Effects of mashing on total phenolic contents and antioxidant activities of malts and worts

College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China
International Journal of Food Science & Technology (Impact Factor: 1.35). 11/2011; 47(2):240 - 247. DOI: 10.1111/j.1365-2621.2011.02831.x

ABSTRACT Effects of mashing on total phenolic contents (TPC), radical-scavenging activity, reducing power and metal chelating activity of malts and corresponding worts were clarified in this study. Results showed that there were significant variations in TPC and antioxidant activity across malts and worts. An 8.8% of increase in TPC was observed during the early stage of mashing, accompanied by an increase in antioxidant activity. However, 2.6% of decrease in TPC and inconsistent changes in antioxidant activity were found during the mashing at higher temperature. Overall, mashing resulted in 6.0% and >10.0% of increases in TPC and antioxidant activity, respectively. Moreover, Pearson correlation analysis revealed that there were good correlations (ranging from 0.622 to 0.735, P < 0.01) between TPC and antioxidant activity of malts and worts. Additionally, mashing resulted in more positive correlations between TPC and antioxidant activity, emphasising the key role of malt phenolic compounds for wort antioxidant activity.

Download full-text


Available from: Haifeng Zhao, Jun 19, 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: The chemistry of beer flavor instability remains shrouded in mystery, despite decades of extensive research. It is, however, certain that aldehydes play a crucial role because their concentration increase coincides with the appearance and intensity of "aged flavors". Several pathways give rise to a variety of key flavor-active aldehydes during beer production, but it remains unclear as to what extent they develop after bottling. There are indications that aldehydes, formed during beer production, are bound to other compounds, obscuring them from instrumental and sensory detection. Because freshly bottled beer is not in chemical equilibrium, these bound aldehydes might be released over time, causing stale flavor. This review discusses beer aging and the role of aldehydes, focusing on both sensory and chemical aspects. Several aldehyde formation pathways are taken into account, as well as aldehyde binding in and release from imine and bisulfite adducts.
    Journal of Agricultural and Food Chemistry 11/2012; 60(46). DOI:10.1021/jf303670z · 3.11 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The antioxidant properties of various kinds of beers were investigated using electron paramagnetic resonance (EPR) spectroscopy. This was possible by measuring the changes in the intensity of the EPR spectrum that resulted from the interaction of the stable radical DPPH (1,1-diphenyl-2-picrylhydrazyl) with the antioxidants found in a beer sample. The antioxidant capacity was then presented in Trolox Equivalents, e.g. μM trolox in a beer sample of 100ml. The influence of the type, colour, the content of the extract and alcohol on the antioxidant activities of commercial beer samples was investigated using two-way hierarchical clustering and analysis of variance. The results showed that all of the beers investigated exhibit antioxidant properties. By performing an analysis of variance, it was found that the value of the antioxidant capacity significantly (0.05 level of significance) depends on the content of the extract and the colour of the beer. It seems that additives also influence the antioxidant properties to some extent, but neither the alcohol content nor the kind of fermentation affects the antioxidant properties of beer.
    Food Chemistry 12/2013; 141(3):3042-9. DOI:10.1016/j.foodchem.2013.05.133 · 3.26 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Sahti, a strong, unhopped farmhouse beer flavoured with juniper is still actively brewed in rural areas in Finland. Presented here is the first comprehensive analysis of the physical and chemical properties of this unique beer style. Twelve sahti samples from the southwest of Finland were analysed and while properties varied, the beers generally had high levels of alcohol (mean = 7.9% ABV) and high residual extract (mean =
    Journal- Institute of Brewing 01/2015; 121(4). · 0.84 Impact Factor