Microencapsulation of natural compounds with antioxidant activity as food preservers

ASENSIO CM; GROSSO AL; RIVEROS CG; QUIROGA PR; GROSSO NR; NEPOTE V

Cordoba

Jornada; I Jornada del ICTA; 2015

FCEFyN-UNC

Quality of food products inevitably changes during storage. The addition of natural additives instead of synthetic ones covers the present trend in food technology. There is a growing demand for delivering antioxidants through functional foods with the challenge of protecting their bioactivity. Sensitive ingredients can be packed within a coating that protects them and controls their release. In addition, microcapsules can convert liquids into powders, which are easy to handle. The objective of this study was one side, to evaluate the antioxidant activity of three natural products before and after encapsulation process: mint essential oil (M), peanut skins polyphenols(P),and carotenoids (C) and for the other side to characterize the microcapsules.A carbohydrate-based microcapsule was prepared. Neutralized peanut oil was used as the core. Antioxidant compounds were dissolved at 10% w/w. Wall components were a combination of maltodextrin (32.8%), carboxymethylcellulose (65.6%), and lecithin (1.6%). The ratio of oil?wall material was 1:1.5.Emulsions were prepared using ahomogenizerand were frozen at −80 °C, freeze-dried by a lyophilizer. A 3D confocal microscope was used to determine geometry surface, shape, and size of the emulsion droplets. Moisture content, antioxidant activity assays (DPPH, ABTS, hydroxyl radical scavenging activity, and chelating activity of ferrous ion), and total phenolic content (TPC) were determinedafter and before encapsulation. ANOVA and Fisher-LSD test were used for statistical analysis.Antioxidant activity values and TPC of M, P, and C differ significantly before andafter the encapsulation process (p˂0.001). Before encapsulation C exhibited the lowest IC50 for DPPH (156.3 µg) and the highest TPC(0.365mg gallic acid/mL) whereas M exhibited the highest DPPH value (22.09 mg) and the lowest TPC (0.073 mg gallic acid/mL). After encapsulation,P microcapsules showed higher antioxidant activity (IC 50 DPPH 807.13 µg; TPC 0.07 mg gallic acid/mL; ABTS 11.10 mg trolox/g P) than M and C. Polyphenols microcapsules areas were smaller (average areas: 22.29 µm2) than C and M capsule areas (50.13 and 39.13 µm2, respectively).Natural products as P, M, and C preserve their antioxidant activity after encapsulation and can be used as food preserving agents.These microcapsules could be easily incorporate in different food matrixes as natural additives with antioxidant properties.