GB1604349A

GB1604349A - Milk products containing emulsifiers

Info

Publication number: GB1604349A
Application number: GB25668/78A
Authority: GB
Original assignee: Nexus ApS
Current assignee: Nexus ApS
Priority date: 1978-05-31
Filing date: 1978-05-31
Publication date: 1981-12-09
Also published as: GR67632B; DE2922317A1; NL7904291A

Description

(54) MILK PRODUCTS CONTAINING EMULSIFIERS (71) We, NEXUS APS, a Danish Body Corporate residing at Palsgaard, DK-7130 Juelsminde, Denmark, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to the use of certain emulsifiers in milk products, and to the milk products per se when containing such emulsifiers, and to a process for the preparation of the milk products. In particular, the milk products are whippable or whipped creams and cream-like products.

According to the present invention, it has been found that a particular class of emulsifiers selected from the group consisting of monoglyceride and polyglyceride partial esters of C4-C26 fatty acids show a remarkable effect with respect to improving and preserving the desired properties of milk products, in particular creams or cream-like products which are to be whipped. The said monoglyceride and polyglyceride partial esters are characteristic in that they contain unsaturated carboxylic acid residues. The monoglyceride and polyglyceride partial esters useful for the purposes of the present invention may contain a high proportion of unsaturated carboxylic acid residues, or they may contain a combination of a proportion of unsaturated carboxylic acid residues with a proportion of lower (C4- C,O) saturated carboxylic acid residues. Examples of emulsifiers suitable for the purpose of the invention are monoglyceride and polyglyceride partial esters of typical oils of high unsaturation such as soy bean oil, olive oil, sunflower oil, linseed oil, peanut oil, cotton seed oil, corn oil, rape oil, whale oil, and herring oil, and monoglyceride and polyglyceride partial esters of butterfat which is a typical fat showing the above-mentioned combination of a certain proportion of unsaturation (about 2830%, depending upon the season and other factors) and a certain proportion of C4-C10 saturated carboxylic acid residues (about 810%).

Emulsifiers which have been found less useful or not useful for the purpose of the present invention are, for example, monoglyceride or polyglyceride partial esters of coconut oil, stearic acid, and saturated tallow. The above-indicated requirements concerning the carboxylic acid residues in the monoglyceride or polyglyceride partial esters used for the purpose of the present invention may be expressed mathematically by the following expression: (A%+3K)B% > 500, preferably (A%=3K)B%515, wherein A% is the weight percentage of lower (ChClo) saturated carboxylic acid residues in the monoglyceride or polyglyceride partial ester, B% is the weight percentage of unsaturated carboxylic acid residues in the monoglyceride or polyglyceride partial ester and K is a constant which is 3 when the partial ester in question is a polyglyceride ester and 32/3 when the partial ester is a monoglyceride partial ester, A and B being calculated on the total weight of acid residues in the glyceride or polyglyceride partial ester. Within this expression, furthermore, it is preferred that B% is at least about 20%, preferably at least about 25%, such as explained above.

In the Table I below, the weight percentages of unsaturated carboxylic acid residues, and C4-C10 saturated carboxylic acid residues, respectively, are stated for a number of oils and fats, together with the calculated value for the expression (A%+9)B% for these oils and fats, indicating the usefulness of polyglyceride partial esters of these oils and fats for the purpose of the present invention.

TABLE I Weight percentage Weight percentage of of unsaturated C4C1o saturated carboxylic acid carboxylic acid Oil or fat residues (B%) residues (A%) (A%+9 soy bean oil 85.4 0 769 olive oil 88.5 0 797 sunflower oil 92.5 0 833 peanut oil 81 0 729 cotton seed oil 76.5 0 689 corn oil 88.3 0 795 rape oil 96.5 0 869 whale oil 78.5 0 707 herring oil 85 0 765 butterfat 29.4 9.2 535 coconut oil 8.5 15.2 206 lard 51.3 0 462 saturated tallow 0 0 0 palm kernel oil 19.2 9.7 359 cocoa butter 40.2 0 362 It will be noted that the criterion (A%+9)B%'500, preferably '515, is satisfied for the ten first fats and oils in the table which will therefore also satisfy the expression (A%+3.32/3)B%#500, preferably #515, and perform well as glyceride partial esters, while coconut oil, lard, saturated tallow, palm kernel oil, and cocoa butter have a carboxylic acid composition which will not satisfy the expression. It is noted that the above-stated values for the content of unsaturated acid residues are typical values, but that they may change somewhat depending on the place of origin, season etc. Hence, it cannot be precluded that e.g. butterfat from some sources may have such low contents of unsaturated carboxylic acid residues that it will not satisfy the expression (A%+9)B%'500 or '515, and hence will not perform well in polyglyceride partial esters, but may still satisfy the expression (K=32/3 relevant to glyceride partial esters. for glyceride partial esters of lard, the value (A%+3x32/,)B% is 564 satisfying the expression (A%+3K)B% > 515, indicating that such lard glyceride partial esters will perform well, whereas glyceride partial esters of palm kernel oil and cocoa butter will not even satisfy the expression for glyceride partial esters.

To the Applicants' knowledge, glyceride or polyglyceride partial esters used in milk products, especially in creams or cream-like products, in the known art are partial esters in which the carboxylic acid residues are saturated or, if unsaturated, do not contain sufficient unsaturation to satisfy the above mathematical expression and hence, the use in milk products of the above-mentioned glyceride or polyglyceride partial esters satisfying the above mathematical expression, is believed to be novel and constitutes an aspect of the present invention.

It is known to prepare emulsifiers by partial esterification of glycerol or polyglycerol (glycerol condensates) with fatty acids. Such emulsifiers are conventionally prepared in commercial scale by heating a mixture of glycerol or a glycerol condensate with one or more fatty acids or a natural fat or oil, i.e., a material consisting essentially of triglyceride, to a high temperature of the order of 2O(260CC in the presence of a basic catalyst such as sodium hydroxide. It has also been suggested to prepare fatty acid monoglyceride partial esters in a solvent such as tert.butanol.

The question of whether or not an emulsifier conforms with the expression (A%+3K)B%#515 depends upon the identity and proportion of the fatty acid residues in the glyceride or polyglyceride esters constituting the emulsifier which, in turn, depend upon the identity and relative proportion of the acids or acid residues in the starting material used for preparing the emulsifier. As indicated above, the expression (A%+3K)B%#515 is satisfied when the glyceride or polyglyceride ester is prepared from butterfat, soy bean oil, cotton seed oil, peanut oil, olive oil, corn oil, and sunflower oil, but is not satisfied with glyceride or polyglyceride esters prepared from coconut oil, or fully hardened fats. Mixtures of oils or fats or of oils and fats may, depending upon their identity and relative proportion, give emulsifiers satisfying the expression (A%+3K)B% > 515. As an example may be mentioned that a mixture of 50 /O by weight of soy bean oil and 50% by weight of coconut oil satisfies the expression (A%+3K)B% > 515; a mixture of 30% by weight of soy bean oil and 70% by weight of coconut oil will also satisfy the expression and a mixture of 70% by weight of soy bean oil and 30% by weight of hardened tallow will also result in glyceride or polyglyceride esters satisfying the expression.

Examples of preferred emulsifiers used according to the invention are polyglyceride partial esters prepared from unhardened soy bean oil or butterfat.

The preferred monoglyceride partial ester used according to the invention is a mono-diglyceride of butterfat.

In the polyglyceride partial esters used as emulsifiers according to the invention, the degree of esterification may vary within relatively wide limits, and both partial esters prepared from a mixture of 80% by weight of polyglycerol and 20% by weight of fat or oil and emulsifiers prepared from 5% by weight of polyglycerol and 95% by weight of fat or oil will perform satisfactorily, the preference for most partial esters being a weight ratio between the polyglycerol and the triglyceride of about 20:80 to 70:30, for example about 50:50.

The polyglyceride partial ester emulsifiers used according to the invention are preferably prepared from a polyglycerol (glycerol condensate) starting material which has been subjected to a distillation treatment to remove monomeric glycerol, as it has been found that such emulsifiers result in products with improved organoleptic properties compared to products containing emulsifiers prepared from non-distilled glycerol condensate products.

As mentioned above, the glyceride and polyglyceride partial esters satisfying the above mathematical expression, in the following also called "the emulsifiers used according to the invention", show remarkable effect with respect to improving and preserving the desired properties of milk products. In particular, in connection with creams or cream-like products which are to be whipped, the effects of the addition of the emulsifiers according to the invention are better whipping performance, whippability of creams with such low milkfat contents that they normally would not be whippable, better water retention of the whipped cream (less tendency to separation of a water phase ("serum") from the whipped cream on standing), better performance on prolonged whipping (no or less tendency to churning), and ability of the cream to be effectively whipped upon temperature cycling such as freezing and thawing. Also, the addition of the emulsifiers used according to the invention results in acceptably low viscosities of whipping creams on homogenization at pressures which would, in products without the added emulsifiers, result in products with an unsatisfactorily high viscosity or even solid products, while on the other hand low viscosity whipping creams (unhomogenized or homogenized at low pressure) containing the emulsifiers used according to the invention will not, on standing or long term storage, separate in the container such as is the case with certain unhomogenized whipping creams or whipping creams treated at low homogenization pressures.

It is not known with certainty why the emulsifiers used according to the invention result in these beneficial and desired effects on their addition to milk products, especially creams or cream-like products which are to be whipped. It is believed, however, that the emulsifiers used according to the invention somehow co-operate, perhaps synergistically, with milk proteins which are responsible for the whipping, non-separation, viscosity, and other properties of the products, and that this co-operation assists in compensating for the reductions in the effects of these milk proteins which apparently result from the more or less severe heattreatments which milk products must undergo before they are allowable as commercial products for human consumption, and the various other treatments, for example homogenization treatments, which milk products often undergo.

In accordance with the above, the invention also relates to a whippable cream or cream-like product containing a glyceride or polyglyceride partial ester of C4- C26 fatty acids, said partial ester conforming with the expression (A%+3K)Bo500, preferably (A%+3K)B%~515 wherein A% is the weight percentage of lower (C4- CtO) saturated carboxylic acid residues in the glyceride or polyglyceride partial ester and B% is the weight percentage of unsaturated carboxylic acid residues in the glyceride or polyglyceride partial ester, A and B being calculated on the total weight of acid residues in the glyceride or polyglyceride partial ester, and K is as defined above.

(The term "C4-C28 fatty acids" indicates that the fatty acids of the glyceride or polyglyceride partial ester will be in this interval, but is not to be construed as indicating that the partial ester will always contain each of these acid residues over the whole spectrum within the interval).

In the present specification and claims, the term "cream" means the liquid milk product high in fat separated from milk which may have been adjusted by adding thereto milk, concentrated milk, dry whole milk, skim milk, concentrated skin milk, or non-fat dry milk, the product containing not less than 18% by weight of milkfat. The term "cream" is also intended to cover the so-called "recombined" products prepared from milkfat, skim milk or skim milk powder and water and having substantially the same composition as native cream. The whippable cream of the invention may, but will not necessarily, correspond to the various national food standard definitions of whipping cream, for example to U.S. Food Standard definitions of "light whipping cream" (which contains not less than 30 but less than 36% by weight of milkfat) or "heavy cream" (which contains not less than 36% by weight of milkfat), but the whippable cream of the invention may also contain less milkfat than stipulated in the various national food standards. In the present specification and claims, the term "cream-like product" means a product which consists of cream containing one or more of the safe and suitable optional ingredients, including nitritive sweeteners and flavouring ingredients such as fruit, fruit juice and natural or artificial fruit flavouring ingredients. Under some national standards, the presence, in the whippable cream or creamlike product, of the emulsifiers used according to the invention, may not be provided for in the standard definition of "cream", but for the purpose of the terminology of the present specification, the term cream is intended to cover a cream containing such an emulsifier and optionally a stabilizer (as defined below).

The proportion of emulsifier in the whippable cream or cream-like product of the invention will normally be in the range of 0.2-2.0% bv weight, calculated on the total product, a preferred range being about 0.4 0.8% by weight.

The amount of emulsifier to be used will to some extent depend upon the fat content of the cream and will normally increase with decreasing fat content in the cream. It has been found that useful whippable products are obtainable with milkfat contents as low as 20% by weight, and it is one of the features of the present invention that it provides whippable creams or cream-like products with such low milkfat contents, for example in the range of 20-28% by weight. The upper limit for the milkfat content in the cream or cream-like product is not critical from a functional point of view and is normally about 40 /O by weight. Important whippable cream products of the present invention will also be creams or cream-like products containing about 238% by weight of milkfat and an emulsifier used according to the present invention. For example, a very satisfactory product has a milkfat content of about 30 /O by weight and contains 0.6% by weight of an emulsifier which is a polyglyceride partial ester of butterfat.

Compared to an ordinary pasteurized whipping cream of the same milkfat content, a whipping cream according to the present invention will show better whipping performance, i.e., it will be whippable to a more satisfactory consistency and has less tendency to churn out on prolonged whipping. Also, the whipped cream will show better water retention, i.e., less tendency to separate a water phase on standing. Furthermore, a whipping cream according to the present invention is able to be whipped to a satisfactory whipped cream after freezing and thawing, whereas the corresponding whipping cream without the emulsifier used according to the invention loses its whippability on freezing and thawing.

If desired, a stabilizer may be incorporated in the whippable creams or creamlike products according to the invention together with the emulsifier used according to the invention. Suitable stabilizers are, for example, stabilizers known in the art for addition to whippable creams or cream-like products, such as gelatine, agar-agar, alginates, or soluble modified starches. When stabilizers are added, these are preferably added in an amount of 0.55% by weight, more preferably 1-2% by weight and for example about 1.5% by weight, calculated on the total product. The stabilizers may be used, if necessary or if desired, to improve the water retention properties of the whippable creams or cream-like products but as would appear from the examples bellow, whippable creams according to the invention and showing excellent water retention can also be formulated without stabilizer with appropriate selection of emulsifier and emulsifier concentration.

However, local legal regulations or considerations concerning organoleptic qualities may in some cases dictate the use of an emulsifier of an identity or in a concentration which will not yield an optimum water retention. Thus, for example, the organoleptic properties tend to improve with decreasing percentage of the emulsifier used according to the invention, and the emulsifiers prepared from butterfat often tend to give the best organoleptic properties. For this reason, the use of low concentrations of the emulsifiers prepared from butterfat may often be attractive even though this combination may not yield optimum water retention, and in such cases, the water retention properties may be improved by incorporation of a stabilizer.

Various dairy products are now available in forms which have been subjected to more severe heat-treatments than the normal pasteurization and which therefore have improved storage qualities. Such more severe heat-treatments are ultrapasteurization, U.H.T. treatment (ultra high temperature, ultra short time pasteurization), and sterilization. For example, dairy products such as whole milk subjected to U.H.T. treatment may be stored in refrigerator for several weeks or months without deterioration.

However, it has not previously been possible to successfully provide a whippable cream or cream-like product with improved storage qualities and satisfactory whipping properties. Apparently, the more severe heat-treatment and/or the more severe homogenization which is necessary after such heattreatment interferes with the components of the cream which are responsible for the whippability: A U.H.T.-treated whipping cream which is unhomogenized or homogenized at a low homogenization pressure will, without additives, not perform satisfactorily even after after a few days' storage, unhomogenized U.H.T.-treated whipping cream separates completely into a serum (water) phase and a fat phase, and homogenization at for example 30 kg/cm2 will not prevent separation on prolonged storage. On the other hand, homogenization of a U.H.T.-treated whipping cream at the homogenization pressures which will in fact prevent separation, will, at the same time, result in a highly viscous or even solid product.

Incorporation of an emulsifier used according to the present invention solves the above-mentioned problems associated with whippable creams or cream-like products having improved storage qualities due to a more severe heat-treatment than the normal pasteurization. Thus, with incorporation of an emulsifier used according to the invention, U.H.T.-treated whippable creams or cream-like products may be prepared which show excellent bacteriological storage properties combined with retainment of a desired low viscosity, non-separating properties and retainment of whippability over the prolonged storage periods (for example 2-3 months). In addition to this, such U.H.T.-treated whippable creams or cream-like products according to the invention will show, compared to similar products not containing an emulsifier used according to the invention, the improvements discussed above with respect to whippability, water retention and resistance to churning on prolonged whipping.

A typical U.H.T.-treated whipping cream according to the invention is one having a milkfat content of 30% by weight and a content of 0.6% by weight of an emulsifier used according to the invention, for example a polyglyceride partial ester of butterfat, peanut oil, corn oil, or soy bean oil, or a mono-diglyceride of butterfat, and subjected to two homogenization treatments, for example at 80 kg/cm2 and 20 kg/cm2. Such U.H.T.-treated whipping cream can be kept in its sterile container for months, it will not separate, and it will show low viscosity in the containers and excellent whipping properties.

The invention also concerns a process for preparing milk products, in particular whippable creams or cream-like products, which comprises adding, to the milk product, in particular a natural or combined, diluted or undiluted cream or cream-like product, an emulsifier which is a glyceride or polyglyceride partial ester of C4-C26 fatty acids, said partial ester conforming with the expression (A%+3K)B% > 500, preferably (A%+3K)B%~515, wherein A% is the weight percentage of lower (C4-C10) saturated carboxylic acid residues in the glyceride or polyglyceride partial ester and B% is the weight percentage of unsaturated carboxylic acid residues in the glyceride or polyglyceride partial ester, A and B being calculated on the total weight of acid residues in the glyceride or polyglyceride partial ester, and K is as defined above.

Preferably, an emulsifier satisfying the expression (A%+3K)B%~515 15 is added to the cream or cream-like product with gentle heating, for example to about 50"C, and stirring, preferably vigorous stirring, to dissolve the emulsifier in the product.

Any desired heat-treatment or homogenization treatment is suitably performed subsequent to the addition of the emulsifier, but the starting cream may additionally have been heat-treated, for example pasteurized, prior to the addition of the emulsifier.

If it is desired to incorporate other ingredients, for example a stabilizer, this may be done at any suitable stage, for example simultaneously with the addition of the emulsifier, and if desired, the emulsifier and the stabilizer may in advance have been intimately mixed and optionally combined into a product of the so-called "integrated" type.

The homogenization of the whippable cream or cream-like product with added emulsifier may be performed using conventional cream homogenizers in one, two or three stages. It has been found that it is often advantageous to incorporate a final homogenization stage at a relatively low pressure, as this will tend to result in products with lower viscosity than without such additional final low pressure homogenization treatment, via Example 2.

According to an important embodiment of the process, the cream or creamlike product is, subsequent to the addition of the emulsifier, subjected to U.H.T.treatment and homogenization. This U.H.T.-treatment and homogenization is conveniently performed in one of the commercially available integrated units for U.H.T.-treatment and subsequent homogenization. After the U.H.T.-treatment and homogenization, the whippable cream or cream-like product may be packed in sterilized containers, for example bottles or cartons, in a manner known per se.

The invention also concerns whipped creams and cream-like products when containing an emulsifier used according to the invention.

The following examples illustrate the invention but are not to be construed as limiting. In connection with some of the examples, components of a general nature are given, and prior to Example 1, a definition of the various expressions used in the tables of the examples is given: EXAMPLES Definitions of Expressions Viscosity ("Visc."): Determined according to the Ford cup method: The viscosity value is the time, in seconds, which is necessary for 100 ml of the cream to pass through an orifice of about 4 mm diameter under the influence of gravity. A viscosity rating of 200 indicates a solid product. A viscosity rating of 100 indicates a clotted product. Acceptable viscosity ratings are at the most 50 and preferably below about 2030.

Consistency ("Cons."): Determined immediately subsequent to the whipping.

0: liquid, has not taken up any air.

1: liquid, but has taken up some air.

2: acceptable, sprayable.

3: good and easily handled.

4: excellent. shows typical crackling.

Consistency after standing ("Cons. stand."): Determined after 2 hours standing at the temperature indicated.

0: flows out completely.

1: flows out, but partially retains shape.

2: acceptable, somewhat collapsing.

3: good, satisfactorily sharp.

4: excellent, no change from the whipped cream as sprayed.

'Water retention: The rating indicates the number of g of water ("serum") phase separated from 100 g of whipped cream on standing for the stated number of ours at the temperature stated.

Storage period, days ("st. days"): Number of days of storage of the cream in refrigerator at 70C after addition of the emulsifier.

Example 1 Creams having milkfat ("butterfat") contents of 2(0% by weight were prepared from commercial pasteurized whipping cream and skim milk for dilution.

Emulsifier was added, and the cream was warmed to about 55"C with stirring and thereafter homogenized in two stages, first at 30 kg/cm2, and thereafter at the pressure stated. The results appear from Table II below. In Table II and the following tables, the following designations of the emulsifiers are used: PG bu: polyglyceride partial ester prepared from butterfat.

MG bu: mono-diglyceride prepared from butterfat.

PG so: polyglyceride partial ester prepared from soy bean oil.

MG so: mono-diglyceride prepared from soy bean oil.

TABLE II Const. stand.

Whip- Water retention Percent Conc. 2nd homog. ping Liter after 18-20 C 7 C fat in of emul- pressure, time, weight, Room freezcream Emulsifier sifier % kg/cm St. days min. grams Cons. temp. ing 2 h 5 h 2 h 5 h Visc.

20 MG bu 1.2 150 1 5- 260 3 2 - 0 3 0 0 26 4 6 260 2.5 2.5 1 3 12 0 1 13 6 6 260 3 2 0 2 15 - - 13 24 PG bu 1.8 150 1 6 280 2.5 1.5 0 20 28 - - 21 3 6 280 2.5 2 0 30 38 - - 16 7 6 300 2.5 1.5 0 30 42 - - 15 24 MG bu 1.2 150 1 6 270 3 2 0 3 12 - - 14 3 6 270 3 2 0 14 30 - - 14 7 6 280 3 1.5 0 28 40 - - 13 24 PG so 0.6 150 1 5 400 3 3 2 16 29 - - 14 3 5 440 3 2 0 8 20 - - 15 7 5 380 3 3 0 15 21 - - 14 24 MG so 0.6 150 1 5 380 3 2 2 8 17 - - 17 3 4- 360 3.5 2 1 8 18 0 0 19 7 4- 360 3.5 3 1 12 12 - - 15 28 PG so 0.6 150 1 5 440 3.5 3 2 6 11 - - 19 3 5 430 3.5 2.5 1 10 12 - - 17 6 5 400 3.5 3 1 5 8 - - 17 28 PG so 1.2 150 1 5- 360 3 3 0 6 10 - - 21 3 6 340 3 2 0 2 5 - - 32 6 6 400 2 2 0 4 10 - - 41 30 PG bu 0.6 150 1 6- 380 3 28 0 16 21 - - 18 3 7 380 3 2 1 18 30 - - 17 7 6- 410 3 2.5 1 7 10 - - 15 30 PG so 0.6 150 1 4- 480 3 3 3 8 12 0 0 20 3 5 430 3.5 3 3 0 0 - - 21 7 5 410 3 3 1 0 2 - - 16 TABLE II Const. stand.

Whip- Water retention Percent Conc. 2nd homog. ping liter after 18-20 C 7 C fat in of emul- pressure, time, weight, Room freezcream Emulsifier sifier % kg/cm St. days min. grams Cons temp. ing 2 h 5 h 2 h 5 h Visc.

30 PG so 1.2 150 1 6 350 3 3 1 3 8 - - 19 3 5- 360 3 2 1 0 0 0 0 34 7 5- 380 3 2.5 1 0 0 - - 53 34 PG bu 1.8 100 1 5- 300 3 2 0 8 18 - - 16 3 5- 290 3.5 2 0 2 14 - - 14 7 5 290 3 1.5 0 8 16 - - 14 34 MG bu 1.2 100 1 5- 300 3 2 0 10 15 - - 19 3 5- 280 3.5 2 0 2 23 0 0 16 7 5- 280 3.5 2 0 8 18 - - 14 34 PG so 0.6 100 1 4 490 3.5 3 3 0 0 - - 22 3 4 400 3.5 2.5 2 1 2 0 0 19 6 4 440 3.5 3 2 0 0 - - 19 36 PG bu 0.6 75 1 6- 400 3 3 1 3 12 0 0 16 3 7- 370 3 2 1 15 31 - - 15 7 7- 390 3 2 1 21 28 - - 15 36 PG bu 1.2 75 1 6 340 3 2 0 8 12 - - 13 3 7 330 3 2 0 12 28 - - 14 7 7 330 3 2 0 11 20 1 5 14 36 PG bu 1.8 75 1 5- 300 3 2 0 0 3 - - TABLE II (cont.) Cons. stand.

36 MG bu 1.2 75 1 5- 300 3.5 2 0 0 1 - - 20 3 5 280 3.5 2 0 3 14 0 1 18 7 4- 290 3.5 2 0 14 28 - - 16 36 PG so 0.6 75 1 4 480 3.5 3 3.5 1 8 - - 21 3 4 430 3.5 2 2 0 0 - - 18 7 4- 420 3.5 3 1 0 0 - - 16 40 PG bu 0.3 60 1 6 420 3 3 - 2 7 0 0 54 4 5- 430 3.5 3 3 0 1 0 0 36 6 5- 430 3.5 3 2 0 16 - - 35 40 PG bu 0.6 75 1 5- 380 3.5 3 - 1 8 0 0 18 4 5- 370 3.5 3 2 2 8 0 0 16 6 5- 370 3.5 2.5 1 3 20 - - 16 40 MG bu 0.3 50 1 6 430 3 3 - 1 7 - - 36 4 5- 420 3.5 3 3 0 3 - - 25 6 6 420 3.5 3 2 8 22 - - 23 40 MG bu 0.6 60 1 6 400 3.5 3 - 0 5 - - 100 4 5- 380 3.5 3 2 0 5 - - 20 6 5- 370 3.5 300 1 12 26 - - 20 40 PG so 0.3 60 1 2- 580 3.5 3 3 0 0 0 0 60 3 2 churns - - - - - - - out 7 2 churns - - - - - - - out 40 PG so 0.6 60 1 3 520 3.5 3 3.5 0 0 0 0 25 3 4 460 3.5 3 3 0 0 - - 18 7 3- 490 3.5 3 2 0 0 - - 17 40 Pg so 1.2 60 1 5 380 3.5 2 2 0 0 - - 100 3 5 380 3.5 3 1 0 0 0 0 100 7 4- 380 3 3 2 0 0 - - 100 Example 2 Experiments were performed in the same manner as described in Example 1, using varying pressures at the second homogenization. These experiments were compared with corresponding experiments wherein a third homogenization at a lower pressure (30 kg/cm2) was inserted as a final treatment. From the below Table II, it is evident that the third homogenization at this lower pressure resulted in improved products with respect to the viscosity.

TABLE III Cons. stand.

35 MG bu 0.4 30 1 7 430 3 2.5 2.5 3 10 16 5 7- 400 3 2.5 2 14 18 16 7 7- 405 2.5 2 1 34 42 16 35 MG bu 0.4 50 1 7 420 3 3 2.5 3 11 18 5 7 420 3.5 3 2.5 5 6 17 7 7 410 3 3 2 30 41 16 35 MG bu 0.4 100 1 6- 430 3 3 2.5 2 12 59 5 6- 420 3.5 3 3 2 4 33 7 6- 405 3 3 2 25 38 31 35 MG bu 0.4 150 1 6 430 3 3 2.5 2 10 100 5 6 420 3.5 3 2.5 3 4 67 7 5- 400 3.5 3 2 18 23 68 35 MG bu 0.4 200 1 5- 450 3.5 3 2.5 0 3 100 5 5- 440 3.5 3 2.5 0 1 100 7 5- 410 3.5 3 2.5 6 13 100 35 MG bu 0.4 30x 1 7 430 3 3 2.5 2 15 17 5 7 400 3 3 2 10 13 16 7 7 380 3 3 2 19 30 16 35 MG bu 0.4 50x 1 6- 440 3 3 2.5 0 3 18 5 6- 420 3 3 2 2 3 18 7 7 400 3 3 1.5 18 28 19 35 MG bu 0.4 100x 1 6- 450 3.5 3 2.5 0 0 31 5 6- 420 3.5 3 2 1 3 26 7 6- 400 3.5 3 1.5 12 21 26 Cons. stand.

35 MG bu 0.4 150x 1 6 440 3.5 3 2.5 0 3 46 5 6- 430 3.5 3 2.5 1 3 41 7 6- 410 3.5 3 2 12 18 39 35 MG bu 0.4 200x 1 6 450 3.5 3 2.5 0 0 67 5 6- 440 3.5 3 2.5 0 0 54 7 6- 410 3.5 3 2 6 8 55 30 MG so 0.6 200 1 4 550 3.5 3.5 3.5 0 0 100 3 3- 580 3.5 3 2.5 0 0 100 7 3 610 3 3 2.5 0 5 100 30 MG so 0.6 200x 1 5 520 3.5 3.5 3.5 0 0 22 3 3- 550 3.5 3 2.5 0 0 42 7 3- 620 3 3 3 0 10 30 x) indicates that after the second homogenization, a third homogenization was performed at a pressure of 30 kg/cm2.

Example 3 A commercial pasteurized whipping cream having a milkfat content of 38% by weight was diluted with skim milk to a milkfat content of 30% by weight. Then, emulsifier was added in an amount of 0.6% by weight of the total product, and the cream was warmed to about 55"C with stirring, and thereafter homogenized in two stages, first at 30 kg/cm2, and thereafter at 150 kg/cm2. As emulsifiers, polyglyceride partial esters prepared from various oils were used.

The results appear from Table IV below: TABLE IV Whipping liter time, weight, Water retention % Emulsifier St. days min. grams Cons. 2 h 5 h Visc.

Polyglyceride partial ester from peanut oil 1 5-1/2 370 3 0 1 23 3 4-1/2 390 3 1 2 29 7 4-1/2 460 3 3 7 27 Polyglyceride partial ester from sunflower oil 1 5 390 3.5 0 0 23 3 4-1/2 430 3.5 3 5 25 7 4-1/2 450 3.5 3 3 24 Polyglyceride partial ester from rape oil 1 5-1/2 480 2.5 3 6 34 3 4-1/2 420 3.5 3 5 29 7 4-1/2 430 3 2 7 29 Polyglyceride partial ester from corn oil 1 5 400 3 0 2 21 3 4-1/2 440 3.5 5 8 21 7 4-1/2 480 3.5 3 7 22 Polyglyceride partial ester from unhardened lard 1 7 500 0 - - 14 3 7 440 1 1 - 14 7 7 440 1 - - 15 It is evident that the emulsifier prepared from unhardened lard was useless for the purpose whereas the other emulsifiers performed excellently.

Example 4 To a cream having a milkfat content of 30% by weight was added 0.6% by weight of a polyglyceride partial ester of butterfat prepared from- polyglycerol and butter-fat in the weight ratio of 50:50 in tertiary butyl alcohol as solvent. Cream and emulsifier were thoroughly mixed with heating to 600C, whereafter the cream was U.H.T.-treated and homogenized, first at 125 kg/cm2 and thereafter at 50 kg/cm2.

After storage for 28 days in refrigerator at 7 C, the cream was whipped. The whipping time was 5-1/2 minutes, the liter weight was 350 g, the consistency rating was 3.5, and the water retention values, at room temperature and 7"C, respectively, were 0 and 0, respectively. The viscosity of the cream before whipping corresponded to a rating of 15.

Example 5 U.H.T.-Treated whipping creams were prepared in the same manner as described in Example 4, but usinghomogenization pressures of first 80 kg/cm2 and thereafter 20 kg/cm2. The emulsifiers were: A) a polyglyceride partial ester prepared from polyglycerol and corn oil in the weight ratio of 50:50; B) a polyglyceride partial ester prepared from polyglycerol and peanut oil in a weight ratio of 50:50.

The amount of emulsifier was 0.6%, calculated on the total product. The performance of the whipping creams after two months' of storage in refrigerator was as follows: Water retention

Whip room ping Liter temp. 70C Emulsi- time, weight, ifier min. grams Cons. 2h 5h 2h 5h Visc.

A 3 590 3.5 0 5 0 0 22 B 3-1/2 480 3.5 0 0 0 0 15 Example 6 A commercial pasteurized whipping cream having a milkfat content of 38% by weight was frozen in a household freezer. After thawing one day later, the cream was clotted and was not whippable.

To the same commercial whipping cream was added 0.6% by weight of a polyglyceride partial ester prepared from polyglycerol and butterfat in a weight ratio of 50:50. The cream and the polyglyceride partial ester were admixed with vigorous stirring at 50"C. The resultmg product was frozen and thawed in the same manner as above. After thawing, the whipping cream was clotted, but it had retained its whippability. After a whipping time of 4-1/2 minutes, it resulted in a whipped cream having a liter weight of 480 g, a consistency rating of 3, a rating for consistency after standing of 2.5 and a water retention value of I at room temperature and 0 at 7 C.

Example 7 In the same manner as described in Example 3, various emulsifiers and emulsifier mixtures were added to cream having a milkfat content of 30 SO by weight. The results appear from the below Table V.

TABLE V

Conc. of Whip- Water retention emul- ping liter 22-25 C 7 C sifier time, weight, Emulsifier % St. days min. grams Cons. 2 h 5 h 2 h 5 h Visc.

100% polyglyceride 0% polyglyceride partial ester + partial ester from from soy bean full hardened oil tallow 0.6 1 4- 390 3.5 0 0 0 0 22 100% " 0% " 0.6 4 4- 430 3.5 0 0 0 0 21 100% " 0% " 0.6 6 4 440 3.5 0 3 0 0 23 Polyglyceride partial ester from: 30% soy bean oil + 70% fully hardened tallow 0.6 1 7 460 1 - - - - 14 30% " 70% " 0.6 4 7 460 1 - - - - 13 30% " 70% " 0.6 6 7 460 1 - - - - 14 50% " 50% " 0.6 1 7 430 1 - - - - 18 50% " 50% " 0.6 4 7 440 1.5 - - - - 14 50% " 50% " 0.6 6 7 380 2 17 31 8 12 15 70% " 30% " 0.6 1 6 380 3 5 15 0 0 14 70% " 30% " 0.6 4 5- 360 3 3 15 0 0 14 70% " 30% " 0.6 6 5- 350 3 11 28 2 4 14 90% " 10% " 0.6 1 6 380 3.5 0 3 0 0 17 90% " 10% " 0.6 4 4- 390 3.5 0 2 0 0 17 90% " 10% " 0.6 6 4 380 3.5 0 2 0 0 18 TABLE V (cont.)

60% polyglyceride 40% polyglyceride partial ester + partial ester from from soy bean fully hardened oil tallow 0.6 1 6 360 3 12 18 3 4 17 60% " 40% " 0.6 4 6 360 3.5 10 24 0 0 18 60% " 40% " 0.6 6 5- 350 3 18 26 0 0 16 70% " 30% " 0.6 1 5- 360 3.5 6 8 0 0 19 70% " 30% " 0.6 4 5 350 3.5 3 8 0 0 19 70% " 30% " 0.6 6 4- 350 3.5 8 16 0 0 17 80% " 20% " 0.6 1 5 360 3.5 0 3 0 0 20 80% " 20% " 0.6 4 5 360 3.5 0 5 0 0 21 80% " 20% " 0.6 6 4- 360 3.5 1 6 0 0 20 85% " 15% " 0.6 1 5 370 3 0 0 0 0 17 85% " 15% " 0.6 4 5 370 3.5 0 2 0 0 18 85% " 15% " 0.6 6 4- 360 3.5 0 5 0 0 18 90% " 10% " 0.6 1 5 370 3 0 0 0 0 20 90% " 10% " 0.6 4 5 400 4 0 0 0 0 21 90% " 10% " 0.6 6 4- 380 4 0 3 0 0 21 TABLE V (cont.)

Polyglyceride partial ester from olive oil 0.6 1 5 420 3 1 2 0 0 20 " 0.6 3 5 400 3.5 0 3 0 0 22 " 0.6 6 4- 420 3.5 0 3 0 0 20 Polyglyceride partial ester from soy bean oil 0.6 1 4- 400 3.5 0 0 0 0 18 " 0.6 3 4- 410 3.5 0 2 0 0 21 " 0.6 6 4- 410 3.5 0 1 0 0 20 Polyglyceride partial ester from corn oil 0.6 1 4- 400 3.5 0 0 0 0 19 " 0.6 3 4- 410 3.5 0 2 0 0 19 " 0.6 6 4- 410 3.5 0 1 0 0 17 Polyglyceride partial ester from butterfat 0.6 1 7 440 1 - - - - 15 " 0.6 3 7 420 1.5 - - - - 15 " 0.6 6 7 400 2.5 10 21 5 15 14 70% by weight of polyglyceride partial ester from corn oil+ 30% by weight of polyglyceride partial ester from butterfat 0.6 1 5 400 3 2 8 0 0 16 " 0.6 3 4- 380 3 0 8 0 0 16 " 0.6 6 5 380 3.5 0 1 0 0 15 TABLE V (cont.)

85% by weight of polyglyceride partial ester from corn oil+ 15% by weight of polyglyceride partial ester from butterfat 0.6 1 4- 390 3 0 0 0 0 10 " 0.6 3 4- 390 3.5 0 5 0 0 17 " 0.6 6 4- 400 3.5 0 1 0 0 17 Polyglyceride partial ester from corn oil 0.45 1 5 500 3 3 8 0 0 29 " 0.45 3 3 570 3.5 3 7 0 0 32 " 0.45 7 3 590 3.5 1 5 0 0 36 Polyglyceride partial ester from corn oil 0.75 1 5 400 3.5 0 3 0 0 17 " 0.75 3 3- 390 3.5 0 0 0 0 17 " 0.75 7 4 400 3.5 0 0 0 0 17 Polyglyceride partial ester from soy bean oil and distillation-treated polyglycerol 0.6 1 5 420 3.5 0 0 0 0 22 " 0.6 4 4- 460 3.5 0 0 0 0 23 " 0.6 6 4- 500 3.5 9 20 0 0 22 Polglyceride partial ester from soy bean oil fatty acids and distillationtreated polyglycerol 0.6 1 5 470 3.5 0 0 0 0 24 " 0.6 4 4- 430 3.5 0 1 0 0 24 " 0.6 6 4- 460 3.5 0 0 0 0 31 Fresh whipping cream 1 3- 400 3 0 0 0 0 " 3 3- 400 3 3 8 0 0 " 6 3- 400 3 0 0 0 0 - Example 8 In the same manner as described in Example 3, various emulsifiers and emulsifier mixtures were added to cream having a milkfat content of 30% by weight. The results appear from the below Table VI.

TABLE VI

Whip- Water retention ping liter 21-23 C 7 C time, weight, Emulsifier St. days min. grams Cons. 2 h 5 h 2 h 5 h Visc.

Polyglyceride partial ester from soy bean oil: 20% by weight of soy bean oil: 80% by weight of polyglycerol 1 3- 510 3.5 6 16 3 5 15 " 3 3- 480 3.5 5 17 0 3 16 " 6 3 520 3 6 15 3 6 16 Polyglyceride partial ester from soy bean oil: 35% by weight of soy bean oil: 65% by weight of polyglycerol 1 4 480 3.5 5 14 3 5 16 " 3 4 420 3.5 5 16 0 5 17 " 6 4- 420 3.5 1 10 0 1 16 Polyglyceride partial ester from soy bean oil: 65% by weight of soy bean oil: 35% by weight of polyglycerol 1 5 460 3.5 3 13 3 6 18 " 3 5 410 3.5 3 11 2 5 19 " 6 4- 410 3.5 1 10 3 6 18 Polyglyceride partial ester from soy bean oil: 80% by weight of soy bean oil: 20% by weight of polyglycerol 1 6- 520 3 11 22 4 8 21 " 3 5- 460 3.5 10 18 3 7 21 " 6 5 480 3.5 2 11 2 5 22 TABLE VI (cont.)

Polyglyceride partial ester from coconut oil+soy bean oil: 100% by weight of coconut oil: 0% by weight of soy bean oil 1 8 600 1 - - - - 12 " 3 8 510 1 - - - - 12 " 7 8 510 1 - - - - 13 polyglyceride partial ester from coconut oil+soy bean oil: 90% by weight of coconut oil: 10% by weight of soy bean oil 1 8 600 1.5 - - - - 13 " 3 8 500 1.5 - - - - 13 " 7 8 520 1 - - - - 13 Polyglyceride partial ester from coconut oil+soy bean oil: 80% by weight of coconut oil: 20% by weight of soy bean oil 1 8 580 2 12 18 12 15 13 " 3 8 460 1 - - - - 14 " 7 8 520 1 - - - - 13 Polyglyceride partial ester from coconut oil+soy bean oil: 70% by weight of coconut oil: 30% by weight of soy bean oil 1 7 470 2.5 11 18 12 12 14 " 3 6 480 2 5 6 3 3 14 " 7 8 510 1 - - - - 13 Polyglyceride partial ester from coconut oil+soy bean oil: 50% by weight of coconut oil: 50% by weight of soy bean oil 1 6 430 3 6 13 3 5 14 " 3 5- 420 3 0 0 0 0 14 " 7 5- 430 3 5 15 0 0 14 Example 9 Preparation of polyglyceride partial ester of soy bean oil.

As starting materials are used 607.5 g of glycerol condensate having a viscosity, measured at 700C of 500 cps (this is the same polyglycerol as is mentioned in the above examples), and 742.5 g of soy bean oil. As catalyst is used 6 g of sodium hydroxide, and as solvent is used 750 ml of tert.-butyl alcohol. In a reaction vessel provided with reflux condenser and steam jacket, the sodium hydroxide is dissolved in the glycerol condensate with stirring and heating to 1300C for 35 minutes, whereafter the remaining above-mentioned ingredients are added. The mixture is heated to reflux temperature (89960 C), whereafter it is kept at this temperature with reflux for 60 minutes. (After refluxing for 50 minutes, the mixture has become completely clear). Thereafter, the reaction mixture is neutralized with 10.05 ml of 86% phosphoric acid and then filtered and evaporated on rotary evaporator at 13W140 C and a pressure of about 30 mm Hg abs. After decanting from glycerol condensate precipitated on standing, a fat phase of 1163 g having a saponification number of 128.0, an acid number of 7.8 and a pH of 3.8 is obtained.

Preparation of olyglyceride partial ester from butterfat.

Butterfat was first prepared from non-acidified butter which was heated to about 80"C and kept at this temperature for 45 minutes, whereafter the fat phase was decanted off and evaporated twice over thin layer evaporator at 130"C and 40 mm Hg abs. The following ingredients were used: 3.7 kg of glycerol condensate, viscosity 500 cps at 700 C.

37 g of sodium hydroxide.

4.5 kg of butterfat.

3.7 kg of tert.-butyl alcohol.

The sodium hydroxide was first dissolved in the polyglycerol at 1 300C with stirring for 45 minutes, whereafter the remaining ingredients were added, and the reaction was performed at 88--930C with refluxing for 70 minutes. After neutralization with 58 ml of 86% phosphoric acid, the product was finally evaporated several times over thin layer evaporator. Prior to the last two evaporations, water in an amount of 5% of the product was added. The yield was 7.25 kg of product with saponification number 138.7, acid number 7.0 and pH 3.8.

The product had a nice yellow colour and showed a paste-like consistency upon crystallization.

Claims

WHAT WE CLAIM IS:

1. An emulsifier for a milk product, which emulsifier comprises a monoglyceride or polyglyceride partial ester of C4 to C2, fatty acids, which partial ester conforms with the expression (A%+3K)B%'500, in which A% is the weight percentage of lower (C4 to C,) saturated carboxylic acid residues in the monoglyceride or polyglyceride partial ester, B% is the weight percentage of unsaturated carboxylic acid residues in the monoglyceride or polyglyceride partial ester, A and B being calculated on the total weight of acid residues in the monoglyceride or polyglyceride partial ester, and K is a constant which is 3 when the partial ester in question is a polyglyceride ester and 32/3 when the partial ester in question is a monoglyceride partial ester.

2. An emulsifier as claimed in Claim 1 in which the monoglyceride or polyglyceride partial ester conforms with the expression (A%+3K)B%~'515, in which A%, B% and K are as defined in Claim 1.

3. An emulsifier as claimed in Claim 1 substantially as herein described with reference to any of the Examples.

4. A whippable cream or cream-like product which contains an emulsifier as claimed in any of Claims 1 to 3.

5. A product as claimed in Claim 4 which contains from 0.2 to 2.0% by weight of the emulsifier, based on the total product.

6. A product as claimed in Claim 5 which contains from 0.4 to 0.8% by weight of the emulsifier, based on the total product.

7. A product as claimed in any of Claims 4 to 6 which additionally contains a stabiliser in an amount of from 0.5 to 5-0 /O by weight, based on the total product.

8. A product as claimed in Claim 7 which contains the stabiliser in an amount of from 1.0 to 2.0/o by weight, based on the total product.

9. A product as claimed in any of Claims 4 to 8 which is a U.H.T.-heated cream product.

10. A product as claimed in Claim 4 substantially as herein described with reference to any of the Examples.

11. A process for the preparation of a milk product which comprises the step of adding the milk product an emulsifier as claimed in any of Claims 1 to 3, with heating and stirring to dissolve the emulsifier.

12. A process as claimed in Claim 11 which further comprises the step of heattreating and/or homogenization.

13. A process as claimed in Claim 11 or Claim 12 in which the milk product comprises a whippable cream or cream-like product.

14. A process as claimed in Claim 13 in which the cream or cream-like product is subjected to U.H.T. treatment and homogenization after addition of the emulsifier.

15. A process as claimed in Claim 11 substantially as herein described with reference to any of the Examples.

16. A milk product when prepared by a process as claimed in any of Claims 11 to 15.