Synthesis of Boron Nitride Nanosheets/Polyvinyl Butyral Thin Film: An Efficient Coating for UV Protection of Extra Virgin Olive Oil in Glass Bottles

In this study, we research the long-term UV protective effect of BNNSs/PVB multilayer thin film coating on the properties of extra virgin olive oil. Boron nitride nanosheets (BNNSs) were synthesized using the liquid exfoliation method. BNNSs/PVB multilayer thin film was coated on tubes by dip-coating. After the UV irradiation of coated and uncoated glass tubes at different times, the total phenol content (TPC) and antioxidant activity of olive oil (TAA) were determined. Specific absorption coefficients K232 and K270 in the ultraviolet region were measured for estimating the oxidation degree of olive oil after irradiation. Free fatty acid (FFA) in olive oil after UV irradiation was determined by the titration method. Olive oil quality analysis indicates that BNNSs/PVB coating on the glass is effective on the protection of TPC and TAA of olive oil. In addition, the results show that extra virgin olive oil in the coated glass tube is maintained nearly 2 times more than the amount of phenol in the uncoated tube. While olive oil samples in glass tube coated with 30 and 50 times exceeded the limit of K270 value (0.22) after 400 hrs, it was determined that olive oil samples in uncoated glass exceeded this limit after 215 hrs. After 720 hours of UV irradiation, the free fatty acid value of the UCOL (uncoated) sample increased by 24.7% compared to the initial value, while the increase in the COL50 (coated) sample was 15%.