Applications of natural ingredients in baked goods - Natural Food Additives, Ingredients and Flavourings - page 322

days at 75°C and 79% relative humidity. This was claimed to improve the stability
of a cloudy emulsion compared with the gum or protein separately.
There are other extracts and exudates of plants that can be functional as
emulsifi ers in food systems. Examples of these include pectin and gum Arabic,
both natural components of plants but required to be labelled as additives and
assigned E numbers. A suggested way to overcome the issue of labelling may be
to include the whole plant in the recipe (private communication, Dr C I Speirs,
Campden BRI) and to activate the function of a specifi c component through
processing in situ . This can be illustrated by considering the scenario using sugar
beet pulp, which contains about 20% pectin. By using the whole beet pulp in the
recipe the pulp could be modifi ed by heat treatment during processing to act as an
emulsifi er. There is a precedent for this with citrus fruits where the pectin content
of the whole material is altered so that it develops gelling properties similar to
chemically modifi ed pectin (Speirs et al. 1980).

14.2.3 Modifi cation of components of raw materials in situ to generate
functional materials
It is known that lipids naturally present in fl our, especially polar lipids, can
improve loaf volume and delay staling in bakery products such as bread. The
polar lipids of interest in wheat fl our consist of phospho- and glycolipids
comprising about 40% of the total lipids. Some of these lipids consist of two fatty
acid chains, which give the molecules predominantly hydrophobic character that
limits the properties of these molecules as surface active agents. Commercial
lipases are available that can cleave a single fatty acid chain from a lipid molecule
chain and alter the hydrophobic/hydrophilic balance of the molecules so that the
surfactant properties of the remaining molecule are enhanced. Such enzyme
action has been shown to improve bread volume and can match the effects of
typical bread emulsifi ers such as diacetyltartaric esters of monoglycerides
(Christiansen et al. 2003). In this respect the lipase is acting as a dough-
strengthening agent to give the dough more resistance to mechanical abuse during
processing. In a separate study, Moreira Gandra et al. (2008) showed that
monoglyceride could be substituted by a lipase in a fi bre-enriched pan bread.
Lipase use has also been shown to substitute for emulsifi ers in high-ratio layer
cakes (Guy and Sahi 2006).

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14.2.4 Utilisation of enzymes to improve the quality of baked goods
Enzymes can be used to improve the emulsifi cation properties of conventional
emulsifi ers. A commercialised microbial phospholipase, which converts lecithin
into lysolecithin, has been marketed for baking applications. Hille (2008)
describes the use of this enzyme to improve the emulsifi cation properties of egg
lecithin in the manufacture of pound and sponge cakes (a pound cake is a type of
cake traditionally made with equal amounts of fl our, sugar, fat (butter) and egg).
Addition of 0.1% of the enzyme to pound and sponge cake formulations improved