Applications of natural ingredients in baked goods - Natural Food Additives, Ingredients and Flavourings - page 320

which is essential for the production of plant bread using no-time dough processes.
In the presence of oxygen and an enzyme naturally present in fl our, the ascorbic
acid is converted to dehydroascorbic acid - the active form in dough systems.
Such processes require the dough to be developed quickly, and once developed,
to be stabilised in order to give the dough mechanical strength and good gas
holding properties. Although ascorbic acid is naturally present in many fruits and
vegetables, most of the supply for industrial use is produced from chemical
reactions using glucose as the starting material. It is therefore classed as a chemical
and has the E number E300. Recent work at Campden BRI has demonstrated that
plant materials with high concentrations of naturally present ascorbic acid can be
used to replace the chemically produced ascorbic acid (see Section 14.2.4).
Fruits and nuts are widely used in bakery products to make traditional fruit
pies, cakes and pastry products. Dried fruits such as currents and sultanas are used
in breadmaking. Mixed peel, although not classed as a fruit, can also be used and
the usual form of addition is to mix it together with other fruit. It is also important
to appreciate that fruits such as sultanas and currents become fragile when washed
and therefore prone to being damaged in dough systems where high energy mixing
is involved.
Finally, preservatives such as propionic acid and sorbic acid are used to inhibit
the growth of many mould and yeast species that cause spoilage in bakery goods
such as bread and cakes. Although the permitted preservatives are chemicals,
certain amounts of the active material (e.g. propionic acid) can be produced during
the fermentation process and may be a route to provide a natural source of
materials with preservative action.

14.2.1 Yeast as a potential source of natural ingredients for
bakery applications
In addition to its fundamental role in fermentation, yeast has been investigated for
its ability to produce a range of functional materials. The key constituents of the
yeast cell wall are the β -glucans (about 60% of the cell wall dry mass) and
polymers of mannose associated with protein (mannoprotein) comprising about
40% of the cell dry mass (Aguilar-Uscanga and François 2003). A recent patent
application (Kawahara et al. 2007) describes how, through the culture of an edible
yeast, an emulsifi er based on protein and sugar complex can be produced. Another
patent application (Kunst et al. 1997) claims that the mannoprotein obtained by
heat treatment of a food grade yeast can be used as an emulsifi er in food and
beverages, particularly for the stabilisation of beer foam. Spent yeast from the
manufacture of beer and wine has been demonstrated to be a possible source for
the large-scale production of this bio-emulsifi er (Cameron et al. 1988) with
applications in the food industry (Gaňnan et al. 2008).
Recently, a new breadmaking process has been reported where exposing
baker's yeast to a salt solution prior to breadmaking can improve the volume,
texture, taste and aroma of the fi nished product (Yeh et al. 2009). Exposure of the
yeast to a 7% salt solution prior to bulk fermentation leads to an accumulation of

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