and seed gums such as locastobin gum, guar gum, and tamarind gum are carbohydrates used as stabilizers and emulsifying agents in food, cosmetics, and medicine (Wei et al. 2013).
Algae typically have thick cell walls. Cellulose is found in most types, but not in
large quantities; mannan and xylan are present in red and green algae. The chief
ingredients of the dietary fiber contained in algae are the mucilaginous polysaccharides present between cells. These include agar, carrageenan, funoran, and
porphyran in red algae; alginic acid and fucoidans in brown algae; water soluble
uronic acid sulfated polysaccharides and water soluble neutral sulfated polysaccharides in green algae. Laminaran, a storage polysaccharide in brown algae, is also
a dietary fiber that is not broken down by human digestive enzymes. Characteristics
of these forms of dietary fiber in algae include the presence of ingredients not found
in land plants, such as agar, carrageenan, and alginic acid. Many carboxyl groups
and ester-linked sulfate groups are present, although this is believed to be the result
of structural differentiation to regulate the passage of ions for growth in highly
saline environments.
All of the above are derived from plant life. Animal-based forms of dietary fiber
also exist, including the chitin that is the chief ingredient in shrimp and crab shells,
and the hyaluronic acid present in the connective tissues of mammals. Derivatives
resulting from chemical modifications to polysaccharides, including methyl cellulose and polydextrose, are also treated as dietary fiber.
B. Algae Consumption
A national nutritional study on the consumption of dietary fiber by South Koreans
calculated an average of 20 g per day per person—a far higher level than in either
Japan (16 g) or the U.S. (13 g).
Dietary fiber contribution rates calculated for different types of food include 38%
for vegetables, mushrooms, and algae; 29% for rice/grains, potatoes, sweet potatoes, and seeds; 9% for tofu; and 14% for fruit. By themselves, algae accounted for
around 7%. In Japan, dietary fiber consumption was down to 16 g from 21 g thirty
years before, a decline that has reportedly become even sharper in recent years.
Different regions also show considerable variation in consumption. Among
Americans, survey reports in the U.S. have shown daily dietary fiber consumption
of 13 g. Contribution rates included 28% from vegetables, 19% from breads, 17%
from fruits, and 14% from beans. The numbers show considerable differences in
dietary fiber consumption from South Korea, which may be attributable to differences in diet (Lee et al. 2010).
C. Roles of Algae Within the Body
Physicochemical properties of dietary fiber vary according to its components, but
major physiological roles include water adsorption, ion exchange, and gel formation. Table 8.6 shows the roles of dietary fiber in different parts of digestive organs.
Because people naturally chew more when consuming food containing large
8.4 Functional Food Materials
273
Algae typically have thick cell walls. Cellulose is found in most types, but not in
large quantities; mannan and xylan are present in red and green algae. The chief
ingredients of the dietary fiber contained in algae are the mucilaginous polysaccharides present between cells. These include agar, carrageenan, funoran, and
porphyran in red algae; alginic acid and fucoidans in brown algae; water soluble
uronic acid sulfated polysaccharides and water soluble neutral sulfated polysaccharides in green algae. Laminaran, a storage polysaccharide in brown algae, is also
a dietary fiber that is not broken down by human digestive enzymes. Characteristics
of these forms of dietary fiber in algae include the presence of ingredients not found
in land plants, such as agar, carrageenan, and alginic acid. Many carboxyl groups
and ester-linked sulfate groups are present, although this is believed to be the result
of structural differentiation to regulate the passage of ions for growth in highly
saline environments.
All of the above are derived from plant life. Animal-based forms of dietary fiber
also exist, including the chitin that is the chief ingredient in shrimp and crab shells,
and the hyaluronic acid present in the connective tissues of mammals. Derivatives
resulting from chemical modifications to polysaccharides, including methyl cellulose and polydextrose, are also treated as dietary fiber.
B. Algae Consumption
A national nutritional study on the consumption of dietary fiber by South Koreans
calculated an average of 20 g per day per person—a far higher level than in either
Japan (16 g) or the U.S. (13 g).
Dietary fiber contribution rates calculated for different types of food include 38%
for vegetables, mushrooms, and algae; 29% for rice/grains, potatoes, sweet potatoes, and seeds; 9% for tofu; and 14% for fruit. By themselves, algae accounted for
around 7%. In Japan, dietary fiber consumption was down to 16 g from 21 g thirty
years before, a decline that has reportedly become even sharper in recent years.
Different regions also show considerable variation in consumption. Among
Americans, survey reports in the U.S. have shown daily dietary fiber consumption
of 13 g. Contribution rates included 28% from vegetables, 19% from breads, 17%
from fruits, and 14% from beans. The numbers show considerable differences in
dietary fiber consumption from South Korea, which may be attributable to differences in diet (Lee et al. 2010).
C. Roles of Algae Within the Body
Physicochemical properties of dietary fiber vary according to its components, but
major physiological roles include water adsorption, ion exchange, and gel formation. Table 8.6 shows the roles of dietary fiber in different parts of digestive organs.
Because people naturally chew more when consuming food containing large
8.4 Functional Food Materials
273