Wine Chemistry and Biochemistry

544 C. Santos-Buelga and V. de Freitas

λ / nm

400 500 600 700

0,0

0,2

0,4

0,6

0,8

Absrobance

503 nm 520 nm

Fig. 9D.5Absorption spectra in the visible region of malvidin 3-glucoside (Mv3glc) and a pyra-
noanthocyanin (pyranoMv3glc-catechin)

λ(nm)

0,1

0,3

0,5

0,7

0,9

350400450500550600650 700750

pH 1

pH 5

(a) (b)

(c) (d)

pH 3

Absorbance

Cy3glc

0,0

400 500 600 700 800

0,2

0,4

0,6

0,8

1,0

1,2

200 ppm

150 ppm

100 ppm

50 ppm

0 ppm

Absorbance

Cy3glc

λ (nm)

0.1

350 400450500 550600650 700

0.5

0.7

0.9

750

pH 5

pH 3

pH 1

0.3

λ(nm)

Absorbance

Cy-pyA

Cy-pyA

0,0

400 500 600 700 800

0,1

0,2

0,3

0,4

0,5

100; 150 ppm 50 ppm

200 ppm

0 ppm

Absorbance

λ (nm)

Fig. 9D.6Absorption spectra in the visible region of cyanidin 3-glucoside (Cy3glc) and car-
boxypyranoCy3glc (Cy-py A) as a function of pH and concentration of SO 2 (adapted from
Oliveira et al. 2006a)