title: Tracing flavonoid degradation in grapes by MS filtering with stable isotopes.
abstract: Anthocyanin degradation has been proposed as one of the primary causes for reduced colour and quality in red wine grapes grown in a warm climate. To study anthocyanin degradation we infused berries with L-phenyl-(13)C₆-alanine and then tracked the fate of the anthocyanins comparing normal (25 °C) and warm (45 °C) temperature conditions. An untargeted metabolomics approach was aided by filtering the MS data using software algorithms to extract all M and M+6 isotopic peak pairs, allowing the analysis to focus solely on the metabolites of phenylalanine. A paired-comparison t-test was performed over the 8 biological replicates revealing 13 metabolites that were statistically different between 25 °C and 45 °C treatments. Most of these features had lower abundances in 45 °C samples, confirming that 45 °C treatment caused anthocyanin degradation. In addition, resveratrol was significantly reduced following heat treatment. However, 5 metabolites increased following the 45 °C treatment. These unidentified metabolites are therefore suspects for anthocyanin degradation products.
authors: Department of Viticulture and Enology, University of California Davis, Davis, CA 95616, USA.
authors: Alexander W
authors: AW
authors: Chassy
authors: Department for Agrobiotechnology (IFA-Tulln), Center for Analytical Chemistry, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Str. 20, 3430 Tulln, Austria.
authors: Christoph
authors: C
authors: Bueschl
authors: Department of Food Science and Technology, University of California Davis, Davis, CA 95616, USA.
authors: Hyeyoung
authors: H
authors: Lee
authors: Department of Viticulture and Enology, University of California Davis, Davis, CA 95616, USA.
authors: Larry
authors: L
authors: Lerno
authors: Department of Viticulture and Enology, University of California Davis, Davis, CA 95616, USA.
authors: Anita
authors: A
authors: Oberholster
authors: Department of Food Science and Technology, University of California Davis, Davis, CA 95616, USA.
authors: Daniela
authors: D
authors: Barile
authors: Department for Agrobiotechnology (IFA-Tulln), Center for Analytical Chemistry, University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Str. 20, 3430 Tulln, Austria.
authors: Rainer
authors: R
authors: Schuhmacher
authors: Department of Viticulture and Enology, University of California Davis, Davis, CA 95616, USA. Electronic address: alwaterhouse@ucdavis.edu.
authors: Andrew L
authors: AL
authors: Waterhouse
mesh_terms: D000872:Anthocyanins / Q000032:analysis; D005638:Fruit / Q000737:chemistry*; D007554:Isotopes / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D055432:Metabolomics / Q000379:methods*; D027843:Vitis / Q000737:chemistry*
chemical_list: D000872:Anthocyanins; D007554:Isotopes
keywords: Anthocyanin degradation; Isotope tracer; Malvidin 3-(6″-acetylglucoside) (PubChem CID: 72193646); Malvidin 3-(6″-p-coumarylglucoside) (PubChem CID: 72193651); Malvidin-3-glucoside (PubChem CID: 443652); Metabolomics; Petunidin 3-glucoside (PubChem CID: 443651); Phenylpropanoid; Quercetin 3′-O-glucoside (PubChem CID: 54758678); Resveratrol (PubChem CID: 445154); Scirpusin A (PubChem CID: 5458896)