Preparation and characterization of chitosan-coated nanostructured lipid carriers (CH-NLC) containing cinnamon essential oil for enriching milk and anti-oxidant activity

The cinnamon essential oil (CEO) was loaded in nanostructured lipid carriers (NLC) and NLC surfaces were coated with chitosan (CH-NLC). The particle size increased significantly from 99.98 nm, in the control NLC to 107.1, 112.2, and 119.4 nm in the CH-NLC coated with 0.05%, 0.1%, and 0.15% chitosan solution, respectively. After 40-day storage the mean size of all formulations slightly increased, however, the CH-NLC indicated less growing than NLC. The PDI value of NLC was lower than the CH-NLC (0.252 in comparison to 0.325). In addition, the negative zeta potential of NLC ( -17.56) was changed to + 21.4 for CH-NLC. The entrapment efficiency (EE%) of CH-NLC (93.68%) was significantly (P < 0.05) higher than NLC (88.14%) which could be attributed to the higher particle size of CH-NLC system. The encapsulation stability (ES%) of CH-NLC (84.6%) was significantly higher than NLC (78.12%). Furthermore, the FTIR spectrum showed no creation of new peaks after coating the NLC however the intensity of the peaks was shifted. The endothermic peaks of NLC illustrated low melting point (38.50 degrees C) and less ordered crystalline structure. The stability of milk fortified with this system against oxidation during the storage time was proved by thiobarbituric acid test and peroxide value.