Effect of the time and temperature of germination on the phenolic compounds of Triticum aestivum, L. and Panicum miliaceum, L.

This study was carried out to evaluate how short sprouting time and temperature affect the nutritional values of different wheats and a millet. Grains and their sprouts were evaluated for the polyphenol content, monitoring also the change of the phenolic acids and sugars profile during germination. Results indicate that wheats show different availability for free and bound polyphenols according with the different sprouting temperatures. Low temperature (15 degrees C) appears to promote the availability of the free polyphenols in common wheats, while wheat genotype affect the bound fraction levels. High temperature (20 degrees C) appear to positively influence the availability of free and bound polyphenols in millet. The content of free phenolic compounds was positively influenced by low temperatures, while opposite trend was detected for the bound fraction. Relevant differences were observed in millet that showed a significantly higher content at higher temperature. Sugars availability during wheats sprouting was higher at 20 degrees C, but was no significant differences were detected at the end of the germination process, while for millet the higher temperature positively affect the sugars level. It was concluded that grain type, germination temperature and time, play a key role for the improvement of the nutritional quality of the sprouts.