Aim: In this study, the effect of pulsed infrared (PIR) irradiation on saffron microbial, chemical and sensory properties were evaluated.
Methods and results: The PIR power (250, 350 and 450 W), the distance of sample with irradiation source (10, 20 and 30 cm), irradiation time (0-20 min) and PIR pulse (1, 2 and 3 pulse/s) were investigated. Decontamination of total bacteria and total mould and yeast flora and microbial inactivation kinetics were determined. Saffron quality by FTIR and HPLC and sensory attributes were also measured. The highest reduction of the total bacterial count (2.203 log10 CFU per g) and total mould and yeast counts (2.194 log10 CFU per g) were obtained in Sargol Negin saffron at 350 W PIR power, 10 cm distance, 1.5 min treatment time and 3 pulse/s. The Double Weibull model is the best-fit model for the prediction of the microbial population.
Conclusion: Until now, there have been no reports of application for PIR in food processing and decontamination. According to the results, it can be concluded that PIR can be used as a safe method of saffron processing.
Significance and impact of the study: Utilization of a proper decontamination method for spices especially saffron as the most expensive agricultural product is challengeable. It is recommended to use the PIR method for food processing because due to the reduction of microbial population, it can maintain foodstuff quality at an acceptable level.
Keywords: FT-IR; microbial decontamination; microbial modelling; pulsed infrared; saffron.
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