Stabilisation of natural dyes by an acerola powder

Abstract

The invention concerns a powder consisting of 0.5 to 8% by weight of water and a dry material consisting of 88 to 95% by weight of an acerola fruit dry extract and 5 to 12% by weight of magnesium, calcium, zinc, sodium or potassium hydroxide or carbonate, the method of preparing same and the applications thereof for stabilizing a natural dye.

Claims

1. A food additive or ingredient, comprising: a natural dye comprising one or more natural pigments; and a powder component consisting of: 0.5% to 8% by weight of water, relative to the total weight of the powder component; and a dry material consisting of: 88% to 95% by weight of an acerola fruit dry extract, relative to the total weight of the dry material; and 5% to 12% by weight of a hydroxide or carbonate of magnesium, calcium, zinc, sodium or potassium, relative to the total weight of the dry material, wherein the acerola fruit dry extract provides the powder component with a natural vitamin C content of 30% to 40% by weight, relative to the total weight of the powder component.

2. The food additive or ingredient according to claim 1, wherein the natural dye comprises a red beet juice concentrate or a red beet powder.

3. A food or food composition comprising the food additive or ingredient according to claim 1 combined with a food component.

4. The food additive or ingredient according to claim 1, wherein the one or more natural pigments include betanin.

5. The food additive or ingredient according to claim 1, wherein the powder component contains a natural vitamin C content of 34%3% by weight, relative to the total weight of the powder component.

6. The food additive or ingredient according to claim 1, wherein the powder component has a pH varying from 4 to 8.

7. The food additive or ingredient according to claim 1, wherein the powder component consists of 0.5% to 5% by weight of water, relative to the total weight of the powder component.

8. A method of producing a food additive or ingredient, the method comprising combining a powder component with a natural dye, the powder component consisting of: 0.5% to 8% by weight of water, relative to the total weight of the powder component, and a dry material consisting of: 88% to 95% by weight of an acerola fruit dry extract, relative to the total weight of the dry material; and 5% to 12% by weight of a hydroxide or carbonate of magnesium, calcium, zinc, sodium or potassium, relative to the total weight of the dry material, wherein the acerola fruit dry extract provides the powder component with a natural vitamin C content of 30% to 40% by weight, relative to the total weight of the powder component, the natural dye comprising one or more natural pigments, the powder component stabilizing the natural dye.

9. The method according to claim 8, wherein the one or more natural pigments include betanin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1: Change in vitamin C content of the powder of the invention during storage at 4 C. or 20 C. in an aluminium bag or without an aluminium bag.

(2) FIG. 2: Demonstration of the importance of magnesium hydroxide content on the yield of the powder of the invention.

(3) FIG. 3: Demonstration of the effect of the powder of the invention, of acerola extract alone (acerola juice concentrate, 50 Brix, diluted to 0.06%) and of magnesium hydroxide (Mg(OH)2 powder diluted to 0.002%) on the heat stability of betanin (red beet juice concentrate diluted to 0.2% in water).

(4) FIG. 4: Demonstration of betanin-degrading effect or absence of betanin-degrading effect in the presence of ascorbic acid or powder of the invention, respectively.

(5) FIG. 5 presents Table 3: Analyses of the colour obtained in a cooked meats food model after incorporation or not of dyes, alone or stabilised.

DETAILED DESCRIPTION

Examples

Example 1Production and Solubilisation Properties of a Powder According to the Invention

i. Production of a Powder According to the Invention

(6) Taking into account the features of the acerola fruit juice concentrate employed (50 Brix, 17% vitamin C), the pH of the mixture was stabilised at 4.5 with 92% acerola fruit juice concentrate and 8% magnesium hydroxide (percentages expressed relative to the dry material).

(7) The amount of water to be added was then calculated so as to obtain a Brix value for the acerola fruit juice concentrate/magnesium hydroxide/water mixture of 30 Brix.

(8) Consequently, the following formulation was prepared according to the method below:

(9) TABLE-US-00001 Recipe Raw (% of dry Amount employed material material) pH (kg) Acerola fruit 92 3.01 420 juice concentrate Magnesium 8 14 15 hydroxide Water 7.61 300

(10) The materials were mixed in a vat and the mixture was spray-dried (inlet temperature 160 C., outlet temperature 86-88 C.). The powder was screened with a 650 m mesh and packaged in aluminium bags.

(11) The yield obtained is 73.5% and productivity is about 84 kg/h.

(12) The powder is characterised by a vitamin C content of 36.7% by weight of the total weight of the powder, which is stable over time as shown by the ageing test applied to the powder (see FIG. 1).

(13) The product has excellent solubility (absence of a pellet visible to the naked eye after dissolution of the powder at a concentration of 10% by weight of the total weight of the powder in water and then centrifugation at 10,000 g for 10 minutes) and the solution obtained is bright and clear.

ii. Effect of Magnesium Hydroxide Content in the Powder of the Invention

(14) In order to illustrate the importance of magnesium hydroxide content in the powder of the invention, spray-drying tests were carried out with various levels of Mg(OH)2 (here, pilot-stage tests).

(15) As the graph in FIG. 2 proves, the yield of the powder of the invention decreases with decreasing amounts of magnesium hydroxide, reaching values below 65% (poor yield) with a magnesium hydroxide content of 5% by weight (content expressed relative to the dry material of the powder of the invention).

iii. Solubilisation Properties of a Powder of the Invention

(16) In order to show the lower solubility of a freeze-dried acerola powder, solubilisation tests were performed on the sprayed powder of the invention compared with a freeze-dried powder. The results are presented below in Table 1:

(17) TABLE-US-00002 TABLE 1 Solubilisation tests of acerola powders obtained by means of two different drying methods (spraying for the powder of the invention and freeze-drying) Insoluble Sample (diluted to materials 10% in water) (%) Acerola powder of the 1.8 0.3 invention Freeze-dried acerola 5.7 0.1 powder

(18) These tests clearly show the lower solubility of the freeze-dried powder (quantification of insoluble materials presented in Table 1). About three times more insoluble compounds are generated from a 10% solution of freeze-dried powder. Furthermore, the appearance of a pellet visible to the naked eye is noted in the case of the test performed with the freeze-dried powder, which is not the case for the test performed with the powder of the invention.

(19) This criterion may act to curb the use of the product in bright and clear products (beverages, for example). Furthermore, it may be assumed that in a freeze-dried powder characterised by many insoluble particles when in solution, vitamin C is less available and is less effective in terms of the effects attributed thereto (role as antioxidant, stabiliser, etc.). On the other hand, the spectrum of use of the powder of the invention (obtained by spraying) is not subject to this constraint.

Example 2Antioxidant Potential of the Powder of Example 1 Versus Ascorbic Acid

(20) Tests performed in vitro illustrate the properties of the powder of the invention in comparison with the single effect of ascorbic acid. The table below shows that the powder of Example 1, in comparison with ascorbic acid, has a greater antiradical and antioxidant activity than that of equivalent concentrations of ascorbic acid.

(21) TABLE-US-00003 TABLE 2 Evaluation of the antioxidant power of acerola powder versus ascorbic acid Powder of the Method invention Ascorbic acid Antiradical activity (% of 90.1 70.6* trapping of the free radical DPPH at the fixed concentration of 0.44 mg/ml ascorbic acid eq) Overall antioxidant power 58 34 (g/100 g of product in ascorbic acid eq) *Ascorbic acid tested in combination with Mg(OH).sub.2 in the proportions present in the powder of the invention.

Example 3Effect of the Powder of the Invention on the Stabilisation of Red Pigments from Red Beet

i. Proof of Stabilisation of Red Beet in a Cooked Meats Model

(22) The powder of Example 1 was tested in a food model as stabiliser of red beet pigments. It was incorporated into a red beet juice concentrate in a proportion of 40%, 10% and 4% (40 g, 10 g and 4 g of the powder of Example 1, respectively, added to 100 g of red beet concentrate of about 70 Brix and with about 0.6% to 0.7% of betanin and a pH of 4.44), these mixtures (the pH of which is not significantly different following addition of the powder of the invention taking into account the pH and the proportion of the powder of the invention used) themselves having been incorporated into an emulsion base used for the manufacture of fine-texture sausages. After heating for 20 minutes at 80 C., colour was measured using a L*a*b* system (Minolta CM5 spectrocolorimeter, D65 light source, 10 angle, reflection).

(23) The table presented in FIG. 5 presents the results obtained according to six conditions: a negative control without dye, a test with the red beet concentrate alone, three tests with the red beet concentrate combined with the acerola powder of the invention in the various proportions listed above, and a positive control with carmine.

(24) Delta E is an indicator for evaluating colour variation between a sample and a standard. It is calculated according to the following formula: E=[(a.sub.std*a.sub.samp*).sup.2+(b.sub.std*b.sub.samp*).sup.2+(L.sub.std*L.sub.samp*).sup.2].

(25) The standard chosen here corresponds to the condition with 0.01% carmine. A E value (called carmine delta E) below 4 corresponds to a product whose colour variation in comparison with the standard is considered to be acceptable.

(26) The tests performed highlight the effect of the powder of the invention on the stabilisation of the red beet concentrate and in particular its potential to yield a heat-stable cooked meats product whose colour approaches a target prepared with carmine.

ii. Proof of Red Beet Stabilisation in a Cream Dessert Model

(27) The powder of Example 1 was also tested for its ability to heat-stabilise red pigments from red beet in a cream pudding/dessert-type application. The acerola powder of the invention was incorporated into a red beet juice concentrate of about 70 Brix and with about 0.6% to 0.7% of betanin in a proportion of 66% (66 g of acerola powder at 34% vitamin C, added to 100 g of red beet juice concentrate), this mixture itself having been incorporated into a preparation containing water, milk, cream, sugar and texturisers heated at 90 C. for 10 minutes before being cooled. Absorbance at 540 nm was measured by means of a spectrocolorimeter in order to quantify betanin levels before and after heating, and the percentage loss of betanin was calculated from these data according to the following formula: [(A540 nm before heatingA540 nm after heating)/A540 nm before heating]100.

(28) On the basis of the L*a*b* measurements (Minolta CM5 spectrocolorimeter, D65 light source, 10 angle, reflection), delta E also was calculated in order to evaluate colour variation in comparison with a standard before heating (called heating delta E).

(29) TABLE-US-00004 TABLE 4 Betanin loss and colour change in red beet juice concentrate stabilised or not by the product of the invention measured in a cream dessert food matrix Ingredient and proportion incorporated into the cream Betanin loss after dessert heating (%) Heating E 0.1% red beet concentrate 29.3 18.5 0.06% red beet concentrate + 11.6 11.3 0.04% powder of the invention

(30) These tests show that the fact of adding the powder of the invention to the red beet juice induces a red beet-pigment stabilisation effect, whatever indicator is considered (chemical, by means of percentage loss of betanin; or colorimetric, by means of heating delta E values).

iii. Effect of the Powder of the Invention, of Acerola Extract Alone and of Magnesium Hydroxide on Heat Stability of Betanin

(31) FIG. 3 shows the positive effect of acerola extract alone (not associated with magnesium hydroxide) and of the powder of Example 1, and the negligible effect of magnesium hydroxide, on the heat stability of betanin.

(32) After 150 minutes of heating at 60 C. in an aqueous model: Acerola provided in the form of a 50 Brix juice concentrate diluted to 0.06% reduces by 23% the betanin loss observed in a red beet concentrate diluted to 0.2% in water. The powder of the invention reduces by 28% the betanin loss observed in a red beet concentrate diluted to 0.2% in water. Magnesium hydroxide has a negligible contribution because it reduces by less than 5% the betanin loss observed in a red beet concentrate diluted to 0.2% in water.

(33) This test clearly shows the specific effect of the powder of the invention, which does not result from a simple effect of addition of the effect of acerola alone and of the negligible effect of magnesium hydroxide (effect of the powder of the invention always superior to the effect of acerola alone added to the effect of Mg(OH).sub.2).

iv. Absence of Negative Effect at High Concentrations

(34) The graph in FIG. 4 shows that in an aqueous medium (dilution of red beet juice concentrate of about 70 Brix and with about 0.6% to 0.7% of betanin and of the acerola powder at 34% vitamin C of Example 1 in water, heating at 60 C. for 60 minutes and cooling), high concentrations of ascorbic acid induce greater levels of betanin loss than low concentrations. Conversely, if the powder of Example 1 is used to stabilise betanin, the stabilising effect increases as the concentration of acerola powder increases.

(35) The powder of the invention thus prevents all the harmful effects of over-proportioning of ascorbic acid.