Imelda Ryona

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We describe an optimized protocol for analysis of the herbaceous smelling 3-alkyl-2-methoxypyrazines (MPs) in whole berries that predicts MPs in resultant red wines. Berries are homogenized by bead-milling with a deuterated standard prior to headspace solid phase microextraction (HS-SPME) and quantification by two-dimensional gas chromatography(More)
The effects of light exposure on 3-isobutyl-2-methoxypyrazine (IBMP) accumulation and degradation in Vitis vinifera L. cv. Cabernet Franc berries were assessed by comparison of shaded and exposed clusters within the same vine throughout a growing season. Twenty-seven vines were shoot-thinned to create regions of high and low cluster-light exposure within(More)
Environmental factors affecting degradation of 3-isobutyl-2-methoxypyrazine (IBMP, "green pepper aroma") in wine grapes (V. vinifera) are widely studied, but the degradation pathway is not defined. We hypothesized that IBMP is demethylated to 3-isobutyl-2-hydroxypyrazine (IBHP) during fruit maturation effectively reversing the final putative step of IBMP(More)
3-Isobutyl-2-hydroxypyrazine (IBHP) is thought to be a key intermediate in both the biosynthesis and degradation of the herbaceous smelling 3-isobutyl-2-methoxypyrazine (IBMP), but its behavior during the growing season is not well understood. First, an improved method for IBHP quantification was developed. A deuterated IBHP standard was added to samples(More)
Despite many benefits including simple point-of-care sample collection, reduced costs, and simplified shipping and storage, dried blood spot (DBS) techniques have faced adoption resistance due to factors such as the hematocrit (Hct) effects and the established preference for bioanalysis of plasma rather than whole blood. One way to potentially circumvent(More)
Analyses of key odorous polyfunctional volatile thiols in wines (3-mercaptohexanol (3-MH), 3-mercaptohexylacetate (3-MHA), and 4-mercapto-4-methyl-2-pentanone (4-MMP)) are challenging due to their high reactivity and ultra-trace concentrations, especially when using conventional gas-chromatography electron impact mass spectrometry (GC-EI-MS). We describe a(More)
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