No abstract

A novel nanopackaging was synthesised by coating polyvinyl chloride (PVC) film with nano-ZnO powder, and its effects on the preservation quality of fresh-cut 'Fuji' apple were investigated at 4°C for 12 days. Compared with the control (PVC film), nanopackaging significantly reduced the fruit decay rate (P < 0.05), as well as decreased the accumulation of malondialdehyde (MDA) from 74.9 nmol g )1 in the control to 53.9 nmol g )1 in the nanopackaging. Cutting caused an increase in ethylene level, suggesting wound-induced ethylene production, which was suppressed in nanopackaging. Both the polyphenoloxidase and pyrogallol peroxidase activities were decreased in nanopackaging fruit. The initial appearance of apple slices was retained, and the browning index was prevented in nanopackaging samples, which was only 23.9, much lower than the control of 31.7 on day 12. These results indicated that nano-ZnO active packaging could be a viable alternative to common technologies for improving the shelf-life properties of 'Fuji' apples as a fresh-cut product.

No abstract

The solubilities of naringin and naringenin in methanol, isopropanol, ethyl acetate, petroleum ether, nbutanol, and hexane were measured by using UV spectrophotometric methods at the maximum absorption wavelength of (283 and 372) nm from (288.15 to 328.15) K. The solubilities of naringin and naringenin in different solvents increase with an increase of temperature. The solubility of naringin in the six solvents was in the order methanol > ethyl acetate > n-butanol > isopropanol > petroleum ether > hexane, and the solubility of naringenin in these solvents follows the order ethyl acetate > isopropanol > methanol > n-butanol > petroleum ether > hexane. The solubility of naringenin was significantly higher than naringin in all selected solvents because of the more similar polarity of naringenin with solvents. The solubilities of naringin and naringenin are calculated by using the modified Apelblat equation model, ideal model, and the λH equation model. From solubility data, the changes of dissolution enthalpy, entropy, and the free Gibbs energy of naringin and naringenin in six solvents were also calculated using the van't Hoff equation. The course of naringin and naringenin dissolving in the selected solvents in the experimental temperature range was endothermic. The dissociation constants (pK a ) of naringenin were determined at 298.2 K by ultraviolet (UV) spectroscopy method. The pK a1 and pK a2 values of naringenin are 7.05 ± 0.06 and 8.84 ± 0.08.