Résumé
Dietary diversification, which starts between 4 and 6 months, is a pivotal period in the infant development. Complementary foods such as infant flours are gradually introduced into the infant diet and are widely consumed especially in southern countries. However, infant flours have often an unbalanced lipid profile in favor of omega 6 and overages in certain vitamins content (especially A and E). The aim of this study was to optimize the formulation of vitamin A and E-fortified infant flours in order to improve its nutritional profile and oxidative stability. For this purpose, model infant flours were formulated by optimizing the lipid profile through the inclusion of flours with balanced omega 6/omega 3 ratios, i.e. teff and cowpea flours, and/or by adding long-chain polyunsaturated fatty acids (LC-PUFA) powders. In order to limit their sensitivity to oxidation, two strategies were studied, namely the addition of amaranth leaf powder for their carotenoid content and brown rice peripheral tissues for their phenolic compounds composition. These model infant flours were submitted to storage test during 6 months at 25 or 40°C. As expected the inclusion of LC-PUFA significantly increased the oxidation sensitivity of the flours. The use of raw materials with balanced fatty acid profiles resulted in contrasted omega 6/omega 3 ratio of 6.7 in un-enriched in LC-PUFA model infant flours versus 3.9 for the LC-PUFA enriched model infant flours. As expected, the addition of LC-PUFA increased the sensitivity to oxidation with a significantly higher increase of peroxide value for the flours enriched with these fatty acids. Despite a significant increase of peroxide value, the fatty acid profiles and vitamin E contents remained stable after 1 month of storage. A significant degradation of vitamin A was however observed mainly on short time with up to 50% of retinyl acetate degraded after 2 weeks of storage. This degradation was significantly delayed for model infant flours enriched with amaranth leaf or black rice peripheral tissue. In conclusion optimized omega 3 enriched infant flours could be proposed with fair stability over 3 months of storage.