Effect of gamma irradiation and microwave heating treatments on microbial load and antioxidant potentials in cinnamon, fennel and hot pepper

This study was carried out to investigate the effect of gamma irradiation (5 and 10\ua0kGy) and microwave treatments (500\ua0W for 45 and 90\ua0s) on the microbial load (bacterial and fungal counts), total phenolics (TPC), total flavonoids (TFC) and antioxidant activity of cinnamon, fennel and hot pepper. Both treatments reduced the total counts of bacteria and fungi in the three spices (P < 0.05). Gamma irradiation at the applied doses reduced TPC in hot pepper, TFC and antioxidant activity in all spices, while it increased TPC in cinnamon and fennel at 10\ua0kGy (P < 0.05). Microwave treatment also reduced the TPC in hot pepper, TFC in cinnamon and fennel, and antioxidant activity in all spices, whereas it increased TPC in cinnamon (P < 0.05). Thus, compositional differences should be considered when treating spices with gamma rays and microwave to avoid losses in antioxidant power of these important phytochemicals