1. Stephanie Diamond, Emilee Landers, Andrea Sierra-Cadavid
Tannins
Stephanie Diamond, Emilee Landers, Andrea Sierra-Cadavid

2. What are tannins? Large molecular weight phenolic compounds
Condensed and Hydrolyzable
chemistry.about.com

3. Chemistry of Tannins Hydrolyzable Tannins Condensed Tannins
Mainly gallic acid and related compounds
Hydrolyzed by acid, alkali, enzymes and hot water
Condensed Tannins
Also called proanthocyanins
Polymerized flavan-3-ols
E. Haslam / Chemistry of Vegetable Tannins. (1966)
Fao.org

4. Chemistry of Tannins Astringency Antioxidants Prooxidants
Tannins bind carbohydrates and proteins and become insoluble
“roughness” mouthfeel
Antioxidants
Free-radical scavengers
Highly reactive phenols
Prevents oxidation
Lowers risk of CVD and cancer
Prooxidants
As with any antioxidant, at high levels can act as a prooxidant.
E. Haslam / Chemistry of Vegetable Tannins. (1966)

5. Consumption of Tannins
Ubiquitous nature in foods
Fruits
Berries, pomegranate, persimmons, and more.
Nuts
Herbs and Spices
Beverages
Tea and wine
Consumption estimated between 1 and 1.1 g/day
Potential to be a main source of antioxidant in the human diet
Traditionally used in herbal medicines and teas

6. Tannins as an anti-nutrient
Reduces the nutritional value of a food
Inhibition of digestive enzymes (due to protein binding ability)
Reduction in bioavailability of iron, vitamin A and B12
Anti-nutrient activity found only in in-vitro studies
Inhibition not thoroughly understood
Caused by tannins or other mechanisms?
Absorption affected by glycosylation, conjugation, size, degree of polymerization, solubility
Contradictory research
Bioavailability of iron in high and low tannin foods essentially the same
L. Bravo / Nutrition Reviews (1998)

7. Tannins as Carcinogens
Oral cancer
Betel nuts, containing 20% tannins
Esophageal cancer
Associated with hot tea consumption
May have actually been associated with the temperature of the water
Prevailing sentiment: Tannins exhibit primarily health-promoting properties.
L. Bravo / Nutrition Reviews (1998)

8. Tannins in Nuts
Nuts more widely known for other health-promoting properties
High in unsaturated fatty acids
Cholesterol lowering
Condensed tannins
Almonds and hazelnuts
Hydrolyzable tannins
Walnuts
Current research on nuts and tannins almost entirely quantification
Karamać (2009) looked at levels of antioxidant activity related to tannins in nuts
Walnuts > hazelnuts > almonds
Huge research potential for nuts
Nutstop.com
M. Karamać / Eur. J. Lipid Sci. Technol. (2009)

9. Berries
Popular in USA
Popular in other countries
Exotic berries

10. Berries Highly nutritious fruit: Vit A and Vit C
Ca, Fe, Mg
Good source of dietary fiber
High content of antioxidant compounds
Schwartz and others 2008
Antioxidants: Reference from Food Chenistry book
Agrilife.org/phytochemicals
N.P. Seeram NP / J. Agric. Food Chem. 56 (2008) 627–629

11. Tannins in Berries
Different types of phytochemicals: One of the most important ones are TANNINS
Condensed: Proanthocyanidins
Hydrolyzables: ellagitannis and gallotannis
N. Seeram et al. / Separation and Purification Technology 41 (2005) 49–55

12. Bioavailability reported to be low!!
Tannins in Berries
Bioavailability reported to be low!!
BUT
Addison Wesley Longman Inc
Bioavailability reported to be low!! Since blood levels after consumption seems to be low
But
Well metabolized and rapidly converted to related molecules by the colon microflora
Metabolized and stored in the target tissues where they accomplish the biological effect
Difficult to detect due to laboratory and extraction techniques limitations
N.P. Seeram / J. Agric. Food Chem. 56 (2008) 627–629

13. Tannins in Berries
Type of tannins varies according to the specific berry and give each berry a different beneficial effect.
Proanthocyanidins: Cranberries and blueberries.
Ellagitannins: Strawberries, cloudberries and raspberries.

14. Tannins in Berries
Proanthocyanidins from blueberry act on striatum of the brain helping to keep the memory function while ageing.
Ging model in rodets: Comparison of natural aging vs. irradiated mices. Both got beneffits from bluberry and strawberry extracts
Ellagitannins from strawberry act on hippocampus of the brain reducing the effect of aging on spatial orientation.
B. Shukitt-Hale B et al. / Neurobilogy of Aging, 20 (2007)

15. Tannins in Berries
Proanthocyanidins from Cranberry have a protective effect against urinary track infections
The beneficial effect was explained by the anti-adhesion mechanism imparted by tannins which avoided the attachment of Echerichia coli to uroepithelial cells reducing the risk of urinary tract infection
Gunraj S. 2013
A.B. Howell / Critical Reviews in Food Science and Nutrition, 42 (2008)

16. Tannins in Berries
Ellagitannins from cloudberry and raspberry may reduce the incidence of some foodborne diseases.
Inhibits growth of Staphyloccocus aureus and partial growth ofSalmonella sv. Typhimurium during ferementation
Add salmonella or colon or cloudberry
R. Puupponen-Pimiä et al. / J. Applied Microbiology 98 (2005) 991–1000.

17. Tannins in Berries
Ellagitannins from pomegranate may work as preventive agents for Arthritis Rheumatoid and Osteoarthritis Block the signal transduction pathways and the response of pathogenic cells
Copeland 2013
Mice model using a pomegrante extract to fed the mice
M. Shukla et al. / Nutrition 24 (2008) 733–743

18. Tannins in Berries
Punicalagin an ellagitannin from pomegranate, inhibits cyclooxygenase enzyme COX-2, protein kinase B (AKT) and the nuclear factor kappa-B (NFκB) mechanism in colon cells.
Extract from pomegranate ellagitannins could be used for colon cancer prevention and treatment .
L.S. Adams et al. / J. Agric. Food Chem. 54 (2006)

19. Red Wine Tannins Belongs to Non-hydrolyzable group
Condensed tannin (aka proanthocyanidins) source is from grapes
Skins: prodelphinidins and procyanidins
Seeds: only procyanidins
Gomez-Plaza E, Hernandez- Jimenez A, Bautista-Ortin AB Proanthocyanindins in Grapes and Wine: A Review. In: Petridis GK (editor) Tannins: Types, Food Containing, and Nutrition. Hauppauge, New York: Nova Science Publishers p.
Images from: and

20. Red Wine Tannins Contains 1.2-4.4g of condensed tannins per liter
Amount of tannins depends on various attributes
Fermentation of skins and seeds
Solubility of tannins
Maceration time
Calculate contribution
Berdanier CD CRC Desk Reference for Nutrition. Boca Raton, Florida: CRC Press LLC. 321 p.
Gomez-Plaza E, Hernandez- Jimenez A, Bautista-Ortin AB Proanthocyanindins in Grapes and Wine: A Review. In: Petridis GK (editor) Tannins: Types, Food Containing, and Nutrition. Hauppauge, New York: Nova Science Publishers p.

21. Red Wine Tannins Health benefits Bioavailability
Antioxidant/cancer prevention
Scavenge free radical, chelate transition ions
Cardiovascular disease prevention
Lowers plasma cholesterol levels, inhibits oxidation of LDLs, prevent blood clots
Bioavailability
34mg catechin/120mL red wine, and 0.072µM was the max concentration in human plasma
Due to larger structure that can bind other materials, believe that condensed tannins are better absorbed in the large intestine
Colon microbiota
Gomez-Plaza E, Hernandez- Jimenez A, Bautista-Ortin AB Proanthocyanindins in Grapes and Wine: A Review. In: Petridis GK (editor) Tannins: Types, Food Containing, and Nutrition. Hauppauge, New York: Nova Science Publishers p.
Serrano J, et al./ Molecular Nutrition and Food Research.53:
Donovan JL, et al./British J. Nutrition. 87:

22. Tea Tannins Green Tea Black Tea
Fresh leaves that are steamed or pan-fried, then dried to deactivate enzymes
Black Tea
Withered leaves are crushed and polyphenol oxidase can act on the catechins and gallocatechins to form oligomeric theaflavins and polymeric thearubigens
Babich H, Gottesman RT, Liebling EJ, Schuck AG Theaflavin-3-gallate and Theaflavin-3'-gallate, Polyphenols in Black Tea with Prooxidant Properties. Basic & Clinical Pharm & Tox. 103:66-74.

23. Tea Tannins Epidemiological studies: drinking tea regularly
Reducing risk for diseases (cancer & CVD) even subject is constantly exposed to toxic substances (consuming alcohol and smoking)
Bioavailability
Flavon-3-ol in green tea = 39% bioavailability in humans
Great differences in excretion, this may be due to difference in participants’ microbiota
Smiechowska M, Dmowski P Influence of Selected Factors on the Content of Tannins in Tea Extracts. In: Petridis GK (editor) Tannins: Types, Food Containing, and Nutrition. Hauppauge, New York: Nova Science Publishers p.
Zhu M et al./Planta medica 66:
Del Rio D at al./ Nutrition 26:

24. Persimmon Belong to non-hydrolyzable group of tannins
Specific repeating units to form tannins within persimmons
Catechin
Catechin-3-gallate
Gallocatechin
Gallocatechin-3-gallate
Besada C, Salvador A. Tannins of Persimmon Fruit: Artificial Removal of Astringency. In: Petridis GK (editor) Tannins: Types, Food Containing, and Nutrition. Hauppauge, New York: Nova Science Publishers p.

25. Persimmon Health benefits Structure cause for health benefits
Antioxidant activity
Anti-inflammatory activity
Hypolipidemic activity
Enzyme inhibiting
Detoxification of snake venom
Structure cause for health benefits
Monomeric flavan-3-ol units
Types of interflavan bonds
Degree of polymerization
Li et al./ Acta Horticulturae 996:
Images from: en.wikipedia.org

26. Conclusion Large molecular weight phenolic compounds
Two categories: Condensed and Hydrolyzable
Wide variety of health benefits
Antioxidants
Lowers risk of CVD and cancer
Found in a large variety of foods and beverages
Further research is needed
Understand benefits and possible risks as an anti-nutrient
Understand bioavailability
Colon microbiota

27. Thank you
Questions?