Quantification of free sugars, fructan, pungency and sweetness indices in onion populations by FT-MIR spectroscopy.
J Sci Food Agric
; 98(14): 5525-5533, 2018 Nov.
Article
em En
| MEDLINE
| ID: mdl-29687887
ABSTRACT
BACKGROUND:
To facilitate faster phenotyping of onions (Allium cepa L.), Fourier-transform mid infrared (FT-MIR) spectroscopy with partial least squares (PLS) regression modelling was evaluated for the determination of pungency (pyruvate), sweetness (free sugars) and fructan in juice samples (n = 605) expressed from bulbs from breeding populations.RESULTS:
Fourier-transform infrared (FTIR) spectra (range 1700-900 cm-1 ) were obtained from droplets (30 µL) of unprocessed juice. Goodness-of-fit (r2 ) and prediction errors (standard error of cross validation) for optimal PLS models were soluble solids (0.997, 0.1 °Brix), pyruvate [0.825, 0.8 µmol g-1 fresh weight (FW)], fructan (0.98, 1.9 mg g-1 FW), glucose (0.941, 1.1 mg g-1 FW), fructose (0.967, 1.0 mg g-1 FW) and sucrose (0.919, 1.7 mg g-1 FW). FTIR models for industry sweetness indices based on glucose or sucrose equivalents were also developed. Because of its very low concentration (0.8-12 µmol g-1 FW) relative to other compounds, pyruvate was the weakest model developed. Fructan could be determined spectroscopically without the need for enzymatic digestion.CONCLUSIONS:
All of the chemometric models developed are acceptable for screening purposes. Those for soluble solids, fructan and fructose are also suitable for routine analysis. FT-MIR can therefore be utilised for the simultaneous determination of pungency, sweetness and fructan in this crop. © 2018 Society of Chemical Industry.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Espectroscopia de Infravermelho com Transformada de Fourier
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Cebolas
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Açúcares
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Aromatizantes
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Frutanos
Tipo de estudo:
Evaluation_studies
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Prognostic_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article