304
13 Starch
longer periods of time. In reducing the production of non-biodegradable plastics,
other replacements which serve the same purpose are increasing in demand. Starch
is one of the most widely used alternatives to non-biodegradable plastics. Starch
can be processed into plastic films which have the same mechanical properties as
non-biodegradable plastic films made up of synthetic, fossil-derived plastics such as
polyethylene. However, these starch-derived plastics degrade into compounds that
are absorbed into the environment and utilized by living organisms without causing
harm.
One of the limitations of bioplastic applications is their ability to retain their properties at the service conditions. Properties such as water absorbance and thermomechanical properties in bioplastics vary more with environmental conditions compared
to the non-biodegradable plastics. Plastics made from aquatic-derived starch could
potentially have higher temperature tolerance.
13.8.3 Waxy Starch
Starches with high amylopectin content and little amylose content are desirable in
the formation of waxy starch. Waxy starch is used as a food thickener, bread making, emulsion stabilizers, coating and film forming. It is preferred for its improved
digestibility due to its branched structure. Branched polymers tend to be less stable than linear polymers, thus making waxy starch more prone to break down by
digestive enzymes. The branched nature of the waxy starches also makes then suitable for nanoparticles formation. These nanoparticles can then be used in a variety
of applications such as drug delivery and scaffold formation (Sarka and Dvoracek
2017). Waxy starch has preferred gelatinization properties compared with starch with
higher amylose content. It is also more resistant to retrogation and hence acts as a
more stable viscosity enhancer (Sarka and Dvoracek 2017).
Floridean starch which is found in the cytoplasm of red algae is similar in structure
to these waxy starches (Dauvillee et al. 2009) since they contain only amylopectin
with no amylose content (McCracken and Cain 1980). Although waxy starch is most
commonly sourced from maize, maize is also largely used in other applications; the
unique aquatic floridean starch could potentially replace or augment the use of maize
for production of waxy starch.
13.8.4 Food
Starch is the major staple food across the world. About 35% of the daily calorie intake comes from starch (Gifuni et al. 2017). Starch is also widely used as a
thickening agent in food products. Isolated starch is also on its own a meal such as
cornmeal or tapioca. The gelatinization property in hot water makes it a good viscosity enhancer. Combination of different types of starch results in a hybrid material
13 Starch
longer periods of time. In reducing the production of non-biodegradable plastics,
other replacements which serve the same purpose are increasing in demand. Starch
is one of the most widely used alternatives to non-biodegradable plastics. Starch
can be processed into plastic films which have the same mechanical properties as
non-biodegradable plastic films made up of synthetic, fossil-derived plastics such as
polyethylene. However, these starch-derived plastics degrade into compounds that
are absorbed into the environment and utilized by living organisms without causing
harm.
One of the limitations of bioplastic applications is their ability to retain their properties at the service conditions. Properties such as water absorbance and thermomechanical properties in bioplastics vary more with environmental conditions compared
to the non-biodegradable plastics. Plastics made from aquatic-derived starch could
potentially have higher temperature tolerance.
13.8.3 Waxy Starch
Starches with high amylopectin content and little amylose content are desirable in
the formation of waxy starch. Waxy starch is used as a food thickener, bread making, emulsion stabilizers, coating and film forming. It is preferred for its improved
digestibility due to its branched structure. Branched polymers tend to be less stable than linear polymers, thus making waxy starch more prone to break down by
digestive enzymes. The branched nature of the waxy starches also makes then suitable for nanoparticles formation. These nanoparticles can then be used in a variety
of applications such as drug delivery and scaffold formation (Sarka and Dvoracek
2017). Waxy starch has preferred gelatinization properties compared with starch with
higher amylose content. It is also more resistant to retrogation and hence acts as a
more stable viscosity enhancer (Sarka and Dvoracek 2017).
Floridean starch which is found in the cytoplasm of red algae is similar in structure
to these waxy starches (Dauvillee et al. 2009) since they contain only amylopectin
with no amylose content (McCracken and Cain 1980). Although waxy starch is most
commonly sourced from maize, maize is also largely used in other applications; the
unique aquatic floridean starch could potentially replace or augment the use of maize
for production of waxy starch.
13.8.4 Food
Starch is the major staple food across the world. About 35% of the daily calorie intake comes from starch (Gifuni et al. 2017). Starch is also widely used as a
thickening agent in food products. Isolated starch is also on its own a meal such as
cornmeal or tapioca. The gelatinization property in hot water makes it a good viscosity enhancer. Combination of different types of starch results in a hybrid material