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71.
Antioxidant properties of flavonoids and ellagic acid were characterized in eight wines and juices produced by various processing methodologies from red and white muscadine grape cultivars (Vitis rotundifolia). Juices and wines were produced by hot- and cold-pressed techniques, and additional wine was produced following on-hull fermentation for 3, 5, and 7 days. Chromatographic conditions were developed to simultaneously separate anthocyanins, ellagic acid, and flavonols and correlated to a measurement of overall antioxidant capacity (AOX), and their changes were monitored after storage for 60 days at 20 and 37 degrees C. Regression coefficients between concentrations of individual polyphenolics and AOX ranged from 0.55 for ellagic acid to 0.90 for kaempferol. Both red and white wines had higher AOX values after storage than juices made from an identical grape press, despite lower concentrations of individual polyphenolic compounds. Red wines fermented on-hull had higher initial concentrations of antioxidant polyphenolics as compared to a corresponding hot-pressed juice, but changes in AOX during storage were more affected by time than by storage temperature despite lower concentrations of flavonoids and ellagic acid present at 37 degrees C as compared to 20 degrees C. Oxidative or polymerization reactions significantly decreased levels of monomeric anthocyanins during storage with the greatest losses observed for delphinidin and petunidin 3,5-diglucosides. Processing methods for muscadine wine and juice production were important factors influencing concentrations of antioxidant flavonoids and ellagic acid, while the role of fermentation and time had the greatest influence on retention of AOX properties during storage. 相似文献
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旋毛虫感染兔血清抗体消长规律的研究 总被引:1,自引:0,他引:1
应用旋毛虫肌幼虫干燥冷浸可溶性抗原与聚醛化聚苯乙烯(PAPS)载体微球共价交联制成快诊试剂,对旋毛虫感染兔血清进行检测,初步探明其血清抗体的消长规律。实验显示,以16000条肌幼虫/只经口饲喂感染10只兔,于第7天可检出抗体,并分别于感染后第45 ̄49天先后达到抗体最高水平,然后维持一段时间(20 ̄30天左右),以后逐渐缓缓下降。此结果与旋毛虫肌幼虫感染宿主后的生活周期相吻合。肌幼虫在肠道内发育为 相似文献
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Identification of ellagic acid conjugates and other polyphenolics in muscadine grapes by HPLC-ESI-MS
Ellagic acid, ellagic acid glycosides, and ellagitannins found in various fruits and nuts, including muscadine grape, are reported to have potential health-promoting benefits and antioxidant properties. This study isolated and identified several ellagic acid derivatives present in muscadine grapes and determined their relative antioxidant properties (AOX). Compounds were extracted from grape skins and pulp using methanol, and the solvent was evaporated. Isolates were dissolved in citric acid buffer (pH 3.5) and absorbed onto C18 cartridges. Nonretained polyphenolics were collected separately and again partitioned from Sephadex LH-20, whereas retained polyphenolics were first eluted with ethyl acetate followed by methanol. Ellagic acid derivatives were identified on the basis of UV and mass spectra, and the presence of ellagitannins was confirmed by a significant increase in free ellagic acid with HPLC followed by acid hydrolysis. Muscadine grapes contained phenolic acids, flavonols, anthocyanins, ellagic acid, and numerous ellagic acid derivatives. AOX varied in the order ethyl acetate > methanol > C18 nonretained fractions; each correlated to both total phenolics (r = 0.90) and total ellagic acid (r = 0.99) contents. Results of this study revealed previously unidentified ellagic acid derivatives in muscadine grapes. 相似文献
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The survival of salmon lice. Lepeophtheirus salmonis (Krøyer) on Arctic charr. Salvelinus alpinus (L.). in fresh water was studied. The results showed that salmon lice were able to survive for up to 3 weeks, in contrast with previous published information that the parasite is quickly shed when the fish enters fresh water. 相似文献
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MICHAEL A. ST. JOHN J. STEVENSON MACDONALD PAUL J. HARRISON RICHARD J. BEAMISH EDWARD CHOROMANSKI 《Fisheries Oceanography》1992,1(2):153-162
Zooplankton and fish densities in the southern Strait of Georgia were observed to coincide with variations in surface salinities resulting from the outflow of the Fraser River. Vertical net hauls in the euphotic zone revealed that copepods, amphipods, and euphausiids were significantly more abundant per m3 in the brackish estuarine plume (surface salinities - 10–15 ppt) when compared to the area covered by the freshwater of the Fraser River plume (0–10 ppt) and the region of the Strait of Georgia (25–30 ppt) unaffected by the outflow of the Fraser River.
The estuarine and riverine plumes had significantly higher fish densities (adult and juvenile herring, and juvenile salmonids [excluding chinook]) than the Strait of Georgia region, with no significant differences in densities of juvenile chinook salmon observed between regions. The highest catches of juvenile salmonids were at the boundary between the estuarine plume and the Strait of Georgia. Zooplankton found in the stomach contents of both adult and juvenile herring suggested that the herring were filter-feeding on the zooplankton in the estuarine plume. Juvenile salmonids fed primarily on small unidentifiable juvenile fish. The existence of increased densities of prey items in the estuarine plume is proposed to be the primary mechanism resulting in increased residence time in this region by outmigrating juvenile salmonids. Utilization of aggregated zooplankton could lead to increased salmonid growth rates and therefore to enhanced survival of individuals utilizing the Fraser River plume environment. 相似文献
The estuarine and riverine plumes had significantly higher fish densities (adult and juvenile herring, and juvenile salmonids [excluding chinook]) than the Strait of Georgia region, with no significant differences in densities of juvenile chinook salmon observed between regions. The highest catches of juvenile salmonids were at the boundary between the estuarine plume and the Strait of Georgia. Zooplankton found in the stomach contents of both adult and juvenile herring suggested that the herring were filter-feeding on the zooplankton in the estuarine plume. Juvenile salmonids fed primarily on small unidentifiable juvenile fish. The existence of increased densities of prey items in the estuarine plume is proposed to be the primary mechanism resulting in increased residence time in this region by outmigrating juvenile salmonids. Utilization of aggregated zooplankton could lead to increased salmonid growth rates and therefore to enhanced survival of individuals utilizing the Fraser River plume environment. 相似文献