Food Chemistry

714 15 Cereals and Cereal Products

ious indices have been defined (cf. Fig. 15.26);
usually they refer to doughs with a maximum
consistency of 500 FU.
Flours with strong gluten absorb more water
and show longer dough development and sta-
bility times than do flours with weak gluten
(Table 15.41). Corresponding results are obtained
with the Swanson and Working mixographs.
A standardized piece of dough is stretched with
the hook of a Brabender extensograph until the
piece breaks (Fig. 15.27). As shown in Fig. 15.29,
a graph of force (resistance to extension) versus
stretching distance (extensibility) provides infor-
mation about the stability of a dough, its gashold-
ing capacity and fermentation tolerance. Of the
examples given in Table 15.41, the “Monopol”
cultivar obviously has strong gluten. The “Nim-
bus” cultivar has short gluten, as reflected by its
low extensibility. The “Maris Huntsman” cultivar
has a very weak gluten, as shown by the low re-
sistance of its dough to extension and also by its
low extensibility, and very small extension area.
Similar results are obtained with the Chopin ex-
tensograph or alveograph used widely in France.
A piece of dough mounted on a perforated plate
is blown into a ball. The pressure in the ball of
dough is plotted against the time (cf. Fig. 15.28).
In contrast to the Brabender extensograph, the
dough is extended in two dimensions. As in the
extensogram, the resistance of the dough to ex-
tension and its extensibility are obtained from the
maximal height and width of the alveogram.

Fig. 15.26.Farinogram. The following data are perti-
nent for quality assessment of flour:Adough develop-
ment time,Bdough stability (dough consistency does
not change),Cdecrease in dough consistency after
a given time, here 12 min. FU: farinogram units

Fig. 15.27.Extensograph (according toRohrlichand

Thomas, 1967). The cylindrical piece of dough(1)is

fixed by dough clamps(3)and placed on the balance

fork(2).Themotor(4)of the stretching unit(5)is

then started. The arm moves downward into the dough

and extends it at constant speed. Simultaneously, the

forces opposing the stretching action are transmitted

through the lever system(6)to the balance system(7).

This is coupled to a recording arm of the strip chart

recorder(8). The fork of the balance system is coupled

to an oil damper(9)to reduce the recoil

Fig. 15.28.Alveogram (cf. text)

15.4.1.1.3 Baking Tests

Direct information about the baking quality

of a flour is obtained from baking tests under

standardized conditions. Baking volume (cf. Ta-