GB2572036A

GB2572036A - Enhancing the bioavailability of iron in teff

Info

Publication number: GB2572036A
Application number: GB1900334.2A
Authority: GB
Inventors: Ashenafi Mandefro Aden
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-02-26
Filing date: 2019-01-10
Publication date: 2019-09-18
Anticipated expiration: 2039-01-10
Also published as: GB2572036B; GB201900334D0; GB201803020D0

Abstract

A method of processing teff to increase iron bioavailability comprises autoclaving the teff at a temperature of around 125-130°C for a duration of around 45-55 minutes, incubating the teff at a temperature of around 40-50°C for a duration of around 50-60 minutes, milling the teff groat to produce a teff flour, extracting iron from the teff bran, and recombining at least some of the extracted iron with the teff flour. The autoclaving step preferably comprises autoclaving at a temperature of around 125°C for around 45 minutes with around 0.9 moisture content. The incubating step preferably comprises incubating at a temperature of around 45°C for a duration of around 60 minutes. The teff may be cleaned before autoclaving, dehydrated after incubating, and dehulled after dehydrating. The teff groat and bran may be separated prior to milling the groat. The iron may be extracted from the bran using a solvent, preferably Sodium Chloride (NaCl). Ascorbic acid may be added as an absorption enhancer, and flavourings, sweeteners, stabilisers and/or preservatives may be added to the teff flour to produce an iron-enriched drink powder for human consumption. The autoclaving and incubating steps may be intended to reduce phytic acid levels.

Description

ENHANCING THE BIOAVAILABILITY OF IRON IN TEFF

BACKGROUND OF THE INVENTION [0001] The present invention relates to a method of processing teff to enhance the intestinal bioavailability of iron.

[0002] Teff is the edible seed of Eragrostis tef, a species of lovegrass. It is widely cultivated and used in Eritrea and Ethiopia, accounting for about a quarter of total cereal production in Ethiopia. Teff is gaining popularity in the western United States as an alternative forage crop, in rotation with a legume such as alfalfa, because it uses C4 photosynthesis, similar to corn. It is noted for its high quality and high yield compared to other forage rotations. It is also gluten-free and therefore suitable for celiacs.

[0003] It is high in dietary fibre, iron, protein and calcium. The high protein content is believed to be due to the relatively large germ for its small seed size compared to grains such as wheat; larger grains have increased levels of starch due to larger proportion of endosperm.

[0004] The majority of the iron in teff is contained in the bran. However, absorption inhibitors in teff limit the bioavailability of iron and other nutrients with the result that a reasonable serving size of teff does not provide significant amounts of iron. Relieving or eliminating the absorption inhibitors would enhance the intestinal bioavailability and absorption of iron in teff.

[0005] Iron absorption in teff grains can be affected by many compounds, chemicals and nutrients. It can also be affected by human physiological factors such as vitamin D status, age, pregnancy, lactation and disease. Additionally, factors such as foods and nutrients interaction, caffeine, and alcohol can inhibit or promote absorption and often these factors overlap.

[0006] Phytic acid (C6H18O24P6) , also known as inositol hexaphosphate (IP6) or phytate, is the main absorption inhibitory compound to iron in teff. Phytic acid is a storage form of phosphorous in all grains and seeds but the accumulation site and the level of accumulation varies. The level of phytic acid in grains varies from 0.5 to 2.0% and can account for 60%-80% of a seed's total phosphorus compound. The concentration of phytic acid is mostly determined by the phosphate available in the soil.

[0007] Phytic acid's inhibitory activity to iron and other minerals is through the formation of a stable complex between these two compounds. Humans have no capacity to hydrolyse the combined molecule, which makes it unavailable for intestinal absorption, and approximately 30 to 97% of consumed phytic acid remains undigested when it reaches the colon.

[0008] Phytic acid's interaction with minerals can take place through ionic nature or though charged groups of proteins containing minerals such as calcium. Phytic acid can also bind with starch directly through phosphate groups. This interaction also reduces solubility, digestibility and bioavailability of starch and proteins as well as minerals.

[0009] The stability and binding capacity of phytic acid to minerals such as iron is pH and site dependent. Phytic acid has a pronounced binding capacity between pH 5 and 7.1. Of the four phosphorylated forms of phytic acid, binding capacity of minerals such as iron is more pronounced with inositol hexaphosphate (IP6) and inositol pentakisphosphate (IP5).

[0010] Even small amounts of phytic acid can have an inhibiting effect on iron absorption. Teff is reported to contain relatively high amounts of phytic acid compared with other cereals and this hinders the bioavilability of minerals such as iron.

[0011] Unfortunately, teff cannot be refined using normal processes due to its small size compared to grains such as wheat.

[0012] What is needed is a method of processing and/or refining teff which improves the bioavailability of iron and other nutrients.

BRIEF SUMMARY OF THE INVENTION [0013] The present invention provides a method of processing teff to increase iron bioavailability comprising autoclaving the teff at a temperature of around 125°C to 130°C for a duration of around 45 to 55 minutes; incubating the teff at a temperature of around 40°C to 50°C for a duration of around 50 to 60 minutes; milling the teff groat to produce a teff flour; extracting iron from the teff bran; and recombining at least some of the extracted iron with the teff flour .

[0014] Embodiments of the present invention provide a teff flour that is rich in bioavailable iron.

[0015] The method of any preceding claim further comprising dehydrating the teff after incubating to prepare the teff for duelling. For example, the teff moisture content is reduced to around 10% ± 2%.

[0016] Preferably, extracting iron from the teff bran comprises adding a solvent such as sodium chloride to the teff bran. The process avoids the use of non-natural chemicals.

[0017] Embodiments of the present invention solve the problem of limited bioavailability of iron in teff at the processing stage. Processing teff in this way improves the intestinal absorption of iron in teff and subsequently improves the health of consumers, particularly individuals who suffer from iron deficiency.

[0018] Embodiments of the invention also include the production of a gluten and lactose free drink or shake rich in bioavailable iron.

BRIEF DESCRIPTION OF THE DRAWING [0019] Preferred embodiments of the invention will now be described with reference to the accompanying drawing in which:

[0020] Figure 1 is a flowchart of method for processing teff embodying the present invention.

DETAILED DESCRIPTION OF THE INVENTION [0021] In brief, a method of processing teff to enhance iron absorption includes the steps of cleaning the teff 10; autoclaving the teff 20 at a suitable temperature and moisture content, for a suitable duration, to remove the majority of phytic acid from the teff; incubating the teff 30 at a suitable temperature and for a suitable duration to further eliminate phytic acid and allergens from the teff; dehydrating the teff 40; and dehulling the teff 50 at a suitable moisture content and to a suitable ratio of groat to hull. The groat is collected 60 and milled 70 to create a teff flour. The bran is collected 80 and iron is extracted 90. The teff flour and a desired percentage of the extracted iron are recombined 100 and the processed flour is combined with other additives 110 to produce a powder that can be used to create a drink or shake for consumption.

[0022] The powder and subsequent drinks arising from this method of processing teff have significantly higher bioavailable iron due to the reduction or elimination of phytic acid.

[0023] The processing method does not require the use of soy, dairy and gluten containing ingredients, and does not require the use of non-food chemicals, non-natural chemicals and genetically modified organism (GMOs). The final end product for consumers may be packaged and sold in dry, powdered or liquid form.

[0024] The step of cleaning the teff 10 can involve rinsing the teff with a fluid such as water, optionally containing suitable cleaning additives that clean the teff more effectively but do not leave a residue that may affect the taste and nutritional content of the teff. All cleaning additives are preferably natural. The rinsing may also be controlled to leave the teff at a desired moisture content.

[0025] The step of autoclaving the teff 20 can involve autoclaving the teff at a temperature of around at least 125°C, preferably in a range from 125°C to 130°C, for a duration of around at least 45 minutes, preferably in a range from 45 minutes to 55 minutes at a moisture content of around 0.9.

[0026] The step of incubating the teff 30 can involve incubating the teff at a temperature of around 45°C, preferably in a range from 40°C to 50°C, for a duration of around 60 minutes but optionally as low as 50 minutes.

[0027] Autoclaving 20 and incubating 30 the teff significantly reduces or eliminates the absorption inhibitory factors for iron, particularly phytic acid. Consequently, there is approximately 80% more bioavailable iron in the processed teff compared to unprocessed teff.

[0028] The step of dehydrating the teff 40 can involve dehydrating the teff at around 125°C, preferably in a range from 120°C to 130°C, for around at least 2 hours, preferably in a range from 2 hours to 2.5 hours. In preparation for dehulling 50, the teff is preferably dehydrated to a moisture content of 10% ± 2%.

[0029] The step of dehulling the teff 50 involves removing the skin of the grain from the main grain and may use equipment known for sesame seed peeling, for example, but with a smaller mould due to the size of the teff grain and the thickness of the bran. The dehulling 50 is carried out at a moisture content of 10% ± 2% and a groat/hull ratio of around 4% is used in order to isolate the bran from the groat.

[0030] The groat is collected 60 from the dehulled teff and the step of milling the groat 70 can involve milling or grinding the teff by any suitable method to produce a teff flour .

[0031] The bran is also collected 80 from the dehulled teff and the iron is extracted from the teff bran 90 by any suitable process. A preferred process for extracting the iron from the teff bran involves using sodium chloride as a natural solvent at a molar ratio of around 1:1.5 (Fe:NaCl). The amount of iron in the teff bran may be determined based on an analysis of a sample of the collected bran to determine its iron content or may be based on an average known iron content of raw or untreated teff, for example. Based on the quantity of bran collected, the amount of solvent required to precipitate the iron is determined and added.

[0032] Iron (ferrous) extraction using sodium chloride solutions may be carried out in a liquid-liquid extraction process. During investigations under various HC1, sodium chloride, and iron (Fe2) concentrations, it was found that ferrous was extracted quickly and efficiently in a wide range of sodium chloride concentrations. The selective separation of Fe3 from the bran in acidic sodium chloride solutions was achieved with a separation factor of Fe3 using 3M HC1 solution. Using 25mM of NaCl per lOOg of bran, Fe3 separations was 15.56%. The maximum separation of Fe3 was 83.2% using lOOmM sodium chloride per lOOg of bran. The ferrous complexes in aqueous phase were characterized using spectroscopic techniques. Ultraviolet-visible spectrophotometer confirmed that Fe3 formed a series of iron complexes in acidic sodium chloride solutions. Both FeC13 ion association and FeC14 anion exchange with the chloride anion play the key role during ferrous extraction.

[0033] The step of recombining the extracted iron and the teff flour 100 involves mixing a desired percentage of the extracted iron with the milled teff flour 100 to produce a processed teff flour. The iron will be bioavailable on consumption so the desired percentage of extracted iron to be recombined is determined based on recommended daily allowances (RDA) of iron and the intended serving size of the end product (s) .

[0034] The processed teff flour can be further processed in several different ways to produce different products.

[0035] For example, various additives can be added to the teff flour 110 to create a drink powder, often marketed as a shake powder which an end user mixes with water to produce a nutritious shake drink. Additives, preferably natural additives, may include sweeteners (such as sugar, honey, stevia, fructose and sucrose), preservatives and absorption enhancers (such as citric acid, and ascorbic acid in a suitable proportion), stabilisers (such as pectin, xanthan gum, polyphosphates and polyglycerole), flavourings (such as vanilla and cocoa), thickeners, emulsifiers, vitamins and other supplements in any desired combinations.

[0036] These additives may be combined with the processed teff flour simultaneously or over time and in any order. Some additives may be added to the teff flour before recombining the flour with the extracted iron, for example. The drink powder may also be mixed with water, milk or milk alternatives (e.g. soy milk or almond milk), and packaged as a pre-mixed drink.

[0037] The resulting mixtures of ingredients can create a wide variety of food products rich in bioavailable iron and with different combinations of nutrients. These food products are capable of providing 100% of an adult's or child's RDA of iron and other nutrients including, if desired, combined protein to cater for macronutrient balance.

[0038] The described teff-based shake powder, rich in bioavailable iron, can be further processed to mix and blend it with various whole ingredients to create a synergetic food product. The synergetic food product consists of a base which can be used or eaten plain or can be mixed with any combination of other food groups and ingredients to make a diversity of nutritional content (protein, carbohydrates, vitamins, minerals and oils/fats), flavours, colours, textures, feels, shapes, etc.

Claims

1. A method of processing teff to increase iron bioavailability comprising:

autoclaving the teff at a temperature of around 125°C to 130°C for a duration of around 45 to 55 minutes;

incubating the teff at a temperature of around 40°C to 50°C for a duration of around 50 to 60 minutes;

milling the teff groat to produce a teff flour; extracting iron from the teff bran; and recombining at least some of the extracted iron with the teff flour.

2. The method of claim 1 wherein autoclaving the teff comprises autoclaving at a temperature of around 125°C for around 45 minutes with around 0.9 moisture content.

3. The method of claim 1 or claim 2 wherein incubating the teff comprises incubating at a temperature of around 45°C for around 60 minutes.

4. The method of any preceding claim further comprising cleaning the teff prior to autoclaving.

5. The method of any preceding claim further comprising dehydrating the teff after incubating.

6. The method of claim 5 wherein dehydrating the teff comprises dehydrating at a temperature of around 125°C for around 2 hours .

7. The method of claim 5 or claim 6 further comprising dehulling the teff at a moisture content of 10% ± 2% after dehydrating.

8. The method of any of claims 5 to 7 further comprising dehulling the teff at a groat to hull ratio of around 4%.

9. The method of any preceding claim further comprising separating the teff groat from the teff bran prior to milling the teff groat.

10. The method of any preceding claim wherein extracting iron from the teff bran comprises adding a solvent to the teff bran.

11. The method of claim 10 wherein the solvent is sodium chloride (NaCl).

12. The method of claim 11 wherein the sodium chloride is added in a molar ratio of around 1:1.5 (Fe:NaCl) to the amount of iron in the teff bran.

13. The method of any preceding claim wherein a quantity of the extracted iron is recombined with the teff flour to obtain a desired percentage of iron in the teff flour.

14. The method of any preceding claim further comprising adding ascorbic acid as an absorption enhancer.

15. The method of any preceding claim further comprising adding at least one of flavourings, sweeteners, stabilisers and preservatives to produce a drink powder.

16. A drink formed from a drink powder produced according to claim 15.