Effet des polyphénols sur la résistance à l’infestation fongique dans le grain de blé dur.

Abstract

Contamination by microorganisms is one of the major causes of deterioration of stored grain, and their importance is too often underestimated. Mold storage, may lead to a series of changes, resulting in loss of technological, commercial, hygienic and nutri tional. The polyphenols are compounds generating in recent years a growing interest from the industrial food processing. Some studies have shown that the ability of a plant to resist attack by micro - organisms is often correlated with phenolic content. This work is done in this context, it is the demonstration of correlation between the total polyphenol content and fungal infestation in wheat grains of four varieties (MBB, CIRTA, VI TRON and SIMETO). This work also focuses on the evaluation of the in vitro an tifungal activity of total polyphenols extracted from wheat grains. The principal results show firstly , that the samples healthy have a higher concentration of total polyphenols compared to samples altered, a significant difference for total polyphenol con tent in the varieties of wheat analyzed and in the samples from healthy and altered wheat. Secondly, research molds from wheat varieties shows that despite the healthy appearance of some samples, they were found contaminated, the percentage of contaminatio n is higher in the sample altered than in the sample healthy for all varieties of wheat analyzed . The results of the antifungal activity, for different concentrations of total polyphenols extracted from samples of healthy and altered wheat, showed inhibiti on of mycelial growth in different ways. The polyphenolic extracts have not the same percentage of inhibition at the same concentration vis - à - vis the mold strains tested. Moreover, the results obtained by the correlation test revealed a significant negativ e correlation between total polyphenol content and the percentage of contamination. With the rise of this study, we can conclude that the high content of total polyphenols in wheat grains appears to reduce the fungal infestation