To date, the use of alginic acid polysaccharides has involved the sodium salt
form’s application to bread, noodles, and mayonnaise as a thickener and gelling and
stabilizing agent. Recently, however, they have also been used in imitation shark’s
fin and caviar and as a foam improvement agent in beer. As can be seen from their
use as a thickening agent, alginic acid polysaccharides are highly viscous and do
not readily dissolve in water, which presents some limitations in their application as
a food ingredient.
Recent years have seen the development and marketing of alginic acids reduced
to a molecular mass of 50,000 ± 10,000 through heating hydrolysis under pressure
(hereafter “depolymerized alginic acids”), with alginic acid polysaccharides found
in foods designed for specific health benefits such as lowering of cholesterol and
intestinal regulation. Alginic acid oligosaccharides are produced not through
pressure and heat application to alginic acid polysaccharides, but through the use of
naturally microbe-produced enzymes to break those polysaccharides down to a
molecular weight below 1000. This section presents an introduction to the characteristics and physiological functions of alginic acid oligosaccharides
(Chaki 2005; Kawada et al. 1999; Yoshida et al. 2004; Uno et al. 2006).
(1) Alginate Lyase-Producing Bacteria
Since the first reports by Waksman in the 1930s, research on the isolation of
bacteria producing enzymes that break down alginic acid polysaccharides has been
conducted on various subjects, including mollusks, seawater, the intestinal content
of saltwater fish, land organisms, and decomposed brown seaweed. This section
will examine the production and characteristics of alginic acid oligosaccharides
using enzymes obtained from ocean bacteria.
(2) Characteristics of Alginic Acid Oligosaccharides
1. Structure: Alginic acid oligosaccharides may be identified as shown in
Fig. 6.14 through placement in a DEAE-HPLC (Cosmogel DEAE glass,
8 Â 75 mm), resulting the appearance of eight kinds of peaks (see
Fig. 6.13; these have been labeled P1, P2, P3, P4, P5, P6, P7, and P8 by
emission order) that can be subjected to MS and NMR analysis.
2. Nutritional Component Analysis Values: The analysis values for the
nutritional components in alginic acid oligosaccharides show almost no
change from the alginic acid polysaccharide sodium salts (hereafter alginic
acid polysaccharides) that provide their material, as the reaction is a simple
breaking down of those polysaccharides with enzymes (Table 6.15).
3. Physiochemical Properties: Table 6.16 shows physiochemical properties of
alginic acid oligosaccharides. They show little difference from alginic acid
polysaccharides in terms of taste, smell, or pH, but can be seen to have
much lower viscosity and color acceptance. Viscosity in particular was
greatly reduced from 810 mPa s (25 °C) in a 2% solution of alginic acid
polysaccharides to 55 mPa s in a 75% solution of alginic acid oligosaccharides. The value is nearly identical to the 41 mPa s for a 75% sucrose
solution, indicating that alginic acid oligosaccharides may be used as a
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form’s application to bread, noodles, and mayonnaise as a thickener and gelling and
stabilizing agent. Recently, however, they have also been used in imitation shark’s
fin and caviar and as a foam improvement agent in beer. As can be seen from their
use as a thickening agent, alginic acid polysaccharides are highly viscous and do
not readily dissolve in water, which presents some limitations in their application as
a food ingredient.
Recent years have seen the development and marketing of alginic acids reduced
to a molecular mass of 50,000 ± 10,000 through heating hydrolysis under pressure
(hereafter “depolymerized alginic acids”), with alginic acid polysaccharides found
in foods designed for specific health benefits such as lowering of cholesterol and
intestinal regulation. Alginic acid oligosaccharides are produced not through
pressure and heat application to alginic acid polysaccharides, but through the use of
naturally microbe-produced enzymes to break those polysaccharides down to a
molecular weight below 1000. This section presents an introduction to the characteristics and physiological functions of alginic acid oligosaccharides
(Chaki 2005; Kawada et al. 1999; Yoshida et al. 2004; Uno et al. 2006).
(1) Alginate Lyase-Producing Bacteria
Since the first reports by Waksman in the 1930s, research on the isolation of
bacteria producing enzymes that break down alginic acid polysaccharides has been
conducted on various subjects, including mollusks, seawater, the intestinal content
of saltwater fish, land organisms, and decomposed brown seaweed. This section
will examine the production and characteristics of alginic acid oligosaccharides
using enzymes obtained from ocean bacteria.
(2) Characteristics of Alginic Acid Oligosaccharides
1. Structure: Alginic acid oligosaccharides may be identified as shown in
Fig. 6.14 through placement in a DEAE-HPLC (Cosmogel DEAE glass,
8 Â 75 mm), resulting the appearance of eight kinds of peaks (see
Fig. 6.13; these have been labeled P1, P2, P3, P4, P5, P6, P7, and P8 by
emission order) that can be subjected to MS and NMR analysis.
2. Nutritional Component Analysis Values: The analysis values for the
nutritional components in alginic acid oligosaccharides show almost no
change from the alginic acid polysaccharide sodium salts (hereafter alginic
acid polysaccharides) that provide their material, as the reaction is a simple
breaking down of those polysaccharides with enzymes (Table 6.15).
3. Physiochemical Properties: Table 6.16 shows physiochemical properties of
alginic acid oligosaccharides. They show little difference from alginic acid
polysaccharides in terms of taste, smell, or pH, but can be seen to have
much lower viscosity and color acceptance. Viscosity in particular was
greatly reduced from 810 mPa s (25 °C) in a 2% solution of alginic acid
polysaccharides to 55 mPa s in a 75% solution of alginic acid oligosaccharides. The value is nearly identical to the 41 mPa s for a 75% sucrose
solution, indicating that alginic acid oligosaccharides may be used as a
182
6 Seaweed Biotechnology