Effects of time and temperature on stability of bioactive molecules, color and volatile compounds during storage of grape pomace flour

Background: Grape pomace is highly attractive for the food industry, since its relevant content of bioactive molecules with numerous healthy properties. In order to exploit pomace flour as functional food ingredient for food industry, in this work, stability of bioactive molecules, color and volatile compounds during storage over six months at 4°C and 25°C in the dark of whole pomace flour from red grape was tested. Methods: The parameters monitored were Antioxidant activity (TEAC assay), Total Phenols (Folin-Ciocalteu assay), characterization of phenolic composition by High Performance Liquid Chromatography, fatty acids composition by Gas Chromatography-Mass Spectrometry, volatile compounds profiles by Headspace-Solid phase micro-extraction and color of grape pomace flour. Results: the obtained results show that the content for both total phenols, antioxidant activity and characterized bioactive molecules (polyphenols, fatty acids) was significantly preserved. The only detected variations during storage were a slight whitening and the analysis on volatile fraction, showed a slight increase of long chain esters and ketons after six months at 25°C. Conclusions: Results suggest that at 4° C pomace flour is stable for 6 months. These results support the possible use of grape pomace flour as an ingredient for functional foods