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Ban Z.J.,Jinan Fruit Research Institute | Ban Z.J.,Tianjin University of Science and Technology | Ban Z.J.,Key Laboratory of Food Nutrition and Safety | Feng J.H.,Jinan Fruit Research Institute | And 4 more authors.
Advanced Materials Research | Year: 2011

A mathematical model to predict oxygen, carbon dioxide, and water vapour exchanges in non-perforated and micro-perforated thin films in modified atmosphere packaging system has successfully been proposed. Validation of the mathematical model was found to yield good prediction for gas exchanges in the mass of the produce after comparison with the experimental results of modified atmosphere packaging for Lycopersicon esculentum fruit. © (2011) Trans Tech Publications. Source

Chen J.,Key Laboratory of Food Nutrition and Safety | Hu Y.,Tianjin University | Wang J.,Key Laboratory of Food Nutrition and Safety | Hu H.,Key Laboratory of Food Nutrition and Safety | Cui H.,Tianjin University
Journal of Food Processing and Preservation | Year: 2016

The changes in respiration rates, malondialdehyde (MDA) content and antioxidant enzyme activities of fresh-cut green peppers treated with ozone (6.42 mg/cm3, 15 min), modified atmosphere packaging (MAP; 3% O2, 4% CO2 and 93% N2) and ozone+MAP during storage at 5C for 21 days were investigated in a laboratory environment. The three treatments all reduced respiration rates and MDA content compared to the control group. The enzyme activities in fresh-cut green peppers including peroxidase (POD), superoxidase dismutase (SOD) and L-phenylalanin ammonia-lyase (PAL) were induced by ozone and MAP treatments while polyphenol oxidase (PPO) activities were inhibited. And a much better effect was observed when the ozone and MAP treatment were combined which indicated ozone and MAP had a synergistic effect on inhibiting the respiration rates and the predication of MAD by enhancing the effectiveness of the antioxidant defense system through enhancing the activity of POD, SOD, PAL and inhibiting the activity of PPO. Practical Applications: Because of the nutritional qualities and convenience, fresh-cut fruits and vegetables have gained popularity in recent years. However, fresh-cut fruits and vegetables shelf ife are limited due to the natural inherent barriers of fruits and vegetables are damaged during processing. The antioxidant defense system which consists of a series of antioxidase such as superoxidase dismutase, peroxidase, catalase, is an important enzyme system which can inhibit oxidation reactions in tissues. It is beneficial for extending shelf life of fresh-cut fruits and vegetables. This study has given an experimental evidence that ozone and modified atmosphere packaging (MAP) both can enhance the effectiveness of the antioxidant defense system. And the combination of ozone and MAP treatment can enhance the induction. Thus, ozone and MAP treatment have the advantages of prolonging shelf life of fresh-cut fruits and vegetables. © 2016 Wiley Periodicals, Inc. Source

Xu Z.,Key Laboratory of Food Nutrition and Safety | Xu Z.,Shandong Agricultural University | Fang G.,Key Laboratory of Food Nutrition and Safety | Wang S.,Key Laboratory of Food Nutrition and Safety
Food Chemistry | Year: 2010

In this paper, we prepared a highly selective imprinted polymer by a room temperature ionic liquid-mediated bulk polymerization technique, using dichlorvos as the template, methacrylic acid as the functional monomers, and trimethylolpropane trimethacrylate as the cross-linker. This functionalized material was characterized by FT-IR, static and kinetic adsorption experiments, and the results showed that this imprinted sorbent exhibited good recognition and selective ability, and offered fast kinetics for the adsorption and desorption of dichlorvos. Using the prepared material as a solid phase extraction sorbent, a novel sample pre-treatment technique that can be coupled to high-performance liquid chromatography (HPLC) had been developed for determination of trace dichlorvos residues in foods. Under the selected experimental condition, the detection limit (S/N = 3) of dichlorvos was 94.8 ng L-1, and the peak area precision (RSD) for five replicate detections of 10 μg L-1 dichlorvos was 4.41%. The blank samples of cucumber and lettuce spiked with dichlorvos at 0.005 and 0.02 μg g-1 levels were determined with recoveries ranging from 82.1% to 94.0%. Crown Copyright © 2009. Source

Fang G.,Key Laboratory of Food Nutrition and Safety | Fang G.,Tianjin University of Science and Technology | Wang X.,Key Laboratory of Food Nutrition and Safety | Wang X.,Tianjin University of Science and Technology | And 2 more authors.
Chromatographia | Year: 2010

An effective and rapid method was developed for simultaneous determination of seven sulfonylurea herbicides in environmental water using multiwalled carbon nanotubes as solid-phase extraction sorbent coupled with liquid chromatography-tandem mass spectrometry. Important parameters influencing the extraction efficiency such as pH of the sample solution, flow rate of sample loading, the eluent and its volume were optimized. Under optimum conditions, good linearity was obtained for all herbicides (r 2 > 0.99) over the range of 0.05-5,000 ng L-1, and precisions (RSD) for nine replicate measurements of a standard mixture of 200 ng L-1 were 1.9-7.4%. The limits of detection and quantification were 0.01-0.20 and 0.05-1.00 ng L-1, respectively. The proposed method was successfully applied to the analysis of tap water, spring water, ground water and well water, and mean recoveries for seven analytes at three spiked concentration levels were from 81.5 to 110.5% with RSDs between 0.3 and 7.0%. The results showed that the established method has wide application to analyze sulfonylurea herbicides at trace level in water. © 2010 Vieweg+Teubner Verlag | Springer Fachmedien Wiesbaden GmbH. Source

Yang Y.,Key Laboratory of Food Nutrition and Safety | Yang Y.,Tianjin Key Laboratory of Food Nutrition and Safety | Yang Y.,Tianjin University of Science and Technology | Fang G.,Key Laboratory of Food Nutrition and Safety | And 11 more authors.
Biosensors and Bioelectronics | Year: 2016

A novel strategy is reported for the fabrication of bis-aniline-crosslinked Au nanoparticles (NPs)-CdSe/ZnS quantum dots (QDs) array composite by facil one-step co-electropolymerization of thioaniline-functionalized AuNPs and thioaniline-functionalized CdSe/ZnS QDs onto thioaniline-functionalized Au elctrodes (AuE). Stable and enhanced cathodic electrochemiluminescence (ECL) of CdSe/ZnS QDs is observed on the modified electrode in neutral solution, suggesting promising applications in ECL sensing. An advanced ECL sensor is explored for detection of 2-methyl-4-chlorophenoxyacetic acid (MCPA) which quenches the ECL signal through electron-transfer pathway. The sensitive determination of MCPA with limit of detection (LOD) of 2.2nmolL-1 (S/N=3) is achieved by π-donor-acceptor interactions between MCPA and the bis-aniline bridging units. Impressively, the imprinting of molecular recognition sites into the bis-aniline-crosslinked AuNPs-CdSe/ZnS QDs array yields a functionalized electrode with an extremely sensitive response to MCPA in a linear range of 10pmolL-1-50μmolL-1 with a LOD of 4.3pmolL-1 (S/N=3). The proposed ECL sensor with high sensitivity, good selectivity, reproducibility and stability has been successfully applied for the determination of MCPA in real samples with satisfactory recoveries. In this study, ECL sensor combined the merits of QDs-ECL and molecularly imprinting technology is reported for the first time. The developed ECL sensor holds great promise for the fabrication of QDs-based ECL sensors with improved sensitivity and furthermore opens the door to wide applications of QDs-based ECL in food safety and environmental monitoring. © 2015 Elsevier B.V. Source

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