Abstract:
Ceylon black pepper (Piper nigrum L.), commonly known as the “King of Spices”, has
dominated the international spice market due to its high piperine content, strong aroma,
and rich flavor. Ceylon black pepper is highly susceptible to contamination with different
types of microorganisms. This study focused on evaluating the effects of different doses
of gamma irradiation on physicochemical and microbial properties of Ceylon black
pepper. Samples were collected from a particular exporter in the western province, Sri
Lanka. The collected samples were irradiated at five different doses (0, 5, 10, 20, and 30
kGy) by using an industrial Co-60 gamma irradiator. Treated samples were analyzed for
water activity (Water activity meter -Novasina LabMATER), moisture content (Moisture
analyzer -MRS 120-3), antioxidant activity (DPPH assay method), total polyphenol
content (Folin ciocalteu reagent method), flavonoid content (Colorimetric method) and
volatile content (GC-MS). Total plate count and yeast and mold counts of these samples
were enumerated. This experiment was repeated thrice. Irradiation dose did not affect
significantly (p<0.05) on the tested physicochemical properties of Ceylon black pepper.
All tested irradiation doses were capable of reducing total plate count and yeast and mold
count significantly (p<0.00) as compared to the control. Therefore, it can be concluded
that irradiation with 5 kGy dose will ensure the microbial quality of Ceylon black pepper
while preserving its original physicochemical properties.
Keywords: Ceylon black pepper, Gamma irradiation, Dose, Microbial safety
