Preparation and Characterization of Nanostructured Lipid Carriers for Epigallocatechin Gallate, and Their Application in the Antioxidant Preservation of Peanut Oil

Peanut oils, which are rich in unsaturated fatty acids (UFAs), offer significant health benefits, but are susceptible to oxidative rancidity during storage, resulting in a degraded nutritional value and potential health risks. Epigallocatechin gallate (EGCG), a potent natural antioxidant found in tea, exhibits promise for mitigating the oxidation of such oils; however, its poor lipophilicity limits its direct application in oil-based systems. EGCG was encapsulated using nanostructured lipid carriers (NLCs), and its effectiveness in preserving the quality and oxidative stability of peanut oil during storage was compared with a natural antioxidant, α-tocopherol. The EGCG-NLCs, with an average particle size of 156.7 ± 12.9 nm, exhibited encapsulation and loading efficiencies of 99.79 ± 0.00% and 6.74 ± 0.02%, respectively. Compared to the free EGCG, the EGCG-NLCs exhibited a superior radical scavenging activity and an improved lipophilicity. After 180 d storage under natural light, the EGCG-NLCs inhibited color changes in the peanut oil, increased the relative UFA content, and demonstrated reduced oxidative stability indices, with an optimal dose of 400 mg/kg. Compared to α-tocopherol, the EGCG-NLCs demonstrated a superior performance in preserving the oxidative stability and overall quality of peanut oil, highlighting their potential for use in food oil preservation applications.