58
collectively referred to as dietary fiber. Most of these polysaccharides are usually
resistant to digestion in the human alimentary system. A very good example is the
resistant starch which is a starch fraction that can only be fermented by the large
intestinal microbiota. The reason for this is that the human genome does not encode
adequate gastrointestinal enzymes that can metabolize polysaccharides. Hence, the
degradation of polysaccharides can only be achieved through a series of enzymes
derived from intestinal microbiota (Karaduman et al. 2010).
The intestinal microbiota is a dynamic organ that plays a key role in maintaining
health. It is a complex aggregation of microscopic organisms in the gut which may
involve more than 100 trillion microorganisms (Gilbert et al. 2016). The diversity
and density of these microorganisms are highest in the colon (Hornung et al. 2018).
These microbes participate in vital physiological functions for the host. They also
establish complex interactions with each other. The interactions could range from a
mutual relationship to competitive relationships that may directly or indirectly
influence the well-being of the host (Partida-Rodríguez et al. 2017). One evidence
for this is that the germ-free animals are more vulnerable to germs than the colonized animals (Shang et al. 2018).
Dietary polysaccharides are known to impact gut microbial ecology and studies
have indicated that gut microbiota can impact host nutrition, immune modulation,
resistance to pathogens, intestinal epithelial development and activity, and energy
metabolism (Jacobs et al. 2009). Bacteria in the human gut produce hundreds of
polysaccharide degrading enzymes, which account for roughly 2.62% of the total
enzymes encoded by the intestinal microbiome (Karaduman et al. 2010). Hence,
these polysaccharides serve as unique carbon sources for the intestinal bacteria during fermentation. Arabinogalactans, galactomannans, glucomannans, laminarin (a
glucan), and other mixed polysaccharide products are examples of bioactive polysaccharides that can be metabolized by human colonic bacteria (Kalia et al. 2011).
Jiang et al. (2016) documented that apple pectin can increase Firmicutes phylum,
decrease Bacteroidetes phylum and ameliorate the fat accumulation and body
weight in diet-induced obese rats. According to Wang et al. (2011) for any carbohydrate to be defined as prebiotic carbohydrates, it must meet the following criteria:
(i) The carbohydrate must be resistant to
• gastric acidity
• hydrolysis by mammalian enzymes
• gastrointestinal absorption
• fermentation by intestinal microflora.
(ii) The carbohydrate in question must have selective stimulation on the growth and
activity of intestinal probiotic bacteria
The beneficial effect of many polysaccharides is mainly dependent on their fermentability since human alimentary system cannot digest most of the polysaccharides completely. Other benefits include physiochemical properties such as
water-holding capacity and bile acid-binding ability. The natural polysaccharides
therefore, benefit human health by slowing gastric emptying, improving the bowel
T. A. Oyedepo and A. A. A. Kayode
collectively referred to as dietary fiber. Most of these polysaccharides are usually
resistant to digestion in the human alimentary system. A very good example is the
resistant starch which is a starch fraction that can only be fermented by the large
intestinal microbiota. The reason for this is that the human genome does not encode
adequate gastrointestinal enzymes that can metabolize polysaccharides. Hence, the
degradation of polysaccharides can only be achieved through a series of enzymes
derived from intestinal microbiota (Karaduman et al. 2010).
The intestinal microbiota is a dynamic organ that plays a key role in maintaining
health. It is a complex aggregation of microscopic organisms in the gut which may
involve more than 100 trillion microorganisms (Gilbert et al. 2016). The diversity
and density of these microorganisms are highest in the colon (Hornung et al. 2018).
These microbes participate in vital physiological functions for the host. They also
establish complex interactions with each other. The interactions could range from a
mutual relationship to competitive relationships that may directly or indirectly
influence the well-being of the host (Partida-Rodríguez et al. 2017). One evidence
for this is that the germ-free animals are more vulnerable to germs than the colonized animals (Shang et al. 2018).
Dietary polysaccharides are known to impact gut microbial ecology and studies
have indicated that gut microbiota can impact host nutrition, immune modulation,
resistance to pathogens, intestinal epithelial development and activity, and energy
metabolism (Jacobs et al. 2009). Bacteria in the human gut produce hundreds of
polysaccharide degrading enzymes, which account for roughly 2.62% of the total
enzymes encoded by the intestinal microbiome (Karaduman et al. 2010). Hence,
these polysaccharides serve as unique carbon sources for the intestinal bacteria during fermentation. Arabinogalactans, galactomannans, glucomannans, laminarin (a
glucan), and other mixed polysaccharide products are examples of bioactive polysaccharides that can be metabolized by human colonic bacteria (Kalia et al. 2011).
Jiang et al. (2016) documented that apple pectin can increase Firmicutes phylum,
decrease Bacteroidetes phylum and ameliorate the fat accumulation and body
weight in diet-induced obese rats. According to Wang et al. (2011) for any carbohydrate to be defined as prebiotic carbohydrates, it must meet the following criteria:
(i) The carbohydrate must be resistant to
• gastric acidity
• hydrolysis by mammalian enzymes
• gastrointestinal absorption
• fermentation by intestinal microflora.
(ii) The carbohydrate in question must have selective stimulation on the growth and
activity of intestinal probiotic bacteria
The beneficial effect of many polysaccharides is mainly dependent on their fermentability since human alimentary system cannot digest most of the polysaccharides completely. Other benefits include physiochemical properties such as
water-holding capacity and bile acid-binding ability. The natural polysaccharides
therefore, benefit human health by slowing gastric emptying, improving the bowel
T. A. Oyedepo and A. A. A. Kayode