Abstract:
Butterfly pea flower tea is a caffeine-free herbal fusion made from flowers of the Clitoria ternatea
plant and is rich in antioxidants. It is difficult to clean large quantities before processing as butterfly
pea tea is made from small flowers. In consequence, microorganisms can be present in the final
product. This product has a good demand in the foreign market and is expected to increase in the
future. Large-scale production is more profitable and efficient if contamination is reduced. Gamma
irradiation can be used as an effective treatment to destroy microorganisms. Samples collected from
an exporter were irradiated 3 days after processing at different target doses of 3kGy, 5 kGy and 7
kGy and non-irradiated sample was used as the control. Co-60 gamma irradiator was used with the
rate of 0.15Gys-1. Total Plate count, total coliform and fecal count and yeast and mold count of
butterfly pea were determined according to modified ISO standard methods. Water activity, moisture
content %, powder color and infusion color (∆E value based on L, a, b in Hunter color scale) were
measured for each treatment under physical parameters. All treatments were done within a week
after irradiation and replicated three times. The highest microbial contamination was observed in
the non-irradiated sample. The total plate count dramatically decreased with increasing irradiation
doses. Escherichia coli were identified in the control sample. There were no yeast and mold count,
total coliform and total fecal count observed in all the treated samples. The average water activity
and moisture % of control samples were 0.263±0.00 and 7.860±0.18% whereas irradiated butterfly
pea tea samples were 0.31±0.01 and 7.37±0.20% respectively. The mean ∆E values of powder and
infusion of the irradiated samples were not significantly different (P>0.05) from the control sample.
The study shows that 3kGy is the possible dose to eliminate microbial contamination and has no
considerable effect on the physical parameters of butterfly pea.
