State Key Laboratory of Food Science and Technology

Wuxi, China

State Key Laboratory of Food Science and Technology

Wuxi, China
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Katiyo W.,State Key Laboratory of Food Science and Technology | Yang R.,State Key Laboratory of Food Science and Technology | Zhao W.,State Key Laboratory of Food Science and Technology
Journal of Food Safety | Year: 2017

The influence of combined pulsed electric fields (PEF) and mild temperature on the inactivation of Escherichia coli, Salmonella enteritidis, and Saccharomyces cerevisiae suspended in a novel cloudy red apple juice (Malus pumila Niedzwetzkyana (Dieck)) was investigated to define treatment conditions that meet the U.S. Food and Drug Administration (FDA) regulation for fruit juice pasteurization. There was significant microbial inactivation (p<.05) with increased experimental treatment conditions (electric field strength: 25-35 kV/cm, treatment time: 86-258 μs, post-treatment temperature: 30-50°C). The highest level of inactivation for E. coli, S. enteritidis, and S. cerevisiae was 5.21, 6.02, and 5.49 log reduction, respectively. PEF treatment at 35 kV/cm for 258 μs combined with heating at 50°C was selected as pasteurization conditions. Pasteurization did not cause significant changes (p<.05) in pH, titratable acidity, total soluble solids, conductivity, and particle size of cloudy red apple juice, in comparison with conventional treatment. Practical applications: Red-fleshed apples are increasingly becoming a subject of interest in the fruit industry due to their remarkable anthocyanin content. However, mere identification or development of novel fruits is insufficient for the fruit juice industry to cater for consumer demand. There is need to combine this with novel processing technologies that ensure preservation of the desired unique quality attributes. This study indicated that combined PEF and mild heat can be successfully applied for the pasteurization of a novel cloudy red apple juice without significantly affecting important juice properties such as pH, acidity, conductivity, and particle size. This work provides a basis for new product development as numerous red-fleshed apple cultivars are being developed and PEF technology is progressing toward industrial application. © 2017 Wiley Periodicals, Inc.

Xia X.,Jiangnan University | Xia X.,Xinjiang University | Dong X.J.,Jiangnan University | Wei Q.F.,Jiangnan University | And 2 more authors.
Express Polymer Letters | Year: 2012

The present study investigates the formation mechanism of hollow SnO 2 nanofibers and the form of nanograin growth in nanofibers. SnO 2 hollow nanofibers were fabricated by directly annealing electrospun polyvinylpyrrolidone (PVP)/Sn precursor composite nanofibers. In this approach, an appropriate proportion of PVP/Sn precursor with co-solvents established a system to form core/shell PVP/Sn precursor structure, and then PVP was decomposed quickly which acted as sacrificial template to keep fibrous structure and there existed a Sn precursor/SnO 2 concentration gradient to form hollow SnO 2 nanofibers due to the Kirkendall effect and surface diffusion during the calcination process. This deduction was also confirmed by experimental observations using transmission electron microscopy. The study suggested that surface diffusion and lattice diffusion were both driving force for nanograin growth on the surface of SnO 2 nanofibers. As supporting evidence, the tetragonal rutile SnO 2 hollow nanofibers were also characterized by X-ray diffraction, scanning electron microscopy and Brunauer-Emmett-Teller analysis. © BME-PT.

Xiong T.,State Key Laboratory of Food Science and Technology | Xiong T.,Nanchang University | Guan Q.,State Key Laboratory of Food Science and Technology | Guan Q.,Nanchang University | And 5 more authors.
Food Control | Year: 2012

Chinese sauerkraut (also known as "PaoCai"), a kind of sound fermented vegetable product, is widely consumed in China. Changes of lactic acid bacteria flora throughout spontaneous fermentation of Chinese sauerkraut were analyzed in this study. Results have shown that Enterococcus faecalis, Lactococcus lactis subsp. lactis, Leuconostoc mesenteroides subsp. mesenteroides, Lactobacillus plantarum, Lactobacillus casei and Lactobacillus zeae dominated the fermentation. E. faecalis and L. mesenteroides subsp. mesenteroides were present in the brine as soon as the vegetable was pickled while other four species were isolated successively during fermentation. E. faecalis and L. lactis subsp. lactis were mainly present in the early stage of fermentation and died at the later stage; L. mesenteroides subsp. mesenteroides did not die until the 5th day; L. zeae existed in the middle stage and disappeared at the 5.5th day. L. plantarum and L. casei dominated the final stage of fermentation. In summary, the fermentation process was initiated by L. mesenteroides subsp. mesenteroides, followed by E. faecalis, L. lactis, L. zeae and finally succeeded by L. plantarum and L. casei. © 2012 Elsevier Ltd.

Daou C.,State Key Laboratory of Food Science and Technology | Zhang H.,Jiangnan University | Zhang H.,Sudan University of Science and Technology
Comprehensive Reviews in Food Science and Food Safety | Year: 2012

This article presents an overview of the recent advances into the health promoting potentials of oat β-glucan. Oat β-glucan (OβG) consists mainly of the linear polysaccharide (1→3), (1→4)-β-D-glucan and is often called β-glucan. This soluble oat fiber is able to attenuate blood postprandial glycemic and insulinemic responses, to lower blood total cholesterol and low-density lipoprotein (LDL) cholesterol, and to improve high-density lipoprotein (HDL) cholesterol and blood lipid profiles as well as to maintain body weight. Thus, OβG intake is beneficial in the prevention, treatment, and control of diabetes and cardiovascular diseases. In addition, OβG can stimulate immune functions by activating monocytes/macrophages and increasing the amounts of immunoglobulin, NK cells, killer T-cells, and so on, which will improve resistance to cancer and infectious and parasitic diseases, as well as increase biological therapies and their prevention. All these health benefits of OβG may be explained by its physicochemical properties (such as viscosity, molecular weight) which can be affected by extraction methods and its behavior in gastrointestinal tract. Articles documenting these health benefits and effects are reviewed. © 2012 Institute of Food Technologists®.

Ning Y.,State Key Laboratory of Food Science and Technology | Ning Y.,Jiangnan University | Wang J.,Jiangnan University | Chen J.,Jiangnan University | And 4 more authors.
Bioresource Technology | Year: 2010

The effects of production parameters on the biotransformation of sucrose were investigated to enhance the yield of neo-FOS by Xanthophyllomyce dendrorhous cells. Cells showed optimal β-fructofuranosidase activity at neutral pH condition and the yield of neo-FOS showed no significant differences between buffer and buffer-free systems. Cell concentrationnegatively affected the maximum neo-FOS yield. Sucrose concentration positively increased the maximumyield of neo-FOS. Elevating the reaction temperature to 30 °C, the neo-FOS productivity increased 1.85-fold compared with that at 20 °C. Meanwhile, cell age of 32 h enabledthe biotransformation of sucrose more efficiently. In addition, free cells exhibited a higher productivity over immobilized cells. The maximum neo-FOS concentration finally reached 227.72 g/l from 400 g/l sucrose under the optimal conditions. © 2010 Elsevier Ltd. All rights reserved.

Chen T.,Chongqing Medical University | Chen T.,State Key Laboratory of Food Science and Technology | Yuan J.,Chongqing Medical University | Feng X.,State Key Laboratory of Food Science and Technology | And 2 more authors.
International Journal of Antimicrobial Agents | Year: 2011

An anaerobic, continuous-flow culture method has been developed to assess the effects of different levels of enrofloxacin (ENR) on the human intestinal microbiota. Chemostats containing human faecal flora were exposed to 1.25, 12.5 and 125 μg/mL ENR. Before and during drug exposure, samples aspirated from culture vessels were analysed using viable cell counting and denaturing gradient gel electrophoresis (DGGE). In addition, the colonisation resistance (CR) of the microbiota to Candida albicans SC5314 was evaluated. When exposed to 1.25 μg/mL ENR, total counts of aerobic bacteria, anaerobic bacteria, Lactobacillus, enterococci, Escherichia coli and Bacteroides fragilis were similar to the control group, except for Bifidobacterium; when exposed to 12.5 μg/mL and 125 μg/mL ENR, numbers of categorised microorganisms changed significantly, except for B. fragilis. DGGE indicated that although 1.25 μg/mL ENR had little effect on the total number of microbiota, several bands representing dominant bacteria disappeared. The bands disappeared more quickly when exposed to 12.5 μg/mL and 125 μg/mL ENR. In addition to their influence on microbial diversity, different levels of ENR reduced the CR of the intestinal microbiota to C. albicans SC5314. © 2011 Elsevier B.V. and the International Society of Chemotherapy.

Wang Q.,Jiangnan University | Du Y.,Jiangnan University | Feng Q.,Anhui Polytechnic University | Huang F.,Jiangnan University | And 3 more authors.
Journal of Applied Polymer Science | Year: 2013

In this work, polyacrylonitrile (PAN)/graphene oxide (GO) composite nanofibers were prepared by a facile compounding and electrospinning processes. A small amount of GO powders were first dispersed in N,N-dimethylformamide by sonication, and then, PAN powders were added to prepare an electrospinning solution. The surface morphology was analyzed by atomic force microscopy and transmission electron microscopy, whereas the chemical properties of the PAN and PAN/GO composite nanofibers were compared by infrared (IR) spectroscopy. Also, lateral force microscopy and force-distance curves (FDC) were employed to investigate the surface properties, such as friction force and elasticity. The experimental results indicate that with increasing GO concentration, the surface friction force and adhesive force increased, so the nanofibers showed promise for applications as supports for enzyme immobilization. © 2012 Wiley Periodicals, Inc.

Wang P.,Jiangnan University | Ma C.,Jiangnan University | Chen S.,State Key Laboratory of Food Science and Technology | Zhu S.,State Key Laboratory of Food Science and Technology | And 2 more authors.
Tropical Journal of Pharmaceutical Research | Year: 2014

Purpose: To develop a more green, efficient and low cost process for the extraction of steroidal saponins from Dioscorea Zingiberensis C. H. Wright. Methods: Six kinds of ionic liquids with different cations and anions were evaluated. In addition, the extraction parameters of the ionic liquid based ultrasonic/microwave extraction were studied. In order to quantify the total saponin content accurately, all steroidal saponins were converted into diosgenin and quantified with an appropriate HPLC procedure. IL-UMAE under optimal conditions was compared with heat reflux extraction (HRE) and ultrasonic assisted extraction (UAE). Results: 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIm]BF4) solution at concentration of 0.5 mol L-1 was selected as extraction solvent. The optimum conditions were as follows: solvent to solid ratio 15:1, microwave power 500 W and extraction time 8 min. Under these optimal conditions, the highest extraction yield of diosgenin 10.24 ± 0.31 mg g-1 was obtained. It took only 8 min to obtain the 91.67 % content of diosgenin obtained by traditional HRE. Extracting on time was shortened from 120 min to 8 min. Conclusion: Compared with traditional methods, IL-UMAE method uses Ionic liquid-solvent which greatly shortens the extraction time. IL-UMAE as a simple, effective and environmentally friendly approach shows a broad prospect for active ingredient extraction. © Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria. All rights reserved.

Sha C.,State Key Laboratory of Food Science and Technology | Yu X.-W.,State Key Laboratory of Food Science and Technology | Li F.,State Key Laboratory of Food Science and Technology | Xu Y.,State Key Laboratory of Food Science and Technology
Applied Biochemistry and Biotechnology | Year: 2013

In this work, the high-level expression of the lipase r27RCL was achieved by optimization of the lipase gene copy number in the host strain Pichia pastoris. The copy number of the lipase gene proRCL from Rhizopus chinensis CCTCC M201021 was quantified by real-time quantitative polymerase chain reaction and a range of Mut+ P. pastoris strains carrying one, three, five, and six copies of proRCL were obtained. The maximum lipase activity was achieved at 12,500 U/mL by the five-copy recombinant strain after 96 h of methanol induction in the 7-L fermenter. However, the enzyme activity of the six-copy recombinant strain decreased remarkably. By transcription analysis of proRCL, ERO1, and PDI, it suggested that unfolded protein response seemed to be triggered in the highest copy recombinant strain after 24 h. Thus, elaborate optimization of foreign gene dosage was very important for the high-level expression of foreign proteins in P. pastoris. © Springer Science+Business Media New York 2013.

Hao F.,State Key Laboratory of Food Science and Technology | Wu Q.,State Key Laboratory of Food Science and Technology | Xu Y.,State Key Laboratory of Food Science and Technology
Applied Biochemistry and Biotechnology | Year: 2013

Tetramethylpyrazine (TTMP) is a widely used flavoring additive with a nutty and roasted taste. Solid-state fermentation (SSF) of wheat bran for producing TTMP was studied with Bacillus subtilis CCTCC M208157, which was an exogenous precursor-independent TTMP-producing strain. Factors influencing endogenous precursor supply and TTMP formation in this strain were investigated. According to the findings, glucose and diammonium phosphate contributed to TTMP production but excess salts caused an inhibition on cell growth and TTMP formation. Then a two-step supply strategy was applied: 10 % glucose was added at the beginning of the process to allow acetoin formation, which was the precursor of TTMP, while 3 % diammonium phosphate was added only after acetoin accumulation reached its maximum. By applying this strategy, acetoin increased from 5.44 to 13.2 g/kg dry substrate (kgds), and consequently the yield of TTMP increased by 6.8 folds from 0.44 to 3.01 g/kgds. This was the first report of using a two-step supply strategy for TTMP production by SSF, which proved to be conducive to TTMP production in this strain. © Springer Science+Business Media New York 2013.

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