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Rapid measurement of 3-alkyl-2-methoxypyrazine content of winegrapes to predict levels in resultant wines.
J Agric Food Chem. 2009 Sep 23; 57(18):8250-7.JA

Abstract

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 time-of-flight-mass-spectrometry (GCxGC-TOF-MS). In the case of 3-isopropyl-2-methoxypyrazine (IPMP), GCxGC-TOF-MS successfully resolved interferences that coeluted with the analyte in the first dimension. HS-SPME parameters (pH, queue time, incubation time, extraction time, extraction temperature) were optimized by a statistical experimental design. Good method accuracy was observed (consistent ratio of unlabeled analyte to labeled standard) at 10 min extraction times when 80 degrees C extraction temperatures were employed, although increasing sensitivity was observed for longer extraction times (up to 140 min). Standard addition of 3-isobutyl-2-methoxypyrazine (IBMP) and IPMP into preveraison and harvest ripe berry matrices showed good linearity (r(2) >0.99 in all cases), with limits of detection ranging from 0.6 to 1.8 pg/g. The protocol was validated by comparing IBMP in 16 lots of Cabernet Franc berries (range = undetectable to 18.4 pg/g) to the resulting wines (range = undetectable to 14.5 pg/g). Berry and wine MP content were strongly correlated, (r(2) = 0.97, p < 0.0001). Following correction for CO(2) loss, the observed concentration of IBMP in wines was 67 +/- 13% of the IBMP concentration observed in berries.

Authors+Show Affiliations

Department of Food Science and Technology, Cornell University, Geneva, New York, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19754166

Citation

Ryona, Imelda, et al. "Rapid Measurement of 3-alkyl-2-methoxypyrazine Content of Winegrapes to Predict Levels in Resultant Wines." Journal of Agricultural and Food Chemistry, vol. 57, no. 18, 2009, pp. 8250-7.
Ryona I, Pan BS, Sacks GL. Rapid measurement of 3-alkyl-2-methoxypyrazine content of winegrapes to predict levels in resultant wines. J Agric Food Chem. 2009;57(18):8250-7.
Ryona, I., Pan, B. S., & Sacks, G. L. (2009). Rapid measurement of 3-alkyl-2-methoxypyrazine content of winegrapes to predict levels in resultant wines. Journal of Agricultural and Food Chemistry, 57(18), 8250-7. https://doi.org/10.1021/jf9019695
Ryona I, Pan BS, Sacks GL. Rapid Measurement of 3-alkyl-2-methoxypyrazine Content of Winegrapes to Predict Levels in Resultant Wines. J Agric Food Chem. 2009 Sep 23;57(18):8250-7. PubMed PMID: 19754166.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Rapid measurement of 3-alkyl-2-methoxypyrazine content of winegrapes to predict levels in resultant wines. AU - Ryona,Imelda, AU - Pan,Bruce S, AU - Sacks,Gavin L, PY - 2009/9/17/entrez PY - 2009/9/17/pubmed PY - 2010/1/29/medline SP - 8250 EP - 7 JF - Journal of agricultural and food chemistry JO - J Agric Food Chem VL - 57 IS - 18 N2 - 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 time-of-flight-mass-spectrometry (GCxGC-TOF-MS). In the case of 3-isopropyl-2-methoxypyrazine (IPMP), GCxGC-TOF-MS successfully resolved interferences that coeluted with the analyte in the first dimension. HS-SPME parameters (pH, queue time, incubation time, extraction time, extraction temperature) were optimized by a statistical experimental design. Good method accuracy was observed (consistent ratio of unlabeled analyte to labeled standard) at 10 min extraction times when 80 degrees C extraction temperatures were employed, although increasing sensitivity was observed for longer extraction times (up to 140 min). Standard addition of 3-isobutyl-2-methoxypyrazine (IBMP) and IPMP into preveraison and harvest ripe berry matrices showed good linearity (r(2) >0.99 in all cases), with limits of detection ranging from 0.6 to 1.8 pg/g. The protocol was validated by comparing IBMP in 16 lots of Cabernet Franc berries (range = undetectable to 18.4 pg/g) to the resulting wines (range = undetectable to 14.5 pg/g). Berry and wine MP content were strongly correlated, (r(2) = 0.97, p < 0.0001). Following correction for CO(2) loss, the observed concentration of IBMP in wines was 67 +/- 13% of the IBMP concentration observed in berries. SN - 1520-5118 UR - https://www.unboundmedicine.com/medline/citation/19754166/Rapid_measurement_of_3_alkyl_2_methoxypyrazine_content_of_winegrapes_to_predict_levels_in_resultant_wines_ L2 - https://doi.org/10.1021/jf9019695 DB - PRIME DP - Unbound Medicine ER -