7.6 Environmental Implications
159
et al. 2013). The process also leads to release of toxins to human and aquatic life
and acidification of the atmosphere, although these adverse effects are not directly
linked to the production of sodium hydroxide, but to the consumption of electricity
and energy required for the process. This should therefore be considered in the real
cost of producing biopolymers to the environment. Table 7.1 gives a summary of the
estimated consumption for agar production based on reviewed works thus far.
7.7 Applications
7.7.1 Food
As an additive agar is required in relatively low amounts, a teaspoon of agar powder
can achieve thickening effect in approximately 250 ml of liquid food (Marcus 2014),
and at a concentration of 0.03 g per ml, agar fluid gels achieve optimal stability and
half-life of up to 6 days (Ellis et al. 2017). Agarose is used in icings and frosting. This
particular application is possible due to its compatibility with sugar and its stability
at the relatively high room storage temperature used for such products, especially
during transportation. It is used as a substitute for low-fat products such as oil-free
salad dressings, creams and low-fat yoghurts. Other applications include in canned
meat and fish to retain texture, in pie fillings to improve mouthfeel and in candies for
gel strength. Agar can remain stable at the heat sterilization temperatures; hence, this
makes it applicable for processed foods requiring heat sterilization such as canned
foods.
Colloidal systems such as emulsions, gels and foams are used widely in the food
industry. Some food products are aerated to form foam; these are dispersion of air
within a continuous phase. Foams are used in some food products such as whipped
cream and aerated chocolates. This foam structure gives a desirable texture to these
foods and also serves to reduce mass per volume and calorie since less product is
required within a pack. Typically, foams require a stabilizer to ensure even dispersion of air within the continuous phase, hence maintaining stability. Such stabilizer
could be in the form of a surfactant such as Tween 20 (Ellis et al. 2017). Foams
are even much less stable since the dispersed phase is air with low viscosity and
surface tension, hence a higher chance of coalescence. Agar fluid gels are used in the
stabilization of foams. Fluid gels, particles of agar gels suspended in a continuous
phase, can be used to form stable foams. These fluid gels can serve as substitutes for
colloidal systems which are conventionally made using fat. Agar gels stabilize foams
via two mechanisms: absorption of water from the foam cavities hence preventing
the release of water leading to destabilization of the foam and by acting as a viscosity
enhancer. This increased viscosity prevents separation of the phases through coalescence of the dispersed phase. The presence of the gel particles also serves as a barrier
to fluid drainage from the foam (Ellis et al. 2019). Agar therefore has a significant
159
et al. 2013). The process also leads to release of toxins to human and aquatic life
and acidification of the atmosphere, although these adverse effects are not directly
linked to the production of sodium hydroxide, but to the consumption of electricity
and energy required for the process. This should therefore be considered in the real
cost of producing biopolymers to the environment. Table 7.1 gives a summary of the
estimated consumption for agar production based on reviewed works thus far.
7.7 Applications
7.7.1 Food
As an additive agar is required in relatively low amounts, a teaspoon of agar powder
can achieve thickening effect in approximately 250 ml of liquid food (Marcus 2014),
and at a concentration of 0.03 g per ml, agar fluid gels achieve optimal stability and
half-life of up to 6 days (Ellis et al. 2017). Agarose is used in icings and frosting. This
particular application is possible due to its compatibility with sugar and its stability
at the relatively high room storage temperature used for such products, especially
during transportation. It is used as a substitute for low-fat products such as oil-free
salad dressings, creams and low-fat yoghurts. Other applications include in canned
meat and fish to retain texture, in pie fillings to improve mouthfeel and in candies for
gel strength. Agar can remain stable at the heat sterilization temperatures; hence, this
makes it applicable for processed foods requiring heat sterilization such as canned
foods.
Colloidal systems such as emulsions, gels and foams are used widely in the food
industry. Some food products are aerated to form foam; these are dispersion of air
within a continuous phase. Foams are used in some food products such as whipped
cream and aerated chocolates. This foam structure gives a desirable texture to these
foods and also serves to reduce mass per volume and calorie since less product is
required within a pack. Typically, foams require a stabilizer to ensure even dispersion of air within the continuous phase, hence maintaining stability. Such stabilizer
could be in the form of a surfactant such as Tween 20 (Ellis et al. 2017). Foams
are even much less stable since the dispersed phase is air with low viscosity and
surface tension, hence a higher chance of coalescence. Agar fluid gels are used in the
stabilization of foams. Fluid gels, particles of agar gels suspended in a continuous
phase, can be used to form stable foams. These fluid gels can serve as substitutes for
colloidal systems which are conventionally made using fat. Agar gels stabilize foams
via two mechanisms: absorption of water from the foam cavities hence preventing
the release of water leading to destabilization of the foam and by acting as a viscosity
enhancer. This increased viscosity prevents separation of the phases through coalescence of the dispersed phase. The presence of the gel particles also serves as a barrier
to fluid drainage from the foam (Ellis et al. 2019). Agar therefore has a significant