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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.


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.


Yang Y.,Key Laboratory of Food Nutrition and Safety | Yang Y.,Tianjin University of Science and Technology | Wang X.,Key Laboratory of Food Nutrition and Safety | Wang X.,Tianjin University of Science and Technology | And 8 more authors.
Progress in Chemistry | Year: 2016

Electrochemiluminescence (ECL) analysis based on molecular imprinting technique, as a new analysis method, has made great progress in recent years. Molecular imprinted ECL analysis owns the advantages of both ECL analysis and molecular imprinting technology, namely high sensitivity, high selectivity, good controllability, easy miniaturization and simple operation, suggesting a wide range of applications in the fields of life sciences, food safety and environmental monitoring. In this review, the common ECL systems and basic ECL principles are introduced in detail, and the research advances of molecular imprinted ECL analysis are reviewed. The ECL mechanism mainly includes annihilation type ECL mechanism and co-reactant type ECL mechanism, examples based on ECL mechanism are introduced. Construction procedure, principles and performance of different types of molecular imprinted ECL analysis, including sensitivity, selectivity, detection range and stability of the established methods, are remarked extensively. The development of molecular imprinted polymers (MIPs)-based ECL analysis could be divided into three types:MIPs-ECL sensor based on solid-state light-emitting electrode, MIPs-ECL sensor based on non-solid-state light-emitting electrode and MIPs based-solid phase extraction coupled with ECL analysis. Among the three types mentioned above, the fabrication of solid-state light-emitting electrode to establish molecular imprinted ECL sensor is the most promising direction, in which the organic combination of ECL light-emitting materials and molecular imprinted material is achieved. In addition, the outlook of future development directions and trends of molecular imprinted ECL analysis are discussed. © 2016, Editorial Office of Progress in Chemistry. All right reserved.


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.


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.


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.


Chen J.,Key Laboratory of Food Nutrition and Safety | Hu Y.,Key Laboratory of Food Nutrition and Safety | Wang J.,Key Laboratory of Food Nutrition and Safety | Yao Y.,Key Laboratory of Food Nutrition and Safety | Hu H.,Key Laboratory of Food Nutrition and Safety
Journal of Food Process Engineering | Year: 2016

This work investigated the effects of temperature and gas concentration on respiration rate of mung bean sprouts in the closed system. Then, the chemical kinetic model was developed with the help of respiration data. Temperature and gas concentration both had significant effects on respiration rate of mung bean sprouts. Mung bean sprouts had higher respiration rate at higher temperature. The values increased from 10.21 to 66.86 mL/(kg h) and 13.00 to 68.71 mL/(kg h) for R_(CO_2) and (R_(O_2)) at the equilibrium position by increasing the temperature from 8 to 28C, respectively. And the production rate of CO2 (R_(CO_2)) and the consumption rate of O2 (R_(O_2)) were both decreased with increasing of carbon dioxide concentration and decreasing of oxygen concentration. Respiration rate of mung bean sprouts was successfully modelled using the chemical kinetic model. The coefficient of determinations of O2 and CO2 were respectively 0.9734 and 0.9851 indicating that the relationship between respiration rate O2 and CO2 concentrations fitted well with the chemical kinetic model. Moreover, the developed models were tested for their validity at 5C and 15C. Results of the mean absolute percentage error (MP) values at 5C and 15C were respectively 9.32 and 9.97 further confirmed that the chemical kinetic model can be used to predict the respiration rate. © 2016 Wiley Periodicals, Inc.


Wu X.,Key Laboratory of Food Nutrition and Safety | Liu Y.,Key Laboratory of Food Nutrition and Safety | Wang W.,Key Laboratory of Food Nutrition and Safety | Han Y.,Key Laboratory of Food Nutrition and Safety | Liu A.,Key Laboratory of Food Nutrition and Safety
Journal of Food Process Engineering | Year: 2016

To fabricate gelatin films with excellent mechanical and thermal properties, nanoscale hydroxyapatite (nHA) was introduced into a gelatin matrix. The effect of added nHA content (0-20 wt %) on the physicochemical properties of the nHA-gelatine films was investigated. Morphology analyses confirmed that the nHA particles were tightly and uniformly incorporated into the gelatin matrix. The thickness, water vapor permeability, light transmission, and moisture content of the films varied considerably depending on the added nHA amount. The addition of 15 wt % nHA increased the tensile strength of the gelatin films to 58.38 MPa but decreased the elongation to 27.85%. Furthermore, adding nHA improved the thermal properties, with the highest melting temperature of 80.98°C for the 10 wt % nHA-reinforced film. Few changes in the conformation of the gelatin molecule were observed. Therefore, based on the particle nature and good compatibility with gelatin, nHA reinforcement provides a potential approach to improve gelatin film performance in food packaging field. © 2016 Wiley Periodicals, Inc.


PubMed | Key Laboratory of Food Nutrition and Safety
Type: Journal Article | Journal: Chemical & pharmaceutical bulletin | Year: 2016

The coacervation between gelatin and sodium alginate for ginger volatile oil (GVO) microencapsulation as functions of mass ratio, pH and concentration of wall material and core material load was evaluated. The microencapsulation was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and thermal gravimetric analysis (TGA). SEM and FT-IR studies indicated the formation of polyelectrolyte complexation between gelatin and sodium alginate and successful encapsulation of GVO into the microcapsules. Thermal property study showed that the crosslinked microparticles exhibited higher thermal stability than the neat GVO, gelatin, and sodium alginate. The stability of microencapsulation of GVO in a simulated gastric and an intestinal situation in vitro was also studied. The stability results indicated that the release of GVO from microcapsules was much higher in simulated intestinal fluid, compared with that in simulated-gastric fluid.

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