In this work, the effects of two different amounts of zinc oxide (ZnO) nanoparticles on the antimicrobial activities of poly (vinyl chloride)-based films to inactivate food pathogens were investigated. Results showed that the ZnO-coated film exhibited a good inhibition effect on the growth of Escherichia coli and Staphylococcus aureus and its ability was attributed to the ZnO nanoparticles. The ZnO-coated films exhibited more effective antibacterial activity for S. aureus. However, antifungal activity of the ZnO-coated films (20 mm · 25 mm) against Aspergillus flavus and Penicillium citrinum was not observed. It is likely due to the complexity of the fungal cell wall and the ZnO nanoparticles without UV light irradiated or the insufficient amount of nanoparticles. Our findings reveal that ZnO nanoparticles have a good potential to be coated on a plastic film to make antimicrobial packaging against bacteria such as E. coli and S. aureus.
In this study, tannic acid (TA), a natural antioxidant, is successfully encapsulated into a plant‐based guar gum fibrous mat by electrospinning without using an organic solvent. An upper threshold of 10 wt% TA (based on the dry weight of guar gum [GG]) and 2 wt% guar gum is the optimum composition to achieve a defect‐free structure through electrospinning. The obtained nanofibers have a mean diameter of 96 ± 22 nm. The effect of the encapsulated TA in the fibrous mat (200 ppm) on the oxidation of unrefined flaxseed oil (FO) is investigated over 30 days of storage at an elevated temperature (60 °C) and compared with the effect of butylated hydroxytoluene (BHT), a synthetic antioxidant, and non‐encapsulated TA at the same concentrations. Changes in the fatty acid composition, the conjugated diene content, the peroxide value, the content of thiobarbituric acid reactive substances (TBARS) and the p‐anisidine content are monitored as indicators of the oxidative stability. The TA fibrous mat exhibits different inhibitory effects on the oxidation of unsaturated fatty acids and is more effective than non‐encapsulated TA and BHT in reducing the rate of primary oxidation and secondary oxidation of FO as evaluated by all the oxidation indicators except the TBARS values for which BHT displays the greatest inhibition. Overall, the results demonstrate that the encapsulation of natural antioxidants into fibrous mats could potentially be used to preserve edible oils.
Practical Applications: This is the first paper using plant‐based fibrous mats encapsulating natural antioxidant to improve the oxidative of flaxseed oil (FO) during storage. Compared with macro Tannic acid (TA), encapsulating TA in nano‐scale delivery system is more effective in delaying both the primary and secondary oxidation reactions of FO throughout the entire storage time. The results demonstrate that encapsulation of TA in fibrous mat could be potentially used to preserve oil. The formation of this nanofiber mat in this system is manufactured without using any synthetic chemicals. The plant‐derived components (GG and TA) are both recognized as safe by FDA and even edible. It can be directly added to crude oil systems during oilseed refining processing or used as coating material to fix on the surface of existing packaging bottle in order to prevent edible oil from oxidation, which would be beneficial in oil preservation and other related fields.
This is the first paper using plant‐based nanoscale delivery system encapsulating natural antioxidant to improve the oxidative of flaxseed oil during storage. The plant‐derived components (guar gum and tannic acid) are both recognized as safe by FDA and even edible. The simple preparation process, effectiveness, and food‐grade functionality provide a novel alternative to synthetic antioxidants to protect edible oil from oxidation.
To
eliminate the feeding device coking deposit in a commercial
pyridine synthesis reactor, a coupled fluidized bed reactor is proposed.
The coupled reactor is composed of a feeding zone (FZ), a riser reaction
zone (RRZ), and a fluidized bed reaction zone (FRZ). During 15 days
of continuous operation, there is no coke deposit in the feeding device.
Experimental results show that the product yield reaches as high as
75%. The selectivity is around 2.5 and is higher than that in commercial
reactors, which is around 2.2. A core–annulus model and a dispersion
model are proposed to model different zones of this coupled reactor,
and the predicted average deviation from experimental data is 12%.
The prediction results show that the main reactions take place at
FZ and FRZ. RRZ contributes the least conversion, because of the limit
by the mass transfer between the core and the annulus.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.