Food or edible material: processes – compositions – and products – Products per se – or processes of preparing or treating... – Fat or oil is basic ingredient other than butter in emulsion...
Reexamination Certificate
2001-07-30
2003-07-08
Paden, Carolyn (Department: 1761)
Food or edible material: processes, compositions, and products
Products per se, or processes of preparing or treating...
Fat or oil is basic ingredient other than butter in emulsion...
C426S564000, C426S606000, C426S312000, C426S319000
Reexamination Certificate
active
06589587
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a pourable water and oil containing emulsion comprising a continuous fatty phase and a dispersed aqueous phase, and gas bubbles. The invention also relates to a process to prepare such products.
BACKGROUND OF THE INVENTION
Pourable emulsions of a fat and a water phase are known. Examples are emulsions of water in oil such as liquid margarines. Further examples are oil in water emulsions such as dressings or sauces.
The dispersed aqueous phase of water in oil emulsions is present in the form of water droplets.
Pourable products are considered easily dosed and are therefore desired products.
The physical storage stability of pourable water and oil emulsion type products is considered quite important.
Liquid or pourable emulsions may be relatively unstable in that water droplets which are part of the dispersed aqueous phase can sediment to the bottom of the emulsion. In the current application where reference is made to a “stable” system, avoiding the phenomenon of sedimentation of one phase is referred to. Sedimentation is observed with products comprising a fat phase and a dispersed aqueous phase, whereby water droplets sink to the bottom of the system, where a water droplet layer is formed.
Simultaneously an oil layer may be formed on top of the product, although most oil will often still be present in an emulsion layer. Under extreme circumstances sedimentation may lead to the formation of a separated aqueous phase and a separated oil phase. Formation of this oil layer is referred to as oil exudation.
Sedimentation of the aqueous phase could also have adverse effects on the product performance in use since functional ingredients might be part of the water phase sedimenting.
Phase separation of a water in oil emulsion is not desired by the consumer who tends to desire that the product as bought stays intact and unchanged upon storage.
It is known that the separation of a liquid margarine into two layers can be overcome at least partly by selection of a specific hardstock fat composition.
However hard stocks that improve stability of liquid margarines often lead to products with increased viscosity and reduced pourability. This increased viscosity can be undesired for pourable products.
Moreover the use of fats comprising (poly) unsaturated triglycerides is often preferred over the use of hardened hardstock fats with saturated carbon-carbon bonds.
Therefore there is a desire for storage stable products which comprise no or reduced amounts of hardstock compared to the products which are currently on the market which comprise generally about 3 to 5 wt % hardstock.
Other measures to increase physical stability of pourable water in oil emulsions have been suggested in the art.
GB-A-1,333,938 discloses that the separation of a pourable margarine into two phases can be at least partly overcome by incorporating in the emulsion an emulsion-stabilising amount of gas bubbles. The gas content in the pourable margarine according to this document is from 0.5 to 20% by volume. Stabilising gas may be introduced into water in oil emulsions which comprise all ingredients, either before or after a chilling stage. In this process the majority of gas bubbles is believed to end up in the fat phase.
Furthermore WO-A-94/12063 discloses the use of gas cells in food products. Water continuous food products such as low fat spreads and dressings are disclosed, said products comprising gas cells and having a thermodynamic stability in excess of 2 weeks. More than 90% by number of the gas cells in said products have an average D3,2 particle size of less than 20 &mgr;m. The gas cells are prepared by application of high shear to the product or a pre-mix.
Although some of the above disclosed products show some improvement in stability against phase separation the above described methods and products often do not give satisfactory results in terms of storage stability.
Several problems are encountered with prior art products. The presence of gas cells essentially in the continuous fat phase leads to products which showed an undesired increase in viscosity, compared to products wherein no or almost no air was introduced in the fat phase.
The use of hardstock fats which are rich in saturated triglyceride fats, is undesired as the use of (poly) unsaturated fats is preferred in view of health benefits.
DEFINITION OF THE INVENTION
It has now surprisingly been found that the above indicated problems can be overcome by a fat continuous water and oil emulsion comprising an aqueous phase whereby gas bubbles are substantially dispersed in the aqueous phase.
Accordingly the present invention provides a pourable water and oil containing emulsion comprising a continuous fatty phase and a dispersed aqueous phase, and gas bubbles, characterised in that said gas bubbles are substantially dispersed in the aqueous phase.
In another aspect, the invention relates to a process for the preparation of amn emulsion according to the invention.
DETAILED DESCRIPTION
The pourable emulsions according to the invention are emulsions showing a Bostwick value of more than 12, preferably more than 15 at 15° C. The method to determine Bostwick value is described in the examples.
Where ranges are mentioned throughout the description and claims, the expression from a to b is meant to indicate from and including a, up to and including b, unless indicated otherwise.
The term gas bubbles refers to individual gas units which are all part of a dispersed gas phase.
In this application the terms “gas cells” and “gas bubbles” are used interchangeably.
In this application the terms “oil” and “fat” are used interchangeably.
Emulsions according to the invention comprise a dispersed aqueous phase and a continuous fatty phase. Pourable products according to the invention are for example dressings, sauces, liquid margarines.
A liquid margarine is a pourable water in oil emulsion comprising generally from 1 to 40, preferably 5 to 30 wt % water on total product weight.
The current invention is especially suitable for pourable water in oil emulsions comprising from 1 to 40 wt % aqueous phase on total product.
In a preferred embodiment beverages are not included in the term “emulsion”.
It has been found that the incorporation of gas bubbles, substantially in the aqueous phase of water in oil emulsions leads to products which are stable against sedimentation for at least 4 weeks, and often even for at least 2 months at storage temperatures of from 4° C. to ambient temperature.
Emulsions according to the invention are storage stable. This implies that said products preferably do not show exudation of the fatty phase or the aqueous phase after storage at temperatures from 4° C. to ambient temperature for a period of 4 weeks, preferably 2 months, most preferred 3 months. For water in oil emulsions this stability can be measured by a test wherein the emulsion is stored at about 5° C. for a time of 6 weeks. After a certain storage period the emulsion is checked on the formation of an oil layer on top of it. Preferred products show after 1 months of storage an oil layer of less than 20 vol %, more preferably less than 10 vol %, more preferred less than 3 vol %, most preferred less than 1 vol % on total emulsion. The method to determine the oil layer is described in the examples.
This improved stablity is surprising in that the skilled person, on the basis of common knowledge, would not have expected that the mere addition of gas to the aqueous phase of a water in oil emulsion would give the desired improvement in stability.
Moreover it was found that emulsions according to the invention, comprising gas bubbles substantially in the aqueous phase, show improved spattering behaviour.
To obtain the desired effect of density matching of the aqueous phase and the oil phase, gas bubbles comprised in products according to the invention, should be substantially dispersed in the aqueous phase of said emulsions. This means that preferably at least 50 vol %, more preferably at least 70 vol %, even more preferably at least 80 vol %, mo
Benjamins Jan
Effey Jochen
Floeter Eckhard
van Gelder Rowdy
Lipton division of Conopco, Inc.
McGowan, Jr. Gerard J.
Paden Carolyn
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