Assessment of amino acids and total soluble solids in intact grape berries using contactless Vis and NIR spectroscopy during ripening

The amino acid concentration assessment along grape ripening would provide valuable information regarding harvest scheduling, wine aroma potential and must nitrogen supplement addition. In this work the use of Visible (Vis) and near-infrared (NIR) spectroscopy to estimate the grape amino acid content along maturation on intact berries was investigated. Spectral data on two ranges (570–1000 and 1100–2100 nm) were acquired contactless from intact Grenache berries. A total of 22 free amino acids in 128 grape clusters were quantified by HPLC. Partial least squares was used to build calibration, cross validation and prediction models. The best performances (R2P ~ 0.60) were found for asparagine (SEP: 0.45 mg N/l), tyrosine (SEP: 0.33 mg N/l) and proline (SEP: 17.5 mg N/l) in the 570–1000 nm range, and for lysine (SEP: 0.44 mg N/l), tyrosine (SEP: 0.26 mg N/l), and proline (SEP: 15.54 mg N/l) in the 1100–2100 nm range. Remarkable models (R2P~0.90, SEP~1.60 ºBrix, and RPD~3.79) were built for total soluble solids in both spectral ranges. Contactless, non-destructive spectroscopy could be an alternative to provide information about grape amino acids composition.

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Bibliographic Details
Main Authors: Fernández-Novales, Juan, Garde-Cerdán, Teresa, Tardáguila, Javier, Gutiérrez-Gamboa, Gastón, Pérez-Álvarez, Eva Pilar
Other Authors: Ministerio de Economía y Competitividad (España)
Format: artículo biblioteca
Language:English
Published: Elsevier 2019-07-01
Subjects:Grape, Amino acids, NIR spectroscopy, Partial least squares, HPLC, Nitrogen, Total soluble solids,
Online Access:http://hdl.handle.net/10261/193841
http://dx.doi.org/10.13039/501100000780
http://dx.doi.org/10.13039/501100003329
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