Cerqueira, M. A.

Cunha, Rosiane Lopes

Fasolin, Luiz Henrique

Pastrana, Lorenzo

Picone, Carolina S. F.

Vicente, A. A.

Universidade do Minho: RepositoriUM

Thermal behaviour of organogels : effect of concentration and organogels structure

BOOK OF ABSTRACTS* www.iufost2014.org Congress Hosts* Please note if you do not find a set of abstracts for a Concurrent Session, this is because we did not receive a set of abstracts for that session.   behavior and microstructure of composite dough. The influence of BGC into standard wheat flour dough was evaluated through small and large deformation rheological measurements at different levels (2.5-10%) of BGC incorporation and at selected temperatures (25-85 ℃). Oscillatory rheological and creep measurements of BGC samples were carried out using a controlled strain rheometer and large deformation rheological properties (e.g. water absorption, dough development time, maximum resistance to extension, extensibility) were measured by farinograph and extensograph. Thermal properties of dough were measured by a differential scanning calorimetry and scanning electron microscopy was employed to investigate microstructure of composite dough. The water absorption increased with the addition of BGC into wheat flour. An increase in mixing time and stability were recorded upon addition of BGC (≤ 5%), and the extensibility decreased at similar condition. The wheat flour and composite dough exhibited predominating solid-like behavior (G′> G″). The mechanical strength of the composite doughs showed a decreasing trend with the increase of the water content but it increased with BGC incorporation at constant moisture content within the studied frequency range (0.1 to 10 Hz). Both the elastic modulus (G′) and the complex viscosity (η*) of dough samples within the studied frequency range showed temperature dependency. Time-temperature superposition of η*-ω curves fitted well for up to 5% BGC incorporation when G′-ω failed at similar condition. Creep-recovery tests for BGC incorporated doughs showed greater resistance to deformation. Thermal scanning of doughs revealed that the magnitude of protein denaturation temperature was influenced by both level of BGC incorporation and moisture content, and the values ranged between 110 and 117 ℃. Scanning electron microscopy showed that BGC particles embedded on wheat flour doughs.     Thermal Behaviour of Organogels: Effect of Concentration and Organogels Structure  MP39.3  Miguel Cerqueira1; Luiz Fasolin2; Carolina Picone2; Lorenzo Pastrana3; Rosiane Cunha2; António Vicente1 1Centre of Biological Engineering, University of Minho, Braga, Portugal; 2Department of Food Engineering, Faculty of Food Engineering, University of Campinas, Campinas, SP, Brazil; 3Biotechnology Group, Department of Analytical Chemistry and Food Science, University of Vigo, Ourense, Spain   The interest on organogels is increasing and a full understanding of their structure should addressed in order to fully understand their properties and functionality. The aim of this work was to evaluate the influence of different gelators on the thermal behaviour of organogels produced with medium-chain-triglycerides (MCT). For this purpose four different gelators (glyceryl tristearate-GT, glyceryl monostearate-GM, sorbitan tristearate-ST and sorbitan monostearate-SM) were used for the formation of organogels. Gelators at concentrations of 15 and 20% (w/w) were mixed with oil phase (MCT) at 80°C during 30 min under magnetic stirring. Rheological oscillatory measurements were performed at cooling (80--10°C) and a heating sweeps (10--80°C) at 5°C/min, 0.1 Hz and 1% strain. Small angle X-ray scattering (SAXS) measurements were performed using a synchrotron beamline at 25, 50 and 70ºC. The crystallization and melting thermograms were obtained by differential scanning calorimetry (DSC) at heating-cooling cycles between 25 and 100 at 5°C/min. Rheological results showed that G' and G" values for organogels were very similar during all temperatures presenting at low temperatures a gel-like behaviour (G' > G"). Sol-gel temperature values were very close to GM and SM organogels being higher than the organogels produced with GT and ST. DSC thermograms showed that organogels produced with GM gelator (at 20%) have the highest temperature and energy of melting (63ºC and 39 J/g, respectively). In    all cases, the sol-gel transition temperatures during the cooling were lower than the values obtained during the heating ramp. Comparing sol-gel transitions values obtained by rheological analyses and DSC is possible to see that values can be compared for organogels of GT and GM, however for ST and SM the values obtained by DSC are lower than the obtained by rheology studies. By the evaluation of SAXS spectra, following Braggs Law, was possible to see that all structures were organized as lamellas but with different d-spacings. With the increase of the temperature (25 to 50ºC) happens a shift of the spectra peaks for organogels of GM and SM indicating a change of the structure. For all the organogels the intensity of SAXS peaks disappear at 70ºC showing that at this temperature all the crystalline structure is melted. Thus, different gelators lead to different thermal properties of organogels showing that is possible to modulate their properties according to the gel application.    Phloretin and Apple Peel Flavonoids Cause the Death of Triple-negative Breast Cancer Cells via a Reactive Oxygen Species-independent Mechanism  MP39.4  Wasundara Fernando1; David Hoskin2; H.P. Vasantha Rupasinghe1 1Dalhousie University, Truro, NS, Canada; 2Dalhousie University, Halifax, NS, Canada   Introduction and Objectives: Plant flavonoids as cancer prevention agents have been studied for a couple of decades [1,2]. Apple is widely recognized as a rich dietary source of polyphenols as well as some unique polyphenols such as phloretin (PT) and phloridzin (PZ) [3]. The current study explored the antiproliferative effects of PT, PZ and a flavonoid-rich apple peel extract (AF4) on triple-negative MDA-MB-231 breast cancer cells and the possible mechanisms of action.  Methods: The antiproliferative activity of PT, PZ and AF4 was evaluated using MTS and acid phosphatase assays at 5 different time points with a range of concentrations. Caspase-3 activation was measured at 3 time points with doxorubicin, docetaxel and staurosporine treatment as positive controls. Flow cytometric analysis of Annexin-V-FLUOS/propidium iodide (PI) staining was performed to determine whether cell death was by apoptosis and/or necrosis. Cells were incubated with or without N-acetylcysteine prior to treatment with test compounds and analysis by Annexin-V-FLUOS/PI staining to determine the involvement of reactive oxygen species (ROS) production. An amplex red assay was carried out with epigallocatechin-3-gallate (EGCG) in place as the positive control in a cell-free system to determine whether the test compounds induced H2O2 production in bicarbonate-containing tissue culture medium. Results: PT and AF4 induced apoptosis/necrosis of MDA-MB-231 cells was both time- and dose-dependent while PZ had no effect. A noticeable activation of caspase 3 was observed with AF4 within 3 hour of treatment and this activation was comparable to that obtained with doxorubicin. N-acetylcysteine failed to protect breast cancer cells from apoptosis/necrosis induced by PT and AF4, and none of the treatments caused substantial H2O2 production in culture medium in the absence of breast cancer cells.  Conclusion: PT and AF4, but not PZ, inhibited the growth of triple-negative breast cancer cells. ROS production was not required for PT and AF4 mediated inhibition of breast cancer cell growth.      Image Analysis Operations Applied to Hyperspectral Images for Food Quality Assessment  MP39.5  Gamal ElMasry1; Shigeki Nakauchi2 1Suez Canal University, Ismailia, Egypt; 2Department of Computer Science and Engineering, Toyohashi University of Technology, Toyohashi, Japan  

Thermal behaviour of organogels : effect of concentration and organogels structure

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Universidade do Minho: RepositoriUM

Universidade do Minho: RepositoriUM