کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7584585 | 1492026 | 2018 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Enantiomeric ratios of 2-methylbutanoic acid and its methyl ester: Elucidation of novel biogenetic pathways towards (R)-methyl 2-methylbutanoate in a beverage fermented with shiitake
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
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چکیده انگلیسی
Up to 35% of (R)-methyl 2-methylbutanoate (M2MB) was observed in a beverage fermented with shiitake. As M2MB naturally occurs typically in high excesses of the (S)-enantiomer, the origin of the (R)-ester was elucidated by stable isotope labeled precursor-feeding studies. (R)-2-Methylbutanoic acid was identified as the main precursor in the substrate wort. Trace amounts of (R)-M2MB were produced by transformation of unsaturated secondary metabolites (tiglic aldehyde and tiglic acid) derived from l-isoleucine. Surprisingly, shiitake esterified (R)-2-methylbutanoic acid faster to (R)-M2MB than the corresponding (S)-enantiomer. Concurrently, spontaneous non-enantioselective degradation of M2MB occurred in shiitake. This explains diverse enantiomeric ratios of M2MB and different enantiomeric ratios of 2-methylbutanoic acid and M2MB in the beverage. As the odor threshold values of (R)-and (S)-M2MB differ significantly, these findings are of high relevance for the overall flavor of the fermented beverage and elucidate the discrepancy of enantiomeric ratios of 2-alkyl-branched acids and esters reported in nature.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Food Chemistry - Volume 266, 15 November 2018, Pages 475-482
Journal: Food Chemistry - Volume 266, 15 November 2018, Pages 475-482
نویسندگان
Yanyan Zhang, Marco Alexander Fraatz, Florian Birk, Marina Rigling, Andreas Hammer, Holger Zorn,