GB2571594A - Enhancing the bioavailability of calcium in teff - Google Patents

Abstract

A method of processing teff to increase calcium bioavailability comprises autoclaving the teff at a temperature of around 120-125°C for a duration of around 32-38 minutes and incubating the teff at a temperature of around 30-37°C for a duration of around 60-80 minutes. The autoclaving step preferably comprises autoclaving at a temperature of around 121°C for around 35 minutes with around 0.9 moisture content. The incubating step preferably comprises incubating at a temperature of around 35°C for a duration of around 60 minutes. The autoclaving and incubating steps may be intended to reduce phytic acid levels. The teff may be cleaned before autoclaving, dehydrated after incubating, and milled after dehydrating to produce a teff flour. The teff flour may be mixed with water to produce a gluten and lactose free teff milk for human consumption, rich in bioavailable calcium. Preferably the teff flour is blended with water, boiled, cooled, and filtered to produce teff milk. Citric acid may be added to the teff flour prior to producing teff milk. The teff milk may be inoculated with a starter culture and fermented to produce a probiotic mixture. Flavourings, sweeteners, stabilisers and/or preservatives may be added to the teff milk.

Description

ENHANCING THE BIOAVAILABILITY OF CALCIUM IN TEFF

BACKGROUND OF THE INVENTION [0001] The present invention relates to a method of processing teff to enhance the intestinal bioavailability of calcium, and for using the processed teff to produce teff milk and probiotic drinks.

[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. However, absorption inhibitors in teff limit the bioavailability of calcium and other nutrients. Relieving or eliminating the absorption inhibitors would enhance the intestinal bioavailability and absorption of calcium in teff.

[0004] Calcium 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 two factors overlap.

[0005] Phytic acid (C6H18O24P6) , also known as inositol hexaphosphate (IP6) or phytate, is the main absorption inhibitory compound to calcium 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.

[0006] Phytic acid's inhibitory activity to minerals such as calcium 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.

[0007] 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.

[0008] The stability and binding capacity of phytic acid to minerals such as calcium 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 calcium is more pronounced with inositol hexaphosphate (IP6) and inositol pentakisphosphate (IP5).

[0009] Even small amounts of phytic acid can have an inhibiting effect on calcium 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 calcium. For example, the reported molar ratio of calcium to phytic acid in in-vitro extracted foods varies from 1 to 3 moles of calcium per mole of phytic acid.

[0010] Unfortunately, teff cannot be refined using normal processes due to its small size compared to grains such as wheat.

[0011] What is needed is a method of processing and/or refining teff which improves the bioavailability of calcium and other nutrients.

BRIEF SUMMARY OF THE INVENTION [0012] The present invention provides a method of processing teff to increase calcium bioavailability comprising: autoclaving the teff at a temperature of around 120°C to 125°C for a duration of around 32 to 38 minutes; and incubating the teff at a temperature of around 30°C to 37°C for a duration of around 60 to 80 minutes.

[0013] Autoclaving and then incubating the teff at suitable temperatures and for suitable durations significantly reduces the quantity of phytic acid in teff, making calcium more bioavailable.

[0014] In one preferred process, autoclaving the teff comprises autoclaving at a temperature of around 121 °C for around 35 minutes with around 0.9 moisture content and/or incubating the teff comprises incubating at a temperature of around 35°C for around 1 hour. These conditions are believed to be close to optimal for reducing phytic acid in teff.

[0015] Preferably, processing the teff further comprises cleaning the teff prior to autoclaving in order to remove dirt, pesticide residue or other contaminants.

[0016] Preferably, processing the teff further comprises dehydrating the teff after incubating, most preferably at a temperature of around 100°C to 125°C for around 2 to 3 hours, in order to dry the teff ready for milling.

[0017] Preferably, processing the teff further comprises milling the teff after dehydrating to produce a teff flour. A teff flour is convenient for subsequent processing.

[0018] Preferably, processing the teff further comprises producing a teff milk from the teff flour by mixing the teff flour with water, more preferably by blending the teff flour with water, boiling the mixture, cooling the mixture and filtering the supernatant. A teff milk is convenient for subsequent processing.

[0019] Optionally, a preservative such as citric acid is added to the teff flour prior to producing a teff milk.

[0020] In one embodiment, processing the teff further comprises inoculating the teff milk with a starter culture and fermenting. The resulting probiotic mixture has multiple uses as part of a healthy food product such as a probiotic drink.

[0021] Preferably, processing the teff further comprises adding at least one of flavourings, sweeteners, stabilisers and preservatives to the teff milk. A suitably processed teff milk may then be packaged and sold to consumers.

[0022] Embodiments of the present invention solve the problem of limited bioavailability of calcium in teff at the manufacturing level. Processing teff in this way improves the intestinal absorption of calcium in teff and subsequently improves the health of consumers, particularly individuals who suffer from calcium deficiency.

[0023] Embodiments of the invention also include the production of teff milk rich in bioavailable calcium. Embodiments of the invention also include the production gluten and lactose free probiotic drinks rich in bioavailable calcium.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) [0024] Preferred embodiments of the invention will now be described with reference to the accompanying drawing in which:

[0025] Figure 1 is a flowchart of method for processing teff embodying the present invention.

DETAILED DESCRIPTION OF THE INVENTION [0026] In brief, a method of processing teff to enhance calcium 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; and dehydrating the teff 40 in preparation for milling 50 to produce teff flour. The teff flour is mixed with water to produce teff milk 60.

[0027] Teff milk may be further processed by adding sweeteners, stabilisers, preservatives and flavourings 70 to produce a range of different products ready for consumption.

[0028] Alternatively, the teff milk may be inoculated with a starter culture 80 and fermented to produce a probiotic drink 90, commonly marketed as probiotic shots.

[0029] The teff flour and subsequent products arising from this method of processing teff have significantly higher bioavailable calcium due to the reduction or elimination of phytic acid.

[0030] The end products may be in dry, powdered or a liquid form. 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).

[0031] 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.

[0032] The step of autoclaving the teff 20 can involve autoclaving the teff at a temperature of around 120°C to 125°C for a duration of around 32 to 38 minutes. For example, a temperature of around 121°C for around 35 minutes. The moisture content is around 0.9.

[0033] The step of incubating the teff 30 can involve incubating the teff at a temperature of around 30°C to 37°C for a duration of around 60 to 80 minutes. For example, a temperature of around 35°C for around 1 hour.

[0034] Autoclaving 20 and incubating 30 the teff significantly reduces or eliminates the absorption inhibitory factors for calcium, particularly phytic acid. Consequently, there is approximately 80% more bioavailable calcium in the processed teff compared to unprocessed teff.

[0035] The step of dehydrating the teff 40 can involve dehydrating the teff at around 100°C to 125°C for around 2 to 3 hours .

[0036] The step of milling the teff 50 can involve milling or grinding the teff by any suitable method to produce a teff flour .

[0037] The step of producing teff milk 60 involves high speed blending the teff flour with water (preferably filtered water) at a ratio of 1:8 (teff:water) then boiling at between around 100°C and 105°C, cooling and filtering the supernatant.

[0038] The teff milk can be further processed in several different ways to produce different products.

[0039] For example, various additives can be added to the teff milk 70 to create a product ready for enjoyable human consumption. Additives may include sweeteners (such as sugar, honey, stevia, fructose and sucrose), preservatives (such as citric acid and ascorbic acid), stabilisers (such as pectin, xanthan gum, polyphosphates and polyglycerole), flavourings (such as vanilla and cocoa), thickeners, vitamins and other supplements. Optionally, some of these additives may be included before the step of producing teff milk 60 to optimise the processing method. Citric acid or similar preservatives may be added to the teff flour before producing the teff milk 60, for example. The resulting mixture of whole ingredients creates a wide variety of synergistic food products with different combinations of nutrients.

[0040] As an alternative the teff milk can be further processed with the addition of a starter culture 80 (such as acidophilus and bifidobactrum) to produce a probiotic drink 90. Typically, the teff milk is inoculated with a starter culture at 0.03g per 500ml followed by 12 to 24 hours fermentation at a temperature of 20°C to 25°C.

[0041] Fermentation allows proliferation of naturally occurring prebiotics and probiotics, such as lactic acid and healthy microorganisms. Additionally, the fermentation process enhances taste, texture, natural flavours and long shelf life. Generally, no further additives are added to the mixture during fermentation, though the addition of warm water may sometimes be required.

[0042] Further additives, such as the additives listed in step 70, may be combined with the mixture as desired either before adding the starter culture or after fermentation as desired.

[0043] The methods embodying the present invention produce a range of synergistic food products consisting of a base which can be used or eaten plain or can be mixed in any desired combinations with other foods and ingredients.

Claims (12)

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

autoclaving the teff at a temperature of around 120°C to

125°C for a duration of around 32 to 38 minutes; and incubating the teff at a temperature of around 30°C to 37°C for a duration of around 60 to 80 minutes.

2. The method of claim 1 wherein autoclaving the teff comprises autoclaving at a temperature of around 121 °C for around 35 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 35°C for around 1 hour.

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 100°C to 125°C for around 2 to 3 hours.

7. The method of claim 5 or claim 6 further comprising milling the teff after dehydrating to produce a teff flour.

8. The method of claim 4 further comprising producing a teff milk from the teff flour by mixing the teff flour with water.

9. The method of claim 8 wherein producing a teff milk comprises :

blending the teff flour with water, boiling the mixture, cooling the mixture and filtering the supernatant.

10. The method of either claim 8 or claim 9 further comprising adding citric acid to the teff flour prior to producing a teff milk.

10

11. The method of any of claims 8 to 10 further comprising inoculating the teff milk with a starter culture and fermenting to produce a probiotic mixture.

12. The method of any of claims 8 to 11 further comprising 15 adding at least one of flavourings, sweeteners, stabilisers and preservatives to the teff milk.