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. 2014 Feb 20;14(2):3528–3542. doi: 10.3390/s140203528

Table 3.

Calibration statistics for quality parameters in wine vinegars.

Parameter Instrument Mathematic treatment Spectral range (nm) Mean 1 SD 2 SECV 3 r 2,4 RPD 5 CV 6
Total acidity (g acetic acid/100 mL vinegar) FNS I 2,5,5,1 SNV + DT 400–2500 9.49 2.07 0.25 0.99 8.35 2.62 *
FNS II 1,5,5,1 None 400–2500 9.50 2.08 0.26 0.98 7.95 2.76
Corona 1,5,5,1 None 500–1690 9.39 2.17 0.29 0.98 7.44 3.12
Fixed acidity (g acetic acid/100 mL vinegar) FNS I 1,10,5,1 SNV + DT 1100–2500 0.24 0.08 0.04 0.79 2.19 15.62 *
FNS II 1,10,5,1 SNV + DT 1100–2500 0.25 0.09 0.04 0.78 2.15 16.70
Corona 2,5,5,1 SNV + DT 500–1690 0.25 0.08 0.05 0.58 1.53 19.77
Volatile acidity (g acetic acid/100 mL vinegar) FNS I 2,5,5,1 SNV + DT 400–2500 9.24 2.03 0.25 0.98 7.99 2.76 *
FNS II 1,5,5,1 None 400–2500 9.11 2.10 0.29 0.98 7.16 3.22
Corona 1,5,5,1 None 500–1690 9.10 2.13 0.31 0.98 6.92 3.38
pH FNS I 1,5,5,1 None 1100–2500 2.82 0.14 0.05 0.85 2.60 1.85 *
FNS II 1,5,5,1 None 400–2500 2.81 0.12 0.05 0.81 2.25 1.95
Corona 1,5,5,1 None 500–1690 2.80 0.13 0.07 0.72 1.89 2.43
Dry extract (g/L and percentage point of acetic acid) FNS I 2,10,5,1 SNV + DT 400–2500 2.33 1.13 0.14 0.99 8.16 5.94
FNS II 1,5,5,1 SNV + DT 1100–2500 2.32 1.12 0.12 0.99 9.41 5.14 *
Corona 1,5,5,1 None 1100–1690 2.10 0.75 0.18 0.94 4.14 8.65
Ash (g/L) FNS I 1,5,5,1 SNV + DT 1100–2500 3.26 1.33 0.41 0.91 3.28 12.49
FNS II 1,10,5,1 SNV + DT 1100–2500 3.28 1.37 0.30 0.95 4.59 9.10 *
Corona 2,10,5,1 SNV + DT 500–1690 3.29 1.35 0.55 0.83 1.62 16.71
Acetoin (mg/L) FNS I 2,5,5,1 SNV + DT 400–2500 439.26 237.45 127.33 0.71 1.86 28.99 *
FNS II 1,10,5,1 SNV + DT 400–2500 436.34 239.58 158.82 0.56 1.51 36.40
Corona 2,10,5,1 None 500–1690 459.69 244.56 155.92 0.59 1.56 33.92
Methanol (mg/L) FNS I 2,10,5,1 None 1100–2500 46.94 17.04 9.85 0.67 1.73 20.98
FNS II 1,5,5,1 SNV + DT 400–2500 46.64 17.25 7.81 0.80 2.21 16.74 *
Corona 2,5,5,1 None 500–1690 44.35 14.67 7.93 0.71 1.85 17.87
Total polyphenols (ppm gallic acid) FNS I 1,5,5,1 SNV + DT 400–2500 337.08 133.35 56.69 0.82 2.35 16.82 *
FNS II 1,10,5,1 None 400–2500 337.08 133.35 58.42 0.81 2.28 17.33
Corona 2,5,5,1 SNV + DT 500–1690 337.99 136.33 63.58 0.78 2.14 18.81
Intensity FNS I 1,10,5,1 SNV + DT 400–2500 1.31 1.55 0.31 0.96 4.96 23.93
FNS II 2,10,5,1 SNV + DT 400–2500 1.48 1.66 0.23 0.98 6.86 16.41 *
Corona 1,5,5,1 SNV +DT 500–1690 1.31 1.56 0.27 0.97 5.88 20.32
Tonality FNS I 2,10,5,1 SNV + DT 400–2500 2.54 1.31 0.49 0.86 2.68 19.30
FNS II 2,5,5,1 None 400–2500 2.60 1.28 0.41 0.90 3.13 15.79 *
Corona 1,5,5,1 SNV + DT 500–1690 2.67 1.25 0.30 0.94 4.19 11.14
Alcohol content (% vol.) FNS I 2,5,5,1 SNV + DT 400–2500 0.98 0.81 0.06 0.99 14.42 5.71
FNS II 2,10,5,1 None 400–2500 0.96 0.81 0.04 0.99 22.31 3.76 *
Corona 1,5,5,1 SNV + DT 1100–1690 1.09 0.99 0.20 0.96 4.98 18.21

Note:

1 Mean of the calibration set;

2 Standard deviation;

3 Standard error of cross-validation;

4 Coefficient of determination of cross-validation;

5 Ratio SD/SECV;

6 Coefficient of variation;

*

The best of the best equations for each parameter and instrument tested.