KR20040054717A - Tea fortified with iron - Google Patents

Abstract

The present invention relates to tea fortified by ferrous-vegetable protein hydrolyzate complexes. The complex does not cause precipitation of iron-polyphenols; Complexes in tea are also bioavailable. Tea drinks made from the car of the present invention have a nice color.

Description

Iron Reinforced Car {TEA FORTIFIED WITH IRON}

Iron deficiency is common in people. Depending on age and gender, the recommended dietary intake is 28-30 mg per day, but it is known that over one sixth of the world's population suffers from nutrient iron deficiency. Anemia is a common consequence of iron deficiency.

It is one way to supply iron to a population that lacks iron fortification. This is especially necessary in developing countries, such as India, where the average iron intake is only 50-80% of the recommended dietary intake. Moreover, iron can only be used as non-haem iron because a large proportion of the country's population is vegetarian in India.

Common sources of iron used for food or beverage fortification include ferrous sulfate, ferrous lactate, ferrous gluconate and ferrous citrate. Soluble forms of iron are preferred because insoluble or slightly soluble iron sources, such as elemental iron and some ferric salts, exhibit insufficient bioabsorption.

Tea is a popular, inexpensive drink that is consumed around the world. Thus, fortifying tea with iron compounds can be an excellent way to supply iron. However, iron fortification with a soluble iron source has always been a problem because the polyphenols in tea are complexed with iron compounds to create insoluble iron-polyphenol complexes that precipitate during the manufacture of tea beverages. In addition, the produced tea juice has a dark and undesirable color.

Encapsulation of iron compounds or iron complexes has been reported in the prior art. They are expected to reduce iron reactivity and increase bioabsorption. For example, US 3969540, US 4020158, US 4172072, US 4216144 relate to metal-protein complexes and methods for their preparation. Stable ferrous or ferric complexes with casein, collagen, albumen, soybean or gelatin have been reported. The complex can be used as an iron source for plant or animal feed.

WO 0051447 (Societe des Produits Nestle SA) relates to an iron-protein complex, wherein the protein is a hydrolyzed egg white protein having a molecular weight ranging from about 500 to 10,000. And the iron source is ferrous salt. The complex can be used to fortify foods or beverages, especially for fortifying chocolate containing beverages. Strengthening of sterile liquid tea beverages by the complex is also claimed.

WO 0051446 (Societ des Produit Nestle S. A.) relates to a ferric-caseinate composite that can be used to fortify polyphenol containing beverages. The invention is particularly concerned with chocolate drinks. Iron complexes can also be used to enhance hermetically sterilized liquid tea beverages.

Thus, the prior art relates to the use of iron-protein complexes in which proteins are obtained from animal sources. In countries like India, where the population is largely vegetarian, animal proteins are not available for fortification. Globally, preference is given to vegetable products as opposed to animal products. Moreover, the prior art complexes can be used to fortify beverages. However, the prior art is mainly for chocolate drinks and powders and does not solve the problems associated with iron fortification of tea, such as precipitation, uneven color and insufficient bioabsorption.

The inventors have now found that they can provide iron-vegetable protein complexes that can be stably and easily incorporated into tea. Iron compounds are ferrous salts and vegetable proteins are hydrolyzed proteins. The complex is stable and can be incorporated during the black tea manufacturing process. They may also be suitably used in ready-to-drink water soluble tea powders or liquid tea beverages. The resulting tea juice has good color and clarity and has no bad visual and sensory properties associated with iron fortified teas known to date.

Summary of the Invention

Therefore, the present invention relates to ferrous-hydrolyzed vegetable protein complexes that can be suitably used to fortify tea. Vegetable proteins can be obtained from any part of the plant. Examples of hydrolyzed vegetable proteins include those obtained from cereals and legumes such as wheat, rye, corn, barley or peas. The complex may be incorporated into tea during or after the preparation of the drinkable powder as well as during or after the preparation of black tea. The complex can also be suitably used in liquid tea beverages. Tea juice obtained using the inventive fortification system shows good color and clarity and ferrous-hydrolyzed vegetable proteins are readily bio-absorbable.

The present invention relates to teas fortified with stable and bio-absorbable iron-vegetable protein complexes and methods for making fortified teas.

Throughout the specification, all parts are by weight unless otherwise indicated.

According to a first aspect of the invention, a tea fortified with a stable ferrous-hydrolyzed vegetable protein complex having an average molecular weight of the hydrolyzed protein of 250 D to 5000 D (preferably 500 D to 5000 D) is provided. .

Preferably the ratio of ferrous ions to hydrolyzed vegetable protein is 1: 3 to 1:13, more preferably 1: 6 to 1:13, and most preferably 1:10 to 1:13.

As used herein, "tea" is black tea, ready-to-drink tea powder and liquid tea drink.

According to a second aspect of the invention, there is provided an acidic solution of hydrolyzed vegetable protein having a pH of preferably 1 to 5, adding ferrous salt to the solution, alkaline pH, preferably 6.8 To a ferrous-hydrolyzed vegetable protein complex, comprising changing the pH from to 10, heating the mixture, optionally drying the mixture to obtain a complex, and adding the complex to a tea product. A method is provided for making a fortified one.

The mixture can be dried by any suitable means. Spray drying is a particularly preferred method.

Tea manufacturing methods include:

a. Withering steps

b. Invasion stage

c. Fermentation stage and

d. Drying steps

Black tea is obtained at the end of the process. The ferrous-hydrolyzed vegetable protein complex may be added at any stage after fermentation, including the prepared tea.

The source of ferrous iron used in the process of the invention is essentially ferrous salt. Suitable food grade ferrous salts that can be used are ferrous sulfate, ferrous chloride, ferrous citrate, ferrous lactate or ferrous fumarate or mixtures thereof. Especially preferred is ferrous sulfate.

Ferric salts are not readily available as an effective source of iron because they tend to precipitate out of solution very quickly when the pH is increased above 2. Once precipitated, they become inert and do not react with the tea polyphenols. For this reason, the color and appearance (after pH increased above 2) of the end-cup of tea made from fermented tea reinforced with ferric salt looks similar to that of the usual cup of tea. However, precipitated ferric iron is not available in the body in meaningful amounts because of its very limited solubility. In contrast, if ferric salt is added to tea without increasing the pH above 2, the color of tea becomes very dark due to the reaction of ferric ions with tea polyphenols.

Preferably, the amount of ferrous-hydrolyzed vegetable protein complex added to the tea is sufficient to provide 0.15% to 0.3% ferrous ions based on the total weight of tea solids present.

The term hydrolyzed vegetable protein refers to the hydrolysis product of a vegetable protein ranging from long chain polypeptides to amino acids.

In one preferred embodiment, the hydrolyzed vegetable protein has an average molecular weight of 500 D to 5000 D.

Vegetable proteins can be obtained from any part of the plant, such as seeds, tubers, stems, leaves, and the like. Preferably the plant protein is obtained from the seed. Vegetable proteins can be obtained from cereals or legumes.

Hydrolyzed vegetable proteins suitable for the present invention include those obtained from wheat, peas, rye, barley, corn and the like. Hydrolyzed vegetable proteins can be obtained commercially or protein hydrolysates can be made by enzymatically or chemically hydrolyzing the protein.

The ferrous-hydrolyzed vegetable protein complex of the present invention is suitably formed by the following process.

Hydrolyzed vegetable proteins, either commercially obtained or obtained by chemical or enzymatic hydrolysis of vegetable proteins, are dissolved in an acidic medium. Preferably the pH of the acidic medium is 1-5, more preferably 2-4. Both organic and inorganic acids are suitable for preparing acidic media. Ferrous salt is then added to the acidic medium. The pH of the mixture is then raised using an appropriate base. Preferably the pH is between 6.8 and 10, more preferably between 6.8 and 8. The mixture is then optionally heated to a temperature of at least 50 ° C. The mixture is then dried by conventional means to obtain the ferrous-hydrolyzed vegetable protein complex in powder form. Spray drying is a particularly preferred drying method.

The powder can be used in solid form or reconstituted with water and added during the tea manufacturing process.

Ferrous-hydrolyzed vegetable protein complexes are stable and do not cause odor or discoloration when added to tea. The complex may also be readily bio-absorbable and provide the required iron intake required.

Ferrous-hydrolyzed vegetable protein complexes are used to fortify tea, especially black tea. The complex may also be incorporated into ready-to-drink tea powder and also liquid tea drinks.

Black tea preparation includes a wilting step, a wetting step, a fermentation step and a drying step. The complex may be added at any stage after fermentation. The complexes may also be added to the black tea produced by the process.

The resulting black tea is further processed to yield a water soluble ready-to-drink tea powder or a liquid tea beverage.

Other ingredients, including flavors, sweeteners, herbal extracts, vitamins, vegetable or animal proteins, carbohydrates, minerals, can be added to the fortified tea products without affecting the sensory and visual properties of the tea.

The invention is now illustrated by the following non-limiting examples.

Comparative Example A

An aqueous solution of papain was prepared. Then the pH was adjusted to 3.28 using orthophosphoric acid. Ferrous sulfate was then added to the solution. The pH was adjusted to 7.1-9 with ammonium hydroxide. The solution was then heated at 80 degrees Celsius and then spray dried. Ferrous-papain composite was obtained as a powder. The ratio of ferrous salt to papain was 1: 117. The complex was added to commercially available A1 black tea to obtain a fortified black tea product containing 0.15% by weight ferrous ions.

Example 1

200 g glutamine peptide hydrolysate (hydrolyzed wheat protein with an average molecular weight of 690 D obtained from DMV International (Netherlands), product code WGE80GPN) was dissolved in 450 g of water. Then the pH was adjusted to 3.28 using orthophosphoric acid. 15 g of ferrous sulfate was added to the solution. The pH was adjusted to 7.1 with ammonium hydroxide. The solution was heated at 80 degrees Celsius until the contents were homogeneous. The solution was then spray dried. Ferrous-glutamine peptide complex was obtained as a powder. The ratio of ferrous salt to glutamine peptide was 1: 13.33. The complex was added to commercially available A1 black tea to obtain a fortified black tea product containing 0.15% by weight ferrous ions.

Example 2

200 g glutamine peptide hydrolysate (hydrolyzed wheat protein of average molecular weight 690 D, obtained from DMB International (Netherlands), product code WGE80GPN) was dissolved in 450 g of water. The pH was then adjusted to 3.1 using orthophosphoric acid. 60 g of ferrous sulfate was added to the solution. The pH was adjusted to 7.5 with ammonium hydroxide. The solution was heated at 80 degrees Celsius until the contents were homogeneous. The solution was then spray dried. Ferrous-glutamine peptide complex was obtained as a powder. The ratio of ferrous salt to glutamine peptide was 1: 3.33. The complex was added to commercially available A1 black tea to obtain a fortified black tea product containing 0.15% by weight ferrous ions.

Comparative Examples B and C

A1 black tea (Example B) without iron was used as a control in the experiments reported here. Ferrous sulfate was added to A1 black tea obtained on the market to obtain Comparative Example C containing 0.15% by weight of ferrous ions.

The details of this example are shown in Table 1.

Example Iron source / iron quantity Amount of Fe (not iron salt) added (% by weight difference) B - 0 C FeSO ₄ 0.15 A FeSO ₄ + Papain 0.15 One FeSO ₄ + Glutamine Peptide (1: 13.33) 0.15 2 FeSO ₄ + Glutamine Peptide (1: 3.33) 0.15

Car's rating:

Color of the last glass: 5 gm of tea of Comparative Example B and 10 gm of sugar were added to a mixture of 150 ml of milk and 100 ml of water and the mixture was boiled for 3 minutes. The tea was then filtered and the color was measured on a Minolta Reflectance Meter. The color was measured and expressed in three color dimensions, L *, a * and b *. L * indicates light / dark, where L = 0 is black and L = 100 is white or colorless. a * represents red / green, where a high positive value of a * is red and a high negative value of a * is green. B * represents blue / yellow, where a high positive value of b * is yellow and a high negative value of b * is blue.

This procedure was repeated for the differences between Comparative Examples C and A and Examples 1 and 2.

The details of the study are shown in Table 2.

Example Iron compounds L * A * B * observe B - 56 7.1 21.8 Normal / normal car color C FeSO ₄ 43.7 5.5 6.6 Dark grayish black color in the last cup of tea made with milk A FeSO ₄ + Papain 51 5.4 15.1 Brown light colors. Chemical record; Deterioration of flavor. One FeSO ₄ + Glutamine Peptide (1: 13.33) 56 7.1 20.4 Same color as the control tea. There is no other fall record. 2 FeSO ₄ + Glutamine Peptide (1: 3.33) 54 7 20.1 Same color as the control tea. There is no other fall record.

Iron Content of the Last Cup: The iron content of the last cup was determined using Atomic Absorption Spectroscopy (AAS). 2 gm of tea of Example 1 containing 3 mg of iron was selected to make a mixture and then dried. The residue obtained became ash and the ash was dissolved in concentrated hydrochloric acid. The solution was analyzed for iron using an atomic absorption spectrometer. 1.7 mg of iron was detected in the mixture. Therefore, it was found that about 60% of the iron added to the tea leaves is present in the cup of tea.

Claims (9)

Tea fortified with a stable ferrous-hydrolyzed vegetable protein complex having an average molecular weight of hydrolyzed protein of 250 D to 5000 D. The difference of claim 1, wherein the average molecular weight of the hydrolyzed protein is 500 D to 5000 D. The method of claim 1, wherein the ratio of ferrous ions to hydrolyzed vegetable protein is from 1: 3 to 1:13, more preferably from 1: 6 to 1:13, most preferably 1. The car is from 10 to 1:13. The tea according to any one of claims 1 to 3, wherein said hydrolyzed vegetable protein is obtained from a protein derived from cereals or legumes. 5. The tea of claim 4, wherein said hydrolyzed vegetable protein is derived from a protein derived from wheat, rye, corn, barley or peas. 6. The method of any one of claims 1 to 5, wherein the amount of ferrous-hydrolyzed vegetable protein complex added to the tea is 0.15% to 0.3% first based on the total weight of tea solids present. Sufficient car to provide iron ions. preparing an acidic solution of hydrolyzed vegetable protein having a pH of preferably 1 to 5, adding ferrous salt to the solution, changing the pH to an alkaline pH, preferably 6.8 to 10, A method of making a tea according to any one of claims 1 to 6, comprising heating the mixture, optionally drying the mixture to obtain a complex and adding the complex to a tea product. 8. The method of claim 7, wherein the ferrous salt is ferrous sulfate, ferrous chloride, ferrous citrate, ferrous lactate, ferrous fumarate, or mixtures thereof. The method of claim 7 or 8, wherein the optional drying step is a spray drying step.