Carbohydrates in Kangaroo grass (Themeda triandra Forssk.) grain and perspectives on its food potential

This paper presents the optical characterization of five commercial classes of rice: two classes of white rice, one fortified, one integral, and one parboiled. The differences between the line shapes of the photoluminescence spectra of rice grains and the contribution of its components, starch, fat, and ash, to the rice spectrum were discussed. The fat contributes to rice emission at wavelengths 676 nm and 715 nm, while the starch components contribute at low wavelengths with maxima at 552 and 591 nm. As for the ash, the photoluminescence spectra are of low intensity for all samples, with no significant incidence in the rice photoluminescence spectrum. However, the ashes of the fortified rice and parboiled rice show structures in the line shape at 744, 774, 842, and 881 nm, attributed to minerals not present in the other classes of rice. Additionally, we present these comparisons on absorption spectra in the infrared region; it was observed that there are differences between the white classes of rice and the classes of rice with husk; a high similarity between the absorption spectrum of rice and its starch was also observed, masking the contribution of fat and ash, thus validating the sensitivity of the photoluminescence technique.