Download Figure S4.

Figure S4: Monosaccharide content in wheat dry grain, flour, isolated outer
pericarp and intermediate layers (var. Recital.)
Material and methods:
Samples:
flour (type 55) from milled Recital grains (800 mg)
dry whole grain grinded in liquid nitrogen (100 mg)
manually dissected outer pericarp grinded in liquid nitrogen (100 mg)
manually dissected intermediate layers (cross cells tube cells, testa and nucellar epidermis )(100
mg) grinded in liquid nitrogen (100 mg)
Preparation of alcohol-insoluble residue (AIR)
Small sugars (glucose, sucrose, etc.) were removed using 80% ethanol for 10 min; the insoluble
residue was isolated by centrifugation (6300g; 10 min). The procedure was repeated once and the
residue was washed with 95% ethanol and again isolated by centrifugation (6300g; 10 min). The
supernatant was discarded and the residue was dried in two steps: first in an oven at 40 °C for 24 h
and then with P2O5 in a vacuum oven at 40 °C for 48h.
Individual neutral sugar content was determined following hydrolysis and alditol acetate
derivatisation as described in Dervilly et al. (2000) according to the method of Englyst and
Cummings (1988).
Uronic acids were assayed by an automated m-hydroxydipenyl method (Blumenktrantz & AsboeHansen, 1973; Thibault 1979). Galacturonic acid was estimated taking advantage of the differential
response of glucuronic acid and galacturonic acid in the presence of sodium tetraborate (Thibault
1979).
Results (mean of two measurements)
In wheat grain :
Rhamnose indicates the presence of rhamnogalacturonans
Arabinose mainly comes from arabinoxylans, also from arabinogalactan proteins
Xylose mainly comes from arabinoxylans
Mannose comes from mannans
Glucose comes mainly from mixed-linked glucans and cellulose and from starch in flour and whole
grain
Galactose mainly comes from arabinogalactan proteins and possibly from heteroxylans
Galacturonic acid indicates the presence of pectic homogalacturonans and/or
rhamnogalacturonans
% of AIR
whole grain
outer pericarp
interm layers
flour
Rhamnose (Rha)
0.28
0.00
0.00
0.33
Arabinose (Ara)
2.72
27.10
10.75
0.89
Xylose (Xyl)
4.52
24.12
32.1
1.54
Mannose (Man)
0.25
0.83
0.00
0.23
Galactose (Gal)
0.41
1.54
1.05
0.25
Glucose (Glc)
75.93
27.51
19.62
91.00
Galacturonic acid
0.17
0.31
0.70
0.03
Glucuronic acid
0.33
3.17
2.64
0.14
Gas-liquid chromatograms from dry wheat grain and intermediate layers.
mV
Fuc
Standards
Ara
Rha
Xyl
Man Gal
Glc
Inositol
mV
Inositol
Xyl
Grain
Glc
Ara
Rha
Man Gal
mV
Xyl
Intermediate layers
Inositol
Ara
Glc
Gal
Dervilly et al. (2000) Isolation of homogeneous fractions from wheat water-soluble arabinoxylans. J. Agric. Food
Chem. 48, 270-278.
Englyst HN and Cummings JH (1988) Improved method of measurement of dietary fiber as non-starch
polysaccharides in plant foods. J. Assoc. Off. Anal. Chem. 71, 808-814.
Blumenkrantz N and Asboe-Hansen (1973) New method for quantitative determination of uronic acids. Analytical
Biochemistry 54, 484-489.
Thibault J-F (1979) Automatisation du dosage des substances pectiques par la méthode au méta-hydroxydipenyl.
Lebensmitell Wissenschaft und Technologie (LWT) 12, 247-251