Investigations of the Protective Mechanism of Sulfite Against Beer Staling and Formation of Adducts with<i>Trans</i>-2-Nonenal

Improving beer flavour stability is an important brewing goal. Pilot scale brewing trials (50 L) were performed that focused on the determination of the influence of hop pellet dosage and dosage timing on carbonyl compounds in stored beer. The reducing activity of experimental worts, beers and stored beers appeared to depend on the hop pellet dose. Brews with lower amounts of hop antioxidants showed an enhanced formation of carbonyl compounds over the course of beer storage. A correlation between DPPH reducing activity and the content of some carbonyls, including the important markers 2-furfural and (E)-2-nonenal, was found. Fresh and aged beers hopped by different amounts of hop pellet doses were clearly distinguishable according to their carbonyl content using Cluster analysis. Results of the sensorial analysis corresponded to the analytical criteria values. Results of this study bring further evidence of the indispensable impact of hop antioxidants on the suppression of undesirable carbonyl compound formation in the course of beer staling, which can be significant in beers hopped by aroma hops. However, hop antioxidants are only one of many factors affecting beer staling.

Section: Resultsmentioning

confidence: 99%

The Influence of Hopping on Formation of Carbonyl Compounds During Storage of Beer

Mikyška

Krofta

Hašková

et al. 2011

“…The PLS regression coefficients contribution of E-2-nonenal suggests that the use of this compound, as a quality control marker for stale character, is justified 7,8,11,12,18 . From this model the suggestion is that 5-HMF is also a staling marker 13 although it may also contribute to character, as in European lagers where 5-HMF concentrations of 0.5-4.0 ppm are typical, with 71.5 ppm reported in a German dark beer 2 .…”

Section: Discussionmentioning

confidence: 96%

“…These originate from Strecker degradations of amino acids, melanoidin-mediated oxidations of higher alcohols, lipid breakdown and aldol condensations of short and secondary oxidation of longer aldehydes 2,18 . Trans-2-nonenal is often considered central to staling and reported to confer "cardboard" notes 7,8,11,12,18 but previous multivariate modelling 3 suggested limited contributions. Moreover, 5-hydroxymethylfurfural (5-HMF) is also thought to be important 3,13 and other aldehydes reported to have influence include furfural 2,3,17,18 , acetal 3 , 2-furfuryl ethyl ether 5,11 and hexanal 18 .…”

Section: Introductionmentioning

confidence: 99%

“…Trans-2-nonenal is often considered central to staling and reported to confer "cardboard" notes 7,8,11,12,18 but previous multivariate modelling 3 suggested limited contributions. Moreover, 5-hydroxymethylfurfural (5-HMF) is also thought to be important 3,13 and other aldehydes reported to have influence include furfural 2,3,17,18 , acetal 3 , 2-furfuryl ethyl ether 5,11 and hexanal 18 . Quantifying such aldehydes in lager can be a challenge and solid-phase microextraction (SPME) has advantages in minimising solvent use whilst providing high sensitivity and reproducibility.…”

Section: Introductionmentioning

confidence: 99%

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Relationship of Sensory Staleness in Two Lagers to Headspace Concentrations oftrans-2-Nonenal and Three Staling Aldehydes

Techakriengkrai

Paterson

Taidi³

2006

Key compounds in lager staling include furfural, hexanal, 5-hydroxymethyl furfural (5-HMF), and trans-2-nonenal. Quantitative data of headspace concentration in two lagers -one premium at 5% (abv), the other a standard product at 4% (abv) -were obtained by solid phase microextraction (SPME) followed by gas chromatography using a mass selective detector (GCMS). The concentrations of the aldehydes were used to predict overall stale scoring from sensory assessor data, of lagers stored at 4, 12, 30, and 37°C for 7, 14, 21 and 28 days. Concentrations of all four aldehydes increased with time of storage and with higher temperatures. Correlation coefficients for prediction of staleness in the premium lager were similar at 0.81 and 0.84 for partial least square regression (PLS1) and artificial neural network (ANN) modelling respectively, and the latter showed a lower root mean square error (RMS error). For the standard product, the correlation coefficients were 0.72 and 0.86, with ANN showing lower RMS error respectively. In both PLS models, E-2-nonenal had high regression coefficients and 5-HMF lower coefficients. Furfural and hexanal differed in contributions to the lagers.

“…Sulphite is usually also considered to prevent the oxidative staling. of beer 17,31,34 . Sulphite is produced by yeast during fermentation 4,33 .…”

Section: -2863(9'8-32mentioning

confidence: 99%

The Role of Malt and Hop Polyphenols in Beer Quality, Flavour and Haze Stability

Mikyška

Hrabák

Hašková

et al. 2002

Pilot-scale brewing trials of a 12°P pale lager beer were conducted to look at the effect of a modified dose of hop and malt polyphenols on haze, flavour quality, and stability. Results confirmed that malt polyphenols, and particularly hop polyphenols, in the course of wort boiling, improved reducing activity values and the carbonyl content in fresh and stored beers. Hop polyphenols significantly increased reducing activity and decreased the formation of carbonyls (TBA value) in fresh and stored beer. Reduced content of malt polyphenols, combined with the use of hop CO 2 extract, caused an increase in the TBA value in beer. PVPP stabilized beers tended to be lower in reducing activity. Both malt and hop polyphenols affected the intensity of "harsh taste" in fresh beers and a significant influence from PVPP stabilization of beer was not observed. The staling degree of forcedaged beers depended on the polyphenol content in the brewhouse. Both hop and malt polyphenols had a positive impact on flavour stability. PVPP treatment of beer had a positive effect on the flavour stability of heat-aged beers. Polyphenols, especially hop polyphenols, slowed down flavour deterioration during the nine month storage period, but the primary effect was seen during the first four months of storage. Storage trials did not show any unambiguous effects for PVPP stabilization on beer flavour stability. Results confirmed the negative impact of malt and hop polyphenols on haze stability, and PVPP stabilization minimized differences in shelf life prediction values between beers prepared with the modified dose of polyphenols.