Question

Kindly provide studies on hydrolysis mechanism of inulin in human body

ANSWER

Inulin is soluble dietary fibre that derived from chicory root and belongs to a group of non-digestible carbohydrates called fructans. The basic characteristics of dietary fibres are impervious to hydrolysis by the gastric secretions and absorption occur in the small intestine while they are fermentable by the microflora in large intestine (Shoaib et al., 2016).

References Findings
Miremadi & Shah, 2012
  • To study the physiology of the digestive system in humans and to quantify the amount of inulin exiting the small intestine, they used the ileostomy model.
  • The small loss of inulin during the passage through the small intestine could be due to fermentation by the microbial population colonizing the small intestine in individuals with ileostomies.
  • This microbial population is known to be up to 100 times greater in the people with ileostomy than in normal individuals.
  • During passage through the gastro-intestinal tract, inulin as a non-digestible carbohydrate never produces fructose, glucose, lactic acid and short chain carboxylic acid (the end products of glycolysis and anaerobic fermentation) in the small intestine.
Saeed et al, 2015
  • Inulin is indigestible carbohydrates because β-configuration of the anomeric Carbon No.2 makes inulin resistant to digestion by the enzymes in small intestine.
  • Inulin decreases the pathogens in small intestine thereby increasing the prebiotic count.
Tiefenbacher, 2018
  • Inulins are a mix of high molecular fructans and some low molecular parts, all linked by β(2,1) bonds which are not digestible in the human intestinal tract.
Azpiroz et al., 2017
  • Inulin is a mixture of oligosaccharides and polysaccharides composed of fructose units connected by β (2→1) links.
  • Because of the β-configuration of the anomeric C2 in their fructose monomers, these fructans are resistant to hydrolysis by human digestive enzymes (α-glucosidase, maltase, isomaltase, sucrase) which are specific for α-glycosidic bonds, and are thus classified as non-digestible oligosaccharides on the basis of both in vitro and in vivo data.
  • It is a nondigestible carbohydrate, is a dietary fiber that reaches the colon intact and serves as a substrate for microbiota metabolism.
Watson, Preedy & Zibadi, 2014
  • Inulin resists digestion and is fermented in the colon to produce large amounts of short-chain fatty acids (SCFAs) – mainly acetic acid, propionic acid, butyric acid) and lactate.
Schaafsma & Slavin, 2014
  • Cecal and colonic carbohydrate fermentation of inulin result in the production of SCFA, lactate, gasses (hydrogen, carbon dioxide, and methane) and in a reduction of the luminal pH.
  • The SCFA are largely (95% to 99%) absorbed, covering about 10% of human energy requirement.
  • Butyrate is used directly by the colonic cells, exerting a trophic effect on these cells.
  • SCFA stimulates salt and water absorption and epithelial growth.
  • The saccharolytic activities increase biomass, fecal bulk, stool weight, and stool frequency.

 

References

Azpiroz, F., Molne, L., Mendez, S., Nieto, A., Manichanh, C., & Mego, M. et al. (2017). Effect of Chicory-derived Inulin on Abdominal Sensations and Bowel Motor Function. Journal Of Clinical Gastroenterology, 51(7), 619-625. https://doi.org/10.1097/mcg.0000000000000723

Miremadi, F., & Shah, N. P. (2012). Applications of inulin and probiotics in health and nutrition. International Food Research Journal, 19(4), 1337-1350.

Saeed, M., Yasmin, I., Pasha, I., Atif Randhawa, M., Issa Khan, M., Asim Shabbir, M., & Ali Khan, W. (2015). Potential application of inulin in food industry; A review. Pakistan Journal Of Food Sciences, 25(3), 110-116.

Shoaib, M., Shehzad, A., Omar, M., Rakha, A., Raza, H., Sharif, H. R., Shakeel, A., Ansari, A. & Niazi, S. (2016). Inulin: Properties, health benefits and food applications. Elsevier, 147, 444-454.

Schaafsma, G., & Slavin, J. (2014). Significance of Inulin Fructans in the Human Diet. Comprehensive Reviews In Food Science And Food Safety, 14(1), 37-47. https://doi.org/10.1111/1541-4337.12119

Tiefenbacher, K. F. (2018). The Technology of Wafers and Waffles II: Recipes, Product Development and Know-How (p. 365). San Diego: Elsevier Science & Technology.

Watson, R., Preedy, V., & Zibadi, S. (2014). Wheat and Rice in Disease Prevention and Health: Benefits, risks and mechanisms of whole grains in health promotion (p. 215). Burlington: Elsevier Science.

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