were determined. The contents of total
phenolic compounds in samples of non-irradiated faba bean was found to be 220.55 ± 0.040 μg gallic
acid equivalent/g dry matter, while the total flavonoids in non-irradiated samples were found to be
106.33 ± 0.450 μg quercetin equivalent/g dry matter. Exposing faba bean seeds to ascending doses of
gamma irradiation induced significant gradual increases in the contents of total phenolic and flavonoid
contents. The maximum increases were observed in samples irradiated at dose of 9 kGy showing
increase by about 183% and 283% in phenolic and flavonoid contents, respectively. Based on these
results, phenolic and flavonoid compounds in the ethanolic extracts of non- irradiated faba bean seeds
and those irradiated at dose of 9 kGy were fractionated and quantified by High Performance Liquid
Chromatography (HPLC). The results showed that 21 phenolic and 14 flavonoid compounds could
be separated and quantified from the extract of non-irradiated faba bean seeds by HPLC. The same
compounds were identified in the extract of seeds irradiated at 9 kGy dose but at increased
concentrations. The effect of gamma irradiation on the contents of macronutrients in seeds as well as
their water absorption properties was also determined. Significant differences were observed in the
proximate chemical composition between samples of non-irradiated faba beans and those irradiated at
doses up to 10 kGy. However, irradiation treatments generally induced slight, but statistically
significant, increases in the values of water absorption properties as measured gravimetrically
(hydration properties) and volumetrically (swelling properties). From the obtained results for total
phenolic and flavonoid contents in non-irradiated and irradiated faba bean, it is clear that irradiation
dose of 9 kGy can be selected as an optimal dose for increasing of these phytochemicals in faba bean.