tannins - bogor agricultural universityanuragaja.staff.ipb.ac.id/files/2016/03/2-tannins.pdf ·...
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Department of Nutrition and Feed Technology
Outline
A. IntroductionB. StructureC. InteractionD. Analytical methodsE. Biological effectsF. Treatments/processing methods
Department of Nutrition and Feed Technology
A. Introduction
Plant secondary compounds- Do not function in primary metabolism such as biosynthesis,
biodegradation and other energy conversions of intermediary metabolism
- Do have diverse biological activities ranging from toxicity to hormonal mimicry
- May play a role in protecting plants from herbivory and disease- Examples: alkaloids, terpenes, phenolics
Tannins, definitionWater-soluble phenolic compounds that have ability to precipitate proteins
Department of Nutrition and Feed Technology
ClassificationCondensed tannin (CT, proanthocyanidins): oligomers of two or more flavan-3-ols such as catechin, epicatechin, or gallocatechin.Hydrolysable tannin (HT): consisting of a central core of carbohydrate to which phenolic carboxylic acids are bound by ester linkage.
Department of Nutrition and Feed Technology
Why plants produce phenolics?
A strategy adopted by plants to deter attack by microorganisms,
insects and higher animals.
Factors affecting tannin levels:
- Nutrient stress (N, P, K, S deficiencies)
- High light intensity
- High temperature
- Severe drought
- Tissue damage
Increase tannin
levels
Department of Nutrition and Feed Technology
Condensed tannin (CT)
Hydrolysable tannin (HT)
B. Structure
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Diversity of tannin structures
Source: Mueller-Harvey (2006)
J. Sci. Food Agric. 86, 2010-2037.
Department of Nutrition and Feed Technology
Multiple hydroxyl groups: enable phenolics to form complexes
with proteins, polysachharides and minerals.
Tannin-protein complex:
1. Hydrogen bonds: free phenolic hydroxyl groups
2. Hydrophobic bonds: aromatic ring structures
3. Covalent bonds: polymerization reactions due to heating,
exposure to UV radiation and the action of polyphenol
oxidase
C. Interaction
Department of Nutrition and Feed Technology
Illustration of protein precipitation by tannins
Marangon et al. (2010)Analytica Chimica Acta 660, 110-118
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D. Analytical methods
- Categorized into: (1) chemical methods, (2) protein precipitation methods, (3) gravimetric assays, (4) tannin bioassay, (5) Others.
- Chemical assays: - Total phenols and total tannins: Folin-Ciocalteu (oxidation-reduction),
ferric chloride (metal-complexing property of phenolics)- Condensed tannins: vanilin assay, butanol-HCl assay- Hydrolysable tannins: rhodanine method, HPLC
- Protein precipitation assays: ninhydrin assay, BSA method, radial diffusion assay
- Gravimetric methods: ytterbium acetate, PVPP- Tannin bioassay: in vitro gas production + PEG (e.g. Jayanegara &
Sofyan, 2008)
More detailed methods ....
Department of Nutrition and Feed Technology
E. Biological effects
Negative effects:- Decreasing nutrient utilization, in particular protein utilization- Decreasing feed intake- Toxicity and death of animals
Positive effects:- Prevention of bloat- Protection of protein from rumen degradation- Mitigating methane emission- Modulation of PUFA biohydrogenation in the rumen- Controling of gastro-intestinal nematode parasites
Department of Nutrition and Feed Technology
Mitigating methane emission
Source: Morgavi et al. (2010)
Animal 4, 1024-1036
• Global warming
• Loss of energy
Department of Nutrition and Feed Technology
Evidences:- Jayanegara et al. (2009), Animal Feed Science and Technology 150, 230-
237- Jayanegara et al. (2009), Media Peternakan 32, 120-129- Jayanegara et al. (2010), Sustainable Improvement of Animal Production
and Health (Odongo, N.E., Garcia, M., Viljoen, G.J. (Eds.)), FAO, Rome, pp. 151-157
- Jayanegara et al. (2011), Animal Feed Science and Technology 163, 231-243
- Jayanegara et al. (2012), Journal of Animal Physiology and Animal Nutrition 96, 365-375
- Jayanegara et al. (online first), British Journal of Nutrition
Department of Nutrition and Feed Technology
Source: Bhatta et al. (2009)
J. Dairy Sci. 92, 5512-5522 Phenolics and microbial population
Department of Nutrition and Feed Technology
Protozoa colonized by
methanogens
Ruminal methanogens attached to protozoal
species interspecies H transfer
Protozoa-associated methanogens contribute
up to 37% of total rumen methane emissions
Removal of protozoa from the rumen
(defaunation) may ↓ CH4 emission
Department of Nutrition and Feed Technology
Source: Chilliard et al. (2007)
Eur. J. Lipid Sci. Technol. 109, 828-855
α-Linolenic acid
Linoleic acid
Rumenic acid
Vaccenic acid
Stearic acid
• Reduce the risk of
cardiovascular disease
• Lowering plasma
cholesterol level
• Prevent cancer
proliferation
• Decrease atherosclerosis
• Improve immune system
Modulation of PUFA biohydrogenation
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Source: Khiaosa-ard et al. (2009)
J. Dairy Sci. 92, 177-188
CH: grass-clover hay (control)
TF: dried sainfoin (7.9% CT)
TH: CH + A. mearnsii extract (7.9% CT)
SH: CH + Y. schidigera extract (1.1% saponins)
Condensed tannins (CT)
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Influence of tannins on biohydrogenating bacteria
Source: Vasta et al. (2010)
Appl. Environ. Microbiol. 76, 2549-2555
Containing 6.4% tannins
from quebracho powder
Department of Nutrition and Feed Technology
Inhibition of phenolics on lipase activity
Source: Van Ranst et al. (2011)
Animal 5, 512-521
Department of Nutrition and Feed Technology
Other evidences:- Jayanegara et al. (2011), Animal Production Science 51, 1127-1136- Jayanegara et al. (2012), Livestock Science 147, 104-112- Palupi et al. (online first), Journal of the Science of Food and Agriculture
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F. Treatment methods
- Wood ash: a good source of alkali; 10% solution of oak wood ash decreased the content of TP, CT and protein precipitation capacity by 66, 80 and 75% in oak leaves, respectively.
- Urea-ammoniation: 4% urea in fresh leaves. - Drying: but not effective.- Chemicals: extraction with organic solvents (30% acetone, 50%
methanol, 40% ethanol) removed ca 70% tannins from oak leaves.- Solid-state fermentation: biodegradation of tannins using white-rot
fungi.- Addition of tannin-binding polymers: PEG (polyethylene glycol)
incorporation, PVPP.