Use of agri-food residues for oil structuring and functionalization

The residues from agri-food industry often represent an environmental burden, despite the fact that they are still rich in several intracellular compounds, which can be efficiently valorized if adequately recovered. This work addresses the use of High Pressure Homogenization (HPH) processing as an efficient comminution process to mechanically disrupt the plant cells and release the high-added value intracellular components into vegetable oils for their structuring and functionalization. The vegetable matrices, consisting of tomato peels, or spent coffee grounds, were suspended in water, premilled and screened at 600 μm. Subsequently, the vegetable suspensions were processed from 1 to 5 times by HPH, at 100 MPa. Centrifugation (5000×g for 30 min) was used to separate the different fractions (oil phase, aqueous phase, and insoluble fibers). Vegetable oils were added to the dispersion before the HPH treatment or to the insoluble residues after centrifugation. The results indicate that HPH processing causes the complete disruption of the vegetable cells in suspension and the release of the intracellular material. The resulting vegetable cell debris was exploited as an oil structuring agent, through the formation of a water-based capillary network into the continuous oil phase. The developed structuring capabilities of vegetable oils make possible to replace other undesired ingredients, such as palm oil, in food product formulation. Moreover, the lipophilic bioactive compounds contained in the vegetable cells were released in the oil fraction, becoming more readily bioaccessible.