61A-34 |
Application of FT-Raman spectroscopy for discriminating dry-milled fractions of corns dried at different temperatures |
K. SEETHARAMAN1, M. Rout1, and J. M. K. Irudayaraj2. (1) Dept. of Food Science, Pennsylvania State Univ., 107-A Borland Lab., University Park, PA 16802, (2) Dept. of Agricultural & Biological Engineering, Pennsylvania State Univ., 0227 Ag Engineering Bldg, University Park, PA 16802 Biochemical changes occurring during tempering and dry milling of corn has not adequately characterized. Spectroscopic techniques to characterize chemical changes are a rapid and non-invasive analytical tool that can identify specific chemical changes in processed grains. The objectives of the study were to characterize changes taking place during drying of different corns at different temperatures and their dry milled fractions. Normal, high amylose and waxy corn were dried at 80, 150 and 200 oF prior to storage at 50 oF. Stored corn was milled using standard procedures and separated into five fractions; sieve# 3.5, 5, 7, 12, 30 and <30. A Nicolet FT-Raman spectrometer with a Nd:YAG laser emitting at 1064 nm excitation source with 500 scans, 4cm-1 resolution was used in the study. FT-Raman spectroscopy successfully discriminated normal, waxy and high amylose corn dry milled fractions. No significant changes were observed among dry milled fractions at a given drying temperature. The intensity of the 470 cm-1 bands corresponding to amylopectin was greater in waxy and high amylose corn compared to normal corn. While the position of this band did not change at higher drying temperatures in normal and waxy corn fractions, it increased in high amylose corn. In normal corn dried at ambient temperature, the 1653 cm-1 band corresponding to amylose was observed. At higher drying temperatures this band was not observed, but a new band at 1668 or 1664 cm-1 was observed indicating protein denaturation. The band corresponding to amylose was not observed in waxy corn fractions, but the protein band shifted to lower wave number with increasing drying temperatures. CVA of the 1500-1700 cm-1 region discriminated samples based on genetic variation as well as drying temperatures. FT-Raman can be used for the discrimination of corn types, as well as milled fractions from corn dried at different temperatures.
Session 61A, Carbohydrate
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