A headspace solid-phase microextraction (HS-SPME) method coupled to gas chromatography–ion trap mass spectrometry (GC–ITMS) has been developed and applied for profiling of volatile compounds released from five Ocimum basilicum L. cultivars grown under both organic and conventional conditions. Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC–TOFMS) was employed for confirmation of identity of volatiles extracted from the basil headspace by SPME. 相似文献
The polyphenolic components of Idared and Shampion apple purées were determined by HPLC; chlorogenic acid was the most abundant acid (20.0 mg/100 g in microwaved Idared); other polyphenols identified in high concentrations included (−)-epicatechin, procyanidin B1 and B2; quercetin and cyanidin glycosides were found in minor concentrations. The Shampion purées had higher total phenolics (142 mg/100 g) and procyanidin B2 concentrations (17.3 mg/100 g) than the Idared ones, and polymeric procyanidins represented 41% of all polyphenols. Antioxidant capacities of the samples, determined by spectrophotometric methods and EPR spectroscopy, correlated well with the concentration of polyphenols. The antioxidant properties could be better represented by EPR than by UV–vis measurements. The latter require transparent (clear) samples whereas EPR can be a method of choice in the assessment of radical-scavenging activity of dense and cloudy apple purées. Our results support the putative high antioxidant value of apple purées and define their capacity in terms of the major constituents. Apple purées are a rich source of natural antioxidants, especially of chlorogenic acid and procyanidins. 相似文献
Surface pasteurization is one of the decontamination treatments that can contribute to better preservation of meat products retaining most of their quality characteristics relatively intact if compared with the raw products. The current research compares the kinetics of free-floating and surface attached Listeria innocua cells by using integrated microbial and heat transfer modelling approaches. Surface pasteurization treatments are applied on a (abiotic) Teflon® model system in a novel steam surface decontamination rig. The experimental set-up prevented following four technological aspects to occur, (1) cold purge migration to the surface during the heating process, (2) inactivation kinetics of a cocktail of microbes, (3) protective effect of food components, and (4) physical distribution of bacteria throughout the depth of the product skin. Microbial load predictions are performed based on the inactivation parameters obtained during free-floating cell experiments. These predictions, when compared with the microbial data of the surface treatments, prove that the surface attached cells were much more heat resistant, despite the experimental set-up preventing the aforementioned (technological) events to occur. Indeed, surface attached cells can have different physiological/phenotypical/genetical characteristics, such as cell aggregations, colony formations, presence of flagella. In a final step, three techniques are implemented to evaluate mathematically the kinetics of the surface attached cells. Overall, this research’s significance is lying in the quantitative assessment of microbial heat resistance. The technological reasons underlying the increased microbial heat resistance on biotic and abiotic surfaces should be reevaluated, taking into account possible physiological/phenotypical/genetical characteristics. 相似文献
The aim of this study was to determine the degradation of dietary isoflavones in rumen fluid under 2 feeding regimens. The experiments were performed in vitro using a rumen fluid buffer system. The rumen fluid was taken from cows fed either a hay diet or a concentrate-rich diet (the diet consisted of 34.6% maize silage, 17.6% haylage, 12.8% alfalfa hay, and 35.0% supplemental mixture on a dry matter basis). As a source of isoflavones, 40% soybean extract (Biomedica, Prague, Czech Republic) at levels of 5, 25, 50, and 75 mg per 40 mL of rumen fluid was used. Samples of soybean extract were incubated in triplicate at 39°C for 0, 3.0, 6.0, 12.0, and 24.0 h in incubation solution. The metabolism of daidzein and genistein was faster under concentrate-rich diet conditions. In general, production of equol started after 3 to 6 h of incubation and reached the highest rate after approximately 12 h of incubation regardless of the type of diet or concentration of extract. In most of the experiments, production of equol continued after 24 h of incubation. Generally, equol production was greater under the hay diet conditions. Furthermore, experiments with higher amounts of added soybean extract revealed possible inhibitory effects of high levels of isoflavones on the rumen microflora. 相似文献
Waste disposal at sea – state of the art and developments . The article starts by describing the legal situation governing the disposal of waste at sea and then considers the licensing procedure according to the ?Oslo-London treaty law”?. The Federal German Department of the Environment is also involved in this licensing procedure in that it is responsible for examining the possibilities of disposal on land. The quantities of material for disposal have been considerably reduced in recent years in all areas. The disposal of sewage sludge and of dilute acids (from the production of organic dyes and pigments) in the North Sea has now stopped completely. The amount of waste for disposal from TiO2 production has been greatly reduced and stepwise cessation is planned by the mid -1980's. The incineration of waste on the high seas has also been restricted and will also be stopped in the long term. The results of ongoing and completed research are reported. 相似文献
The classic definitions of inulin and oligofructose are constructively criticized. It is observed that inulin cannot unequivocally be described as a polydisperse 1‐kestose‐based (GFn) β(2 ? 1) linear fructan chain, but that inulin always contains small amounts of Fm and branched molecules. This review article describes the presence of inulin and oligofructose in common foodstuffs. Historical data on human consumption add an extra dimension.
Modern analytical techniques (HPLC, LGC, HPAEC‐PAD) are used to check the variety of data mentioned in the literature throughout the past century. Methods to determine inulin and oligofructose in natural foodstuffs (cereals, fruit, and vegetables) are optimized and used to determine the loss of inulin during storage and during preparation of the food.
These findings allow quantification of the amount of inulin and oligofructose in the average daily western diet. The daily per capita intake is estimated to range from 1 to 10 g, depending on geographic, demographic, and other related parameters (age, sex, season, etc.).
Inulin and oligofructose are not measured by classic methods of dietary fiber analysis and consequently are often not mentioned in food tables. Their significant contribution (1 to 10 g/d/per capita) to the dietary fiber fraction (recommended at 25 g/d/per capita) is not taken into account in any nutritional recommendations. In view of this, inulin and oligofructose deserve more attention, both in food composition tables and in diet or nutrition studies. 相似文献
Technological, chemical, and microscopical studies on waterlogged oakwood from the Mayence Roman Ships (4th century) characterize it, depending on the degree of degradation, as a plasticized or very brittle waterfilled material undergoing heavy shrinkage on drying. The comparison with former results reveils strong common traits in the degradation pattern of wet archaeological oakwoods salvaged from differing environments: The abiotic hydrolytic degradation of the carbohydrates proceeds parallel to the surface, mostly with a sharply marked front. Experiments to optimize the stabilization of the wood with PEG are presented, which form the basis for the conservation treatment of the Mayence Roman Ships. 相似文献
Summary The results obtained between 1980 and 1985 in a Dutch monitoring programme on the presence of arsenic, cadmium, lead and mercury in meat and organs of swine are presented. For meat, livers and kidneys the median values were, respectively, 0.001, 0.001, and 0.003 mg/kg (fresh weight) for arsenic, 0.002, 0.044, and 0.260 mg/kg for cadmium, 0.01, 0.03, and 0.08 mg/kg for lead and 0.001, 0.002, and 0.005 mg/kg for mercury. No significant changes were observed in the tissue arsenic and mercury levels during the investigated period. A decrease was observed in the cadmium and lead concentrations in livers and kidneys. The provisional Dutch legal limits were exceeded only for lead in one kidney sample. A significant recti linear relation was found between the cadmium concentrations in livers and kidneys. In general the cadmium and lead levels found are comparable with published data, reported from other countries. Compared with data from the literature, the arsenic and mercury concentrations found in the present study are low.
Arsen, Cadmium, Blei und Quecksilber in Fleisch, Leber und Niere von Mastschweinen in den Niederlanden während der Jahre 1980–1985
Zusammenfassung Es wird über die Ergebnisse aus den Jahren zwischen 1980 and 1985 eines holländi-schen Überwachungsprogramms uber das Vorkommen von Arsen, Cadmium, Blei and Quecksilber in Fleisch and Organen von Mastschweinen berichtet. Für Fleisch, Leber and Niere lagen die ermittelten Medianwerte für Arsen bei 0,001 bzw. 0,001 and 0,003 mg/kg (bezogen auf Frischgewicht), für Cadmium bei 0,002 bzw. 0,044 and 0,260 mg/kg, für Blei bei 0,01 bzw. 0,03 and 0,08 mg/kg and für Quecksilber bei 0,001 bzw. 0,002 and 0,005 mg/kg. Die Arsen- und Quecksilbergehalte von Fleisch and Organen zeigten keine signifikante Änderung wahrend dieser Periode. Eine Abnahme wurde bei den Cadmium- and Bleigehalten von Leber and Nieren beobachtet. Die vorläu-figen holländischen gesetzlichen Richtwerte wurden nur für Blei in einer Nierenprobe überschritten. Die Cadmiumgehalte von Niere und Leber sind signifikant miteinander korreliert. Die Cadmium- und Bleigehalte sind im allgemeinen gut vergleichbar mit den Angaben anderer Länder. Die Arsen- und Quecksilbergehalte unserer Untersuchung sind im Vergleich mit den Angaben aus der Literatur niedrig.
Analysis of creep buckling using ADINA is described and evaluated. The main emphasis is on the selection of solution time steps. An energy method is presented to find an approximate time to buckle.
The evaluation of ADINA results is based on another numerical solution of creep buckling columns. We also give some practical guidelines for creep buckling analysis in general. 相似文献