Sotolon and Madeira XIV Jean De Clerckchair 12-14 September2012 off-flavour in beer Caroline Scholtes PhD Student, brewing department UCLouvain
Contents Sotolon State of the art in food chemistry In alcoholic beverages New insights Madeira off-flavour in beer Context of this study Evolution of sotolon concentrations during aging for a panel of beers Evidence of efficient pathways in beer Perspectives XIV Jean De Clerckchair 12-14
Sotolon H state of the art in food chemistry
Significantcontribution to variousfoodand beverages flavours Madeirised, burnt, dried fruit, nutty, rancio, curry, spicy, Thr= 8 ppb (in wine(lavigne et al., 2008)) Many precursors described under various conditions Generally results from mild oxydation during aging H
In alcoholic beverages Jura flor-sherry wines, Yellow wines(120 to 268 ppb),sherry (Xeres) Porto, Madeira and other fortified wines H 3 C H 6 yearsand 3 monthsin re-usedoak barrel Development of yeast film (Saccharomyces genus) NH 2 H H 3 C H 3 C Dry white wines + H Agingin woodbarrel oxydative aging conditions (acetaldehyde (Cantarelli, 1967)) H 3 C H 3 C H (Kobayashi et al., 1989) No flor (liquoraddition) no microbialintervention afterthe end of alcoholic fermentation Temperature - residual Maillard reactions sugar content (> 25g/L) (Hofman, T.& Schieberle, P., 1997)
( Perez Locas & Yaylayan, 2004 )
New insights : Dry white wines and citrus soft drinks Vinification conducted under limited oxygen contact No alcohol but citrus essence ethanolic extracts Ascorbic acid degradation (Pons et al., 2010) liberation of high quantities of α-ketobutyric acid Identification of 2 degradation pathways of ascorbic acid leading to sotolon (Koning et al., 1999) (Pons et al., 2007) (Koning et al. 1999)
Madeira flavour In beer
Context of this study (1) In industry: prematureagingof specialtybeers(3-5m) causing off-flavors ( Madeira, nut, curry) Identifiedby GC-MS as sotolon.
Context of this study (2) 160 Analyses of a 6 yearsaged specialty beer Yellow wine! Formation pathways not clear No data about sotolon in beer Concentration of sotolon (ppb) 140 120 100 80 60 40 20 0 6 years Flor Sherry wine
In beer Biochemical origin: Yeast Threonin desamination by saccharomyces Chemical origin: 2 content Low (<0,05 ppm) Diacetyl + amino acids H H H H H Pro-oxydants Ascorbic acid and oxygen radicals Fenton reactions Antioxydants Ascorbic acid S2 Ascorbic acid Polyphenols(catechin, epicatechin) Dehydroascorbic acid
Sulfites Combine to acetaldehyde Blouin (1965) LimitH 2 2 disponibility Combine to α- ketobutyric acid (Kaneda et al., 1999) Pons (2007)
Incriminated compounds in beer : Bio-chemical origin: Refermentation yeast Chemical origin: - Ethanal peroxydation -Ascorbicacid!
Madeira flavour Evolution of sotolon concentrations during aging for a panel of beers
Material : 7 Belgian special beers BL1 BL2 BL3 BL4 Blond AM1 Amber Conventional Triple rganic TR-dh Blond Trappist dry-hopped BR1 Brown Amber Dry-hopped Trappist Brown
Method : 50 ml beer at ph 11,5 + 2g XAD 2 resin, agitation 2h Percolated beer + 50 ml washing resin waters collected and adjusted at ph 3 T.Claes, 2011 L:L extraction with dichloromethane and concentration to 500 µl Extractswereanalysedby GC-MS on FFAP polar column(sim Mode)
Results : 16 14 [sotolon] (ppb) 12 10 8 6 Veryrichin 4 polyphenols & sulfites treatment 2 Ascorbic acid treatment fresh 6 month 0 AM 1 BL 1 BL 2 BL 3 BL 4 TR-dh BR 1 Beer
Results : 25 20 Bottle refermented 15 10 [sotolon] (ppb) 5 0 AM 1 BL 1 BL 2 BL 3 BL 4 TR-dh BR 1 Beer fresh 6 month 1 year
Madeira flavour Evidence of efficient pathways in beer
In beer Biochemical origin: Yeast Threonin desamination by saccharomyces Chemical origin: 2 content Low (<0,05 ppm) Diacetyl + amino acids H H H H H Pro-oxydants Ascorbic acid and oxygen radicals Fenton reactions Antioxydants Ascorbic acid S2 Ascorbic acid Polyphenols(catechin, epicatechin) Dehydroascorbic acid
Sulfites Combine to acetaldehyde Blouin (1965) LimitH 2 2 disponibility Combine to α- ketobutyric acid (Kaneda et al., 1999) Pons (2007)
Incriminated compounds in beer : Bio-chemical origin: Refermentation yeast Chemical origin: - Ethanal peroxydation -Ascorbicacid!
Material : KMS 5mM AA (Ascorbic acid) 5mM Trolox 5mM Fe 2+ 5mM H 2 2 Ageing30 days-40 C
1. xygen 9 8 7 6 5 4 3 Concentration (ppb) 2 1 0 Blanco- no 2 Blanco - 2 Treatment
2. Ascorbicacid 120 100 80 60 Concentration (ppb) 40 20 0 Blanco - 2 AA-2 AA-S2-2 Treatment
3.Pro-oxydant species 700 600 500 400 300 Concentration (ppb) 200 100 0 Blanco - 2 AA-2 AA-Fe-H22-2 Fe-H22-2 Trolox-2 Treatment
Sulfites fight! 120 100 80 60 Concentration (ppb) 40 20 0 Blanco - 2 AA-2 AA-S2-2 Treatment
Perspectives
Assessment of the impact of technological practices on sotolon concentration Determination of the relative contribution of each sotolon synthesis pathway Determination of the impact of yeast strain and yeast metabolism state on sotolon synthesis
Thank you for your attention Thanks to CNSALIM Project and brewers for their kind collaboration!