Entity

Time filter

Source Type

Strasbourg, France

Leitao C.,CNRS Hubert Curien Multi-disciplinary Institute | Leitao C.,Carlsberg Group | Marchioni E.,CNRS Hubert Curien Multi-disciplinary Institute | Bergaentzle M.,CNRS Hubert Curien Multi-disciplinary Institute | And 6 more authors.
Journal of Cereal Science | Year: 2012

Phenolic contents of barley and malt extracts and their corresponding antioxidant activities were investigated using a chromatographic online antioxidant detection system. Ethyl acetate extracts of barley and malt were separated using reverse phase HPLC and compounds eluting from the column were submitted to two UV-visible detections: one for the phenolic compounds; and the other for the reduced form of the radical cation 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS •+) after the compounds were allowed to react online with it. Prodelphinidin B3 and procyanidin B3 were identified as two major contributors in the antioxidant activity of barley, in addition to catechin. Malting had a dramatic impact on these three compounds by resulting in a sharp decrease in their detected amounts and the associated antioxidant activities. Two other antioxidants, ferulic and sinapic acids, showed a better ability to withstand not only malting but also brewing steps. As for the overall phenolic content and antioxidant capacity, the study showed that malting allowed a better release and/or extraction of phenolic compounds, while the first brewing step caused the most significant damage by drastically decreasing the total polyphenols and their activity. Hopping however did not significantly affect neither the phenolic content nor the antioxidant activity. © 2012 Elsevier Ltd. Source


Leitao C.,CNRS Hubert Curien Multi-disciplinary Institute | Leitao C.,Carlsberg Group | Marchioni E.,CNRS Hubert Curien Multi-disciplinary Institute | Bergaentzle M.,CNRS Hubert Curien Multi-disciplinary Institute | And 4 more authors.
Journal of Agricultural and Food Chemistry | Year: 2011

A new analytical method (liquid chromatography-antioxidant, LC-AOx) was used that is intended to separate beer polyphenols and to determine the potential antioxidant activity of these constituents after they were allowed to react online with a buffered solution of the radical cation 2,2′- azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS .+). Using the LC-AOx method, it was possible to demonstrate that the extent of the antioxidant activity was very much dependent on the phenolic compound considered. The method was also applied to the analysis of beer extracts and allowed the evaluation of their antioxidant activity at different steps of beer processing: brewing, boiling, and fermentation. This study showed that the total antioxidant activity remained unchanged throughout beer processing, as opposed to the polyphenolic content, which showed a 3-fold increase. Hopping and fermentation steps were the main causes of this increase. However, the increase measured after fermentation was attributed to a better extraction of polyphenols due to the presence of ethanol, rather than to a real increase in their content. Moreover, this method allowed the detection of three unknown antioxidant compounds, which accounted for 64 ± 4% of the total antioxidant activity of beer and were individually more efficient than caffeic acid and epicatechin. © 2011 American Chemical Society. Source

Discover hidden collaborations