Tannase is an enzyme that plays a role in various biological processes and industrial applications. It is a hydrolase, specifically an acylhydrolase, that breaks down compounds using water. Its activity is valuable in biochemical processes and the food industry. Tannase is produced by various microorganisms, including several species of fungi and bacteria.
The Role of Tannins
Tannins are natural plant compounds classified as polyphenols, which are large molecules containing multiple hydroxyl groups. They are widely distributed in plants, found in bark, leaves, fruits, seeds, and wood. Tannins are responsible for the astringent, dry, or puckery sensation experienced when consuming unripe fruits, strong black tea, or red wine. This characteristic taste serves a protective function for plants, deterring animals from consuming fruits before their seeds are mature. Beyond their taste, tannins have the unique ability to bind with and precipitate proteins and other organic molecules, a property historically significant in leather production where tree bark tannins were used to “tan” animal hides.
How Tannase Functions
Tannase, also known as tannin acyl hydrolase, is a hydrolytic enzyme that specifically acts upon hydrolyzable tannins. Its primary biochemical action involves the hydrolysis of ester and depside bonds within these tannin molecules. This process, which involves the addition of water, breaks down complex tannins into simpler compounds. For instance, tannase can completely hydrolyze tannic acid, a type of hydrolyzable tannin, into gallic acid and glucose. The enzyme’s ability to cleave these specific bonds allows for the modification or degradation of tannins at a molecular level.
Key Applications of Tannase
Tannase has found diverse applications across several industries due to its ability to modify tannins. In the food and beverage sector, it is used to clarify fruit juices and wines by removing turbidity and haze caused by phenolic compounds. The enzyme also de-bitters tea, improving its taste and aroma by breaking down tannins. It aids in instant tea production by preventing insoluble precipitates when cooled.
The pharmaceutical industry uses tannase to produce gallic acid. Gallic acid serves as an intermediate for synthesizing antibacterial drugs like trimethoprim and antioxidants such as propyl gallate. Tannase also plays a role in the leather industry, where it can be used for de-tanning processes. It also improves animal feed quality by reducing the anti-nutritional effects of tannins, enhancing digestibility.
Tannase and Human Health
Tannase is relevant to human health due to its interaction with dietary tannins. Tannins in food can act as anti-nutritional factors by binding to proteins and carbohydrates, potentially reducing their digestibility and hindering nutrient absorption. Tannase can mitigate these effects by breaking down tannins, which may improve the availability of nutrients from tannin-rich foods.
While direct human clinical studies on tannase supplementation are limited, research in food technology and animal nutrition suggests that enzymatic treatment with tannase can enhance protein and starch digestibility. There is also interest in its potential to reduce gastrointestinal discomfort in individuals sensitive to tannins. Some studies have explored the potential health implications of tannins themselves, with conflicting reports on their effects, ranging from anti-carcinogenic properties to associations with certain cancers, depending on the type and concentration of tannins.