Field of the invention

The present invention relates to beverages (aimed for human consumption) containing soy protein. More particular, it relates to soy protein-containing beverages that further contain a colouring agent.

Background of the invention

Soy protein-containing beverages enjoy an increasing popularity. This is partly due to people wishing the goodness of dairy milk (a source of protein and/or minerals like calcium) but from a vegetable source. However, the taste of soy protein-containing beverages does not quite match milk from dairy origin. Hence, a lot of research has been dedicated in the last decades on improving the taste profile of soy protein-containing beverages.

An issue relating to soy protein containing beverages which so far has received much less attention is that also the colour of soy protein-containing beverages is also not always as attractive as desired. Soy protein-containing beverages can have a greyish or yellowish hue. This is unattractive when the consumer pours such soy protein-containing beverages from a commercial packaging (e.g. Tetrapack) into a glass. Dairy milk (herein: from cows) is generally perceived by the average consumer as more attractive.

Without wishing to be bound by theory, it is believed that the greyish- or yellowish hue or colour of soy protein-containing beverages may be caused by some plant cellular material or cell wall material being present in the beverage, as a result of the process to obtain the protein from the soy beans. Also, it is believed that the colour (whether more grey-ish or more yellowish, and how much) is also dependent on the origin (e.g. geography) of the soy beans, the processing the soy beans are subjected to, and perhaps also seasonal variations.

Additionally, there is an increasing tendency (e.g. for cost- and/or environmental- and/or nutritional reasons or to be flexible in the soy bean material from which the protein is extracted) to be able to use non-dehulled soy beans and/or soy beans that have a dark hilum. The hilum (or 'seed scar') is the actual point of attachment to the pod, and is connected to the embryo seedling, the hypocotyl. The hilum can have varying degrees of being light to black coloured, depending on species, and can have a large influence the colour of a beverage that contains the extracted soy protein. Removal of the hypocotyl and/or the hull can, depending on the exact method, also result in (partial) removal of the hilum.

Potter et al (Lebensmittel Wissenschaft und Technologie, 40(5), February 2007, pp 807-814) disclose soy beverages containing wild blueberry juice. The beverages are reported to be dark violet in colour, having an L* value in the CIELAB colour space of approx. 15.6 -19.8, and an a* value of approx. 17 - 22.5 and a b* value of approx. -7.4 to -4.7.

MM Giusti and RE Wrolstad (Biochemical Engineering Journal, 14, 2007 pp 217-225) disclose acetylated anthocyanins and their use in food systems.

KC Kwok et al (Journal of Food Engineering 40(1-2), 1999, pp 15-20) disclose the kinetics of colour changes in soy milk heated (e.g. for preservation) to 80-140°C, and refers to the changes in colour in the CIELAB values due to such heating.

US 3 958 019 discloses a process for preparing a soybean protein material having a red colour, which, when combined with uncured meat makes a product having a uniform red colour in the raw state and a uniform grey-brown colour similar to cooked natural meat. The colouring agents involved in this are betanin and cantahxanthin.

WO 2007/113176 discloses a process for obtaining a soy beverage from soy beans.

US 2003/124223 discloses a process for producing a stabilised soy beverage from dehulled whole soybeans. It also discloses recipes of soy beverages containing 0.2% colouring agent.

Summary of the invention

Hence, there is a desire for a soy (bean) protein-containing beverage having an improved colour, and/or preferably a colour which is (or is perceived as) closer to dairy milk (i.e. milk from cows), and/or preferably a colour which is more appreciated, preferred or liked by consumers or as seen as more attractive to drink. In this, "closer to dairy milk" and "liking" is to be understood as when comparing two or more soy protein-containing beverages with each other by a panel. There is also a desire for being able to use soy protein in a beverage, which soy protein has been extracted from a soy bean material which is non-dehulled and/or non- dehypoctolysed, yet which may achieve one or more of the objectives as above. There is furthermore a desire for a process to obtain such beverage, and preferably being able to deal with a variety of crude soy protein sources used in the preparation of the commercial beverage preparation and various process of obtaining and handling the soy protein used for the beverage preparation. Preferably, the process should be adaptable to give improvements in colour (towards more dairy-like) to soy protein containing beverages having different colours or hues.

It has now surprisingly been found that one or more of these objectives may be achieved, at least in part, by a soy protein-containing beverage which contains a small amount of a colouring agent which has a colour around blue (including violet and other colours that have blue as part of their spectrum). It was found that adding certain colourants in small amounts to soy protein-containing beverages can create an image by a consumer of being more like dairy milk and/or more white, despite the fact that adding the colouring agent makes, at least in theory, the beverage to be darker (i.e. less light). Adding too much of a colouring agent will indeed make the beverage too dark and/or too coloured.

Hence, the invention relates to a beverage comprising, by weight, between 60 and 99% water and between 0.5 and 6% soy protein, characterized in that it further comprises a food colouring agent being one or more of Acid Blue 3, Acid Blue 9, Food Black 1 , Acid Blue 74, or mixtures thereof and wherein said colouring agent is present in an amount of from 0.01x10 ^"4 to 10x10 ^"4 % (by weight, based on the total composition), preferably 0.2x10 ^"4 to 5x10 ^"4 %. The concentrations herein refer to the pure colouring compound. Commercial products may contain dilluants.

The invention further relates to a beverage comprising, by weight, between 60 and 99% water and between 0.5 and 6% soy protein, characterized in that it further comprises a food colouring agent having a hue angle in demin water of between 240 and 345, said colouring agent being present in an amount such that:

Aabcoloured soy 0.9 Aab _SO y wherein:

Aabcoioured soy is a comparison of the a* and b* values in the CIE L*a*b* colour space for full fat dairy milk and said soy beverage containing said colouring agent by the following equation:

Aabcoloured soy ^— ((^dairy ^— ^coloured soy) (bdairy ^— b _C oloured soy) )

wherein a _da ir _y stands for the a* value in the CIE L*a*b* colour space of full fat dairy milk, wherein a _CO ioured soy stands for the a* value in the CIE L*a*b* colour space of said beverage comprising soy protein and said colouring agent,

wherein b _da ir _y stands for the b* value in the CIE L*a*b* colour space of full fat dairy milk, wherein b _CO ioured soy stands for the b* value in the CIE L*a*b* colour space of said beverage comprising soy protein and said colouring agent;

and wherein:

Aabsoy is a comparison of the a* and b* values in the CIE L*a*b* colour space for full fat dairy milk and said soy beverage with no added colouring agent by the following equation:

Aab _SO y ⁼ ((adairy— a _SO y) + ( d _a j _ry — b _soy ) )

wherein a _da ir _y stands for the a* value in the CIE L*a*b* colour space of full fat dairy milk, wherein a _soy stands for the a* value in the CIE L*a*b* colour space of said beverage comprising soy protein not containing said colouring agent,

wherein b _da ir _y stands for the b* value in the CIE L*a*b* colour space of full fat dairy milk, wherein b _soy stands for the b* value in the CIE L*a*b* colour space of said beverage comprising soy protein not containing said colouring agent.

The invention further relates to such beverage wherein the food colouring agent has a hue angle in demin water of between 250 and 340, preferably between 260 and 310.

Detailed description of the invention

The hue angle numbers herein are an indication of the range of "colours" for the colouring agents (reflected by such colouring agent) that can be used in the present invention. In other words: a colouring agent with a hue angle outside the claimed range was found to be not very suitable for the given purpose. The hue angle for this invention is determined in demin water.

Adding a colourant to a liquid may change the a* and/or b* value. So in theory adding a colourant to a liquid may change the colour to something more desired, this would come at the expense of making the liquid darker (i.e. it will lead to a decreased L* value) than desired. This would seem unattractive. However, in the present invention, it was realised that as the present invention deals with liquids which are quite "white-ish"(e.g. like dairy milk) adding a colourant can indeed change the a* and or b* value, the consequential change (decrease) in L* value would not play a role such that it negatively affects the overall result. In other words: due to the white-ish nature of the beverages concerned, and the amount of colourant needed, it was found possible to add a colourant and obtain a colour which can be perceived as more white and/or more close to dairy (i.e. cows) milk. For example in the Stensby Whiteness index, changes in a* and b* have a 3 fold larger effect than changes in L* for the sort of liquids that are coloured in this invention. Consequently changes in L* are less relevant for soy protein containing beverages to be more alike dairy milk than an improvement in a* and b* values.

Following this, in the present invention, "colour" is the colour without account of the lightness.

In this connection, in the present invention it is preferred that the beverage has an L* value greater than 70 in the CIE L*a*b* colour space. More preferably, such beverages have an L* value of between 74 to 90, most preferably from 77 to 87. As to b*, the beverages according to the present invention preferably have a b* value of greater than 0 (i.e. being positive, as opposed to negative b* values), more preferably the b* value is at least 2, more preferably at least 4.

In the present invention, to achieve the desired colour, it was found to be preferred that for the beverage concerned, the amount of the colouring agent is present in an amount such that Aabcoioured soy < 0.8 Aab _soy . Even more preferred in that respect is a beverage according to this invention, wherein said colouring agent is present in an amount such that Aab _CO ioured _soy < 0.7 Aabsoy, and most preferably Aab _CO ioured _soy < 0.6 Aab _soy .

As to the amount of colouring agent in the present invention, it was found, to achieve the desired objective, that depending on e.g. the growing conditions of the soy plants, the source of soy protein, isolation and extraction process of the soy protein from the crude source, and the protein concentration in the product, it is preferred that the amount of food colouring agent is from 0.01x10 ^"4 to 10x10 ^"4 % (by weight, based on the total composition), preferably from 0.2x10 ^"4 to 5x10 ^"4 %.

As to the type of colouring agents, as the soy protein containing beverages are food products, it is preferred that the food colouring agents herein are food grade or allowed in colouring foods and beverages. Likewise, to be able to employ them in the given purpose, it is preferred that the food colouring agents are soluble in water at the concentrations required, it is preferred that the food colouring agents are soluble in water at a concentration of below 0.001 % at 25°C (percentage refers to the sodium salt of the colourants).

Given the above, preferred food colouring agents for the purpose of this invention are one or more of Acid Blue 3, Acid Blue 9, Food Black 1 , Acid Blue 74. This includes mixtures of such food colouring agents. For e.g. reasons of a nutritional profile, the soy protein containing beverages in the present invention preferably comprise minerals, such as one or more of calcium, magnesium, potassium, zinc, copper, iron, manganese. Preferably, such metals are present in an amount of at least 5 mmole per kg of soy protein-containing beverage, preferably of 20-600 mmole per kg soy protein-containing beverage, most preferably of 200-300 mmole per kg soy protein- containing beverage. Expressed differently, the minerals calcium and magnesium are advantageously present in the beverages concerned in an amount of at least 0.4 g/kg, preferably of 1.5-50 g/kg, most preferably 13-30 g/kg of beverage, and e.g. for iron in an amount of at least 0.1 g/kg, preferably of 0.5-20 g/kg of beverage.

The beverages according to the present invention can suitably be prepared by adding the colouring agent of choice to the beverage or one of its precursors in the required amount. Hence, the present invention further relates to a process of making a soy beverage, which process comprises the steps of providing an aqueous mixture comprising, by weight, between 60 and 99% water and between 0.5 and 6% soy protein, measuring the a* and b* values in the CIE L*a*b* colour space of the aqueous mixture and measuring the same for semi-skimmed dairy milk, and adding to the aqueous mixture a food colouring agent having a hue angle in demin water of between 240 and 345 in such an amount that:

Aabcoloured soy 0.9 Aab _SO y wherein

Aabcoioured soy is a comparison of the a* and b* values in the CIE L*a*b* colour space for full fat dairy milk and the aqueous mixture containing said colouring agent by the following equation:

Aabcoloured soy ^— ((^dairy ^— ^coloured soy) (bdairy ^— b _C oloured soy) )

wherein a _da ir _y stands for the a* value in the CIE L*a*b* colour space of full fat dairy milk, wherein a _CO ioured soy stands for the a* value in the CIE L*a*b* colour space of said aqueous mixture comprising soy protein and said colouring agent,

wherein b _da ir _y stands for the b* value in the CIE L*a*b* colour space of full fat dairy milk, wherein b _CO ioured soy stands for the b* value in the CIE L*a*b* colour space of said aqueous mixture comprising soy protein and said colouring agent;

and wherein

Aabsoy is a comparison of the a* and b* values in the CIE L*a*b* colour space for full fat dairy milk and said aqueous mixture with no added colouring agent by the following equation:

Aab _SO y ⁼ ((adairy ^— 3soy) ⁺ (bdairy ^— b _soy ) )

wherein a _da ir _y stands for the a* value in the CIE L*a*b* colour space of full fat dairy milk, wherein a _soy stands for the a* value in the CIE L*a*b* colour space of said aqueous mixture comprising soy protein with not containing said colouring agent,

wherein b _da ir _y stands for the b* value in the CIE L*a*b* colour space of full fat dairy milk, wherein b _soy stands for the b* value in the CIE L*a*b* colour space of said aqueous mixture comprising soy protein with not containing said colouring agent.

For reasons as stated already above, in such process, it is preferred that the food colouring agent has a hue angle of between 250 and 340, preferably between 260 and 310.

Also for reasons as set out already, in the process as claimed herein it is preferred that said type and amount of colouring agent is added such that Aab _CO ioured _soy < 0.8 Aab _soy , more preferably Aab _CO ioured _soy < 0.7 Aab _soy , most preferably Aab _CO ioured _soy < 0.6 Aab _soy .

Likewise, it is preferred that in this process, the beverage has an L* value greater than 70 in the CIE L*a*b* colour space.

Also, it is preferred that in the process according to this invention, the amount added of the food colouring agent is from 0.01x10 ^"4 to 10x10 ^"4 % (by weight, based on the total

composition), preferably 0.2x10 ^"4 to 5x10 ^"4 %. These optimal concentrations, however, will depend e.g. on the concentration of soy protein in the beverage, origin, processing, and such can vary widely.

Preferably, in the process according to this invention, the food colouring agent is one or more of Acid Blue 3, Acid Blue 9, Food Black 1 , Acid Blue 74.

Preferably, e.g. for health and/or taste reasons and/or regulatory requirements, the amount of soy protein in the compositions of this invention is from 0.6 to 5% by weight on the beverage, more preferably from 0.8 to 4% by weight. Preferably, for reasons of e.g. flexibility, cost, nutritional or environmental reasons, the soy protein in the present invention is at least part, to all, obtained from soy beans from which the hypocotyl has not been removed and/or non- dehulled soy beans. The beverages concerned herein preferably have a pH of from 3.5 to 7.5, more preferably from 5.0 to 7.5. The beverages concerned herein preferably have a fat content of from 0.1 % to 4% by weight, based on the beverage, more preferably 0.2 to 3% by weight, based on the beverage. EXAMPLES

Example 1

In this example, the colour of a soy protein containing beverage (with and without certain colouring agents) was measured using a reflectometer (UV included), which expresses colour as the CIE L* a* b* values, and compared with the colour of a commercial (UK supermarket) pasteurised full fat dairy milk.

The soy protein containing beverage measured in this example was a sterilized soy base (i.e. without stabilizer, sugar, flavouring agent, vitamins or minerals added), as used intra-factory, containing about 4% soy protein, and such was obtained by a standard extraction process (e.g. discarding the okara) of "Conquista" beans, with no dehulling. The dairy milk was Standardised Pasteurised Homogenised Whole Milk from UK supermarket chain Morrisons, comprising, per 100 g: 3.2g protein, 4.7g carbohydrates, and 3.6g fat.

The colouring agents used for colouring the soy protein containing beverages in this example are set out in table 1. The hue angle of these colouring agents as aqueous solution in demineralised water (0.5g/L of dye as received) were measured (table 1). The colour of each solution were measured using a reflectometer and expressed as the hue angle (0 = 360 = red; 90 = yellow; 180 = green; 270 =blue.

Table 1.

All colouring agents are given their color index name (Society of Dyers and Colourists and

American Association of Textile Chemists and Colorists):

Acid Blue 3 is Patent Blue V, E131 , a triphenylmethane dye.

Acic Blue 9 is Brilliant Blue FCF, E133, a triphenylmethane dye.

Food Black 1 is Brilliant Black BN, E142, a bis azo dye.

Acid Blue 74 is Indigo Carmine, E132, an indigoid dye.

Natural Red 4 is Carmine, E120, an anthraquinone dye. The concentration of each colouring agent in the soy protein containing beverage was determined by UV_Vis measurement of the amount of concentrated colourant solution, using the Beer-Lambert law and known extinction coefficients for the colouring agents. Herein, triphenyl methane dyes have an extinction coefficient of 140000 mol ^"1 L cm ^"1 , bis azo dyes have an extinction coefficient of 60000 mol ^"1 L cm ^"1 , and indigoid dyes of 17000 mol ^"1 L cm ^"1 .

Generally for CIE colour measurements, L* is the lightness of the colour and a* and b* are measures for the base colour such that:

a* is a measure for the red (+ve values) and green (-ve values) component of the colour b* is a measure for the yellow (+ve values) and blue (-ve values) component of the colour.

The measurements for a* and b* were done by placing the beverage to be measured (without any further sample treatment) in a transparent plastic cell of 2cm width, and the a* and b* values were measured for each of dairy milk, soy protein containing beverage without colouring agent, and then soy protein containing beverage with colouring agent (at various concentrations of colouring agent). Herein, the CIE L*a*b* measurements were made with a Reflectometer through the liquid contained in a transparent plastic cell with a 2 cm liquid depth (25mm aperture, UV excluded, specular included), using the Color i7(TM) reflectometer (from Xrite, Grand Rapids, Michigan USA). The cell used was made form optically clear polystyrene (Corning® 25cm ² Rectangular Canted Neck Cell Culture Flask with Vent Cap, Product #430639).

For mimicking the colour of dairy milk as best as possible, the difference in base colour between the soy protein containing beverage and dairy milk was determined, and such is herein expressed as Aab: and

wherein

a _da iry is the a* value of the dairy milk

b _d airy is the b* value of the dairy milk

a _soy is the a* value of the soy protein containing beverage bsoy is the b* value of the soy protein containing beverage

Aabsoy is a comparison of the a* and b* values in the CIE L*a*b* colour space for semi- skimmed dairy milk and said soy beverage with no added colouring agent a _C oioured soy is the a* value of the soy protein containing beverage further containing a colouring agent

bcoioured soy is the b* value of the soy protein containing beverage further containing a colouring agent.

Aabcoioured soy is a comparison of the a* and b* values in the CI E L*a*b* colour space for semi- skimmed dairy milk and said soy beverage containing said colouring agent

The results are summarised in table 2.

Table 2.

In table 2, the Aab for the control equals Aab _soy , and the other Aab values are the Aab _CO ioured for the given colouring agent. The results are also set out in figure 1 : the Aab values for three concentrations of four colouring agents. Figure 1 sets out Aab _soy (for a an amount of colouring agent being 0% wt) and Aabcoioure _{d soy} (for soy beverages containing one of the 4 colouring agents, at one of the three concentrations of colouring agents, as set out on the X-axis).

Description of figure 1 : Aab values for three concentrations of four colouring agents in a soy protein-containing beverage when compared to dairy milk.

- AB3 stands for Acid Blue 3

- AB9 stands for Acid Blue 9

FB stands for Food Black 1

- Ab74 stands for Acid Blue 74

Lower values of Aab indicate that the colour is closer to cows milk, when Aab =0 they would be identical. It was found that addition of low levels of blue or violet dyes to soy protein containing beverages can provide a colour closer to full fat dairy milk. It was also found that the concentrations required differed for the various colouring agents.

Benefits are obtained, for the given soy protein containing beverage, for the triphenyl methane dyes Acid Blue 3 and Acid Blue 9 when used in the range from 1x10 ^"6 wt% to 1.5x10 ^"4 wt%, preferably 2.0x10 ^"5 wt% to 9.0x10 ^"5 wt%.

Benefits are obtained, for the given soy protein containing beverage, for the bis azo dye, Food black 1 in the range from 1x10 ^"6 wt% to 2.5x10 ^"4 wt%, preferably 5x10 ^"5 wt% to 2.0x10 ^"4 wt%

Benefits are obtained, for the given soy protein containing beverage, for the indigoid dye, Acid blue 74 in the range from 1x10 ^"6 wt% to 7.0 x10 ^"4 wt%, preferably 1.0x10 ^"4 wt% to 5.0x10 ^"4 wt%.

Example 2

To the soy protein base beverage of example 1 , a commercial colouring agent being a mixture of E131 (Acid Blue 3) and E132 (Acid Blue 74) was added from stock solution at various concentrations. For these products L*, a* and b* were measured in the same way as in example 1 , and also for a commercial full fat dairy milk (brand: Campina, type: full fat milk, obtained in a Dutch supermarket), and Aab values were calculated. The concentrations colouring agent (weight % stock solution of total beverage) and L*, a* and b* measuring results are in table 3. Table 3: results L*, a* and b* measurements soy base + commercial colouring agent.

Two soy base products as prepared above, one containing no added colouring agent, and one containing added colouring agent in an amount of 0.009% (wt) stock solution, giving a Aab of 2.61 were subjected jointly in a panel test (20 subjects), using 4 different light sources. The panel members were asked: "of these two soy base beverages, which do you think matches common dairy milk best in colour?". The panel members were asked to score on visual appearance only, and were not allowed to taste the products. The lightsources used were:

- European standard store light 1 (3000 K) (TL83)

- Artificial daylight (6500 K) (D65)

- Home light (2865 K) (I NC-A)

- European standard store light 2 (4000 K) (TL84)

In TL 83 light, panel members 3 and 5 selected the soy base beverages not containing any added colouring agent as the product that matched most closely common dairy milk (in terms of colour appearance) over the product containing colouring, the 18 others chose the sample containing the added colouring agent as most closely matching common dairy milk colour. In D65 light, all 20 panel members chose the sample containing the added colouring agent as most closely matching common dairy milk colour.

In INC-A light, all 20 panel members chose the sample containing the added colouring agent as most closely matching common dairy milk colour.

In TL 84 light, panel members 3 and 10 selected the soy base beverages not containing any added colouring as the product that matched most closely common dairy milk (in terms of colour appearance) over the product containing colouring, the 18 others chose the sample containing added colouring agent as most closely matching common dairy milk colour.

Conclusion: adding a small amount of a commercial blue colourant to a crude soy base beverage can shift the colour appearance to more closely resembling what people consider as a colour of dairy milk (without actually seeing at the evaluation dairy milk).