Thresholds for Botrytis bunch rot contamination of Chardonnay grapes based on the measurement of the fungal sterol, ergosterol

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Abstract

Background and Aims: The threshold for Botrytis contamination of winegrapes is not fully known. Using a measurement of the fungal sterol, ergosterol, we aimed to understand how much grey mould of grapes can be tolerated before there is a
perceivable impact on wine sensory characteristics.
Methods and Results: Chardonnay grape bunches hand-harvested in January 2016 from the Hunter Valley, NSW, were divided into one of five groups based on the visual assessment of the severity of grey mould using a scale of 0–4. Ergosterol analysis indicated that the fungal biomass of the five batches of grapes was 0.06, 0.28, 0.87, 1.50 and 4.25 g dry mass of fungus
per kg wet mass. Grey mould infection resulted in an elevated concentration of benzaldehyde, 2-pentyl furan, ethyl linoleate,
(E)-3-hexenol, 3-octanol, 1,5-dimethyl-naphthalene, 1,5-dimethyl tetralin 1-octen-3-ol, 1-octen-3-one and 3-octanone in the juice. 1-Octen-3-ol, and 3-octanone, ethyl-3-hydroxydodecanoate and isoamyl acetamide were elevated in wine made with Botrytis-affected grapes. Sensory discrimination tests identified a difference between wine made from grapes with ≥0.87 g of dry mass of fungus/kg wet mass of grapes (equivalent to ≥2.57 mg ergosterol/kg grapes) and wine made from asymptomatic grapes.
Conclusions: Ergosterol correlated with the degree of grey mould contamination and the threshold in Chardonnay grapes was 0.28–0.87 g dry mass fungus/kg fresh mass of grapes. Significance of the Study: Measurement of ergosterol has been evaluated as a quantitative estimate of the threshold for Botrytis contamination of winegrapes.
Original languageEnglish
Pages (from-to)79-89
Number of pages10
JournalAustralian Journal of Grape and Wine Research
Volume26
Publication statusPublished - 2020

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Botrytis
ergosterol
sterols
grapes
wines
octenol
acetamides
octanol
fungi
benzaldehyde
naphthalene
furans
sensory properties
juices
hands
valleys
gray mold

Cite this

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title = "Thresholds for Botrytis bunch rot contamination of Chardonnay grapes based on the measurement of the fungal sterol, ergosterol",
abstract = "Background and Aims: The threshold for Botrytis contamination of winegrapes is not fully known. Using a measurement of the fungal sterol, ergosterol, we aimed to understand how much grey mould of grapes can be tolerated before there is aperceivable impact on wine sensory characteristics.Methods and Results: Chardonnay grape bunches hand-harvested in January 2016 from the Hunter Valley, NSW, were divided into one of five groups based on the visual assessment of the severity of grey mould using a scale of 0–4. Ergosterol analysis indicated that the fungal biomass of the five batches of grapes was 0.06, 0.28, 0.87, 1.50 and 4.25 g dry mass of fungusper kg wet mass. Grey mould infection resulted in an elevated concentration of benzaldehyde, 2-pentyl furan, ethyl linoleate,(E)-3-hexenol, 3-octanol, 1,5-dimethyl-naphthalene, 1,5-dimethyl tetralin 1-octen-3-ol, 1-octen-3-one and 3-octanone in the juice. 1-Octen-3-ol, and 3-octanone, ethyl-3-hydroxydodecanoate and isoamyl acetamide were elevated in wine made with Botrytis-affected grapes. Sensory discrimination tests identified a difference between wine made from grapes with ≥0.87 g of dry mass of fungus/kg wet mass of grapes (equivalent to ≥2.57 mg ergosterol/kg grapes) and wine made from asymptomatic grapes.Conclusions: Ergosterol correlated with the degree of grey mould contamination and the threshold in Chardonnay grapes was 0.28–0.87 g dry mass fungus/kg fresh mass of grapes. Significance of the Study: Measurement of ergosterol has been evaluated as a quantitative estimate of the threshold for Botrytis contamination of winegrapes.",
keywords = "Disease threshold, fungal taints, grey mould, sterol, wine sensory characteristics",
author = "Christopher Steel and John Blackman and Leigh Schmidtke and Andrew Clark and Claudia Schueuermann and Lachlan Schwarz and Yu Qiu",
year = "2020",
language = "English",
volume = "26",
pages = "79--89",
journal = "Australian Journal of Grape and Wine Research",
issn = "1322-7130",
publisher = "Wiley-Blackwell",

}

TY - JOUR

T1 - Thresholds for Botrytis bunch rot contamination of Chardonnay grapes based on the measurement of the fungal sterol, ergosterol

AU - Steel, Christopher

AU - Blackman, John

AU - Schmidtke, Leigh

AU - Clark, Andrew

AU - Schueuermann, Claudia

AU - Schwarz, Lachlan

AU - Qiu, Yu

PY - 2020

Y1 - 2020

N2 - Background and Aims: The threshold for Botrytis contamination of winegrapes is not fully known. Using a measurement of the fungal sterol, ergosterol, we aimed to understand how much grey mould of grapes can be tolerated before there is aperceivable impact on wine sensory characteristics.Methods and Results: Chardonnay grape bunches hand-harvested in January 2016 from the Hunter Valley, NSW, were divided into one of five groups based on the visual assessment of the severity of grey mould using a scale of 0–4. Ergosterol analysis indicated that the fungal biomass of the five batches of grapes was 0.06, 0.28, 0.87, 1.50 and 4.25 g dry mass of fungusper kg wet mass. Grey mould infection resulted in an elevated concentration of benzaldehyde, 2-pentyl furan, ethyl linoleate,(E)-3-hexenol, 3-octanol, 1,5-dimethyl-naphthalene, 1,5-dimethyl tetralin 1-octen-3-ol, 1-octen-3-one and 3-octanone in the juice. 1-Octen-3-ol, and 3-octanone, ethyl-3-hydroxydodecanoate and isoamyl acetamide were elevated in wine made with Botrytis-affected grapes. Sensory discrimination tests identified a difference between wine made from grapes with ≥0.87 g of dry mass of fungus/kg wet mass of grapes (equivalent to ≥2.57 mg ergosterol/kg grapes) and wine made from asymptomatic grapes.Conclusions: Ergosterol correlated with the degree of grey mould contamination and the threshold in Chardonnay grapes was 0.28–0.87 g dry mass fungus/kg fresh mass of grapes. Significance of the Study: Measurement of ergosterol has been evaluated as a quantitative estimate of the threshold for Botrytis contamination of winegrapes.

AB - Background and Aims: The threshold for Botrytis contamination of winegrapes is not fully known. Using a measurement of the fungal sterol, ergosterol, we aimed to understand how much grey mould of grapes can be tolerated before there is aperceivable impact on wine sensory characteristics.Methods and Results: Chardonnay grape bunches hand-harvested in January 2016 from the Hunter Valley, NSW, were divided into one of five groups based on the visual assessment of the severity of grey mould using a scale of 0–4. Ergosterol analysis indicated that the fungal biomass of the five batches of grapes was 0.06, 0.28, 0.87, 1.50 and 4.25 g dry mass of fungusper kg wet mass. Grey mould infection resulted in an elevated concentration of benzaldehyde, 2-pentyl furan, ethyl linoleate,(E)-3-hexenol, 3-octanol, 1,5-dimethyl-naphthalene, 1,5-dimethyl tetralin 1-octen-3-ol, 1-octen-3-one and 3-octanone in the juice. 1-Octen-3-ol, and 3-octanone, ethyl-3-hydroxydodecanoate and isoamyl acetamide were elevated in wine made with Botrytis-affected grapes. Sensory discrimination tests identified a difference between wine made from grapes with ≥0.87 g of dry mass of fungus/kg wet mass of grapes (equivalent to ≥2.57 mg ergosterol/kg grapes) and wine made from asymptomatic grapes.Conclusions: Ergosterol correlated with the degree of grey mould contamination and the threshold in Chardonnay grapes was 0.28–0.87 g dry mass fungus/kg fresh mass of grapes. Significance of the Study: Measurement of ergosterol has been evaluated as a quantitative estimate of the threshold for Botrytis contamination of winegrapes.

KW - Disease threshold

KW - fungal taints

KW - grey mould

KW - sterol

KW - wine sensory characteristics

UR - https://onlinelibrary.wiley.com/doi/10.1111/ajgw.12417

M3 - Article

VL - 26

SP - 79

EP - 89

JO - Australian Journal of Grape and Wine Research

JF - Australian Journal of Grape and Wine Research

SN - 1322-7130

ER -