FIELD OF THE INVENTION

The present invention relates to acid-stabilization of natural colorants used for coloring edible products, such as food, beverages and pharmaceutical products. Specifically, the present invention relates to water-dispersible compositions comprising at least one Monascus red pigment and at least one hydrocolloid selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin, preferably a starch octenyl succinate derivative.

The present invention also relates to methods of preparing acid-stable Monascus red pigment compositions and use of at least one hydrocolloid selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin for acid- stabilizing at least one Monascus red pigment.

BACKGROUND ART

Colorants containing natural coloring substances are commonly used in the manufacturing of e.g. food products and pharmaceutical products. Coloring substances from microbial species offer considerable advantages since they can be produced in any quantity and are not subject to the vagaries of nature.

Requirements apply for the color to be stable against chemical interaction with other compounds in the environment of the product. As many food products have a pH in the acidic range, this means that the colorant must be able to stay in solution in media having a low pH . This especially applies in the case of beverages, which have a rela- tively low pH in the range of 2.0-4.5, and more commonly 2.5-3.6.

Another example of an edible product which has a relative low pH is water ice, such as ice lollies, which is often added acids to increase the perceived freshness.

The genus Monascus includes several fungal species that will grow on various solid substrates. Its fermented product of rice, named red fermented rice or red yeast rice has been used as folk medicines, food colorants and fermentation starters for more than 1000 years in China.

It has found that Monascus spp. can synthesize among many secondary metabolites, Monascus pigments. Monascus pigments possess a range of biological activities, such as anti-mutagenic and anti-cancer properties.

Monascus pigments are an azaphilone mixture, which usually include yellow (Monascus yellow), orange (Monascus orange) and red constituents (Monascus red). Monascus red pigments are very important colors for food products especially in Asia. Monascus red pigments have the disadvantage that they precipitate when exposed to pH values below 3-4. This limits the use of these colors in beverages and other acidic applications.

CN102919633A relates to a hawthorn jelly powder, which comprises the following ingredients according to the weight percentage: 40% to 50% of white granulated sugar, 25% to 35% of glucose, 15% to 20% of hawthorn powder, 2.5% to 3.5% of carragee- nan, 2.5% to 3.0% of locust bean gum, 1.2% to 1.5% of citric acid, 0.9% to 1.1% of potassium citrate, 0.5% to 0.7% of hawthorn essence and 0.06% to 0.08% of monascus red, wherein all the ingredients are mixed and processed in a microwave sterilization manner. The described process for preparing a hawthorn jelly from the hawthorn jelly powder is accomplished by adding the definite quantity of water to the hawthorn jelly powder. The content of soluble solid in the hawthorn jelly powder is greater than or equal to 15%, so that the hawthorn jelly powder completely meets the requirement of the existing national standard of a jelly.

As understood by the skilled person - a jelly is not a solution like e.g. a soft drink.

As understood by the skilled person in the present context - in a jelly it may be d iff i - cult (if not impossible) to talk about a herein relevant pH value of the jelly as such.

For instance, the relatively low amount of monascus red present in the jelly as described in above discussed CN102919633A may within the jelly be present in a local environment with different pH values, which do not have to be pH values below 3. Further, within the jelly the monascus red may be present as precipitated particles and still give a commercial relevant acceptable jelly product with an acceptable red color. Said in other words, precipitation problems relating to use of monascus red pigments in soft drinks (or other acidic beverages) are simply not of significant relevance in relation to a jelly product and the fact that monascus red pigments may have been used in a jelly product does not in any way as such imply that it maybe could be used properly in soft drinks (or other acidic beverages).

SUMMARY OF THE INVENTION

Thus, the problem to be solved by the present invention is the provision of a water- dispersible coloring composition comprising Monascus red pigment, wherein the Monascus red pigment does not precipitate at pH values below 3-4. The solution is based on the fact that the present inventor has identified that a water- dispersible composition comprising a hydrocoiioid selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin in the presence of a Monascus red pigment is very good in relation to acid-stabilizing the Monascus red pigment, i.e. the Monascus red pigment will not precipitate but stay in solution at pH values below 3-4.

The present inventor surprisingly found that the presence of a hydrocoiioid selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gela- tin in the coloring composition stabilized the Monascus red pigment against precipitation at low pH not only when the hydrocoiioid was blended directly into an aqueous Monascus red solution (see Examples 2 to 5) but also when the Monascus red pigment was allowed to precipitate by lowering the pH of the coloring composition followed by wet milling in a ball mill the precipitated Monascus red pigment in the presence of hy- drocolloid (see Example 1).

Accordingly, in one aspect the present invention is directed to use of at least one hydrocoiioid selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin for acid-stabilizing at least one Monascus red pigment.

Another aspect of the present invention relates to a water-dispersible composition comprising at least one Monascus red pigment and at least one hydrocoiioid, selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin.

Preferably, the hydrocoiioid is starch octenyl succinate derivative (nOSA starch).

In a further aspect the present invention is directed to a method for preparing a water- dispersible composition comprising precipitating at least one Monascus red pigment at a pH below 3, comminuting the at least one precipitated Monascus red pigment in the presence of at least one hydrocoiioid selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin to obtain a dispersion containing the Monascus red pigment in the form of particles having an average diameter of at the most 10 μιτι and optionally drying the dispersion. Another aspect relates to a composition obtainable by the method according to the previous aspect.

A further aspect relates to a method for preparing a water-soluble composition comprising blending an aqueous solution of at least one Monascus red pigment to an aque- ous solution of at least one hydrocolloid selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin and optionally drying the dispersion. Additionally, an aspect is directed to a composition obtainable by the method according to the previous aspect.

In a further aspect the present invention relates to an edible product comprising at least one Monascus red pigment and at least one hydrocolloid, selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin.

Preferably, the hydrocolloid is starch octenyl succinate derivative (nOSA starch).

The present invention in an even further aspect relates to use of a composition according to the first aspect for coloring an edible product.

BRIEF DESCRIPTION OF FIGURES

FIGURE 1 shows Monascus red pigment in diluted soft drink medium (pH 2.9) after overnight storage at room temperature (A) and Monascus pigment and a nOSA starch in diluted soft drink medium (pH 2.9) after overnight storage at room temperature (B).

FIGURE 2 shows Monascus red pigment in water ice base (pH 2.5) after storage at 80°C for up to 8 hrs (A) and a Monascus pigment formulated with a nOSA starch in water ice base (pH 2.5) after storage at 80°C for up to 8 hrs (B). DETAILED DESCRIPTION OF THE INVENTION

In one aspect the present invention relates to use of at least one hydrocolloid for acid- stabilizing at least one Monascus red pigment.

"Monascus red pigment" as used herein relates to the red to purplish-red pigments synthesized by Monascus spp. The sources of Monascus red pigments include but are not limited to Monascus red (highly pure), Kojic red and rice red which differs in the processes by which the pigments are extracted and the concentration of the pigments.

As mentioned, the Monascus red pigments precipitate at pH values of between 3 and 4.

The presence of precipitation can be followed visually as the Monascus red pigment will precipitate out of solution as a solid which sediments at the bottom of the container (see e.g. Figure 1A). "Acid-stable" and "acid-stabilized" when referring to Monascus red pigment herein refer to Monascus red pigment in aqueous solution which stays in solution when the pH is lowered to 3.

Suitable hydrocoiioids include an animal or vegetable protein, such as gelatin which can be derived from mammals or fish, milk protein or soy protein, an exudate, such as gum arabic, tragacanth and other gums, such as guar gum, locust bean gum or xan- than gum, agar, alginate, carrageenan, furcelleran, pectin, cereal flours and starches, starch derivatives, such as starch octenyl succinate derivatives (nOSA starches), mi- crocrystalline cellulose, cellulose derivatives, such as carboxymethyl cellulose, dextran, and synthetic hydrocoiioids, including as an example polyvinylpyrrolidone. The hydro- colloid may also be a mixture of hydrocoiioids. The inventors have found that when utilizing hydrocoiioids selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin, under the conditions according to the present invention, it is possible to achieve acid stability of a Monascus red pigment in aqueous solution (see the Examples herein) as determined by the formation of a precipitate when the pH of the solution is lowered to pH 3.

Thus, in a preferred embodiment the hydrocolloid is selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin, such as cow gelatin. Preferably, the hydrocolloid is a starch octenyl succinate derivative. Starch octenyl succinate derivatives is the common name given to starch n-octenyl succinate derivatives which are made by treating starch with n-octenyl succinic anhydride (nOSA) at pH 8 - 8.5. Starch octenyl succinate derivatives have the common E- number E1450 according to EU food additive legislation. A further aspect of the present invention relates to a water-dispersible composition comprising at least one Monascus red pigment and at least one hydrocolloid, selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin.

Preferably, the hydrocolloid is starch octenyl succinate derivative (nOSA starch).

In one embodiment, the water-dispersible composition may be a liquid composition, in particular wherein the liquid composition is a liquid solution.

The compositions of the Examples herein are examples of liquid solutions. Preferably, the composition does not comprise a surface active substance.

In this context, the term "surface active substance" includes compounds which are generally referred to as anionic, cationic, non-ionic, amphoteric and zwitterionic surfactants. As used herein the term "surface active substance" does not include hydrocol- loids as mentioned above. It is to be understood, that the expressions "does not comprise a surface active substance" and "in the absence of a surface active substance" do not exclude the presence of a surfactant in minor amounts which substantially does not impart surface activity.

Alternatively, the water-dispersible composition may be a dry powder composition. Drying may be carried out by techniques readily known to the skilled person, such as spray-drying or evaporation. In a preferred embodiment drying is carried out by spray- drying.

In a preferred embodiment the ratio of starch octenyl succinate derivative to Monascus red pigment (w/w) is at least 0.5, such as at least 0.75, such as at least 1.0, such as at least 1.5, such as at least 2.0, such as at least 2.5, such as at least 3.0, such as at least 3.5, such as at least 4.0.

Preferably the ratio of starch octenyl succinate derivative to Monascus red pigment (w/w) is less than 1000, more preferably less than 500 From an economical point of view it may be preferred that the ratio of starch octenyl succinate derivative to Monascus red pigment (w/w) is in the lower ratio range (use of relatively little amount of starch octenyl succinate derivative).

Accordingly, in a preferred embodiment the ratio of starch octenyl succinate derivative to Monascus red pigment (w/w) is at least 0.5 and less than 200 (preferably less than 100, more preferably less than 50 and even more preferably less than 15).

The water-dispersible composition can be prepared by a method comprising precipitating at least one Monascus red pigment at a pH below 3, comminuting the at least one precipitated Monascus red pigment in the presence of at least one hydrocolloid to ob- tain a dispersion containing the Monascus red pigment in the form of particles having an average diameter of at the most 10 μιτι, such as at the most 5 μιτι, such as at the most 2 μιτι, such as at the most 1 μιτι, such as at the most 0.5 μιτι, such as at the most 0.3 μιτι, such as at the most 0.2 μιτι, and optionally drying the dispersion. Preferably, the at least one Monascus red pigment is precipitated and comminuted in the absence of a surface active substance. Thus, in one preferred embodiment the at least one Monascus red pigment is in the form of solid particles with an average size of at the most 10 μιτι, such as at the most 5 μιτι, such as at the most 2 μιτι, such as at the most 1 μιτι, such as at the most 0.5 μιτι, such as at the most 0.3 μιτι, such as at the most 0.2 μιτι. The water-dispersible solution can also be prepared by a method comprising blending an aqueous solution of at least one Monascus red pigment to an aqueous solution of at least one hydrocolloid and optionally drying the dispersion.

Drying is preferably carried out by spray-drying.

Accordingly, in another preferred embodiment the composition is a liquid composition and the at least one Monascus red pigment is dissolved in the liquid.

In a preferred embodiment the at least one hydrocolloid is selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin, such as cow gelatin. Preferably, the at least one hydrocolloid is a starch octenyl succinate derivative.

The present invention also in one aspect relates to an edible product comprising at least one Monascus red pigment and at least one hydrocolloid, selected from the group consisting of starch octenyl succinate derivatives, gum arabic and gelatin.

Preferably, the hydrocolloid is starch octenyl succinate derivative (nOSA starch).

Preferably, the ratio of starch octenyl succinate derivate to Monascus red pigment (w/w) is at least 0.5, such as at least 0.75, such as at least 1.0, such as at least 1.5, such as at least 2.0, such as at least 2.5, such as at least 3.0, such as at least 3.5, such as at least 4.0.

Preferably the ratio of starch octenyl succinate derivative to Monascus red pigment (w/w) is less than 1000, more preferably less than 500. From an economical point of view it may be preferred that the ratio of starch octenyl succinate derivative to Monascus red pigment (w/w) is in the lower ratio range (use of relatively little amount of starch octenyl succinate derivative).

Accordingly, in a preferred embodiment the ratio of starch octenyl succinate derivative to Monascus red pigment (w/w) is at least 0.5 and less than 200 (preferably less than 100, more preferably less than 50 and even more preferably less than 15).

In a preferred embodiment the edible product is a beverage or water ice or ice cream. In an even more preferred embodiment the edible product is a beverage or water ice.

It may be preferred that the edible product is a beverage, such as preferably a soft drink.

In a preferred embodiment, the beverage or water ice has a pH of between 2.0 and 4.5, such as between 2.1 and 4.0, such as between 2.2 and 3.9, such as between 2.4 and 3.7, such as between 2.5 and 3.6, such as between 2.6 and 3.2, such as between 2.7 and 3.1.

The edible product can be prepared by a method comprising incorporating, such as by blending, mixing, dispersing etc., in the edible product a water-dispersible composition according to the invention.

Therefore, the present invention in a further aspect is directed to use of a water- dispersible composition as described above for coloring an edible product.

Any combination of the above-described elements, aspects and embodiments in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. The terms "a" and "an" and "the" and similar referents as used in the context of describing the invention are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Thus, "a" and "an" and "the" may mean at least one, or one or more.

Embodiments of the present invention are described below, by way of non-limiting examples. EXAMPLES

Example 1. 5% Monascus red pigment formulation with nOSA starch.

An acidic solution of HiCap 100 (a nOSA starch supplied by Ingredion, Manchester, UK) and a solution of Monascus Red (Monascus red pigment supplied by Bionature, batch no. 14092C) were prepared as follows:

Acid phase:

Ingredient Amount

Demineralized water 2000 g

K-sorbate (Brenntag Nordic, Ballerup, Denmark) 4 g

Antifoam (Alsiano, Birkerod, Denmark) 1 g

HiCap 100 914 g

H ₂ S0 ₄ 96% 32 g

Color phase:

Ingredient Amount

Monascus Red 216 g

Demineralized water 834 g

The color phase was added to the acid phase while stirring on a magnetic stirrer.

Viscosity increased somewhat due to precipitation of the Monascus red pigment but became lower after continued stirring.

The pH in the final blend was measured to 1.8.

The ratio of hydrocolloid to Monascus red pigment is approximately 4: 1.

The blend was stored at room temperature for 4 days before milling.

Wet milling on LabStar ball mill (Netzsch) using 450 ml 0.6-0.8 mm beads, 0.2 mm sieve, for 1 hour at recirculation mode.

The milled color suspension was measured on a Malvern MasterSizer in demineralized water to which H ₂ S0 ₄ had been added, giving a pH of 2.5 (to secure that the particles did not dissolve).

Average particle size (diameter), D(v,0.5) : 1.99 microns

A concentrated soft drink medium was prepared with the following composition : Ingredient Amount

Sucrose 430.0 g

Na-benzoate, food grade 0.7 g

K-sorbate, food grade 0.9 g

Ascorbic acid 0.1 g

Citric acid monohydrate, food grade 8.6 g

Demineralized water ad 1000.0 g

The concentrate was diluted 1 :4 before use with demineralized water.

A few drops of the 5% Monascus red pigment formulation with nOSA starch was added to a beaker containing diluted soft drink medium. The pH was measured to 2.72.

A few drops of a 5% solution of the same Monascus red (to give about same red color intensity as above formulation) was added to another beaker containing diluted soft drink medium. The pH was measured to 2.74.

Both beakers were stored in the window. After 4 days a precipitate had formed in the Monascus solution but not in the formulation described above.

Example 2. Acid-stabilization of Monascus red pigment with nOSA starch or gelatin. A 20% solution of Purity Gum 2000 (a nOSA starch supplied by Ingredion, Manchester, UK), a 20% solution of Solugel LB (a cow based gelatin supplied by PB Gelatin, Germany) and a 30% solution of Monascus Red (Monascus red pigment supplied by Biona- ture, batch no. 14092C) were prepared as follows: 20% Purity Gum 2000:

Ingredient Amount

Demineralized water 799 g

K-sorbate (Brenntag Nordic, Ballerup, Denmark) 1 g

Anti-foam (Alsiano, Birkerod, Denmark) 0.2 g

Purity Gum 2000 200 g 20% cow gelatin:

Ingredient Amount

Demineralized water 799 g

K-sorbate (Brenntag Nordic, Ballerup, Denmark) 1 g

Anti-foam (Alsiano, Birkerod, Denmark) 0.2 g

Solugel LB 200 g

30% Monascus red pigment:

Ingredient Amount

Demineralized water 700 g

Monascus Red 300 g

Each hydrocolloid solution were blended on a magnetic stirrer with the Monascus red solution in different ratios and a few droplets of each blend were added to diluted soft drink medium prepared as described in Example 1 (pH 2.9). Precipitation was checked 1 hour and two days after mixing.

Results are given in the tables below.

no precipitate

some precipitate

large amount of precipitate

no precipitate

some precipitate

large amount of precipitate Discussion:

Both cow gelatin and Purity Gum 2000 are able to keep the Monascus red pigment from precipitating at low pH.

The amounts needed are different for the two hydrocolloids.

For Purity Gum 2000 (nOSA starch) a ratio of hydrocolloid to Monascus red pigment (w/w) of 1 : 1 is efficient but for cow gelatin a ratio of 4: 1 is needed.

Example 3. Acid-stabilization of Monascus red pigment with gum arabic.

This example shows the acid-stabilizing effect of gum arabic on Monascus red pigment.

A 30% solution of Spraygum AA (gum Arabic supplied by Colloides Naturels International) and a 30% solution of Monascus Red (Monascus red pigment supplied by Biona- ture, batch no. 14092C) were prepared as follows: 30% gum arabic:

Ingredient Amount

Demineralized water 699 g

K-sorbate (Brenntag Nordic, Ballerup, Denmark) 1 g

Anti-foam (Alsiano, Birkerod, Denmark) 0.2 g

Spraygum AA 300 g

30% Monascus red pigment:

Ingredient Amount

Demineralized water 700 g

Monascus Red 300 g

Different blends of the gum arabic solution and the Monascus red pigment solution were prepared.

The blends were blended for 5 minutes on a magnetic stirrer.

Then a few drops of the blends or of the Monascus red solution alone (control) were added to diluted soft drink medium prepared as described in Example 1.

In all solutions the pH were measured. Values were between 2.75 and 2.79

The solutions were then subjected to colorimetric analysis according to the CIELAB L*C*h* color system to measure the lightness (L*), chroma (C*) and hue (h*) to assure that the shade of the solutions were comparable.

Precipitation was checked 1 hour and two days after mixing. Results are given in the table below.

+ : some prec p tate

++ : large amount of precipitate

Discussion:

l_* _c *h* values at the start of the experiment were in the same range for solutions containing Monascus red pigment and gum arabic as well as for the control only containing Monascus red pigment.

Gum arabic in a ratio of hydrocolloid to Monascus red pigment (w/w) of 4: 1 is able to keep the Monascus pigment from precipitating at low pH after 2 days.

Example 4. Acid-stabilization of Monascus red pigment with nOSA starch.

The experiment with nOSA starch described in Example 2 was repeated with ratios of hydrocolloid to Monascus red pigment of 0.5/1, 3/4 and 1/1 and check for precipitation after 1 day. A 20% solution of Purity Gum 2000 (a nOSA starch supplied by Ingredion, Manchester, UK and a 30% solution of Monascus Red (Monascus red pigment supplied by Bionature, batch no. 14092C) were prepared as follows: 20% Purity Gum 2000:

Ingredient Amount

Demineralized water 799 g

K-sorbate (Brenntag Nordic, Ballerup, Denmark) 1 g

Anti-foam (Alsiano, Birkerod, Denmark) 0.2 g

Purity Gum 2000 200 g

30% Monascus red pigment:

Ingredient Amount

Demineralized water 700 g

Monascus Red 300 g

The nOSA starch solution was blended on a magnetic stirrer with the Monascus red solution in different ratios. A few droplets of the blends or of the Monascus red solution only (control) were added to diluted soft drink medium prepared as described in Example 1 (pH 2.9).

Precipitation was checked 1 day after mixing. Results are given in the table below and Figure 1 shows the control soft drink colored with Monascus red solution only (Figure 1A) and the soft drink colored with a blend of nOSA starch and Monascus red in the ratio 3/4 (Figure IB).

no precipitate

+ some precipitate

++ large amount of precipitate

Discussion:

In this experiment a ratio of nOSA starch to Monascus red pigment of as low as 0.5/1 is sufficient to keep the Monascus red pigment in solution after 1 day in soft drink media (pH 2.9), whereas significant precipitation of pigment occurs in the control. Example 5. Acid- and heat-stabilization of Monascus red pigment with nOSA starch for water ice application.

A Monascus red formuation was made up by blending the following components:

Ingredient Amount

Monascus red (Bionature) 9.3 g

Sodium tripolyphosphate (STTP) 0.5 g

Ascorbic acid anhydrous 1.0 g

Glycine 1.0 g

Water 25 g

Glycerol 99.5% 43.2 g

Hi-Cap 100 (Ingredion) 20 g A water ice base was made up with the following composition :

Palsgaard® Waterlce 811 (mixture of stabilizers) 0.2 %

Sugar 18 %

Glucose Syrup Solids (DE-value of 39) 5%

Water 76.8 %

Palsgaard® Waterlce 811 is pre-blended with the sugar. Hot water (~65°C) is added while stirring for 10 minutes until no lumps are observed . Glucose syrup Solids is added and mixed for 5 minutes. The solution is pasteurized at 80°C for 30 seconds and cooled down to ~8°C. The pH is adjusted to 2.5 with citric acid. 0.017 % (w/w) Monascus red (control) and 0.1828 % (w/w) of the Monascus red formulation (test) was added to the water ice base.

The colored mixes were bottled in Iwaki flasks and stored in a water bath at 80°C for 8 hours, removing bottles every 2-3 hours for visual evaluation. Discussion

Figure 2 shows the control water ice base colored with Monascus red only (Figure 2A) and the test water ice base colored with the formulation of nOSA starch and Monascus red in a ratio of ~2/l (Figure 2B).

The Monascus red raw material is difficult to dissolve in the water ice base and shows precipitation whereas the formulation of Monascus red and nOSA starch is easy to dissolve (TO). The Monascus red raw material loses color during the heat treatment. It goes from dark red to light orange after 7Vi hours. The formulated Monascus red also loses color but to a much lesser extent than the control.