The key difference between tannins and tannic acid is that tannins are a class of organic molecules that occur in plant tissues, whereas tannic acid is a type of tannin and has a weak acidity.
Tannins are a group of polyphenols. Tannic acid a specific type of tannin. A polyphenol is an organic compound containing several phenol functional groups. Tannins are polyphenolic biomolecules.
CONTENTS
1. Overview and Key Difference
2. What are Tannins
3. What is Tannic Acid
4. Side by Side Comparison – Tannins vs Tannic Acid in Tabular Form
5. Summary
What are Tannins?
Tannins are a group of polyphenols that can bind with proteins and precipitate them. These compounds can also react with amino acids and alkaloids. Tannins are astringent compounds. We can observe the occurrence of tannins in a wide variety of plant tissues. It plays an important role in providing protection to the plants from predation, and it also helps the regulation of plant growth. We can find tannins in unripe fruits, which cause their dry and pucker felling due to the astringency of tannins.
Figure 01: Tannin Powder
There are three classes of tannins as hydrolysable tannins, phlorotannins and condensed tannins. All these types are polymeric structures having monomer units: the monomer for hydrolysable tannins is gallic acid, while monomer for phlorotannins is phloroglucinol and monomer for condensed tannins is flavan-3-ol. There are different sources for each class of tannin. For example, the source for hydrolysable tannins is the plants, while the source for phlorotannins is the brown algae, and for condensed tannins, the source is heartwood.
For the determination of the presence of tannins in a given sample, we can use three types of methods. They are the alkaloid precipitation method, Goldbeater’s skin test and ferric chloride test. In the alkaloid precipitation method, we can observe that alkaloids can precipitate tannins and other polyphenols. It can be used as a quantitative analysis, as well. We can determine the presence of tannins via Goldbeater’s skin test; when the goldbeater’s skin is dipped in hydrochloric acid and rinsed in water, followed by treatment with ferrous sulfate solution, it gives a blue-black colour if it contains tannin.
What is Tannic Acid?
Tannic acid is an organic molecule which has the chemical formula C76H52O46. It is a specific type of tannin, and it is a polyphenol. It has a weak acidity. That is due to the presence of several phenol functional groups.
Figure 02: Structure of Tannic Acid
There are many important applications of tannic acid. For example, we can apply tannic acid to wood that is low in tannin, which helps to react with chemical stains. Moreover, we can use tannic acid as a mordant in the dyeing process for the production of cellulose fibre forms such as cotton. Furthermore, we can use tannic acid on metal objects for the conservation of the ferrous form from corrosion and passivate. Apart from that, tannic acid is useful in the food industry as well. e.g. beer clarification, wine clarification, colour stabilizing, etc.
What is the Difference Between Tannins and Tannic Acid?
Tannins are a group of polyphenols. Tannic acid a specific type of tannin. The key difference between tannins and tannic acid is that tannins are a class of organic molecules that occurs in plant tissues, whereas tannic acid is a type of tannin and has a weak acidity.
Below tabulation details the difference between tannins and tannic acid.
Summary – Tannins vs Tannic Acid
Tannins are a group of polyphenols, while tannic acid a specific type of tannin. The key difference between tannins and tannic acid is that tannins are a class of organic molecules that occurs in plant tissues ,whereas tannic acid is a type of tannin and has a weak acidity.
Reference:
1. Hirst, K. Kris. “The Origins and History of Winemaking.” ThoughtCo, Feb. 11, 2020, Available here.
2. “Tannin.” Wikipedia, Wikimedia Foundation, 31 Jan. 2020, Available here.
3. “Tannic Acid.” Wikipedia, Wikimedia Foundation, 6 Dec. 2019, m
Image Courtesy:
1. “Tannin heap” By Simon A. Eugster – Own work (CC BY 3.0) via Commons Wikimedia
2. “Tannic acid” By en:User_talk:Ronhjones – Own work (Public Domain) via Commons Wikimedia