Analysis of saccharides in beer samples by flow injection with electrospray mass spectrometry

Saccharides in foods play important roles, as they are essential substrates for fermentation processes. In brewing, the concentration of maltooligosaccharides influences the characteristics of beers and therefore their determination is of great practical interest. Electrospray ionization mass spectrometry (ESI-MS) was applied to identify and characterize maltooligosaccharides in beer samples. The effects due to different cation concentrations and dilution of samples were studied. Furthermore, quantitative analyses of maltooligosaccharides by means of flow-injection ESI-MS (FI/ESI-MS) of 1 microL beer samples (diluted 1000-fold) are described

Carotenoid and polyphenol content of different tomato cultivars and related antioxidant activity

Different tomato phenotypes were analysed for the content of total polyphenols, selected flavonoids, including flavonols (rutin and rutin-derivative), flavanones (naringin and the related chalcone) and carotenoids (lycopene and beta-carotene). The identity of these components was based on their chromatographic, ultraviolet and mass spectrometric behavior. All phenotypes were surveyed for their total antioxidant activity (TAA), correlations beteen TAA values and the content of each group of costituents

Quantitative characterization of flavonoid compounds in Rooibos tea (Aspalathus linearis) by LC-UV/DAD

Rooibos tea originates from the leaves and stems of the indigenous South African plant Aspalathus linearis. It has gained much attention for clinical purposes in the case of nervous tension, allergies (dermatitis), and various indigestive problems. Recently, antioxidative activity was also attributed to the tea on the basis of its flavonoid content. Therefore, an HPLC method using a C 18 reversed phase column was developed for the assay of 10 flavonoids in aqueous and methanolic infusions. Main compounds determined were the dihydrochalcone aspalthin, rutin, and orientin, and their content was in the range of 1.0 to 1.3 mg/g. The identity of detected flavonoids was confirmed by comparing their retention times and UV and MS spectra with those of corresponding standards. In addition, the MS analysis showed evidence of the presence of other compounds such as nothofagin, dihydroisoorientin, and dihydroorientin

Liquid chromatography/atmospheric pressure chemical ionization ion trap mass spectrometry of terpene lactones in plasma of animals

Liquid chromatography/atmospheric pressure chemical ionization ion trap mass spectrometry (LC/APCI-ITMS) was applied to evaluate the bioavailibility of two different forms (free and complexed with soy phospholipids) of pure bilobalide and ginkgolide B in rats after acute administration. The same technique was used to measure the levels of ginkgolide A, B and bilobalide in plasma of guinea pigs fed Ginkgo biloba extract enriched in terpene lactones after chronic administration. The ratio R(P)/R(A) increased two to four times after the administration in the phytosomic form, where R(P) and R(A) represent the percentage ratio between the concentration of each terpene lactone in plasma and in the administrated form, respectivel

Liquid chromatography/atmospheric pressure chemical ionisation mass spectrometry of terpene lactones in plasma of volunteers dosed with Ginkgo biloba L. extracts

Liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (LC/APCI-ITMS) was applied to evaluate the levels of ginkgo biloba extracts in free (Ginkgoselect) or phospholipid complex (Ginkgoselect Phytosome) forms, providing 9.6 mg of total terpene lactones. The maximum plasma concentration, Cmax, of total ginkgolides A, B and bilobalide were 85.0 and 181.8 microg/ml for Ginkgoselect and Ginkgoselect Phytosome, respectively. The Cmax values were reached at 120 min for the free form and at 180-240 min for the phospholipid complex form. In both cases, the mean elimination half-life of each terpene lactone was in the range 120-180 min. Due to its sensitivity (about 1 ng/ml) and specificity. LC/APCI-ITMS proved to be a very powerful tool for pharmacokinetic studies of these phytochemicals

Polyphenol pattern and antioxidant activity of different tomato lines and cultivars

Background/Aims: Besides antioxidant vitamins and minerals, fruits and vegetables contain flavonoids and related phenolics. The biological activities of these Polyphenols have become well known in recent years evidencing their beneficial effects on human health. In this context, the characterization of the flavonoids present in tomatoes is of great interest. Thus the Polyphenol pattern (including flavonols, flavanones and cinnamate derivatives), lycopene and -carotene concentrations and the total antioxidant activity (TAA) of the phenolic fraction from different tomato lines and cultivars have been determined. Methods: The characterization was obtained by means of spectrophotometry and HPLC analyses. Results: Mean values for single flavonoids were 0.68 \ub1 0.16 for naringenin, 0.74 \ub1 0.12 for rutin and 0.32 \ub1 0.06 for a rutin-pentoside. Mean total Polyphenol content was 13.15 \ub1 1.15 mg/100 g and mean TAA value was 1.3 \ub1 0.10 mmol/g. The obtained TAA values resulted in good accordance with the total Polyphenol content (R2 = 0.7928). The main phenolic acids were chlorogenic (mean \ub1 SE 0.20 \ub1 0.03) and caffeic acid (mean \ub1 SE 0.03 \ub1 0.01). Mean levels of lycopene and -carotene were 5.38 \ub1 0.90 and 1.18 \ub1 0.40 mg/100 g, respectively. Conclusions: Almost all the lines characterised by low carotenoid content produce high levels of Polyphenols, and consequently have the most powerful antioxidant potential