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991.
Perla Gómez M Ángeles Ferrer J Pablo Fernández‐Trujillo Antonio Calderón Francisco Artés Marcos Egea‐Cortines Julia Weiss 《Journal of the science of food and agriculture》2009,89(9):1543-1551
BACKGROUND: Cherry tomato fruits cv. Micro‐Tom, a model plant for tomato genetics, were analysed in order to determine the main structural and chemical changes under optimal and chilling storage conditions. The comparison of Micro‐Tom to standard tomato cultivars will give an insight into suitability of this dwarf cultivar as a model for studying the influence of low‐temperature conditions on tomato fruits. RESULTS: During chilling, fruit tissue was progressively destroyed due to the collapse of the deep layers of the pericarp. Chilling lowered the typical tomato kinetics of ripening in sugars (glucose, fructose, sucrose), organic acids (tartaric, malic, citric, ascorbic and succinic) and the antioxidants phenol and lycopene, while carotenoid synthesis seemed to be blocked. Glutathione level was elevated and the activity of ROS scavenging enzymes was altered. Essentially, Micro‐Tom fruits showed a quality evolution that was similar to that described for standard tomato cultivars. CONCLUSION: The cherry tomato cultivar Micro‐Tom could be used as a model for studying the influence of low temperature on biochemical and structural changes taking place during chilling injury conditions. Copyright © 2009 Society of Chemical Industry 相似文献
992.
Studies on the copigmentation between anthocyanins and flavan-3-ols and their influence in the colour expression of red wine 总被引:1,自引:0,他引:1
Susana González-Manzano Montserrat DueñasJulián C. Rivas-Gonzalo M. Teresa Escribano-BailónCelestino Santos-Buelga 《Food chemistry》2009
With the aim of evaluating the importance of the copigmentation process between anthocyanins and flavanols on the colour expression of red wine, assays were carried out in wine model systems with mixtures of compounds obtained from two Vitis vinifera grape varieties (Graciano and Tempranillo). Spectrophotometric and chromatic analyses were performed to evaluate the magnitude of the copigmentation and the modifications induced in the colour of the solutions. Measurement of the changes in the anthocyanin hydration constant (Kh) was also used to determine the strength of the copigmentation process. All the flavanols assayed induced significant changes in the colour, perceptible to the human eye, of the wine-like anthocyanin solutions at concentrations similar to those that can exist in red wines. The percentage contribution of the copigmentation with flavanols to the colour of the anthocyanin solutions was found to range from 2% to 20%. The extent of this effect was related not only to the concentration of flavanols but also to the qualitative composition of the flavanol preparations, as influenced by the part of the grape (either skin or seed) and the variety considered. Divergences were found between the evaluation of the copigmentation based on chromatic parameters in the CIELAB colour space and that based on the measurement at visible λmax, as the latter does not consider the integral colour changes produced in the visible spectrum. The results obtained confirmed the importance of the qualitative phenolic composition, determined in the wine by the type of grape and winemaking practices, to the production of an effective copigmentation process. 相似文献
993.
İbrahim Kivrak Mehmet Emin Duru Mehmet Öztürk Nazime Mercan Mansur Harmandar Gülaçtı Topçu 《Food chemistry》2009
The essential oil of Salvia potentillifolia was analysed by GC and GC–MS. Totally, 123 components were detected in both hydrodistilled and steam-distilled oils, α- and β-pinenes being major compounds. The antioxidant activities were determined by using complementary tests, namely, DPPH radical-scavenging, β-carotene-linoleic acid and reducing power assays. The ethanol extract also showed better activity (IC50 = 69.4 ± 0.99 μg/ml) than that of BHT in the DPPH system, and showed great lipid peroxidation inhibition in the β-carotene-linoleic acid system (IC50 = 30.4 ± 0.50 μg/ml). The essential oil showed meaningful butyrylcholinesterase activity (65.7 ± 0.21%), and α-pinene showed high acetylcholinesterase inhibitory activity (IC50 = 86.2 ± 0.96 μM) while β-pinene was inactive. Antimicrobial activity was also investigated on several microorganisms, and the essential oil showed high activity against Bacillus subtilis and B. cereus. It also exhibited remarkable anticandidal activity against Candida albicans and C. tropicalis with MIC values of 18.5 and 15.5 μg/ml, respectively, while α- and β-pinenes showed moderate activity. 相似文献
994.
Fourteen samples of edible oils and lard have been studied by means of Fourier transform infrared spectroscopy. The spectra
were recorded from a film of pure oil or lard between two discs of KBr. The bands of the spectra were assigned to different
functional group vibrations. The frequencies of some bands have constant values, independent of the nature of the sample.
However, frequencies of other bands, some of them in the fingerprint region, depend greatly on the sample composition. Equations
obtained from frequency of these bands and composition data are valuable to predict the proportions of saturated, monounsaturated
and polyunsaturated acyl groups in oils and lard. 相似文献
995.
Hüseyin Topallar Yüksel Bayrak Mehmet Işcan 《Journal of the American Oil Chemists' Society》1997,74(10):1323-1327
Unhydrogenated and hydrogenated sunflowerseed oils were exposed to the autoxidation process by sunlight under atmospheric
conditions. Experiments were carried out in equal-sized glass, PET (polyethylene terephthalate) polymer, and metal (covered
by tin) containers. The reaction time was 30 d, and the reaction course was observed by determining weight changes and peroxide
values (PV) of the oil samples at the same time within 2-d intervals. The logarithm of the PV was plotted against time, and
straight lines were obtained from the 4th or 6th d. The autoxidation reaction constants were obtained for each oil in each
container. When comparing the reaction constants, the unhydrogenated oils autoxidize easily, and the autoxidation reaction
occurs faster in sunlight in glass than in the PET polymer container and much faster than in the darkness of the metal container. 相似文献
996.
Ramon Díaz de León Graciela Morales Pablo Acuña Florentino Soriano 《Polymer Engineering and Science》2010,50(2):373-383
Different high impact polystyrenes were synthesized using styrene/butadiene copolymers (SB) with PS/PB composition: 30/70 and 20/80 as the precursor rubber, benzoyl peroxide (BPO) as the initiator, and ter‐dodecyl mercaptane (TDM) as the chain transfer agent. During the polymerization, several samples were taken and analyzed under different techniques to evaluate the phase inversion (PI) phenomenon. The PI was determined through transmission electron microscopy (TEM) and through dynamic oscillatory behavior, where the PI takes places when the relaxation process presents the lower value of activation energy. Finally, the Choi and Schowalter emulsion model was employed to elucidate the PI, and relevant information was revealed about the interfacial tension in the PI. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers 相似文献
997.
Patricia Concepción José M. López Nieto Joaquín Pérez-Pariente 《Catalysis Letters》1993,19(4):333-337
VAPO-5 and V/ ALPO-5 catalysts have been tested for the oxidative dehydrogenation of propane. Depending on the vanadium contents and the preparation procedure, different vanadium species and different catalytic behavior are observed. The catalyst containing V5+ species with a tetrahedral coordination presents the higher yield of propene in the oxidative dehydrogenation of propane. The same yields of CO2 are observed on all vanadium aluminophosphate catalysts, while the higher the yield of propene the lower the yield of CO is. 相似文献
998.
Martin Friis Christer Persson Per Nylén Jan Wigren 《Journal of Thermal Spray Technology》2001,10(2):301-310
A detailed investigation of the relationship between the parameters of the spray process and the in-flight properties of the
particles was carried out using a multivariate statistical approach. A full factorial designed experiment concerning the spray
process was performed, the spray gun parameters’ current, argon flow rate, hydrogen flow rate, and powder feed rate being
selected to control the process. The particle properties, viz. velocity, temperature, and diameter, were determined using an optical measurement system, DPV 2000. In addition, the standard
deviations of, and the correlations between, the measured particle properties were analyzed. The results showed current to
have the strongest impact on particle velocity and particle temperature and argon flow rate to be the only parameter with
an inverse effect on velocity and temperature. 相似文献
999.
1000.
Cold‐pressed Japanese quince (Chaenomeles japonica (Thunb.) Lindl. ex Spach) seed oil as a rich source of α‐tocopherol,carotenoids and phenolics: A comparison of the composition and antioxidant activity with nine other plant oils 下载免费PDF全文