**2. Application of tannins in various industry**

Currently, hydrocarbon-based raw materials are exploited in different petrochemical industries ranging from fuel to cosmetology. It leads to the widespread deficiency of raw material eventually that creates high inflations, environmental degradation, and adverse effects on human and animal health. This necessitates to explore new alternative natural biopolymers such as polylactic acid, chitosan, lignin, and tannins for replacing with currently used hydrocarbon based polymers. Tannins can be the best natural raw material for emerging and traditional industries. This is attributed to tannin's unique natural properties, chemical structure, and commercial properties [10]. Tannins provide several advantages like being as good biomaterial, antimicrobial, antioxidant, pharmaceutical, biopesticide, and nutraceutical agent. Tannins can be tapped for their applications in food, wood, leather, pharma, and other industries as possible raw material, as given below.

#### **2.1 Food industry**

Tannins are the secondary metabolites present in a substantial amount in plant-based food products. Due to their positive effects on the food as antibacterial and antioxidants, they are the major constituent of foods. Tannins are used as food preservatives, packaging materials, and food enhancements which owe to their protective nature.

#### *2.1.1 Food packaging*

Currently, most of the food items available in the market are wrapped in the packing materials which are plastic, polyethylene, and low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) due to their lightness, inertness, and easy availability. In fact, packaging increases the shelf-life and prevents physical damage, contamination, and deterioration in view of environmental contaminants. But these synthetic materials pose great level of environmental and health hazards. Hence, the concept of natural and active packaging has been introduced and there being continuous efforts to make packing materials from biological sources like, chitosan, starch, gelatin, tannins, and methylcellulose [11, 12]. In view of consumer awareness and knowledge, it becomes essential to develop new wrapping material for food items. However, nitrocellulose-based package are already in use in food industry, but currently the "active packaging" also introduced. Active packaging is a better option which protects the food material, simultaneously it also acts as an additive to improve antioxidant properties of foods and absorb unwanted substances such as heavy-metals or exhausted oils and to protect against oxidation, UV, and moisture-based degradation.

Recently, a packaging material was prepared by introducing tannins into cellulose nanofibrils in a single step process of mechanical fibrillation. This newly developed packaging film offers high density, and enhanced surface hydrophobicity which resulted in almost six times improvement in air-barrier and antioxidants properties. Simultaneously, nanocellulose-tannin-based films are active packaging materials which also provide a green, sustainable, nontoxic packaging source for food and pharmaceutical products [11, 12].

Two perishable food items, Cherry tomatoes (*Solanum lycopersicum var. cerasiforme*) and grapes (*Vitis vinifera*), were effectively preserved from *Escherichia coli* (*E. coli*) and *Staphylococcus aureus* (*S. aureus*) for 14 days by tannin-based film that was produced by introducing 15% (w/w) tannin into chitosan, gelatin, and methylcellulose films. Hence, tannins improve the physiochemical properties of

**121**

*Applications of Tannins in Industry*

ing packaging material.

*2.1.2 Food preservation*

food industry.

using natural compounds.

tannins [14].

*DOI: http://dx.doi.org/10.5772/intechopen.85984*

in the food preservation and biomedical fields.

biopolymer films, consequently improvement in overall ability to preserve fruits and vegetables. In addition, it reduced the weight loss and improved the browning index of fruits during storage. Another oligomeric procyanidins (OPCs)-based membrane in combination of flaxseed gum (FG) and lauric acid (LA) had more water vapor permeability (WVP), mechanical properties, and peroxide value (POV) of packaging film [13]. The film was evaluated for oil, salt, and vegetable preservation for 75 days. The results indicate that membrane can be used as promis-

Generally, chitin is used as packing material, but its poor antibacterial and antioxidant abilities make it unsuitable for food packaging; therefore, tannic acid was introduced in the chitin film via single step process of interfacial assembly. Tannins addition to packaging has significantly improved the antibacterial and antioxidant properties of chitin-based packaging film. Improved quality of chitin-based film is mainly attributed to hydrogen and hydrophobic bond formation between chitin and

Protein is a major component of food, and its protection is of utmost significance in packed foods. So far, tannin- and carbohydrate-based packaging films were prepared. But, a soluble dietary fiber (SDF) and tannin-based nanocluster assembly is prepared by introducing calcium ions that creates a cross-linking nucleus in membrane. Linkage between nanoassembly and proteins offer additional advantages such as high level of antimicrobial properties and excellent cell biocompatibility which was proved by FT-IR, XRD, and DSC tests [15]. Tannin-based packing materials thus offer green, sustainable, and ecofriendly alternative that can be used

Microorganism, fungus, yeasts, virus, pollens, and chemicals are the biggest threat to food's shelf-life in home as well as in food markets. Biochemically, proanthocyanidins and gallic acid are flavonoid monomers by nature and are major food constituents isolated from pomegranate, strawberry, blackberry, raspberry, walnuts, almonds, and seeds. Various studies have proved that tannins prevent growth of microorganisms. Tannins are quite effective against the resistant methicillinresistant *Staphylococcus aureus* (MRSA) [16, 17]. Moreover, Punicalagin, an ellagitannin, isolated form pomegranate peel show very strong antibacterial properties against *Staphylococcus aureus* and can be used to control *S. aureus* contamination in

Food-based viral infection is another major health problem in human and animals. Currently, blueberry proanthocyanidins were tested against human norovirus growth in apple juice (AJ) and milk with 2% fat tannin-rich fraction from pomegranate rind (TFPR) inhibited the growth of human norovirus [18]. Hence, hydrolysable tannins are potential antiviral agents that used can be used in the food preservation to make food items more safe and preserve for prolonged period by

Guava is a major tropical fruit which is also considered as a model system to study climacteric and non-climacteric fruit ripening process. Hence, it provides enough opportunities to understand post-harvest management of perishable fruits. In order to improve the shelf-life of fruits, various types of wax films, coating, and chemical treatments are used for long time. Tannins isolated from various natural sources act as preservatives due to their antibacterial and antioxidant properties. A coating material of tannic acid cross-linked with zein protein was used for coating on the guava fruit. Actually, zein is a prolamin (protein) isolated from aqueous alcohol-soluble fraction of corn (*Zea mays* L.) that earlier used to improve the

#### *Applications of Tannins in Industry DOI: http://dx.doi.org/10.5772/intechopen.85984*

*Tannins - Structural Properties, Biological Properties and Current Knowledge*

Currently, hydrocarbon-based raw materials are exploited in different petrochemical industries ranging from fuel to cosmetology. It leads to the widespread deficiency of raw material eventually that creates high inflations, environmental degradation, and adverse effects on human and animal health. This necessitates to explore new alternative natural biopolymers such as polylactic acid, chitosan, lignin, and tannins for replacing with currently used hydrocarbon based polymers. Tannins can be the best natural raw material for emerging and traditional industries. This is attributed to tannin's unique natural properties, chemical structure, and commercial properties [10]. Tannins provide several advantages like being as good biomaterial, antimicrobial, antioxidant, pharmaceutical, biopesticide, and nutraceutical agent. Tannins can be tapped for their applications in food, wood, leather, pharma, and other industries as possible raw material, as given below.

Tannins are the secondary metabolites present in a substantial amount in plant-based food products. Due to their positive effects on the food as antibacterial and antioxidants, they are the major constituent of foods. Tannins are used as food preservatives, packaging materials, and food enhancements which owe to their

Currently, most of the food items available in the market are wrapped in the packing materials which are plastic, polyethylene, and low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) due to their lightness, inertness, and easy availability. In fact, packaging increases the shelf-life and prevents physical damage, contamination, and deterioration in view of environmental contaminants. But these synthetic materials pose great level of environmental and health hazards. Hence, the concept of natural and active packaging has been introduced and there being continuous efforts to make packing materials from biological sources like, chitosan, starch, gelatin, tannins, and methylcellulose [11, 12]. In view of consumer awareness and knowledge, it becomes essential to develop new wrapping material for food items. However, nitrocellulose-based package are already in use in food industry, but currently the "active packaging" also introduced. Active packaging is a better option which protects the food material, simultaneously it also acts as an additive to improve antioxidant properties of foods and absorb unwanted substances such as heavy-metals or exhausted oils and to protect against oxidation,

Recently, a packaging material was prepared by introducing tannins into cellulose nanofibrils in a single step process of mechanical fibrillation. This newly developed packaging film offers high density, and enhanced surface hydrophobicity which resulted in almost six times improvement in air-barrier and antioxidants properties. Simultaneously, nanocellulose-tannin-based films are active packaging materials which also provide a green, sustainable, nontoxic packaging source for

Two perishable food items, Cherry tomatoes (*Solanum lycopersicum var. cerasiforme*) and grapes (*Vitis vinifera*), were effectively preserved from *Escherichia coli* (*E. coli*) and *Staphylococcus aureus* (*S. aureus*) for 14 days by tannin-based film that was produced by introducing 15% (w/w) tannin into chitosan, gelatin, and methylcellulose films. Hence, tannins improve the physiochemical properties of

**2. Application of tannins in various industry**

**2.1 Food industry**

protective nature.

*2.1.1 Food packaging*

UV, and moisture-based degradation.

food and pharmaceutical products [11, 12].

**120**

biopolymer films, consequently improvement in overall ability to preserve fruits and vegetables. In addition, it reduced the weight loss and improved the browning index of fruits during storage. Another oligomeric procyanidins (OPCs)-based membrane in combination of flaxseed gum (FG) and lauric acid (LA) had more water vapor permeability (WVP), mechanical properties, and peroxide value (POV) of packaging film [13]. The film was evaluated for oil, salt, and vegetable preservation for 75 days. The results indicate that membrane can be used as promising packaging material.

Generally, chitin is used as packing material, but its poor antibacterial and antioxidant abilities make it unsuitable for food packaging; therefore, tannic acid was introduced in the chitin film via single step process of interfacial assembly. Tannins addition to packaging has significantly improved the antibacterial and antioxidant properties of chitin-based packaging film. Improved quality of chitin-based film is mainly attributed to hydrogen and hydrophobic bond formation between chitin and tannins [14].

Protein is a major component of food, and its protection is of utmost significance in packed foods. So far, tannin- and carbohydrate-based packaging films were prepared. But, a soluble dietary fiber (SDF) and tannin-based nanocluster assembly is prepared by introducing calcium ions that creates a cross-linking nucleus in membrane. Linkage between nanoassembly and proteins offer additional advantages such as high level of antimicrobial properties and excellent cell biocompatibility which was proved by FT-IR, XRD, and DSC tests [15]. Tannin-based packing materials thus offer green, sustainable, and ecofriendly alternative that can be used in the food preservation and biomedical fields.

#### *2.1.2 Food preservation*

Microorganism, fungus, yeasts, virus, pollens, and chemicals are the biggest threat to food's shelf-life in home as well as in food markets. Biochemically, proanthocyanidins and gallic acid are flavonoid monomers by nature and are major food constituents isolated from pomegranate, strawberry, blackberry, raspberry, walnuts, almonds, and seeds. Various studies have proved that tannins prevent growth of microorganisms. Tannins are quite effective against the resistant methicillinresistant *Staphylococcus aureus* (MRSA) [16, 17]. Moreover, Punicalagin, an ellagitannin, isolated form pomegranate peel show very strong antibacterial properties against *Staphylococcus aureus* and can be used to control *S. aureus* contamination in food industry.

Food-based viral infection is another major health problem in human and animals. Currently, blueberry proanthocyanidins were tested against human norovirus growth in apple juice (AJ) and milk with 2% fat tannin-rich fraction from pomegranate rind (TFPR) inhibited the growth of human norovirus [18]. Hence, hydrolysable tannins are potential antiviral agents that used can be used in the food preservation to make food items more safe and preserve for prolonged period by using natural compounds.

Guava is a major tropical fruit which is also considered as a model system to study climacteric and non-climacteric fruit ripening process. Hence, it provides enough opportunities to understand post-harvest management of perishable fruits. In order to improve the shelf-life of fruits, various types of wax films, coating, and chemical treatments are used for long time. Tannins isolated from various natural sources act as preservatives due to their antibacterial and antioxidant properties. A coating material of tannic acid cross-linked with zein protein was used for coating on the guava fruit. Actually, zein is a prolamin (protein) isolated from aqueous alcohol-soluble fraction of corn (*Zea mays* L.) that earlier used to improve the

shelf-life of guava fruit [19]. The coated guava fruits showed reduced ripening process and improved shelf-life compared with uncoated fruits. The coated fruits also showed more positive biochemical parameters associated with better fruit shelf-life, such as total soluble solids, respiration rate, and chlorophyll contents. Moreover, ethylene, ROS production, less water loss, and gas exchanges are also observed, which are attributed to cross-linking between tannic acid and zein [19]. Hence, tannin-based package and coating material may prove more effective and ecofriendly in food industry.

#### *2.1.3 Functional foods or nutraceuticals industry*

Normal food components mainly provide the energy and essential nutrients for the growth and development for animals including human, but food also consist of bioactive molecules or phytochemicals and their inclusion in the appropriate quantity can act as possible therapeutically active agents also known as nutraceuticals, for example, (poly) phenol-rich tannins [20]. Currently, study of molecular mechanisms and pathways such as cell proliferation, apoptosis, inflammation, differentiation, angiogenesis, DNA repair pathway, and carcinogens activation offer new therapeutic targets. The application of tannins has great potential as a nutraceuticals in order to prevent various diseases such as cancer, cardiovascular, kidney diseases, and diabetes. Major sources of tannins are fruits, vegetables, bark, wood, leaves, and seeds such as green tea, apples, cocoa, chocolate, grapes, apricots, and cherries. Among them, role of tannins present in the tea and coffee to prevent the cancers have been studied by large number of scientists. The green tea contains condensed tannin namely epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), which have shown anticancerous activity in terms of inflammatory and antioxidant properties both in vivo and in vitro experimental systems [21]. Actually, EGCG decrease activation of NF-kB and (AP-1) TNF-α pathways simultaneously which ultimately reduced the production of IFN-γ. It can also enhance the apoptosis process through suppression of COX-2 enzyme that leads to the production of PGE2 (prostaglandins) in various types of cell lines of colon cancer cells, such as SW837, HT-29, and HCA-7 cells. Being a polyphenol, EGCG is a strong antioxidant that reduces the activity of nitric oxide (NO) and malondialdehyde (MDA) and conversely increases superoxide dismutase (SOD) activity in case of colonic mucosa. Hence, EGCG can improve the effect of cancer chemopreventive potency by preventing the cell proliferation, migration, and invasion of tumor in cancer patients [20].

In last two decades, a great interest has been emerged in the protective role of tannins against free radicals and reactive oxygen species produced inside cells, which caused degenerations and diseases such as cancer, atherosclerosis, and cardiovascular ailments. Proanthocyanidins have cardiovascular protective effect due to their antioxidant activity, inhibition of LDL oxidation, ability of vasodilation, antiplatelet activity, and protection against ischemia-reperfusion injury. Another tannin-based compound, gallic acid (3,4,5-trihydroxybenzoic acid), a naturally occurring with low molecular weight, plays very important in the protection of cardiovascular health through rejuvenating the antioxidant system which include large number of enzymes such as SOD, CAT, GPx, GRx, and GST which constitutes a scavenging system against the free radicals [22].

Diabetes mellitus, associated with high level of glucose concentration in the blood, is harmful for whole tissues in human body. Several investigations have shown that it can be reduced or managed by adding the appropriate amount of tannins in the nutrition or supplements of patients [23]. Because, tannins improve the glucose uptakes in body cell and simultaneously reduce the synthesis of adipocytes,

**123**

*Applications of Tannins in Industry*

*DOI: http://dx.doi.org/10.5772/intechopen.85984*

Ellagitannin capsules and Ellagic Active Tablets.

**2.2 Wood industry**

hence act as the potential therapeutic agents. In a highly significant study, it shows that epigallocatechin gallate increases the glucose uptake by regulating insulin-signaling pathways, such as PI3K (phosphoinositide 3-kinase) and p38 MAPK (mitogen-activated protein kinase) activation and GLUT-4 translocation [24]. Tannins help reduction of blood glucose levels and offer antioxidants effects [23]. Therefore, it can be concluded that tannin-based foods are potential agents used as either nutraceutical or supplementary agents in food or medicine. A dimer of proanthocyanidin acts against the hyperglycemia that was created by sucrose feeding and by inhibiting the activity of α-glucosidase enzyme. The efficacy of proanthocyanidin has also been

proved by molecular docking and strong inhibitory activity experiments.

It is already mentioned that nutraceuticals or functional foods have the health promoting effect on the human and animal health. Several epidemiological studies have clearly established a relationship between (poly) phenol-rich food items and human health. It has substantially enhanced consumer awareness about the tannin-rich diet, and their disease prevention capability; therefore, there is high demand of functional foods. A large number of tannin-based compounds are isolated and characterized from fruits and vegetables (**Table 1**). But, despite high cost incurred on extraction and separation of tannin, it offer only low yield which is a major cause of concern [25]. Additionally, it does not provide the pure content which hindered to test the efficacy and absorption of tannin-based foods in human subject. Grape-seed proanthocyanidins (GSP) were lyophilized to improve their in vivo absorbability. It was achieved by esterification of the water-soluble GSP and immobilized lipase. Lipophilicity was tested by 1-octanol/water partition coefficient as the absorbability parameter. Further, it was observed that GSP derivatives, 3′,5′-2-O-lauroyl epigallocatechin, 3′-O-lauroyl catechin, 3′-O-lauroyl epicatechin, and 3′,3″,5″-3-O-lauroyl epicatechin gallate show high level of radical scavenging activity; hence, it can be used as the strong antioxidant in food to prevent the major degenerative diseases and aging, which are generally caused by the free radicals in the tissues [25]. Recently, B-type proanthocyanidins were isolated and purified from fruits of elephant apple (*Dillenia indica* Linn.), their structural and bioactive properties were examined by using NMR, electron spray ionization, and matrixassisted laser desorption ionization time of flight mass (MALDI-TOF) spectra. In this experiment, yield of 0.23% was achieved that is far greater than commercial grape-seed proanthocyanidins [26]. Hence, the EAPs may be used as promising functional food agents. In view of above health benefits provided by tannin-based compounds; they are now available in the dietary supplements. These contain biological extracts packed with both types of tannins and their consumption may provide health benefits. Recently, a concoction of ellagitannins, punicalagins, and polyphenols was commercialized by brand name, that is, Healing America

Wood is the inseparable part of the furniture and several important industries. Wood contains organic acids, tannins, and lignocellulosic material which are most susceptible to biological, chemical, and physical decaying agents. Therefore, wood requires a large number of synthetic adhesives, glues, antitermite chemicals, and other coating materials in order to protect it. However, these materials have tremendously benefitted the wood industry, but they adversely affect the environment conditions. Because synthetic phenolics, amino resins, and formaldehyde used in wood industries are generally carcinogenic in nature. To overcome this problem, scientists are investigating natural materials of herbal or animal origins, such as tannins, that can be the best option or alternative material to be used in the wood industries [27].

#### *Applications of Tannins in Industry DOI: http://dx.doi.org/10.5772/intechopen.85984*

*Tannins - Structural Properties, Biological Properties and Current Knowledge*

ecofriendly in food industry.

*2.1.3 Functional foods or nutraceuticals industry*

shelf-life of guava fruit [19]. The coated guava fruits showed reduced ripening process and improved shelf-life compared with uncoated fruits. The coated fruits also showed more positive biochemical parameters associated with better fruit shelf-life, such as total soluble solids, respiration rate, and chlorophyll contents. Moreover, ethylene, ROS production, less water loss, and gas exchanges are also observed, which are attributed to cross-linking between tannic acid and zein [19]. Hence, tannin-based package and coating material may prove more effective and

Normal food components mainly provide the energy and essential nutrients for the growth and development for animals including human, but food also consist of bioactive molecules or phytochemicals and their inclusion in the appropriate quantity can act as possible therapeutically active agents also known as nutraceuticals, for example, (poly) phenol-rich tannins [20]. Currently, study of molecular mechanisms and pathways such as cell proliferation, apoptosis, inflammation, differentiation, angiogenesis, DNA repair pathway, and carcinogens activation offer new therapeutic targets. The application of tannins has great potential as a nutraceuticals in order to prevent various diseases such as cancer, cardiovascular, kidney diseases, and diabetes. Major sources of tannins are fruits, vegetables, bark, wood, leaves, and seeds such as green tea, apples, cocoa, chocolate, grapes, apricots, and cherries. Among them, role of tannins present in the tea and coffee to prevent the cancers have been studied by large number of scientists. The green tea contains condensed tannin namely epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), which have shown anticancerous activity in terms of inflammatory and antioxidant properties both in vivo and in vitro experimental systems [21]. Actually, EGCG decrease activation of NF-kB and (AP-1) TNF-α pathways simultaneously which ultimately reduced the production of IFN-γ. It can also enhance the apoptosis process through suppression of COX-2 enzyme that leads to the production of PGE2 (prostaglandins) in various types of cell lines of colon cancer cells, such as SW837, HT-29, and HCA-7 cells. Being a polyphenol, EGCG is a strong antioxidant that reduces the activity of nitric oxide (NO) and malondialdehyde (MDA) and conversely increases superoxide dismutase (SOD) activity in case of colonic mucosa. Hence, EGCG can improve the effect of cancer chemopreventive potency by preventing the cell proliferation, migration, and invasion of tumor in

In last two decades, a great interest has been emerged in the protective role of tannins against free radicals and reactive oxygen species produced inside cells, which caused degenerations and diseases such as cancer, atherosclerosis, and cardiovascular ailments. Proanthocyanidins have cardiovascular protective effect due to their antioxidant activity, inhibition of LDL oxidation, ability of vasodilation, antiplatelet activity, and protection against ischemia-reperfusion injury. Another tannin-based compound, gallic acid (3,4,5-trihydroxybenzoic acid), a naturally occurring with low molecular weight, plays very important in the protection of cardiovascular health through rejuvenating the antioxidant system which include large number of enzymes such as SOD, CAT, GPx, GRx, and GST which constitutes

Diabetes mellitus, associated with high level of glucose concentration in the blood, is harmful for whole tissues in human body. Several investigations have shown that it can be reduced or managed by adding the appropriate amount of tannins in the nutrition or supplements of patients [23]. Because, tannins improve the glucose uptakes in body cell and simultaneously reduce the synthesis of adipocytes,

**122**

cancer patients [20].

a scavenging system against the free radicals [22].

hence act as the potential therapeutic agents. In a highly significant study, it shows that epigallocatechin gallate increases the glucose uptake by regulating insulin-signaling pathways, such as PI3K (phosphoinositide 3-kinase) and p38 MAPK (mitogen-activated protein kinase) activation and GLUT-4 translocation [24]. Tannins help reduction of blood glucose levels and offer antioxidants effects [23]. Therefore, it can be concluded that tannin-based foods are potential agents used as either nutraceutical or supplementary agents in food or medicine. A dimer of proanthocyanidin acts against the hyperglycemia that was created by sucrose feeding and by inhibiting the activity of α-glucosidase enzyme. The efficacy of proanthocyanidin has also been proved by molecular docking and strong inhibitory activity experiments.

It is already mentioned that nutraceuticals or functional foods have the health promoting effect on the human and animal health. Several epidemiological studies have clearly established a relationship between (poly) phenol-rich food items and human health. It has substantially enhanced consumer awareness about the tannin-rich diet, and their disease prevention capability; therefore, there is high demand of functional foods. A large number of tannin-based compounds are isolated and characterized from fruits and vegetables (**Table 1**). But, despite high cost incurred on extraction and separation of tannin, it offer only low yield which is a major cause of concern [25]. Additionally, it does not provide the pure content which hindered to test the efficacy and absorption of tannin-based foods in human subject. Grape-seed proanthocyanidins (GSP) were lyophilized to improve their in vivo absorbability. It was achieved by esterification of the water-soluble GSP and immobilized lipase. Lipophilicity was tested by 1-octanol/water partition coefficient as the absorbability parameter. Further, it was observed that GSP derivatives, 3′,5′-2-O-lauroyl epigallocatechin, 3′-O-lauroyl catechin, 3′-O-lauroyl epicatechin, and 3′,3″,5″-3-O-lauroyl epicatechin gallate show high level of radical scavenging activity; hence, it can be used as the strong antioxidant in food to prevent the major degenerative diseases and aging, which are generally caused by the free radicals in the tissues [25]. Recently, B-type proanthocyanidins were isolated and purified from fruits of elephant apple (*Dillenia indica* Linn.), their structural and bioactive properties were examined by using NMR, electron spray ionization, and matrixassisted laser desorption ionization time of flight mass (MALDI-TOF) spectra. In this experiment, yield of 0.23% was achieved that is far greater than commercial grape-seed proanthocyanidins [26]. Hence, the EAPs may be used as promising functional food agents. In view of above health benefits provided by tannin-based compounds; they are now available in the dietary supplements. These contain biological extracts packed with both types of tannins and their consumption may provide health benefits. Recently, a concoction of ellagitannins, punicalagins, and polyphenols was commercialized by brand name, that is, Healing America Ellagitannin capsules and Ellagic Active Tablets.
