164
7 Agar
comprises of 80% unmodified starch, 28.5% glycerol, 20% agar, 10% epoxidized
vegetable oil and 0.5% gum arabic (Justyna et al. 2016).
7.7.8 Preservation of Stone Structures
Agar has also recently been investigated for use in the desalination of limestone as a
preservative measure for stone heritage structures which overtime are destroyed by
salt accumulation. Aqueous-based methods are sometimes counterproductive as the
water may cause other forms of damages such as rusting and erosion. Agar gel can
gradually release water to remove the salt in a sponge-like manner (Martins et al.
2017). This is a gentler method than more abrasive sponges. The water released
during syneresis dissolves off the salt, while the pores within the gel absorb the
solution from the surface of the structure. The gel can then be wiped off the surface.
Other applications of agar include use in capsules for pharmaceuticals, glucoselowering effects, in dentistry for preparation of denture molds, in archeology where
it is used in the reproduction of ancient remains and in forensics for fingerprinting.
7.8 Commercial Production
As demand increases for more plant-based products, agar has potentially everincreasing demand in food as a plant-based replacement to the animal-sourced
gelatin. The demands for the hydrocolloids sourced from algae are generally increasing annually. The largest producers, which are the Asia-Pacific regions, have reported
2–3% growth in the hydrocolloids market in recent years, and this includes agar
(Rejeki et al. 2018). There seems to be a general long-term increase in production
rate since earlier years; production rate between 1999 and 2009 had shown an estimated 2% increase in production volume (Bixler and Porse 2011). Although the
market has witnessed considerable price fluctuations over the past decades, the phycocolloid and algae market has gone through different phases since the 1930s. The
Asia-Pacific region remains the highest producer of agar and has been for many
years.
Of the three seaweed-derived hydrocolloids, agar has the highest commercial
value in terms of commodity prices, selling at ~18USD per kg as of 2009 compared to carrageenan and alginates priced at 10.5 USD/kg and 12 USD/kg, respectively. As of 2009, an estimated global sale of 9600 tonnes was estimated for agar,
while carrageenan and alginate were 50,000 tonnes and 26,500 tonnes, respectively
(Bixler and Porse 2011). As of 2014, global agar production of agar was an estimated
10,600 tonnes annually (Rhein-Knudsen et al. 2015). Agar is also sold for research
and laboratory use by chemical supplies company; for example, 100 g agar powder
for microbiology from Sigma-Aldrich is priced at 117 Eur as of June 5, 2019, while
7 Agar
comprises of 80% unmodified starch, 28.5% glycerol, 20% agar, 10% epoxidized
vegetable oil and 0.5% gum arabic (Justyna et al. 2016).
7.7.8 Preservation of Stone Structures
Agar has also recently been investigated for use in the desalination of limestone as a
preservative measure for stone heritage structures which overtime are destroyed by
salt accumulation. Aqueous-based methods are sometimes counterproductive as the
water may cause other forms of damages such as rusting and erosion. Agar gel can
gradually release water to remove the salt in a sponge-like manner (Martins et al.
2017). This is a gentler method than more abrasive sponges. The water released
during syneresis dissolves off the salt, while the pores within the gel absorb the
solution from the surface of the structure. The gel can then be wiped off the surface.
Other applications of agar include use in capsules for pharmaceuticals, glucoselowering effects, in dentistry for preparation of denture molds, in archeology where
it is used in the reproduction of ancient remains and in forensics for fingerprinting.
7.8 Commercial Production
As demand increases for more plant-based products, agar has potentially everincreasing demand in food as a plant-based replacement to the animal-sourced
gelatin. The demands for the hydrocolloids sourced from algae are generally increasing annually. The largest producers, which are the Asia-Pacific regions, have reported
2–3% growth in the hydrocolloids market in recent years, and this includes agar
(Rejeki et al. 2018). There seems to be a general long-term increase in production
rate since earlier years; production rate between 1999 and 2009 had shown an estimated 2% increase in production volume (Bixler and Porse 2011). Although the
market has witnessed considerable price fluctuations over the past decades, the phycocolloid and algae market has gone through different phases since the 1930s. The
Asia-Pacific region remains the highest producer of agar and has been for many
years.
Of the three seaweed-derived hydrocolloids, agar has the highest commercial
value in terms of commodity prices, selling at ~18USD per kg as of 2009 compared to carrageenan and alginates priced at 10.5 USD/kg and 12 USD/kg, respectively. As of 2009, an estimated global sale of 9600 tonnes was estimated for agar,
while carrageenan and alginate were 50,000 tonnes and 26,500 tonnes, respectively
(Bixler and Porse 2011). As of 2014, global agar production of agar was an estimated
10,600 tonnes annually (Rhein-Knudsen et al. 2015). Agar is also sold for research
and laboratory use by chemical supplies company; for example, 100 g agar powder
for microbiology from Sigma-Aldrich is priced at 117 Eur as of June 5, 2019, while