The importance of the furanones HDMF and HEMF in the flavour profile of Japanese barley miso and their production during fermentation

There have been limited studies on the flavour compounds in Chinese soy sauces. In order to obtain wider information about the chemical composition of the volatile fractions in 12 brands of Chinese soy sauces produced by high-salt-diluted state fermentation (HSDSF) and to compare them, a headspace solid microextraction method coupled to gas chromatography-mass spectrometry (HS-SPME-GC-MS) method was proposed and developed. A 50/30μm Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS) fibre was used for extraction of volatiles. The adsorption time and temperature of the SPME fibre were optimized separately for various aroma compounds in the soy sauce (50°C and 40 min for alcohols and esters; 40°C and 50 min for ketones, aldehydes and pyrazines; 60°C and 50 min for acids, phenols and furans). From the study, a total of 80 compounds were identified in the 12 samples, of which 34 volatiles were in common. Alcohols and acids were the main volatiles present in the soy sauces. Dominant volatile alcohols were ethanol, 2/3-methyl butanol and β-phenylethyl alcohol; and important acids were acetic acid, butanoic acid, and 3-methylbutanoic acid. Miscellaneous, esters, furans and phenols also made large contributions to the total volatiles of the soy sauces. According to the scatter point plot obtained from principal component analysis, the 12 soy sauces could be classified into four groups.

Section: Furanssupporting

confidence: 93%

Section: Furansmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Profile of Volatile Compounds in 12 Chinese Soy Sauces Produced by a High-Salt-Diluted State Fermentation

Sun

Jiang²,

Zhao

2010

“…EMHF arises similarly, but with the addition of a C 2 fragment arising from alanine 18 . DMHF also occurs naturally in fruits, for example strawberries 17 and pineapples 11 and in the fermented products soy sauce 10 and miso 4 which also contain high levels of EMHF 4,10 . During fermentation yeast is thought to transform Maillard intermediates to DMHF and EMHF rather than make direct use of sugars and amino acids 5,12 .…”

Section: -2863(9'8-32mentioning

confidence: 99%

“…With only the one exception of the maize wort, MHF content decreased after fermentation. This result was to be expected as this furanone is a product of the Maillard reaction but not of yeast metabolism 4 . At its highest, MHF was found at only one fifth of its aroma threshold in water and is therefore unlikely to play an important role in the flavour of beer.…”

Section: *Ivqirxexmsrmentioning

confidence: 99%

Formation of 4-Hydroxyfuranones and their Precursors during Production of Worts and Beers

Mackie

Slaughter

2002

Laboratory beers and samples taken at each stage of production, were analysed for the flavour active 4-hydroxyfuranones; 5-methyl-4-hydroxy-3(2H)-furanone (MHF), 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) and 5-(or 2)-ethyl-2(or 5)-methyl-4-hydroxy-3(2H)-furanone (EMHF). The length and temperature of mashing, the length of boiling, the rate of cooling the worts and the effects of grist composition were investigated to identify the 4-hydroxyfuranone content of worts and subsequent beers. Fermentation temperature and the use of the stabilising agents, PVPP and Lucilite PC5, on the 4-hydroxyfuranone content of the beer was also investigated. The results demonstrated that several aspects of beer production procedures affect the furanone content of the beer, but in practice the important factors are grist composition, the rate at which the boiled wort is cooled and fermentation temperature. Fermentation has a major effect on final furanone content as yeast produces both DMHF and EMHF. The results suggest that malt levels of precursor compounds, which can be converted to 4-hydroxyfuranones by the Maillard reaction or by yeast, may prove to be more important than the quantities of the furanones found in malt in determining the final furanone content of beer. A clearer understanding of the nature of the precursors should allow manipulation of their production and beer furanone content.

The Contribution of 4-Hydroxyfuranone Derivatives to the Aroma of Commercial Beers and Malts

Mackie

Slaughter

2000

Analysis of hot water extracts from a range of commercial malts showed that 2,5-dimethyl-4-hydroxy-3(2H)furanone (DMHF) varied from undetectable (lager malt) to 4.2 mg/litre (crystal malt), a concentration twenty-six times the flavour threshold in water. 5-Methyl-4-hydroxy-3 (2H)furanone (MHF) was detected in all samples except one but was always well under its flavour threshold value. 2(or 5)-Ethyl-5(or 2)-methyl-4-hydroxy-3(2H)furanone (EMHF) was not detected in any of the samples. Fermentation of lager, ale and crystal malt extracts with an ale strain of yeast led to the appearance of EMHF in all cases as well as additional DMHF. Tlie greatest increases in both compounds was with the ale malt. Both increases and decreases occurred in MHF concentration as a result of fermentation but final levels were always well below the flavour threshold value. Analysis often commercial beers found DMHF in all the samples and in five cases levels exceeded twice the flavour threshold value in beer with flavour units from 2.4 to 9.1. A flavour panel noted that in four of these cases the beer had a distinctly sweet/caramel aroma which is hjpical of DMHF. EMHF was undetectable in six samples, detectable, but unquantifiable, in three cases but at about 80% of the flavour threshold value in the remaining sample. MHF was found in all samples but at insignificant levels. Tlte results show that DMHF is an important flavour compound in British ales and EMHF may make a contribution in a limited number of situations. The contribution of malt type, brewery processing and yeast strain in determining the concentration of the two 4-hydroxyfiiranones in beer remains uncertain.Key Words: Malt, flavour, 4-hydroxyfuranones, beer. The Contribution of 4-Hydroxyfuratwne Derivatives heated foods but this does not seem to be true for EMHF.This compound appears to always be a product of yeast fermentation and, in some situations, additional amounts of DMHF can also be produced by fermentation10-11.The importance of DMHF in the flavour of lager, particularly dark lager, has been established using the aroma extract dilution technique31. Both DMHF and EMHF have been found in Japanese beers but, on the basis of taste panel work, DMHF appeared to be the main contributer to the sweet flavour in the beers tested27. MHF has not been reported at significant levels in malt or beer. These results indicate a role for DMHF, and possibly EMHF, in the flavour of beer in general and it appears likely that they may be particularly significant in UK ales where a sweet/caramel note is often a major aspect of the overall flavour.The present work was undertaken to clarify the significance of 4-hydroxyfuranones in the flavour profile of commercial British malts and beers. METHODS AND MATERIALS Preparation of malt hot water extractsThe malts used, ale, lager, high enzyme, wheat and crystal were obtained from a commercial maltings. Malt Measurement of colourThe colour of both hot water extracts and beers was measured spectrophotometrically using the IoB recommended method...