Time filter

Source Type

Zhang L.,Zhejiang University | Ye X.,Zhejiang University | Ding T.,Zhejiang University | Sun X.,Wilmar Shanghai Biotechnology Research and Development Center Co. | And 2 more authors.
Ultrasonics Sonochemistry | Year: 2013

The effects of ultrasound on the molecular weight of apple pectin were investigated. The structure and rheological properties of the degradation products were also tentatively identified by High Performance Liquid Chromatography-Photodiode Array Detector (HPLC-PAD), Infrared spectroscopy (IR), Nuclear Magnetic Resonance spectroscopy (NMR) and Rheometer. The results indicated that the weight-average molecular weight of apple pectin decreased obviously after ultrasound treatment. The molecular weight of degradation products had a uniform and narrow distribution. Ultrasound intensity and temperature play an important role in the degradation reaction. Degradation kinetics model of apple pectin fitted to 1/Mt - 1/M0 = kt from 5 to 45 °C. The degree of methylation of apple pectin reduced according to IR analysis when ultrasound was applied. Ultrasound treatment could not alter the primary structure of apple pectin according to the results determined by HPLC, IR and NMR. Meanwhile, the viscosity of apple pectin was 103 times as large as that of ultrasound-treated apple pectin. The ultrasound-treated apple pectin showed predominantly viscous responses (G′ < G″) over the same frequency range. The results suggested that ultrasound provided a viable alternative method for the modification of pectin. © 2012 Elsevier B.V. All rights reserved. Source

Yang H.,Dalian University of Technology | Mu Y.,Dalian University of Technology | Chen H.,Dalian University of Technology | Su C.,Dalian University of Technology | And 3 more authors.
Chinese Journal of Chemical Engineering | Year: 2014

The structured lipids are produced through sn-1,3-specific interesterification of soybean oil with medium-chain triacylglycerol (MCT) in continuous reactions catalyzed by Thermomyces lanuginose lipase (Lipozyme TL IM). Cheap Lipozyme TL IM presents similar interesterification degree (ID), sn-1,3-specificity and residual activity as expensive Rhizomucor miehei in batch reactions. In packed-bed interesterification of soybean oil with MCT catalyzed by Lipozyme TL IM, the residence time has a significant effect on ID, while temperature has a small effect at 45-70 °C. The sn-1,3-specificity of Lipozyme TL IM is not satisfactory when reaction temperature is higher than 60 °C. The optimal residence time and temperature are 30-40 min and 55 °C, respectively. Among the solvents, including acetone, isopropanol, tert-butanol, and isobutanol, used to recover the activity of the used Lipozyme TL IM, acetone is the most suitable one than the other solvents. © 2014 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved. Source

Deng Y.,Jiangnan University | Ma L.,Wilmar Shanghai Biotechnology Research and Development Center Co. | Mao Y.,Jiangnan University
Biochemical Engineering Journal | Year: 2016

Adipic acid has been widely used for producing thermoplastic polyurethane resins, nylon 6-6, adhesives, synthetic lubricants and plasticizers, and the global market for adipic acid is estimated at approximate $6.3. billion per year. Currently, 2.85. million tons of adipic acid are produced from petrochemical sources, mostly by oxidation of KA oil (cyclohexanol and cyclohexanone) catalyzed by nitric acid. The chemical synthesis of adipic acid is of serious consequences such as greenhouse gases and heavy pollution to the environment, etc. The researchers are struggling to establish more reliable, renewable and affordable adipic acid synthesis methods, and among which, biological synthesis of adipic acid is attracting the most attention. There are two biological routes for adipate synthesis: (1) biological accumulations of precursors of adipic acid such as d-glucaric acid and cis,cis-muconic acid, which can be further catalyzed to adipate; (2) synthesis of adipate directly from carbon source. With the emergence of metabolic engineering and synthetic biology, biological synthesis of adipic acid from renewable substrates is now feasible. Here, we review the new approaches and technologies to produce adipic acid biologically, with the direct synthesis of adipic acid from the renewable substrates of special interest. © 2015 Elsevier B.V. Source

Xue D.,Dalian University of Technology | Mu Y.,Dalian University of Technology | Mao Y.,Dalian University of Technology | Yang T.,Dalian University of Technology | And 2 more authors.
Green Chemistry | Year: 2014

The production of biodiesel from soybean oil and ethanol was investigated in switchable-polarity solvent (SPS) media of DBU and ethanol. The highest biodiesel yield catalyzed by DBU could reach 97.9% under optimized conditions, i.e. ethanol-oil molar ratio: 12 : 1, DBU-oil molar ratio: 2 : 1, reaction temperature: 70 °C, reaction time: 2 h. According to the kinetic analysis, the reaction order of oil was estimated to be 0.7, the apparent activation energy was 16.763 kJ mol-1, the pre-exponential factor was 561.31 mol0.3 mL-0.3 min-1 using the Arrhenius equation for the first time, which explains the high efficiency of the DBU catalyst. The DBU-catalyzed transesterification in the DBU-ethanol switchable-polarity solvent offered an interesting alternative, which would be used to simplify the transesterification and separation to a single step. This journal is © the Partner Organisations 2014. Source

Yang N.,Jiangnan University | Zhu L.,Wilmar Shanghai Biotechnology Research and Development Center Co. | Jin Y.,Jiangnan University | Jin Z.,Jiangnan University | Xu X.,Jiangnan University
Journal of Food Engineering | Year: 2016

An experimental impregnation system based on the inductive methodology was established and used to investigate the effect of electric fields on the calcium content of fresh-cut apples. An induced electric field was generated when the Ca2+ solution acted as the secondary coil of the transformer system under the action of an alternating magnetic flux. The calcium content in fresh-cut apples was found to increase with the enhancement of the excitation voltage. Additionally, samples immersed in a CaCl2 solution exhibited a calcium content higher than those suspended in the calcium lactate solution. The latter presented a higher load power factor, the impedance in the CaCl2 solution being lower. Frequency at 20-60 kHz had a negative impact on the calcium content of fresh-cut apples due to the weakening of the electropermeabilization effect. This method utilized the conversion of electric energy into magnetic energy, and the electric field induced needing no insertion of powered electrodes into the solution under treatment. This might provide a reference for rapid impregnation of agricultural materials. © 2016 Elsevier Ltd. All rights reserved. Source

Discover hidden collaborations