Raman spectroscopy is an inelastic

Raman spectroscopy is an inelastic light scattering event and is sensitive for the fundamental vibrations of less polar molecular groups and bonds like C–C symmetric vibration and pyranoid ring vibration. In Raman spectroscopy the interaction between light and matter is an off-resonance condition involving the Raman polarizability of the molecule (Thygesen, Lokke, Micklander, & Engelsen, 2003). The Raman spectrum of rice samples at different stages of puffing are shown in Fig. 2 with the major peaks are shown at 412, 440, 485, 523, 688, 718, 770, 865, 940, 1082,
1340, and 1381 cm1 in raw rice samples. Whereas, the figure indicates that spectrum have low peak intensities after parboiling. There is non-significant difference between the peak intensities of parboiled and expanded rice. Changes in band intensity result from changes in specific conformations, such as long range ordering and crystallinity (Labanowska, Birczynska, Kurdziel, & Puch,2013). The parboiling process caused the restructuring of the intramolecular and intermolecular hydrogen bonding, and directed to a change in the vibrational mode of C–H bonds, which influenced the variable changes in intensities. The puffing process leads to the
increase in temperature which results in changes to some chemical groups like C–C, C–H, skeletal types and pyranose linkage vibrational modes with intense peaks at 413, 485, 529, 941 and 1345 cm1. The disappearance of the vibration absorption peaks
was caused by decreasing intensities which occurred during the
heating treatment. Starch granules or molecules were converted
into retrograded starch molecules during parboiling and these will
rapture during the high heat treatment and the chemical bonds
will be disturbed and the vibrational energy will decrease (Fan
et al., 2012).