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101.
ABSTRACT: Grape juice processing by‐products, grape seed and pomace are a rich source of procyanidins, compounds that may afford protection against chronic disease. This study was undertaken to identify optimal extrusion conditions to enhance the contents of monomers and dimers at the expense of large molecular weight procyanidin oligomers and polymers in grape seed and pomace. Extrusion variables, temperature (160, 170, and 180 °C in grape seed, and 160, 170, 180, and 190 °C in pomace) and screw speed (100, 150, and 200 rpm in both) were tested using mixtures of grape seed as well as pomace with decorticated white sorghum flour at a ratio of 30 : 70 and moisture content of 45%. Samples of grape seed and pomace were analyzed for procyanidin composition before and after extrusion, and total anthocyanins were determined in pomace. Additionally, chromatograms from diol and normal phase high‐performance liquid chromatography were compared for the separation of procyanidins. Extrusion of both grape by‐products increased the biologically important monomer and dimers considerably across all temperature and screw speeds. Highest monomer content resulted when extruded at a temperature of 170 °C and screw speed of 200 rpm, which were 120% and 80% higher than the unextruded grape seed and pomace, respectively. Increases in monomer and dimer contents were apparently the result of reduced polymer contents, which declined by 27% to 54%, or enhanced extraction facilitated by disruption of the food matrix during extrusion. Extrusion processing reduced total anthocyanins in pomace by 18% to 53%. Practical Applications: Extrusion processing can be used to increase procyanidin monomer and dimer contents in grape seed and pomace. Procyanidins in grape by‐products have many health benefits, but most are present as large molecular weight compounds, which are poorly absorbed. Extrusion processing appears to be a promising technology to increase levels of the bioactive low molecular weight procyanidins. 相似文献
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LC-MS method development to evaluate major triterpenes in skins and cuticular waxes of grape berries
Norbert Orbán Imre Olivér Kozák Mónika Drávucz & Attila Kiss 《International Journal of Food Science & Technology》2009,44(4):869-873
Predominant triterpenes (free oleanolic acid, β-sitosterol and β-sitosterol-3-O-β- d -glucoside) in skin and cuticular wax of grape berries have been analysed by liquid chromatography–mass spectrometry (LC-APCI-MS). The validity of the developed method was established by determining linearity, recovery, precision, accuracy, limit of detection and quantification. Detection limits were in the range of 0.12–0.25 mg L−1 , and linearity values ranged up to 105 mg L−1 . The repeatability of the method was good. High variability was found among the measured grape varieties based on triterpene content, quantitites of oleanolic acid of cuticular wax ranged from 31.53 mg kg−1 to 162.01 mg kg−1 of the twelve analysed samples. The highest sitosterol content was measured in the sample 'Othello' (73.12 mg kg−1 ), while maximum sitosterol glucoside content was also found in 'Othello' variety (13.68 mg kg−1 ). The results showed that the study on triterpenes could be an informative tool to characterise grape varieties. 相似文献
104.
Maria Rosaria Corbo Barbara Speranza Alfonso Filippone Amalia Conte Milena Sinigaglia & Matteo Alessandro Del Nobile 《International Journal of Food Science & Technology》2009,44(10):2021-2027
Natural antimicrobial compounds to control the quality decay of a fresh fish burger were studied. In particular, thymol, lemon extract and grape fruit seed extract (GFSE), at 20, 40 and 80 ppm, have been tested against the main spoilage microorganisms inoculated in fish burgers stored at 5 °C. The evolution of mesophilic and psychrotrophic bacteria was also monitored. The sensorial quality decay was determined by means of a panel test, which assessed odour, colour, texture, drip loss and general appearance during the storage period. Results show that all the active substances efficiently slowed down the growth of the spoilage microorganisms. In particular, GFSE was the most efficient against Photobacterium phosphoreum , Shewanella putrefaciens and mesophilic bacteria, whereas thymol was the most efficient against both psychrotrophic bacteria and Pseudomonas fluorescens . Microbial growth was the factor limiting fresh fish burger acceptability. 相似文献
105.
Marta Dizy Pedro Jesus Martín-Alvarez María Dolores Cabezudo M. Carmen Polo 《Journal of the science of food and agriculture》1992,60(1):47-53
Several multivariate statistical methods (principal component, cluster, stepwise discriminant and multiple linear regression analysis) were applied to analytical data obtained by conventional methods and to analytical data for free amino acids, in an attempt to distinguish between grape, apple and pineapple juice. Analysis for methionine, proline, asparagine, arginine and glutamic acid made it possible to differentiate among the 34 samples of grape, apple and pineapple juices studied. Multiple linear regression analysis of computer-simulated mixtures of grape and apple juices made it possible to detect the proportion of each fruit within the blend. 相似文献
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107.
正交设计优化酿酒葡萄皮渣色素提取及其抗氧化性测定 总被引:1,自引:0,他引:1
以酿酒葡萄皮渣为原料,在单因素实验基础上,利用正交设计优化了超声波辅助提取色素工艺,并研究了该色素的抗氧化性能。结果表明,超声波辅助提取葡萄皮色素的最佳工艺为浸提液pH3,固液比为1:20,提取温度为60℃,浸提时间为50min;该色素具有较强的抗氧化能力。 相似文献
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110.
İnci Türk Toğrul 《International Journal of Food Science & Technology》2010,45(6):1146-1152
In this work, heat and moisture transport occurred during drying of black grapes in a laboratory dryer were investigated. In the experiments, the air was passed through the chamber at a variety of flow rates (0.5, 0.75, 1.0 and 1.25 m s?1) and temperatures (40, 50, 60 and 70 °C). Thermal and moisture diffusivities were determined. The possibility of expressing the moisture removal from the grapes was searched with the fourteen one‐layer drying models selected from the literature. Among all the models, the Page model was found the best for explaining the experimental results. The effects of the drying temperature and air velocity on the constants and coefficients of Page model and diffusivities were also investigated by multiple combinations of the different equations as the linear, power, logarithmic, exponential, polynomial, inverse polynomial and Arrhenius type by non‐ linear regression analyses. Models obtained were also analysed statistically using t‐test, RMSE, MBE and χ2. 相似文献