Comparing effects of washing, thermal treatments and gamma irradiation on quality of spieces

Abstract

AbstractSelected five spices were treated with simple natural methods as washing with pure tap water then drying at room temperature, thermal treatment at 70 °C/15 minutes besides irradiation with 5.0 and 10 kGy. The evaluation of the used treatments efficiency depends on microbiological and chemical studies. The results show that untreated samples were highly contaminated with pathogenic and toxigenic microbes. Gamma irradiation was effective in decontamination especially 10 kGy but caused losses in major components of flavour as anethol, mechavicul, anise‐aldehyde in anise, β‐pinen and cineol in black pepper. Also, irradiation induced the changes of monoterpene hydrocarbons to alcohol terpens in essential oils of black pepper.Thermal treatment reduced the microbial count and pathogenic microbes to the same safe range as an irradiation dose of 5 kGy. Thermal techniques improved the flavour, as anisealdehyde in fennel, anethol in anise and B‐pinen in black pepper. Washing of the spices removed slightly the microbes but revealed no changes in flavour except the anise flavour which increased markedly.Finally, thermal and washing treatments could be recommended as simple natural techniques to produce spices with good flavour and in safe range for hygienic quality comparing with sterilized dose 10 kGy.