Microencapsulation of natural antioxidants from by-products of the agroindustry is attracted attention nowadays, due to the limited stability of these bioactive compounds and the use of valuable resource. Saccharides, especially maltodextrin, have been extensively used as wall of the microcapsules, while proteins and enzymes have been less studied [1]. For that, an olive oil extract of tomato peels was firstly made. Then, it was mixed with different proteins (caseinate, caseinate and transglutaminase, and soya and pea proteins) to obtain an emulsion that was subsequently subjected to spray-dry to finally get the microcapsules (C, CT, S, P, respectively). Then, the microcapsules were subjected to a stability assay of different temperatures (4, 25 and 50 ºC) and times (2, 5 and 10 days). A control batch (not subjected to storage) was also included. External oil and secondary lipid oxidation products were determined [2], [3]. The type of microcapsule influence on both external fat and oxidation levels, being higher in S and P than in C and CT. Storage of microcapsules did not significantly modify oxidation levels but if affected the external fat, being higher in stored microcapsules than in the control batch. This effect was more marked in S and P than in C and CT microcapsules, but no statistical differences were found among microcapsules subjected to different temperature and times. These results point out the antioxidant efficacy of tomato peel extracts to get lipid oxidation stability as well as the influence of the wall material to avoid the oil release from the inner of the microcapsules, which is favoured during storage independently of storage conditions. In this sense, the use of C and CT as wall material seem to be more appropriate than S and P proteins.
1. Perez-Palacios, T., et al., Foods, 2022. 11(20): p. 3291.
2. Higgins, S., et al., Journal of Human Nutrition and Dietetics, 1999. 12(4): p. 265-271.
3. Díaz, P., et al., Meat Science, 2014. 98(4): p. 569-573.