Edible emulsions and process for their preparation

This invention provides emulsions comprising a continuous fatty phase and a dispersed liquid aqueous phase and dispersed gelled aqueous ingredients, e.g. prepared by blending a gelling agent containing low fat spread in line with one free from gelling agents.

The present invention relates to emulsions of the continuous fat type (W/O 
type emulsions) and to processes for their preparation. 
The fat-continuous emulsions of the present invention include margarine and 
products of a relatively low fat content, which products, apart from being 
useful for spreading on bread, can find utility in the preparation of, for 
instance, bakery products. 
The emulsions of the present invention comprise a continuous fatty phase, a 
dispersed liquid aqueous phase and dispersed, gelled, aqueous spherical 
ingredients. 
In this Specification by the term "gelled" is understood the condition 
which liquid ingredients have achieved as a result of the formation of a 
rigid colloidal system by molecules and aggregates of molecules of the 
gelling system joining together to form a continuous framework. The 
spherical ingredients used in the emulsions of the invention are in a 
gelled condition at ambient temperature, e.g. 15.degree.-20.degree. C., 
and preferably have a gel stength of 0.1 and 30 N/cm.sup.2 as measured by 
the Instron apparatus, using it in the linear compression test mode at 
room temperature (about 20.degree. C.). 
Similarly, the terms "gel", "gelling", etc. refer to the condition of, and 
the process leading to the formation of such a rigid colloidal system. 
In this Specification the terms "oils" and "fats" are used as synonyms, 
unless otherwise indicated; a fatty phase is within the scope of the 
present invention the continuous phase of an emulsion and contains 
triglyceride oils and fats. 
In the preparation of emulsions of the fat-continuous type it has been 
suggested to thicken one of the phases of the emulsion, and mostly the 
dispersed aqueous phase with, for example, fats, hydrophilic thickening 
agents like gums, proteins, etc. 
Frequently problems in respect of diminished organoleptic qualities, 
insufficient microbiological keeping qualities and/or insufficient 
emulsion stability were observed in such prior art products. 
The emulsions of the present invention are highly useful for many purposes 
and combine the advantages of fat/liquid water emulsions with those of the 
fat/thickened water emulsions, without introducing the disadvantages of 
either system. Moreover, on an average a smaller amount of gelling agent 
is required than in systems in which the entire aqueous phase is gelled. 
The gelled spherical ingredients can be present in the continuous fatty 
phase or in the dispersed liquid aqueous phase or in both. 
Suitably the weight ratio between the continuous fatty phase and both the 
dispersed phases is (20-80): (80-20), preferably (35-65): (65-35), 
particularly about 40:60. The invention is particularly useful for the 
preparation of low-fat spreads, which frequently--as a result of the 
volume ratio between the continuous and dispersed phases--have too watery 
a taste sensation. A suitable weight ratio between the liquid aqueous 
phase and the gelled dispersed phase is e.g. from (85-15): (15-85). The 
average droplet size of both dispersed phases can be the same or about the 
same or of a different order of magnitude. 
By having coarse dispersed gelled spherical ingredients (e.g. 
10-20.mu.diameter) and fine liquid aqueous phase droplets (e.g. 
1-5.mu.diameter) the viscosity of the emulsion at palate temperature may 
be reduced. The gelled spherical ingredients are preferably prepared from 
essentially aqueous constitutents. 
Alternatively a low-fat spread can be provided with small gelled droplets 
(e.g. 1-5.mu.diameter) and relatively coarse water drops (e.g. 
10-20.mu.diameter). When in such systems all the salt is present in the 
free water droplets, the flavour release will be speeded up. In general, 
however, small liquid drops combined with coarse gelled drops are 
preferred, since coarse water droplets may easily cause water separation, 
e.g. during spreading the product on bread, which will give a crumbly 
appearance. 
Gelling can be effected before, but preferably during emulsification of the 
fatty and liquid aqueous ingredients. By proper selection of the gelling 
conditions, in situ separation of liquid aqueous phase from gelled 
dispersed ingredients can take place due to syneresis. 
The invention is particularly concerned with a process of preparing 
fat-continuous emulsions by dispersing in fat both a liquid aqueous phase 
and gelled spherical aqueous ingredients. 
Preferably the emulsions are prepared by using gelled spherical ingredients 
that have been obtained by emulsifying a liquid gelling agent containing 
aqueous phase in a fatty phase, letting the gelled spherical ingredients 
form in situ, and by subsequently dispersing a non-gelling liquid aqueous 
phase in the emulsion obtained to prepare the emulsion containing both 
dispersed liquid and dispersed gelled constituents. 
Finally, emulsions can be prepared by using gelled spherical ingredients 
that have been obtained by emulsifying a liquid gelling agent containing 
aqueous phase in a fatty phase, letting the gelled spherical ingredients 
form in situ, and by blending the emulsion obtained with another 
fat-continuous emulsion containing a dispersed liquid aqueous phase. 
In principle there are no limitations to the fat or fat blend to be used in 
the emulsions of the present invention. 
Fats that are liquid at room temperature can be used in preparing pourable 
fat-continuous emulsions and fats that are plastic at room temperature are 
useful for the preparation of plastic emulsions, e.g. margarines and 
low-fat spreads. 
Preferably the fat-continuous emulsions contain a fatty phase of a 
dilatation value at 10.degree. C. of at least 150, preferably at least 
250, and at 35.degree. C. of no more than 50, preferably no more than 25. 
The liquid aqueous phase of the emulsions of the invention can consist of 
water, but preferably the aqueous phase contains proteins and can, for 
instance, consist of or contain skim-milk, full-fat milk, buttermilk, 
etc.; similarly protein-enriched concentrates can be used or reconstituted 
proteinaceous solutions or dispersions, e.g. obtained by blending 
skim-milk powder, buttermilk power etc. etc. in water. The presence of 
proteins in at least the liquid dispersed aqueous phase will help to 
destabilize the emulsion under palate conditions. 
Any type of protein can be present in either the gelled spherical 
ingredients or in the liquid aqueous phase or in both. Suitably, proteins 
are, for instance, incorporated at a level of between about 0.1 and 20% of 
the dispersed phases, preferably between about 1 and 18% of the dispersed 
phases. 
The emulsions preferably also contain emulsifiers, e.g. phosphatides and/or 
partial glyceride esters, for instance monoglycerides, for stabilizing the 
emulsion. 
The spherical ingredients preferably contain hydrocolloids, e.g. gelatin, 
agar, alginate, carrageenan, etc. The concentration of the hydrocolloids 
in the aqueous system from which the gelled spherical ingredients are 
prepared is determined by the nature of the hydrocolloid, the yield point 
desired and the conditions under which gelling is performed. Suitable 
concentrations will vary from about 0.2-5% by weight of the aqueous system 
to be gelled.

The invention will be illustrated by the following Examples: 
EXAMPLE I 
A low-fat spread of a fat content of about 60% was prepared by combining 
equal parts of W/O Emulsion A of a temperature of 17.degree. C. and W/O 
Emulsion B of a temperature of 20.degree. C. in a surface-scraped heat 
exchanger (Votator A unit) in which the combined emulsion is cooled to 
0.degree. C.; finally the emulsion obtained is mildly agitated and further 
crystallised in a post-crystalliser unit (Votator B unit) and packed at 
17.degree. C. 
Emulsions A and B were separately prepared by blending and emulsifying 
fatty and aqueous ingredients in separate vessels and cooling the 
emulsions in scraped-surface heat exchangers to the temperatures 
indicated. 
The emulsions were composed of (wt.%): 
______________________________________ 
A B 
______________________________________ 
Water 35.47 38.08 
Salt 1.89 2.0 
Dicalcium phosphate 0.34 -- 
Sodium citrate 0.38 -- 
Glucose 0.89 -- 
Sodium alginate 0.64 -- 
Glucono-delta lactone 0.47 -- 
Oil blend 59.68 59.68 
Distilled monoglycerides from lard 
0.2 0.2 
Colour 0.02 0.02 
Flavour 0.02 0.02 
______________________________________ 
(Finely powdered dicalcium phosphate (average particle size less than 1 
micron) was present in A as the Ca.sup.2+ source, the citrate as the 
complexing agent and the glucono-delta-lactone as the Ca.sup.2+ release 
agent; by slow release of Ca.sup.2+ a calcium alginate gel is formed in 
the dispersed aqueous phase provided by A). 
EXAMPLE II 
Example I was repeated, except that 60% by wt. of the fat blend (including 
0.2% of monoglycerides from lard and 0.1% of lecithin) was combined with 
aqueous phases which were composed of: 
______________________________________ 
A B 
gelled liquid 
Ingredients: aqueous phase 
aqueous phase 
______________________________________ 
Skim-milk powder 
0.6 
Na-alginate 0.25 
Glucono-delta lactone 
0.14 
CaHPO.sub.4 (anhydrous) 
0.01 
Na-citrate 0.06 
K-sorbate 0.07 0.07 
Salt 1.5 
Lactic acid 0.02 
Water 18.87 18.41 
Total 20 20 
______________________________________ 
The product of Example II was, in respect of its organoleptic properties, 
preferred to that of Example I. 
EXAMPLE III 
A W/O emulsion was prepared at 40.degree. C. from 20 parts by weight of an 
aqueous phase (2.2 parts whey powder, 0.7 parts gelatin, 0.02 parts 
K-sorbate, 0.09 parts lactic acid and 16.99 parts water) and 40 parts by 
weight of a plastic fatty phase (39.65 parts fat blend, 0.2 parts 
monoglyceride and 6 ppm of .beta.-carotene). The emulsion obtained was 
cooled to 10.degree. C. in a Votator A unit and subsequently crystallised 
in a mildly stirred crystalliser unit. 
To the crystallised emulsion obtained another 40 parts by weight of aqueous 
phase of 15.degree. C. were added in a subsequent crystalliser unit (0.05 
parts K-sorbate, 0.03 parts lactic acid and 39.92 parts water) and the W/O 
emulsion thus formed was subsequently cooled in another Votator A unit to 
10.degree. C. and crystallised in a post-crystalliser unit and finally 
liquid-filled at 12.degree. C. into plastic tubs. 
As compared with a product prepared from identical ingredients, but with 
one combined aqueous phase, the product of the invention had better 
emulsion stability.