Abstract
Low-angle scattering of X-rays is characterized by the presence of one or more peaks in the forward direction of scattering. These peaks are due to the interference of photons coherently scattered from the molecules of the medium. Thus these patterns are closely linked to the molecular structure of the investigated medium. In this work, low-angle X-ray scattering (LAXS) profiles of five spices;
pimpinella anisum (anise),
coriandrum sativum (coriander),
cuminum cyminum (cumin),
foenculum vulgare (fennel) and
nigella sativa (nigella or black cumin) are presented after extensive measurements. It is found that all spices exhibit one characteristic peak at a scattering angle around 10°. This is equivalent to a value
x=0.0565
Å
–1, where
x=sin(
θ⧸2)⧸
λ. The full width at half maximum (FWHM) of this peak is found to be characteristic for each type of the investigated spices. The possibility to detect the irradiation of these spices from their LAXS profiles is also examined after 10, 20, 30 and 40
kGy doses of gamma radiation. Except for anise, coriander and cumin at 40
kGy, there are no detectable deviations from the control samples in the scattering profiles of irradiated samples. These results comply with the recommendations of the FDA (US Food and Drug Administration) which defines 30
kGy as the maximum dose for irradiation of spices. The present technique could be used to detect over-irradiation, which causes damage to the molecular structure of some spices.