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1.
Concentrations of avenanthramides and activity of the biosynthetic enzyme hydroxycinnamoyl‐Co A:hydroxyanthranilate N‐hydroxycinnamoyl transferase (HHT) were analyzed in dry or, steeped nonmilled or milled, non‐heat‐treated (raw) or heat‐treated oat samples (Avena sativa L.). Increased avenanthramide concentrations were found when intact raw groats were steeped. The increase was time‐ and temperaturedependent and maximal after 10 hr of steeping at 20°C. Continuous germination in air, after steeping, only contributed to a further increase in avenanthramides when steeping times were shorter than 10 hr. Concentrations of avenanthramides and HHT activity were positively correlated during steeping of intact groats at 8 and 20°C. The increase in avenanthramides was suggested to be due to de novo synthesis and a whole grain structure seemed to be required as no increase was found when groats were milled before steeping. Avenanthramide levels also increased when heat‐treated samples, lacking HHT activity, were steeped. This increase may be due to release of bound forms, possibly formed during the preceding heat treatment. 相似文献
2.
A sensory profiling analysis of heat-processed oats (Avena sativaL.) was performed. The oat grains were of three varieties (Kapp, Mustang and Svea), stored at different relative humidities (30, 55 or 80%) for 3·5 or 15·5 months and heat-treated either with or without prior dehulling. The main differences in sensory attributes were related to the various thermal processes. Processed dehulled samples, particularly of theMustangvariety, had the highest intensities of oat odour, oat flavour, fresh odour and fresh flavour. Samples processed with hulls, in particular the varieties Kapp and Svea had the highest intensities of odour and flavour, rancid odour and flavour and bitterness. The sensory profile of processed oats were described partly by variations in phenolic compounds of low molecular weight, fat acidity and moisture content after processing. Twenty-nine per cent of the variation in odour and flavour attributes was explained by the 11 phenolic compounds analysed. Water content and the phenolic compoundsp-coumaric acid, vanillin,p-hydroxybenzaldehyde and coniferyl alcohol were significantly correlated (P<0·05) to high levels of rancidity, flavour intensity and bitterness and low levels of freshness, oat odour and flavour. The avenanthramides were related mainly to low levels of flavour intensity and rancid odour and flavour. Caffeic acid and fat acidity were related to low intensities of sweetness and aftertaste. 相似文献
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Low molecular weight phenolic compounds present in heat processed oats (Avena sativaL) were analysed. The oat grains were of three varieties (Kapp, Mustang and Svea), stored at different relative humidities (30, 55 or 80%) and periods (3·5 or 15·5 months) and processed with or without hulls. Eleven UV-absorbing compounds detected by High Performance Liquid Chromatography were subjected to univariate and multivariate statistical analysis. The selected compounds included caffeic acid,p-coumaric acid, ferulic acid, vanillic acid,p-hydroxybenzaldehyde, vanillin, coniferyl alcohol, three avenanthramides and one unidentified substance. The levels of vanillic acid, vanillin and, especially,p-coumaric acid,p-hydroxybenzaldehyde and coniferyl alcohol increased significantly in samples processed with hulls, but not in samples processed without hulls. Ferulic acid increased in both processes, while caffeic acid and the avenanthramides were found to decrease during processing. Storage of unprocessed samples for 1 year generally increased the levels of phenolic acids and aldehydes. For the phenolic acids (except ferulic acid), this increase was most pronounced after storage at high relative humidity (80%). The avenanthramides were present at their highest levels in Mustang, caffeic acid in Svea and Mustang, the unidentified compound in Svea, while all the other compounds studied were present predominantly in the variety Kapp. 相似文献
5.
Kenth Dimberg 《Fish physiology and biochemistry》1995,14(4):323-327
The pseudobranch in rainbow trout was investigated in order to clarify its metabolic and physiological function. Contents of lactate, glycogen, and glycerides and activities of carbonic anhydrase (CA), lactate dehydrogenase (LDH), and 3-hydroxy-acyl CoA dehydrogenase (HAD) were measured and compared with those in the gills and liver. Contents of lactate and glycerides, and activities of CA and HAD were higher in the pseudobranch than in the gills and liver. The results show that the pseudobranch is well equipped with enzymes (HAD and CA) suggested to be coupled to fatty acids breakdown and synthesis respectively. Lactic acid, possibly formed from glycogen and the glycerol component in glycerides, may be involved in the increase in blood P0
2 (Root effect) that is necessary to meet the oxygen needs of the eye. Pseudobranch carbonic anhydrase is probably involved in this process. 相似文献
6.
Kenth Dimberg 《Fish physiology and biochemistry》1994,12(5):381-386
The plasma inhibitor of carbonic anhydrase (CA) from rainbow trout was purified using ion exchange chromatography. The inhibitor
has a high isoelectric point value (pI>10). SDS-PAGE electrophoresis and gel filtration demonstrated that the inhibitor is
a low molecular weight compound of about 6,000 daltons. The plasma inhibitor was more effective against gill CA than against
blood CA in vitro, probably reflecting the presence of various CA-isoenzymes in red blood cells and gill tissue. The apparent Root effect,
i.e., the impairment of the oxygen binding capacity of hemoglobin in red blood associated with increased blood PCO
2was counteracted by the plasma inhibitor, probably by acting on membrane-bound and/or cytosolic blood CA. This interaction
may be of importance in adaptive mechanisms, e.g., during the acidemic phase, when the fish is being acclimated to hypercapnic conditions. 相似文献
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Elements uptake, histological distributions as well as mycorrhizal and physiological statuses of Atriplex halimus were determined on trace metal and metalloid polluted soils from the surrounding spray zones of a former lead smelter in the South-East coast of Marseille (France). Analyses of heavy metal and arsenic distribution in soil and plant organs showed that A. halimus tolerance is largely due to exclusion mechanisms. No specific heavy metal concentration in leaf or root tissues was observed. However, accumulation of salts (NaCl, KCl, Mg and Ca salts) on leaf bladders and peripheral tissues of roots was observed and may compete with metal element absorption. Occurrence of endomycorrhizal structures was detected in roots and may contribute to lower element transfer from root into the aerial parts of plants. The non-destructive measurements of leaf epidermal chlorophylls, flavonols and phenols showed a healthy state of the A. halimus population on the metal and metalloid polluted sites. Considering the low metal bioaccumulation and translocation factors along with a reduced metal stress diagnosis, A. halimus appeared as a good candidate for phytostabilization of trace metals and metalloids and notably arsenic in contaminated soils of the Mediterranean spray zone. However, its invasive potential has to be determined before an intensive in situ use. 相似文献
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Bryngelsson S Dimberg LH Kamal-Eldin A 《Journal of agricultural and food chemistry》2002,50(7):1890-1896
The effects of various commercial hydrothermal processes (steaming, autoclaving, and drum drying) on levels of selected oat antioxidants were investigated. Steaming and flaking of dehulled oat groats resulted in moderate losses of tocotrienols, caffeic acid, and the avenanthramide Bp (N-(4'-hydroxy)-(E)-cinnamoyl-5-hydroxy-anthranilic acid), while ferulic acid and vanillin increased. The tocopherols and the avenanthramides Bc (N-(3',4'-dihydroxy-(E)-cinnamoyl-5-hydroxy-anthranilic acid) and Bf (N-(4'-hydroxy-3'-methoxy)-(E)-cinnamoyl-5-hydroxy-anthranilic acid) were not affected by steaming. Autoclaving of grains (including the hulls) caused increased levels of all tocopherols and tocotrienols analyzed except beta-tocotrienol, which was not affected. Vanillin and ferulic and p-coumaric acids also increased, whereas the avenanthramides decreased, and caffeic acid was almost completely eliminated. Drum drying of steamed rolled oats resulted in an almost complete loss of tocopherols and tocotrienols, as well as a large decrease in total cinnamic acids and avenanthramides. The same process applied to wholemeal made from groats from autoclaved grains resulted in less pronounced losses, especially for the avenanthramides which were not significantly affected. 相似文献
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Shewry PR Piironen V Lampi AM Nyström L Li L Rakszegi M Fraś A Boros D Gebruers K Courtin CM Delcour JA Andersson AA Dimberg L Bedo Z Ward JL 《Journal of agricultural and food chemistry》2008,56(21):9777-9784
The levels and compositions of a range of phytochemicals (sterols, tocols, avenanthramides, folates, phenolic acids) and dietary fiber components were determined in five oat cultivars (four husked and one naked) grown on a single site in 2005. The total levels of tocols, phenolic acids, and avenanthramides varied by over 2-fold between cultivars, but less variation occurred in total sterols and total folates. Limited variation was also observed in the dietary fiber content and composition of the four husked lines. These results indicate that it may be possible to selectively breed for lines with high contents of dietary fiber and specific groups of phytochemicals. 相似文献