Biomedical Engineering Reference
In-Depth Information
of wholemeal breads (Rosell et al. 2009). A blend of improvers containing acid
ascorbic, alpha-amylase, protease and hemicellulase has been proposed for extend-
ing stability of frozen part baked breads (Ribotta and Le Bail
2007
).
Part baking technology has not been immune to the current nutritional trends in
bakery products. In fact, different formulations have been proposed for improving
the nutritional pattern of these products, although the structural effects on crumb
must be assessed. Dietary fi bres have been the most often added ingredient. Despite
the increasing awareness on the benefi cial awareness of fi bre enriched bakery prod-
ucts, a few researches have been focussed on the technological impact (i.e. baking
time, low baking temperatures and low or sub-zero storage) of those ingredients on
partially baked products. It is already established that all polymeric compounds that
interact with water can affect the quality of the fi nal product (Jinshui et al.
2002
).
A study carried out by Rosell and Santos (
2010
) compared the technological
functionality of different fi bres (high methylated ester pectin, resistant starch, and
insoluble-soluble fi bre) in partially baked breads, which could be stored either sub-
zero or low temperatures. Fiber-containing formulations affected bread specifi c vol-
ume and crumb hardness, and those characteristics were also dependent on both the
bread making process (conventional or part baking) and the storage conditions of
the par-baked bread (low or sub-zero temperatures). Particularly, the technological
functionality of pectin was negatively affected by partial baking and partially baked
breads. The bread containing fi bre did not show enough strength for keeping its
crumb structure during storage. Moreover, inclusion of resistant starch and fi bre in
the bread formulation induced a reduction in the specifi c volume and an increase of
crumb hardness (Rosell and Santos
2010
).
At this point, it is important to remark that fi bres addition to part baked bread has
promoted a signifi cant effect on the glycaemic index. Borczak et al. (
2012
) investi-
gated the effect of 10 % addition of dietary fi bre (oat fi bre 75 % and inulin 25 %) to
partially baked frozen wheat rolls on the glycaemic index considering 15 healthy
humans volunteers. The authors concluded that frozen storage of part baked breads
combined with fi bre addition signifi cantly reduced (i.e. 35 %) the glycaemic index
(Borczak et al.
2012
). Similarly, other nutritional effects have been reported for the
frozen stored part baked breads with the addition of fi bres (Kopec et al.
2011
).
Studies also carried to assess the biological value of proteins, lipid profi le, and some
minerals content of frozen part baked breads on selected tissues of rats (Kopec et al.
2011
). Part baked breads, with or without fi bre enrichment, showed signifi cantly
higher chemical score and essential amino acid index when compared with the con-
ventional bread. Part baking also improved protein digestibility, however digest-
ibility decreased with the addition of fi bre. Ronda et al. (
2012
) studied the effect of
rapidly digestible starch (RDS) and slowly digestible starch (SDS) in the wheat
breads prepared from frozen partially baked breads contained different types and
levels of fi bres. The addition of fi bres like inulin or wheat bran increased the starch
digestive index (Ronda et al.
2012
).
Different dietary fi bres, such as resistant starch, locust bean gum and wheat bran
have been used to obtain partially baked bread (Almeida et al.
2013
). It has been
recently reported that fi bres do not affect the specifi c volume and crumb texture of
