Deutsche Lebensmittel-rundschau 

About: Deutsche Lebensmittel-rundschau is an academic journal. The journal publishes majorly in the area(s): High-performance liquid chromatography & Fermentation. It has an ISSN identifier of 0012-0413. Over the lifetime, 847 publications have been published receiving 5307 citations.

Flavonols, phenolic acids and antioxidant activity of some red fruits

Abstract: Red fruits (blueberry, blackberry, chokeberry, strawberry, red raspberry, sweet cherry, sour cherry, elderberry, black currant and red currant) were analyzed for flavonols (quercetin, myricetin, and kaempferol), hydroxycinnamic acids (caffeic, ferulic, p-coumaric acid) and hydroxybenzoic acids (p-hydroxybenzoic, ellagic acid) by using HPLC method. Compounds were analyzed as aglycons after acid hydrolysis with 1.2 mol dm-3 HCl. Each fruit sample was analyzed for total polyphenols (TP) and total anthocyanins (TA). TP ranged from 1763 to 7194 mg kg-1 fresh weight (FW) in red raspberries and chokeberries, respectively. TA ranged from 169 to 4069 mg kg-1 FW in strawberries and blueberries, respectively. Flavonols varied from 4 mg kg-1 in red raspberries to 183 mg kg-1 in blueberries. Hydroxycinnamic acids were found in relatively high concentrations in blueberries (92 mg kg-1) and in black currant (70 mg kg-1) and represented significant portion in sour and sweet cherry phenolics. The amount of ellagic acid was high in blackberry (121 mg kg-1), strawberry (41 mg kg-1) and red raspberry (32 mg kg-1). The strongest antioxidant activity determined by DPPH• and ABTS• + assays showed chokeberry, followed by blueberry, black currant and elderberry. Antioxidant activity correlated better with TP than with TA, total flavonols (TF), or total hydroxycinnamic acids. Additionally, linear relationship was observed between antioxidant activity of fruits and content of caffeic acid, quercetin and p-coumaric acid. Overall results showed that red fruits can serve as good source of bioactive polyphenols in human diet, but due to high concentrations of anthocyanins, flavonols, phenolic acids and strong antioxidant activity, chokeberry, blueberry, elderberry and black currant can be regarded as good candidates for nutritional supplement formulations.

Anthocyanin content and antioxidant activity of various red fruit juices

Abstract: #Summary Anthocyanin content and antioxidant activity of various red fruit juices (black currant, red raspberry, blackberry, sour cherry, sweet cherry, strawberry, chokeberry, and elderberry juice) has been evaluated in this study by using HPLC, pH-differential, and DPPH method. Anthocyanins were the predominant phenolic components (66 % in elderberry juice, 56 % in black currant juice) or represented considerable portion in total polyphenol content of some juices (40 % in blackberry juice, 33 % in chokeberry juice). Amount of anthocyanins determined by HPLC method ranged from 202 to 6287 mg l –1 in strawberry and elderberry juice, respectively. Anthocyanins present in investigated red fruit juices were derivatives of cyanidin, delphinidin, pelargonidin and peonidin. Chokeberry, elderberry, blackberry and sour cherry juice were characterized by cyanidin derivatives, black currant juice by delphinidin and cyanidin derivatives and strawberry juice by pelargonidin derivatives. The major anthocyanins in red raspberry and sweet cherry juice were derivatives of cyanidin although peonidin (in sweet cherry juice) and pelargonidin derivatives (in red raspberry juice) were found in low amount. Antioxidant activity varied from 4 to 72 μmol TE/ml in sweet cherry and chokeberry juice, respectively. High correlation was observed between antioxidant activity and total anthocyanin content of investigated red fruit juices. Overall results showed that red fruit juices can serve as a good source of bioactive phytochemicals in human diet. Chokeberry, elderberry and black currant juice were the richest in anthocyanin content and showed the strongest antioxidant activity, as well. Therefore, these three juices can be regarded as good candidates for raw materials in production of functional foods. Zusammenfassung In dieser Studie wurden Anthocyane-Konzentration sowie antioxidative Aktivitat von Fruchtsafte aus verschiedenen Beerenfruchte-Sorten und Kirschen (schwarze Johannisbeere, Himbeere, Brombeere, Sauerund Suskirschen, Erdbeere, Aronia und Holunderbeere) mittels HPLC, pH-Differenzial und DPPH-Methode bestimmt. In einigen Saften bilden Anthocyane den grosten Anteil der Gesamtpolyphenole (z. B. 66 % im Holunderbeersaft, 56 % im schwarzen Johannisbeersaft), oder stellen einen bedeutenden Anteil am Gesamtpolyphengehalt mancher Safte (40 % im Brombeersaft, 33 % im Aroniasaft) dar. Die Anthocyane-Konzentration, mittels HPLC bestimmt, variierte von 202 mg/l im Erdbeersaft bis 6287 mg/l im Holunderbeersaft. Bei den aus Beerenfruchten und Kirschen hergestellten Fruchsaften vorhandenen Anthocyanen handelt es sich um Cyanidin-, Delphinidin-, Pelargonidin-, und Peonidinderivate. So wurden im Aronia-, Holunderbeere-, Brombeere- und Sauerkirschensaft Cyanidinderivate gefunden. Im schwarzen Johannisbeersaft wurden Delphinidin- und Cyanidin-, im Erdbeersaft Pelargonidinderivate gefunden. Die im Himbeer- und Suskirschensaft enthaltenen Anthocyane sind grostenteils Cyanidinderivate, obwohl auch darin, aber nur in kleinen Mengen, Peonidinderivate (im Suskirschensaft) und Pelargonidinderivate (im Himbeersaft) vorhanden sind. Die antioxidative Aktivitat variierte im Bereich von 4 μmol Troloxaquivalent/ml im Suskirschensaft bis zu 72 μmol Troloxaquivalent/ml im Aroniasaft. Es wurde eine starke Korrelation zwischen der antioxidativen Aktivitat und der Anthocyan-Konzentration in den gepruften Saften aus Beerenfruhten und Kirschen festgestellt. Alle Ergebnisse weisen darauf hin, dass Safte aus Beerenfruchten und Kirschen eine geeignete Quelle an bioaktiven Phytochemikalien fur die menschliche Ernahrung darstellen. Aronia-, Holunderbeer- und schwarzer Johannisbeersaft enthalten die groste Anthocyane-Konzentration und zeigen die starkste antioxidative Aktivitat. Diese Safte sind daher zur Herstellung funktioneller Lebensmittel geeignet.

Formation of acrylamide in heated potato products - model experiments pointing to asparagine as precursor

Abstract: Model experiments were carried out to examine the mechanism of acrylamide formation in heated foodstuff, especially in potato products. For this purpose various substances, like organic acids, sugars and amino acids were heated using starch or silica gel as carrier substances. Low amounts of acrylamide are formed by heating ascorbic acid with an additional nitrogen source like ammonium acetate or glutamine. Significantly higher yields of acrylamide are formed by heating asparagine. The amount of acrylamide dramatically increases if asparagine is heated in the presence of glucose or fructose. Asparagine works not only as a nitrogen source, it seems to be evident, that the complete backbone of the acrylamide molecule is formed from asparagine. There are indications, that in an analogue reaction 3-buteneamide is formed, if glutamine is heated in the presence of reducing sugars.

Nachweis von UV-Filtersubstanzen in Muttermilch

Abstract: Six human breast milk samples have been investigated for contaminations with the sunscreen agents Homosalate (HMS), Isoamyl p-methoxycinnamate (IMZ), Benzophenone-3 (BP-3), Methylbenzylidenecamphor (MBC), Octyl Dimethyl PABA (DABI) and Octyl Methoxycinnamate (OMZ). Sunscreens are preferably utilized in the industrial production of sun protective agents. Moreover those substances are used in many other cosmetic products, partly for means of preservation. In this study a detection of sunscreens in human milk samples from Germany is reported for the first time. Up to 2% of the applied substances can be absorbed via skin according to manufacturers information. In clinical studies some cases of contact and photocontact allergies to certain sunscreens have been reported. Glas-columns filled with differently acitvated silica gel were used for the extraction of each of the 10 ml milk samples. The extracts were cleaned by gel permeation chromatography, afterwards reduced to a volume of 150 μl and quantitatively analysed by Capillary Gaschromatography/Mass Spectrometry in the SIM-mode. BP-3 and OMZ were unambiguously detectable in five of the six investigated samples at a concentration range between 16 and 417 ng/g (fat basis).