Résumé
Infant follow-on formulas (IFF) are usually under the form of oil-in-water emulsions stabilized by protein interfaces with lipids of predominantly plant oils. These oils derived from extraction processes employing organic solvents posing environmental issues and are unstructured affecting the bioaccessibility of nutrients. The aim of this study was to introduce animal and plant oil bodies (OB) obtained from more sustainable procedure into IFF to improve their nutritional profile and assess their stability under different processing conditions. Three IFF (40% dry matter) were formulated: PO based on plant oils, PO/aOB based on plant oils and animal OB, and pOB/aOB based on plant and animal OB. Different operating conditions were tested: 2 passes at 80/20 bar and 140/40 bar for homogenization and 73°C, 1 min and 80°C, 1 min for heat treatment. After 7 days of storage at room temperature, no change in droplet size profile was observed with a mode between 1.2 and 1.4 µm or 0.7 and 1.3 µm for homogenizing pressures of 80/20 and 140/40 bar, respectively. aOB/pOB was characterized by particle aggregation and had a similar size profile to the other IFF in the SDS. A phase separation was observed for aOB/pOB, which was all the more important for less homogenization and heat treatment. It was reversible and probably due to the different nature of the proteins and phospholipids endogenous to the plant OB. A low level of protein denaturation (< 15%) was measured in all IFF. Despite a low initial microbiological load, the best efficiency was attributed to the heat treatment of 1 minute at 80°C. There results demonstrated the feasibility of homogenization and heat treatment on innovative IFF. The influence of spray drying on the bioaccessibility of nutrients using in-vitro models will be necessary to evaluate the overall processability of these IFF.