AEROSOL PRODUCT This invention relates to a composition for use in forming milk shake type products.
This invention was conceived as a means for preparing a flavoured thickened foamy milk-based drink as an alternative to the traditional milk shake which was formed by blending milk with syrup powdered flavours and ice-cream in a mechanical blender. It is an object of the invention to provide a similar milk drink using an aerosol dispenser.
The requirements of a product of this type should include
(i) compatibility with existing aerosol packaging * types in order to minimise manufacturing cost. (ii) a shelf life in an unrefrigerated condition of at least three months.
(iii) full compliance with food regulations, (iv) consumer acceptable flavours as attractive as possible. (v) convenience in use.
(vi) capability of being thickened and frothed in addition to being flavoured.
In order to achieve these objects, it was realised that many constraints existed preventing the formulation of a successful product as discussed below.
Most flavours have a limited shelf life in solution due to oxidation, microbial attack, enzymatic breakdown, etc.
The product should be of a low viscosity initally, so that it can be ejected rapidly from the aerosol can to provide the necessary mixing action. This is not easily achieved because the product needs to be concentrated and the thickeners and viscosity builders required in the composition are also concentrated.
Conventional aerosol cans are not produced to food quality specifications and the lining systems are not able to hold pressurized, low pH liquids for adequate periods of
time. However, most food products are packed in liquids at a low pH in order to avoid microbial spoilage.
The necessity to provide preservation of the product in the absence of low pH compositions must be achieved from the narrow range of food approved added preservatives.
The aerosol propellant is normally restricted to non-condensible gases by food regulations in most countries.
Finally food colours are also affected by some of the above parameters and must be properly regulated.
From the above it can be seen that a large number of difficulties stand in the way of providing an acceptable aerosol product.
In order to achieve the above objects, the present invention provides an aerosol dispensable composition comprising in combination
(i) 0.05 to 5% of a frothing agent, (ii) 0.05 to 75% of a sweetener, (iii) 0.05 to 10% of a thickener, (iv) 0.01 to 1% of a preservative, and the balance being other excipients, flavours and colourants, propellants and water.
The preferred ingredients for the composition of this invention are as follows: A. Frothing agent is selected from emulsifiers of the sorbitol ester, glycerol ester or fatty acid sucrose ester types. Most preferred are glycerol monostearate, sorbitol monostearate which generally produce the best foam with the least affect on flavour. The frothing agent also aids in the stable dispersion of the flavour agents. B. The sweetener may be selected from artificial sweeteners such as saccharine, aεpartame dextrose, fructose or from natural sweeteners such as sucrose. Typically artificial sweeteners are used in the range 0.1 to 5% whilst natural sweeteners are
normally in the range 5 to 75%. The most reliable sweetener is sucrose and the level of sweetener required is constrained by adequacy in providing sweetening effect at the lower end of the scale and by viscosity and solubility at the upper end of the concentration range. Excessive levels when combined with other exipients can produce crystalline growth in the aerosol cans which results in valve blockages. The most preferred sweetener is sucrose used at a level of between 15% - 75%. Typically a representative formula is :
% Flavour 3.0
Sucrose 61.0 Water 28.99
AZO Red Dye 0.010
Nitrous Oxide 7.0
C. Careful selection of the thickener is required because the product is normally used at a dilution of around 10% and with conventional thickeners such as pectin, tragacanth, the ten-fold concentration in the aerosol product would result in a viscosity that was too high to allow proper dispensing from the aerosol can. Thus, preferred thickeners are gums of the polysaccharide type particularly those of a grade which undergo interaction with milk to produce a large increase in milk viscosity after contact. A number of the gums tested showed a tendancy to age thicken when stored over a period of time. This aging tendancy was reduced by addition of water softening components of the phosphate type. Preferred thickeners are carragheenan, methylcellulose, hydroxypropylcellulose, and general polysaccharides.
An example of thickeners follows:-
% Flavour 3.0
Sucrose 50.0 Water 45.95
Xanthane Gum 1.0
Sodium Hexametaphosphate 0.05 Nitrous Oxide 7.0
D. The colouring agents should be present in the range of 0.01 to 5% preferably 0.01 to 1%.
Variation of the other components of the composition tends to produce variable affects on colour. Many- colours also increase the corrosivity of the formula to the aerosol container. The preferred colouring agents are asodyes of the ponceau 4R, erythroscine, carmoisine, and tartrazine type.
E. The preservative needs to be selected from the range of approved food preservatives. Preferred preservatives are selected from methyl p-hydroxybensoate, potassium sorbate, sodium benzoate, sulphur dioxide, and potassium phosphate. By balancing a blend of the previously discussed ingredients and maintaining a pH in the neutral range affective preservation can be achieved. Preferred preservatives are particularly the sodium and potassium benzoates, sorbates and phosphates which ensure a microbiostatic, microbiocidal and fungicidal affect and as well reduce corrosion of lacquered tinplate to the point where shelf life is in excess of twelve months at 20°C are achievable. Microbiological examination of the product was carried out using combinations of potassium sorbate and sodium benzoate. The product was prepared over the pH range of between 2-8. Although effective bacterial control is achieved at low pH i.e. 3-5 there was a considerable tendancy for pitting
corrosion and severe colour fading. Different chemicals were used to adjust the acidity of the solution. These included citric acid, tartaric acid, ascorbic acid, hydrochloric acid, sulphuric acid, phosphoric acid. The most preferred agent was ascorbic acid used at a level of 0.05-0.1%. An example of a preferred formulation is as follows:-
%
Flavour 3.0 Sucrose 60.0
Potassium Sorbate 0.10
Sodium Benzoate 0.05
Water 29.84
Nitrous Oxide 7.0 AZO Red Dye 0.010 pH of the above product was adjusted to pH 4.5 with ascorbic acid.
F. Where unlined aerosol containers are used, rust can be a problem particularly if acidic components are used, thus a rust inhibitor within the range of 0.01 to 2% may be included. Preferably the rust inhibitor is selected from sodium benzoate, glycerine, propylene glycol potassium phosphate, or other food approved bufferable inhibitors. The sodium benzoate and potassium phosphate are preferred because they also function as a preservative.
G. The balance of the mixture is made up with purified water.
H. The propellant to be used to dispense the composition from the aerosol can will comprise 2 to 50% by weight and can comprise any food approved propellant. Preferably nitrous oxide, carbon dioxide and octaflurocyclobutane, or propane may be used. However, the most preferred propellant is nitrous oxide in order to achieve the optimum performance
required for this particular composition. Due to its non-condensable nature a higher pressure can be used to ensure mixing with nitrous oxide than with condensable propellants. In addition, the condensable propellants tend to produce a shaving-cream type foam due to their densities and settle out of the system. Care must be taken if carbon dixoide is used as propellant because it is acidic. However, it could be used where lined aerosol cans are used.
A further preferred composition for an aerosol dispensable thickening and flavouring composition is as follows.
Components Percentage by Weight Flavour 3%
Potassium Sorbate 0.20%
Polysaccharide Gum 0.20%
Aso Red Dye 0.10%
Sorbitan mono stearate 1% Nitrous Oxide 6%
Succrose 40%
Purified Water 49.5%
All percentages given in this specification are by weight. This product can be packaged in plain tinplate or aluminium as the level of preservative is sufficient to prevent corrosion. However, an epon lined tinplate or aluminium aerosol can can also be used. These plastic lined containers are acceptable for food products. From the above, it can be seen that the present invention provides a unique synergistic blend of ingredients which achieves the product requirements required to meet the consumer and Health Regulation requirements.