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排序方式: 共有8413条查询结果,搜索用时 15 毫秒
991.
随着人们对橄榄油的质量安全和营养价值的重视, 对其检测技术的要求也越来越高。核磁共振技术是近年来蓬勃发展起来的一种快速检测手段, 具有快速、高效、无污染、无需繁琐的前处理、重现性高等优点, 在许多领域得到广泛应用。本文介绍了国内外运用核磁共振技术(1H, 13C, 31P)对橄榄油进行品质评价(包括储存历史、氧化稳定性、风味营养品质等)及其掺伪检测的研究现状, 并且分析了该技术应用于橄榄油品质检测时尚存在的问题和今后的研究方向。 相似文献
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993.
Madrera Roberto Rodríguez Valles Belén Suárez García Yolanda Diñeiro del Valle Argüelles Paula Lobo Anna Picinelli 《Food science and biotechnology》2010,19(4):1129-1134
Work has commenced on the study and characterization of wood native species (oak, chestnut, cherry, alder, ash, and beech),
employed to a minor extent in enology, for their application in the elaboration of distillates. To this end, furanic and low
molecular weight phenol compounds, total phenolic content, and antioxidant activity in alcoholic extracts by maceration of
wood chips at 2 toasting levels were studied. Significant differences between samples, technologically relevant, were due
both to species and toasting time. Furthermore, extracts showed interesting antioxidant activities equivalent in some cases
to than those reported for alcoholic beverages aged in wood. 相似文献
994.
Raffaele Guzzon Elena Franciosi Roberto Larcher 《European Food Research and Technology》2014,239(1):117-126
The microflora of grapes involved in the production of a traditional Italian straw wine, “Vino Santo Trentino”, was evaluated as a biocontrol agent against Botrytis cinerea, one of the main diseases affecting fruit and grapes. The microbiota was described using plate counts and genotypic characterisation (sequencing of 16S rRNA for bacteria and 26s rRNA for yeast), allowing identification of yeasts belonging to the Hanseniaspora, Metschnikowia, Cryptococcus and Issatchenkia genera and bacteria (Bacillus, Microbacterium, Acetobacter and Gluconobacter spp.). The distribution of these species is related to the extent of B. cinerea infection. 7 isolates were able to halt the growth of B. cinerea in antagonistic cultures grown in Petri plates, using both synthetic growth and grape juice media. Technological characterisation of potential biocontrol agents, performed with the help of flow cytometry and HPLC-ECD, demonstrated that these microorganisms did not represent a risk for wine production due to their low resistance to ethanol, low pH and the absence of off-flavours. This ensures that the biocontrol agents disappear during winemaking and excludes a negative impact on the quality of wines. In conclusion, the microflora associated with dried grapes is a precious source of biocontrol agents against B. cinerea, both in terms of preventing disease in the vineyard and in control of the grape drying process for the production of straw wines. 相似文献
995.
We have tested the hypothesis that increased concentrate intake induces mRNA abundance alterations of genes involved in short-chain fatty acid (SCFA) absorption in the rumen epithelium of goats and these changes of mRNA abundance are probably related to ruminal SCFA concentration and ruminal pH. Goats (n = 12) were randomly allocated to 2 groups and fed either a low-concentrate (LC) diet (10% concentrate; n = 6) or a medium-concentrate (MC) diet (35% concentrate; n = 6) in 2 equal portions daily. Goats were fed separately with their respective diet for 3 wk. The goats were slaughtered 6 h after the morning feeding on d 22. In vivo, goats in the MC treatment exhibited a greater ruminal SCFA concentration (81.9 mM) compared with those in the LC treatment (58.0 mM), and the pH decreased from 7.03 to 6.63. Correspondingly, mRNA expression of candidates for SCFA−/HCO3− exchangers, namely downregulated in adenoma (DRA), putative anion transporter 1 (PAT1), and anion exchanger 2 (AE2) were increased in the MC group. Further, upregulation in monocarboxylate transporter 1 (MCT1) and monocarboxylate transporter 4 (MCT4) mRNA abundances was observed in the MC group. The expression of genes that help the rumen epithelial cells to maintain intracellular pH, including Na+/H+ exchanger 1 (NHE1), NHE2, NHE3, vacuolar H+ ATPase subunit B (vH+ATPase), and Na+/K+ ATPase pump subunit α1 (Na+/K+ATPase) were also enhanced in the MC group relative to the LC group. During in vitro studies with isolated rumen epithelial cells from goats, exposure to a pH of 6.8 increased MCT1 mRNA expression after 24 h of culture, whereas the mRNA expression of AE2 was downregulated. The presence of SCFA (20 mM) in the medium increased DRA, PAT1, AE2, MCT1, and Na+/K+ATPase mRNA expression. The expression of vH+ATPase was decreased by increased SCFA concentration. The mRNA expression of MCT4 did not vary in vitro with pH (6.8) or SCFA (20 mM). The expression of DRA was increased by synergistic effects of higher SCFA concentration and lower pH, similar to that of MCT1. Thus, diet-dependent rumen epithelial mRNA expression changes in genes involved in SCFA absorption are probably related to ruminal SCFA concentration and pH. 相似文献
996.
997.
Anna Picinelli Lobo Belén Suárez Valles Norman Fernández Tascón Roberto Rodríguez Madrera Ovidio Fernández García 《LWT》2006,39(9):1026-1032
Partial least square regression was used to develop different calibration data sets for multi-parameter routine analysis of ciders. Parameters included were those related with the monitoring of fermentation process and cider quality: specific gravity, total and volatile acidities, alcoholic proof, pH and fructose. Calibration performances were evaluated by means of the prediction residual sum of squares (PRESS), the root mean squared prediction error of cross-validation (RMSECV) and the residual predictive deviation (RPD) values (ratio of the standard deviation of the population to the standard error of cross-validation). Validation of the models was assessed in terms of accuracy and precision. Mean recoveries of the predicted results compared to the reference values were close to 100%, with repeatability and reproducibility similar to those of the reference methods. 相似文献
998.
999.
1000.