Microencapsulation of Natural Compounds With Antioxidant Activity as Food Preservers

ASENSIO C.; GROSSO, A. L.; RIVERO, C. G.; OLMEDO R. H.; GROSSO, N.R.

Chicago

Congreso; IFT 2015; 2015

Institute of Food Technology

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 a homogenizer and 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 determined after 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 and after the encapsulation process (p˂0.001). Before encapsulation C exhibited the lowest IC50 for DPPH (156.3 µg) and the highest TPC (0.365 mg 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 µm ) than C and M capsule areas (50.13 and 39.13 µm , respectively). Natural products as P, M, and C preserve their antioxidant activity after encapsulation and can be used as food preserving agents.