scholarly journals Glucosylation of 4-Hydroxy-2,5-Dimethyl-3(2H)-Furanone, the Key Strawberry Flavor Compound in Strawberry Fruit

2016 ◽  
Vol 171 (1) ◽  
pp. 139-151 ◽  
Author(s):  
Chuankui Song ◽  
Xiaotong Hong ◽  
Shuai Zhao ◽  
Jingyi Liu ◽  
Katja Schulenburg ◽  
...  
Keyword(s):  
Strawberry Fruit ◽  
Flavor Compound ◽  
Strawberry Flavor

scholarly journals Structural Basis for the Enzymatic Formation of the Key Strawberry Flavor Compound 4-Hydroxy-2,5-dimethyl-3(2H)-furanone

2013 ◽  
Vol 288 (23) ◽  
pp. 16815-16826 ◽  
Author(s):  
André Schiefner ◽  
Quirin Sinz ◽  
Irmgard Neumaier ◽  
Wilfried Schwab ◽  
Arne Skerra
Keyword(s):  
Crystallographic Analysis ◽  
Structural Basis ◽  
Exocyclic Double Bond ◽  
Dependent Manner ◽  
Deuterium Labeling ◽  
Quinone Oxidoreductase ◽  
Chiral Phase ◽  
Flavor Compound ◽  
Substrate Analogs ◽  
Strawberry Flavor

The last step in the biosynthetic route to the key strawberry flavor compound 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) is catalyzed by Fragaria x ananassa enone oxidoreductase (FaEO), earlier putatively assigned as quinone oxidoreductase (FaQR). The ripening-induced enzyme catalyzes the reduction of the exocyclic double bond of the highly reactive precursor 4-hydroxy-5-methyl-2-methylene-3(2H)-furanone (HMMF) in a NAD(P)H-dependent manner. To elucidate the molecular mechanism of this peculiar reaction, we determined the crystal structure of FaEO in six different states or complexes at resolutions of ≤1.6 Å, including those with HDMF as well as three distinct substrate analogs. Our crystallographic analysis revealed a monomeric enzyme whose active site is largely determined by the bound NAD(P)H cofactor, which is embedded in a Rossmann-fold. Considering that the quasi-symmetric enolic reaction product HDMF is prone to extensive tautomerization, whereas its precursor HMMF is chemically labile in aqueous solution, we used the asymmetric and more stable surrogate product 2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone (EHMF) and the corresponding substrate (2E)-ethylidene-4-hydroxy-5-methyl-3(2H)-furanone (EDHMF) to study their enzyme complexes as well. Together with deuterium-labeling experiments of EDHMF reduction by [4R-2H]NADH and chiral-phase analysis of the reaction product EHMF, our data show that the 4R-hydride of NAD(P)H is transferred to the unsaturated exocyclic C6 carbon of HMMF, resulting in a cyclic achiral enolate intermediate that subsequently becomes protonated, eventually leading to HDMF. Apart from elucidating this important reaction of the plant secondary metabolism our study provides a foundation for protein engineering of enone oxidoreductases and their application in biocatalytic processes.

scholarly journals FaQR, Required for the Biosynthesis of the Strawberry Flavor Compound 4-Hydroxy-2,5-Dimethyl-3(2H)-Furanone, Encodes an Enone Oxidoreductase

2006 ◽  
Vol 18 (4) ◽  
pp. 1023-1037 ◽  
Author(s):  
Thomas Raab ◽  
Juan Antonio López-Ráez ◽  
Dorothée Klein ◽  
Jose Luis Caballero ◽  
Enriqueta Moyano ◽  
...  
Keyword(s):  
Flavor Compound ◽  
Strawberry Flavor

744 PB 076 IDENTIFICATION OF BOTH ACID AND NEUTRAL INVERTASE ACTIVITY IN DEVELOPING STRAWBERRY FRUIT

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 539f-539
Author(s):  
Kirk W. Pomper ◽  
Patrick J. Breen
Keyword(s):  
Extraction Procedure ◽  
Invertase Activity ◽  
Assimilate Transport ◽  
Strawberry Fruit ◽  
Fruit Extracts ◽  
Neutral Invertase ◽  
Optimum Ph ◽  
Cold Acetone ◽  
Ripe Stage ◽  
Sugar Levels

Invertase (INV) may influence sugar levels and assimilate transport in strawberry fruit. Several groups, including our own, have only detected acid INV (optimum pH 4.6) in strawberry fruit, however, recently Hubbard et al. (Physiol. Plant. 82:191-196, 1991) reported the presence of a neutral INV (pH 7.5). Since dissimilar isolation protocols may have contributed to the different findings, we re-examined our work with developing `Brighton' strawberry using the extraction procedure of Hubbard et al. Neutral INV activity per gFW (pH 7.5-8.0) increased many fold as fruit developed from green to the red ripe stage. Acid INV activity decreased markedly from green-white to the red stage. In addition, when fruit extracts were precipitated with cold acetone, a pellet contained 60% of the acid INV activity, and a surface coagulation of protein contained 60% of the neutral INV activity. This allowed easy separation of these two enzymes. Extraction methodologies affect isolation of neutral INV activity from strawberry fruit.

scholarly journals Sensing when the wall comes tumbling down

2020 ◽  
Vol 71 (22) ◽  
pp. 6865-6868
Author(s):  
David A Brummell
Keyword(s):  
Fruit Softening ◽  
Strawberry Fruit ◽  
Experimental Botany

This article comments on: Paniagua C, Ric-Varas P, Garcia-Gago JA, López-Casado G, Blanco-Portales R, Muñoz-Blanco J, Schückel J, Knox JP, Matas AJ, Quesada MA, Posé S, Mercado JA. 2020. Elucidating the role of polygalacturonase genes in strawberry fruit softening. Journal of Experimental Botany 71, 7103–7117.

scholarly journals An ADH toolbox for raspberry ketone production from natural resources via a biocatalytic cascade

2021 ◽  
Author(s):  
Aileen Becker ◽  
Dominique Böttcher ◽  
Werner Katzer ◽  
Karsten Siems ◽  
Lutz Müller-Kuhrt ◽  
...  
Keyword(s):  
Alcohol Dehydrogenase ◽  
Genetically Modified Organisms ◽  
Optical Purity ◽  
High Yield ◽  
Alcohol Dehydrogenases ◽  
Flavor Compound ◽  
Raspberry Ketone ◽  
Cofactor Recycling ◽  
Cosmetic Industry ◽  
Key Points

Abstract Raspberry ketone is a widely used flavor compound in food and cosmetic industry. Several processes for its biocatalytic production have already been described, but either with the use of genetically modified organisms (GMOs) or incomplete conversion of the variety of precursors that are available in nature. Such natural precursors are rhododendrol glycosides with different proportions of (R)- and (S)-rhododendrol depending on the origin. After hydrolysis of these rhododendrol glycosides, the formed rhododendrol enantiomers have to be oxidized to obtain the final product raspberry ketone. To be able to achieve a high conversion with different starting material, we assembled an alcohol dehydrogenase toolbox that can be accessed depending on the optical purity of the intermediate rhododendrol. This is demonstrated by converting racemic rhododendrol using a combination of (R)- and (S)-selective alcohol dehydrogenases together with a universal cofactor recycling system. Furthermore, we conducted a biocatalytic cascade reaction starting from naturally derived rhododendrol glycosides by the use of a glucosidase and an alcohol dehydrogenase to produce raspberry ketone in high yield. Key points • LB-ADH, LK-ADH and LS-ADH oxidize (R)-rhododendrol • RR-ADH and ADH1E oxidize (S)-rhododendrol • Raspberry ketone production via glucosidase and alcohol dehydrogenases from a toolbox Graphical abstract

scholarly journals Cultivation Conditions Change Aroma Volatiles of Strawberry Fruit

Horticulturae ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 81
Author(s):  
Yunduan Li ◽  
Yuanyuan Zhang ◽  
Xincheng Liu ◽  
Yuwei Xiao ◽  
Zuying Zhang ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Major Contributor ◽  
Fragaria Ananassa ◽  
Strawberry Fruit ◽  
Cultivation Conditions ◽  
Soil Culture ◽  
Aroma Volatiles ◽  
Ms Analysis ◽  
Significant Difference ◽  
Strawberry Cultivars

Volatile compounds principally contribute to flavor of strawberry (Fragaria × ananassa) fruit. Besides to genetics, cultivation conditions play an important role in fruit volatile formation. Compared to soil culture as control, effects of substrate culture on volatile compounds of two strawberry cultivars (‘Amaou’ and ‘Yuexin’) were investigated. GC-MS analysis revealed significant difference in volatile contents of ‘Amaou’ strawberry caused by substrate culture. No significant effect was observed for cultivar ‘Yuexin’. For ‘Amaou’ strawberry from soil culture produced higher volatile contents compared with substrate culture. This difference is contributed by high contents of esters, lactones, ketones, aldehydes, terpenes, hydrocarbons, acids, furans and phenols in ‘Amaou’ strawberry fruit from soil culture. Furanones, beta-linalool, trans-Nerolidol and esters are major contributor to strawberry aroma, whose contents are higher in soil culture planted fruit when compared to substrate culture. Moreover, strawberry fruit from soil culture had higher transcripts related to volatile biosynthesis were observed, including FaQR, FaOMT, FaNES1, FaSAAT and FaAAT2.

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