Skip to main content

Table 2 Top six discriminating wavenumbers, corresponding vibrational modes, and biochemical assignments for the first three LDs as indicated by individual loadings of tomato fruit ripening. (Wavenumber references: [17, 23, 33, 35,36,37])

From: Determination of developmental and ripening stages of whole tomato fruit using portable infrared spectroscopy and Chemometrics

PCA-LDA Loadings

Wavenumber (cm− 1)

Vibrational Mode

Biochemical Assignment

LD1

1719

ν(C=O· · ·H) ester ν(C=O)

Cutin

Pectin, lipid, polysaccharides, phenolic compounds

1603

ν(C-C) aromatic

ν(COO), ν(C=C)

Phenolic compounds

Pectin, lignin

1561

ν(C-C) aromatic

Phenolic compounds

1215

νaPO2

Amide III

Phosphate

Proteins

1156

ν(C-OH)

νa(C-O-C) ester

Cellulose, polysaccharide

Cutin, pectin

1078

ν(C-O), ν(C-C)

ν(C-OH)

νsPO2

Xyloglucan

Oligosaccharide

Phosphate

LD2

1632

ν(C=C) phenolic acid

νs(C-C) ring

Amide I

Phenolic compounds

Cellulose

Proteins

1575

ν(C=N)

ν(C-C) phenyl group

Proteins

Phenolic compounds

1539

Amide II

ν(C=N)

Proteins

Lignin

1504

ν(C=C)

ν(C-H)

Amide II

Lignin

Carotenoid

Protein

1473

δ(CH2) scissoring

Glycerolipids, wax hydrocarbons

1160

νa(C-O-C) ester

ν(C-OH), ν(C-O-C)

Cutin

Cellulose, polysaccharide

LD3

1721

ν(C=O) ester

ν(C=O)

Cutin, pectin

Phenolic compounds, lipids, polysaccharides

1561

ν(C-C) aromatic

Phenolic compounds

1239

Amide III

ν(C-O)

Proteins

Pectin

 

Cellulose / hemicellulose

νaPO2

Phosphate

1218

Amide III

νaPO2

Proteins

Phosphate

1156

νa(C-O-C), ester

ν(C-OH), ν(C-O-C)

Cutin

Polysaccharide, cellulose

1041

ν(C-O), ν(C-C)

ν(O-CH2)

Cellulose

Arabinogalactan