178
Arabinoxylans and Baking Performance
Due to high water binding capacity and viscosity, arabinoxylans greatly influence the
distribution of water and consistency in the dough. Michniewicz et al. (1991) reported
that water soluble pentosans increases the water absorption of dough and enhance the
loaf volume of bread. Buksa et al. (2010) reported bread with the largest loaf volume
was obtained, when the wholemeal rye flour with highest water absorption and soluble
pentosans was used. Maeda and Morita (2003) reported an increase in the loaf volume
of wheat bread in the range of 3.79–4.38 (cm
3
/g) on addition of water soluble pentosans
in the range of 0.2–1.0%. However if the concentration of arabinoxylans is greater than
optimum then there is increase in the viscosity of dough which in turn decreases the
loaf expansion during oven spring (Kulp and Bechtel 1963). The fineness and homogeneity of crumb depends on the foam stability of dough. The arabinoxylans adds to the
strength and extensibility of the gluten-starch films which is surrounding the gas bubbles and thereby reducing the rate of carbon dioxide diffusion from the dough
(Izydorczyk and Bilideris 2000). Courtin and Delcour (1998) reported that crumbs of
bread fortified with arabinoxylans are less firm than those of controls. This positive
effect has been related to the increased moisture content of the samples. Water acts as a
plasticizer of the gluten- starch composite matrix thereby lowering rigidity of the products. Biliaderis et al. (1995) reported the effects of high and low molecular weight
arabinoxylan fractions on bread making quality. The arabinoxylans with higher molecular weight increases the farinograph water absorption to a greater extent than the low
molecular weight counterparts. Adding 1–2% pentosans to poor wheat flours markedly
improves dough properties (Shelton and D’Appolonia 1985; Rouau 1993). Another
important property of arabinoxylans is associated to their role in delaying bread staling.
Bread staling is a complex phenomenon involving loss of aroma, deterioration of crust
characteristics and increase in crumb firmness (Izydorczyk and Biliaderis 1995; Shelton
and D’Appolonia 1985). Biliaderis et al. (1995) reported that after seven day storage
period, the arabinoxylans fortified breads exhibited lower crumb firmness than the controls. Kinetic studies indicated that adding pentosans decreased the amount of starch
components available for crystallization and thus decreased the bread staling rate. The
observed effects were also attributed to a higher moisture content of breads substituted
with arabinoxylans and to the plasticizing effects of water (Shelton and D’Appolonia
1985). Also, breads with added arabinoxylans displays increased rates in starch retrogradation mostly because of their high moisture content (Biliaderis et al. 1995).
Zeleznak and Hoseney (1986) reported increase in rate of retrogradation as the moisture content increased from 20 to 45% in arabinoxylan containing wheat breads.
Modification of Arabinoxylans
Arabinoxylans have various food applications such as thickener, stabilizer, an emulsifier, film former, and water binder (Ayala-Soto et al. 2016; Saeed et al. 2011).
Also, arabinoxylans exhibits their nutritional benefits as soluble and insoluble fiber
A. Shah et al.
Arabinoxylans and Baking Performance
Due to high water binding capacity and viscosity, arabinoxylans greatly influence the
distribution of water and consistency in the dough. Michniewicz et al. (1991) reported
that water soluble pentosans increases the water absorption of dough and enhance the
loaf volume of bread. Buksa et al. (2010) reported bread with the largest loaf volume
was obtained, when the wholemeal rye flour with highest water absorption and soluble
pentosans was used. Maeda and Morita (2003) reported an increase in the loaf volume
of wheat bread in the range of 3.79–4.38 (cm
3
/g) on addition of water soluble pentosans
in the range of 0.2–1.0%. However if the concentration of arabinoxylans is greater than
optimum then there is increase in the viscosity of dough which in turn decreases the
loaf expansion during oven spring (Kulp and Bechtel 1963). The fineness and homogeneity of crumb depends on the foam stability of dough. The arabinoxylans adds to the
strength and extensibility of the gluten-starch films which is surrounding the gas bubbles and thereby reducing the rate of carbon dioxide diffusion from the dough
(Izydorczyk and Bilideris 2000). Courtin and Delcour (1998) reported that crumbs of
bread fortified with arabinoxylans are less firm than those of controls. This positive
effect has been related to the increased moisture content of the samples. Water acts as a
plasticizer of the gluten- starch composite matrix thereby lowering rigidity of the products. Biliaderis et al. (1995) reported the effects of high and low molecular weight
arabinoxylan fractions on bread making quality. The arabinoxylans with higher molecular weight increases the farinograph water absorption to a greater extent than the low
molecular weight counterparts. Adding 1–2% pentosans to poor wheat flours markedly
improves dough properties (Shelton and D’Appolonia 1985; Rouau 1993). Another
important property of arabinoxylans is associated to their role in delaying bread staling.
Bread staling is a complex phenomenon involving loss of aroma, deterioration of crust
characteristics and increase in crumb firmness (Izydorczyk and Biliaderis 1995; Shelton
and D’Appolonia 1985). Biliaderis et al. (1995) reported that after seven day storage
period, the arabinoxylans fortified breads exhibited lower crumb firmness than the controls. Kinetic studies indicated that adding pentosans decreased the amount of starch
components available for crystallization and thus decreased the bread staling rate. The
observed effects were also attributed to a higher moisture content of breads substituted
with arabinoxylans and to the plasticizing effects of water (Shelton and D’Appolonia
1985). Also, breads with added arabinoxylans displays increased rates in starch retrogradation mostly because of their high moisture content (Biliaderis et al. 1995).
Zeleznak and Hoseney (1986) reported increase in rate of retrogradation as the moisture content increased from 20 to 45% in arabinoxylan containing wheat breads.
Modification of Arabinoxylans
Arabinoxylans have various food applications such as thickener, stabilizer, an emulsifier, film former, and water binder (Ayala-Soto et al. 2016; Saeed et al. 2011).
Also, arabinoxylans exhibits their nutritional benefits as soluble and insoluble fiber
A. Shah et al.