Food Chemistry

15.2 Individual Constituents 683

Table 15.14.Classification and properties of gluten proteins

HMW MMW

HMW Subunits ω-Gliadins LMW

Group x-Type y-Type ω 5 ω1,2 α-Gliadins γ-Gliadins LMW
Subunits

Mr× 10 −^3 104–124 90–102 66–79 55–65 32 38–42 36–44
(SDS-PAGE)a
Mr× 10 −^3 83–88 67–74 44–55c 34–44c 28–35 31–35 32–39
(sequence)b
Number of amino 770–827 627–684 n.a. n.a. 262–298 272–308 281–333
acid residues
Content of 4–9% 3–4% 3–6% 4–7% 28–33% 23–31% 19–25%
gluten proteins
Number of 4 7 0 0 6 8 8
cysteine residues
μmolCys/g flour 0. 30 .30 0 6. 06. 75. 0

aResult of electrophoresis.
bCalculated from the amino acid sequence.
cDetermined with MALDI-TOF mass spectrometry.

n.a.: not analyzed.

Table 15.15.Amino acid compositionaof protein groups of wheat gluten (cultivar Rektor)

HMW LMW

subunits ω5- ω1,2- subunits α- γ-

of glutenin Gliadins Gliadins of glutenin Gliadins Gliadins

Asx 0 .7–0. 90 .3–0. 50 .5–1. 30 .7–1. 52 .7–3. 31 .9–4. 0
Thr 3 .2–3. 80 .4–0. 60 .8–2. 31 .8–2. 91 .5–2. 31 .6–2. 4
Ser 6 .4–8. 42 .6–3. 35 .8–6. 37 .7–9. 55 .3–6. 64 .9–6. 8
Glx 35 .9–37. 055 .4–56. 042 .5–44. 938 .0–41. 935 .8–40. 434 .2–39. 1
Pro 11 .2–12. 819 .7–19. 824 .8–27. 414 .0–16. 215 .0–16. 615 .8–18. 4
Gly 18 .2–19. 80 .6–0. 80 .9–2. 12 .3–3. 21 .9–3. 22 .0–3. 0
Ala 2 .9–3. 50 .2–0. 30 .3–1. 31 .7–2. 32 .6–4. 12 .8–3. 5
Cys 0 .6–1.30.0 0.0 1.9–2. 61 .9–2. 22 .2–2. 8
Val 1 .6–2.70.3 0.6–1. 43 .8–5. 34 .2–4. 94 .4–5. 4
Met 0 .1–0.30.0 0.0–0. 31 .2–1. 60 .4–0. 91 .2–1. 6
He 0 .7–1. 14 .3–4. 71 .9–3. 53 .6–4. 43 .6–4. 64 .0–4. 6
Leu 3 .1–4. 32 .7–3. 33 .9–5. 35 .3–7. 56 .5–8. 76 .4–7. 3
Tyr 5 .1–6. 40 .6–0. 70 .8–1. 50 .9–1. 92 .3–3. 20 .6–1. 4
Phe 0 .2–0. 59 .0–9. 57 .6–8. 13 .8–5. 52 .9–3. 94 .7–5. 6
His 0 .8–1. 91 .3–1. 40 .6–1. 11 .3–1. 81 .4–2. 81 .1–1. 5
Lys 0 .7–1. 10 .4–0. 50 .3–0. 60 .2–0. 60 .2–0. 60 .4–0. 9
Arg 1 .6–2. 10 .5–0. 60 .5–1. 41 .5–2. 11 .7–2. 91 .2–2. 9
amol % (without Trp).

and 12 in a series of wheat cultivars is shown in
Figs. 15.8 and 15.9. The amino acid sequences

of the subunits 1Dx5 and 1By9 are shown in

Table 15.17.