Xi Hong Li

Differential Expression of Anthocyanin Biosynthetic Genes and Transcription Factor PcMYB10 in Pears (Pyrus communis L.)

Anthocyanin biosynthesis in various plants is affected by environmental conditions and controlled by the transcription level of the corresponding genes. In pears (Pyrus communis cv. ‘Wujiuxiang’), anthocyanin biosynthesis is significantly induced during low temperature storage compared with that at room temperature. We further examined the transcriptional levels of anthocyanin biosynthetic genes in ‘Wujiuxiang’ pears during developmental ripening and temperature-induced storage. The expression of genes that encode flavanone 3-hydroxylase, dihydroflavonol 4-reductase, anthocyanidin synthase, UDP-glucose: flavonoid 3-O-glucosyltransferase, and R2R3 MYB transcription factor (PcMYB10) was strongly positively correlated with anthocyanin accumulation in ‘Wujiuxiang’ pears in response to both developmental and cold-temperature induction. Hierarchical clustering analysis revealed the expression patterns of the set of target genes, of which PcMYB10 and most anthocyanin biosynthetic genes were related to the same cluster. The present work may help explore the molecular mechanism that regulates anthocyanin biosynthesis and its response to abiotic stress at the transcriptional level in plants.

Effects of nano-ZnO power-coated PVC film on the physiological properties and microbiological changes of fresh-cut 'Fuji' apple

The effects of a novel nano-ZnO coated PVC film on physicochemical quality and microbiological changes of fresh-cut ‘Fuji’ apple were evaluated. Fruit decay were efficiently reduced in nano-packing samples. The content of ascorbic acid and total phenolic dropped to 0.2 g•kg-1, 1.2 g•kg-1 in nano-packing samples and 0.02 g•kg-1, 0.6 g•kg-1 in control on day 12. In addition, the nano-ZnO coated PVC film not only inhibited the growth of total aerobic psychrophilic microorganisms, the count of which did not exceed 5 log cfu g−1 FW, but also suppressed the increasing of yeast and mould, the maximum growth of which reached only 3.6 log cfu g−1 in the nano-packing but 6 log cfu g−1 in control.

Development of Nano-ZnO Coated Food Packaging Film and its Inhibitory Effect on Escherichia coli In Vitro and in Actual Tests

In this study, we investigated antibacterial activity of zinc oxide (ZnO) nanoparticles coated on polyvinyl chloride (PVC) films against Escherichia. coli both in vitro and in actual test. Results showed that the nano-ZnO coated films displayed excellent inhibition effects on the growth of E. coli and the nano-ZnO particular was contributed to the bactericidal ability. The more amounts of the ZnO particulars the film coated, the greater inhibitory effect it exhibited. The disinfection efficiency with ZnO film is relatively constant at pH values in the range of 4.5 to 8.0. In the actual test, the number of E. coli cells from cut apple stored in a ZnO-coated bag in the dark decreased from 8.72 to 6.3 log CFU/ml after 1 day, while that of an same bag irradiated with light decreased from 8.72 to 3.5 log CFU/ml after 2 days of storage. The results reveal that nano-ZnO coated film has a good promise to make antimicrobial packaging again E. coli and reduce the risks of microbial growth on fresh-cut produce.

Antibacterial Property of Active Packaging of Microencapsulated Cinnamon Oil Combined with ZnO-Coated PVC Film

In this investigation, antibacterial property of active packaging of microencapsulated cinnamon oil combined with ZnO-coated PVC film was investigated. Microencapsulated cinnamon oil was prepared by simple coacervation and the morphology of microencapsulation was also analyzed by SEM. Result also showed that microencapsulated cinnamon oil and ZnO-coated PVC film exhibited good antibacterial activities against E. coli and S. aureus. In vivo fruit test, the active packaging of microencapsulated cinnamon oil combined with ZnO-coated PVC film showed good inhibition property the growth of bacteria on the surface of fresh-cut apple slices.

Characteristics and Release Behavior of Sodium Alginate Microencapsulation Containing Cinnamon Oil

Microencapsulation technology is widely used in many industries recently because the stability of core material can be improved and the release characteristics can be modified. In this investigation, cinnamon oil was microencapsulated by simple coacervation. The size distribution is narrow and the mean diameter is 53.79 μm. The surface morphology of the resultant microcapsules was also characterized scanning electron microscopy (SEM). The results showed that the rates of cinnamon oil released from microencapsulation were not only affected by relative humidity in the microenvironment around microencapsulated powder, but also affected by the temperature.

Insecticidal Effects of the Insecticide Based on Porous Starch and Cinnamon Oil against Sitophilus zeamais

We investigated that the bioefficacies of cinnamon oil and insecticide based on the mixture of porous starch and cinnamon oil. They were evaluated for their insecticidal activities and their mortality on adults of Sitophilus zeamais. Fumigant toxicity assayed by hanging in glass jars showed that these chemicals caused significant mortality of the test insect. Cinnamon oil evoked high repellent action and high fumigant toxicity (LD50 = 0.030μL/cm3) against adults of Sitophilus zeamais. The two concentrations of the new insecticide 0.030μL/cm3 (LD50) and 0.040μL/cm3 (the highest) lose their insecticidal activity after a minimum of 144h and 168h, respectively. These results suggest that cinnamon oil starch powder is the most effective insecticide, and could increase its efficacy for use as an alternative to synthetic insecticides.

Effects of Nano-Particles on Resistance of DOP Migration from Flexible PVC

The effects of nano-particles (CaCO3, SiO2 and organic modified montmorillonite (OMMT) on the suppression of DOP migration from PVC matrix and mechanical properties of PVC composites were evaluated. The results indicated that the three kinds of nano-particles could improve the ability of anti-migration of DOP in flexible PVC. A certain content of nano-particle could decrease the migration rate of DOP. The addition of 5 phr SiO2 decreased the extraction rate of DOP to 15.6%, and SiO2-5/PVC composite film possessed superior anti-extraction property. The introduction of 5 phr OMMT reduced the volatilization of DOP to 0.067%, and OMMT-5/PVC exhibited the lowest volatilization of DOP. Inorganic nano-particles with high surface energy were easy to aggregate, and the influences of aggregation on the properties of composites were clearly detrimental, which results in a drastic decrease of polymer anti-migration and mechanical performance.

Effect of Sulfur Dioxide Treatment on Storage Quality and SO2 Residue of Victoria Grape

Taking Victoria Grape as material, studied on the effect of 1000, 500 and 100 μL/L SO2 fumigation treatments on postharvest quality and SO2 residue of fruit stored under 0 °C. The results indicated that after 60 days of storage, all treatment could decrease the decay rate, inhibited the decrease of soluble solids content. The 500 μL/L SO2 fumigation treatment showed an ability to inhibit increasing of MDA content and PPO activity. The SO2 residue in grape pulp treated by 500 μL/L and 100 μL/L of SO2 were 8.31 mg/kg and 6.52 mg/kg respectively which under the FDA safety standard (10 mg/kg) after 60 days storage, while the SO2 residue in 1000 μL/L SO2 fumigation treatment samples was 23.17 mg/kg which beyond the FDA safety standard.

Effect of Polyolefin Film on the Quality of Kiwifruit with 1-MCP Treatment in Modified Atmosphere Packages

Kiwifruit is very perishable especially at 20 °C. The quality of kiwifruit with 1-MCP treatment stored at 20 °C in modified packages was investigated. Three different polyolefin films, including 0.03mm thickness polyethylene (PE), 0.03mm and 0.05mm thickness poly (vinyl chloride) (PVC) films, were used as packaging films. Kiwifruit were fumigated with 1-MCP to delay ripeness and then packaged with the three films and control (air). O2 and CO2 concentrations in the packages, flesh firmness, soluble solids concentration (SSC), titratable acidity (TA) and ascorbic acid were measured. MAP treatments could postpone the increase of TTS, inhibit the reduction of TA, and avoid the decrease of flesh firmness. Kiwifruit packaged in 0.05mm PVC obtained 33% TA more than control fruit and approximate 25 % retention of initial firmness. However, MAP didn’t maintain more ascorbic acid content of kiwifruit. In conclusion, MAP using polyolefin films combination 1-MCP treatment, especially 0.05mm PVC, might be more effective for preserving the quality of kiwifruit.

Antimicrobial Activity of Microencapsulated Cinnamon Oil and Its Application on Cherry Tomato

In this investigation, antibacterial property of microencapsulated cinnamon oil was investigated. Microencapsulated cinnamon oil was prepared by simple coacervation. Microencapsulated cinnamon oil exhibited good antimicrobial activities.Moreover, the effect of microencapsulated cinnamon oil on the quality of cherry tomato was investigated. Result showed microencapsulated cinnamon oil could reduced fruit decay and keep the quality of cherry tomato.