Gamma irradiation of clove: level of trapped radicals and effects on bioactive composition

Elvira M. Gaspar, José C. Santana, Pedro M. P. Santos, João P. Telo, Abel J. S. C. Vieira

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


BACKGROUND: Food irradiation is a widely used technique for improving the safety and shelf life of foods, including most spices. However, growing concerns by consumers about this technique require further investigation on the effects of radiation, both on the safety of the food and on its organoleptic properties. In this work, cloves of diverse origins were submitted to different irradiation doses in a 60Co source. The presence of trapped radicals and their time-dependent decay after irradiation were assessed by electron spin resonance (ESR) spectroscopy. The volatile bioactive composition and the clove oil were evaluated before and after irradiation by gas chromatography time-of-flight mass spectrometry. RESULTS: Results show an increase of the amount of volatiles collected after irradiation, especially of caryophyllene oxide and acetic acid, although these are still minor constituents. No new compound was detected after irradiation. Radicals decay fast, and 60 days after irradiation they were undetectable by ESR. CONCLUSION: Gamma irradiation showed to be a clean technique for clove decontamination, since no significant change in the aroma or oil compositions was found, and low levels of trapped paramagnetic species, after the initial decay period, were detected upon irradiation. Furthermore, irradiation doses higher than those legally allowed are equally safe.

Original languageEnglish
Pages (from-to)1668-1674
JournalJournal of the Science of Food and Agriculture
Issue number4
Publication statusPublished - 15 Mar 2019


  • bioactive composition
  • clove
  • food safety
  • free radicals
  • irradiation
  • spices


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