聚酯瓶的涂层

对抗氧化作用的食品饮料包装需求的日益迫切,使作为发展最快的包装材料的PET也被卷入这股浪潮当中。而新的PET瓶的开发多集中在对其结构和表面涂层的研究方面。作为饮料包装的顾问,Peter Weggeman探讨了近期对PET瓶涂层的一些研究。

Comparison of Antioxidant and Antimicrobial Activities of Methanolic Extracts of the Artemisia sp.Recovered by Different Extraction Techniques

The polyphenol content,antioxidant and antimicrobial activities of the extracts obtained by classical, ultrasonic and Soxhlet extractions from dry aerial parts of two Artemisia species(Artemisia vulgaris and Artemisia campestris)were compared.Ultrasound positively affected the yield of extractive substance and the kinetics of extraction,but the extract obtained by the classical extraction showed the highest antioxidant activities and contained higher total contents of phenolic compounds and flavonoids than the extracts obtained by two other extraction techniques.Both flavonoid aglycones(apigenin,quercetin,quercetin 3,3′-dimethyl ether)and flavonoid glycosides(rutin,hyperoside and kaempferol 3-rhamnoside)were identified by thin layer chromatograph(TLC)analysis in the extracts from both species.A.campestris extracts were richer in quercetin than A.vulgaris and its antimicrobial activity was also better than A.vulgaris.Extracts obtained from both species were found to be more effective on the tested yeasts than bacteria.The kinetics of the total extractive substances,such as phenolic,flavonoids and quercetin extraction,was successfully described by the model of unsteady-state diffusion.

Improved oxidation resistance of chemical vapor reaction SiC coating modified with silica for carbon/carbon composites

To protect carbon/carbon (C/C) composites from oxidation, a SiC coating modified with SiO2 was prepared by a complex technology. The inner SiC coating with thickness varying from 150 to 300 μm was initially coated by chemical vapor reaction (CVR): a simple and cheap technique to prepare the SiC coating via siliconizing the substrate that was exposed to the mixed vapor (Si and SiO2) at high temperatures (1 923?2 273 K). Then the as-prepared coating was processed by a dipping and drying procedure with tetraethoxysilane as source materials to form SiO2 to fill the cracks and holes. Oxidation tests show that, after oxidation in air at 1 623 K for 10 h and thermal cycling between 1 623 K and room temperature 5 times, the mass loss of the CVR coated sample is up to 18.21%, while the sample coated with modified coating is only 5.96%, exhibiting an obvious improvement of oxidation and thermal shock resistance of the coating. The mass loss of the modified sample is mainly contributed to the reaction of C/C substrate with oxygen diffusing through the penetrating cracks formed in thermal shock tests.

Low Pressure Cold Plasma as an Alternative Method for Black Pepper Sterilization

It was found out that spices straight from the package are not sterile. The only way to receive sterile spices is to use radiation technology which means to irradiate spices with ionizing radiation. However, this method is quite expensive and raises great resistance of public. And this is the reason why we are interested in implementing plasma technology. The first step of the research was to choose the most appropriate spice. The range of available spices is nearly unlimited, however, we took into account the following ones： sweet paprika, basil, rosemary, saffron, marjoram, thyme and black pepper. Finally, we chose black pepper because it is most often used by butchers to make meat products. It is also called the ＂King of Spices＂ or the ＂Black Gold＂. Black pepper is one of the most often used spices in the United States and in Europe. It is important to have sterile black pepper when we aim at ripening products for example ripening sausages or some kinds of cheeses. What is more, it was found out that black pepper has antimicrobial properties, antioxidant effects and also antipyretic and analgesic properties. The aim of the research was to receive sterile spices using low pressure cold plasma with oxygen, nitrogen, air, argon and hydrogen peroxide.

Non-alkaloid constituents of Vinca major

The present study was designed to investigate the non-alkaloid compounds from the leaves and stems of Vinca major cultivated in Yunnan Province, China. The compounds were isolated using chromatographic techniques. The structures were elucidated by 1D- and 2D-NMR spectroscopic methods in combination with UV, IR, and MS analyses. The 1, 1-diphenyl-2-picrylhydrazyl （DPPH）-scavenging activity of Compounds 1-7 were evaluated. One new iridoid glycoside （compound 1）, together with 11 known compounds, were isolated from Vinca major. Compounds 1, 5, and 6 showed moderate DPPH-scavenging activity, with IC50 values being 70.6, 32.8, and 62.2μmaol·L 1, respectively. In conclusion, compound 1 is a newly identified iridoid glycoside with moderate antioxidant activity.