WO1986006937A1

WO1986006937A1 - An emulsifier and a method for its preparation

Info

Publication number: WO1986006937A1
Application number: PCT/DK1986/000059
Authority: WO
Inventors: Herbert Schou; Jack Allan Dreyer
Original assignee: Nexus Aps
Priority date: 1985-05-31
Filing date: 1986-05-29
Publication date: 1986-12-04
Also published as: EP0203831A1; FI870413A0; DD265073A5; US4959233A; EP0203831B2; ATE46071T1; JPS62503021A; IL78973A; BR8606702A; GR861402B; DE203831T1; DE3665394D1; FI870413A; AU588337B2; JPH0693993B2; CA1278796C; ZA863917B; PT82681B; IL78973A0; PT82681A

Abstract

A polyglycerol partial fatty acid ester emulsifier comprising polyglycerol which is predominantly mono- and/or diesterified with saturated fatty acid moieties and optionally monomeric glycerol which is predominantly mono- and/or diesterified with saturated fatty acid moieties, in which the fatty acid moieties are selected so that the average number of carbon atoms in the acid moieties is in the range between 13.0 and 16.5 is prepared by reacting a polyglycerol, optionally containing monomeric glycerol, with a fatty acid or a mixture of fatty acids or with a fatty acid glyceride or a mixture of fatty acid glycerides, the number of carbon atoms of the fatty acid or of the fatty acid moiety of the glyceride or the average number of carbon atoms of the fatty acids or the fatty acid moieties of the glycerides being in the range between 13.0 and 16.5.

Description

AN EMULSI FI E AND A METHOD FOR ITS PREPARATION

The present invention relates to a polyglycerol partial fatty acid ester emulsifier, a method for the preparation thereof and a product con¬ taining such an emulsifier applied on a particulate carrier.

I n the present context, the term "polyglycerol" designates condensed glycerol molecules, such as dimeric glycerol (diglycerol) , trimeric glycerol (triglycerol) , etc. Commercial glycerol condensate products or polyglycerol products useful for preparing the emulsifiers of the invention , such as products in which the major proportion is con- stituted by dimeric glycerol (diglycerol) are normally mixtures con- - taining glycerol in varying amounts of polymerization, from monomeric glycerol up to tetrameric or higher glycerol condensates . Important examples of such polyglycerol products are products which contain, e. g . , at the most 30% of monomeric glycerol, and very interesting products are products which contain at the most 25%, such as at the most 20%, of monomeric glycerol and about 60% of dimeric glycerol (diglycerol) , the remainder being higher condensates of glycerol , but the composition of polyglycerol products may vary over a wide range.

Polyglycerol partial fatty acid emulsifiers comprising polyglycerol which is predominantly mono- and/or diesterified with saturated fatty acid moieties and optionally monomeric glycerol which is predominantly mono- and/or diesterified with satu rated fatty acid moieties are nor¬ mally used, e. g . , as emulsifiers or "aerating agents" (aerating agent is a designation used in the food industry for an emulsifier which is used for whipping purposes, in other words for preparing emulsions where air constitutes the disperse phase) in food products, e. g . for preparing cake mixes, or as emulsifiers in ice cream or fine food products .

Such polyglycerol partial fatty acid emulsifiers are normally prepared by reacting a polyglycerol product with a fatty acid or a mixture of fatty acids or with a fatty acid glyceride or a mixture of fatty acid glycerides . The fatty acids or the fatty acid moieties in the fatty acid glycerides are saturated acids or moieties with an average number of carbon atoms in the range of 17-18, such as stearic acid or tallow fatty acids . It has now surprisingly been found that the emulsifier or aerating properties of polyglycerol partial fatty acid ester emulsifiers, in particular emulsifiers in which the major proportion of the polygly¬ cerol is diglycerol, are improved considerably when the fatty acid moieties with which the polyglycerol and, if present, monomeric glyce¬ rol, is esterified, are selected so that the average number of carbon atoms in the acid moieties is in the range between 13.0 and 16.5.

I n the present context, the term "the average number of carbon atoms in the acid moieties" is intended to designate the average re- suiting from dividing the total number of carbon atoms in the acid moieties present as esterifying moieties on the polyglycerol and mono¬ meric glycerol molecules with the total number of these esterifying moieties . As mentioned above, e. g . , products which contain a pre¬ dominant amount of diglycerol may typically contain an amount of monomeric glycerol and an amount of higher glycerol condensates (or higher glycerol condensates may be formed by condensation during the esterification process) . In the normal preparation of the emulsifier product, both the monomeric glycerol and the glycerol condensates will become esterified, normally mono- and/or diesterified at terminal hydroxy groups .

I n practice, there will substantially be concordance between the average carbon number of the acid moieties with which the diglycerol is esterified and the average carbon number of the acids or acid moieties of the acid or glyceride starting material used in the esteri- fication in which the diglycerol partial fatty acid ester emulsifiers are made. Therefore, the average carbon number of the acid moieties of the esterified diglycerol molecujes will , in practice, be substantially identical with the average carbon atom number of the acid moieties of the starting material used .

Preferred polyglycerol partial fatty acid ester emulsifiers of the in¬ vention are emulsifiers in which at the most 30% of the emulsifier consists of partial fatty acid esters of monomeric glycerol . Especially preferred emulsifiers of the invention are emulsifiers in which at least 50%, preferably at least 60%, of the emulsifier consists of diglycerol partial fatty acid esters, and at the most 25%, such as at the most 20%, consists of partial fatty acid esters of monomeric glycerol . These products are very interesting products as aerating agents for cake mixes .

It is preferred that at least 60%, in particular at least 80%, more pre¬ ferably at least 90%, of the fatty acid moieties in the emulsifier con¬ tain at least 12 carbon atoms . The fatty acid moieties are saturated . A small percentage of unsaturated acid moieties may be present, but should preferably be less than 3%, more preferably less than 2%, and most preferably less than 1% by weight.

Very interesting products according to the invention are polyglycerol partial fatty acid ester emulsifiers, such as predominantly diglycerol partial fatty acid ester emulsifiers, in which the average number of carbon atoms of the acid moieties is in the range between 14.0 and 16.0, in particular in the range between 14.0 and 15.8, such as, e. g . , in the range between 14.0 and 15.5.

Acids which , either per se or combined with each other, will be use¬ ful for obtaining the average number of carbon atoms according to the invention are, e. g . , lau ric acid, myristic acid, palmitic acid, and stearic acid . I n practice, it has been found that a very useful emulsi¬ fier or aerating agent is one in which 40-60%, preferably about 50%, of the fatty acid moieties are lauric acid moieties, and 25-50% are stearic acid moieties, 10-20% are palmitic acid moieties, and 0-3% are myristic acid moieties . Such a combination is obtained by esterifying with an about equal mixture of lauric acid and tallow fatty acids . A particular acid composition which is obtainable in this manner is one in which 40-60%, preferably about 50%, of the fatty acid moieties are lauric acid moieties, and 25-35% are stearic acid moieties, 10-20% are palmitic acid moieties and 0-3% are myristic acid moieties .

While the desired average carbon atom number of the acid moieties may result (when more than one type of acid moiety is involved) as well from mixing polyglyceride partial fatty acid esters containing a low average carbon atom number in their acid moieties with poly- glyceride partial fatty acid esters containing a high average carbon atom number in their acid moieties as from preparing the polyglycer- ide partial fatty acid esters directly by esterifying a polyglycerol product with the appropriate acid mixture or triglyceride mixture to result in the desired average carbon atom number, the latter is preferred, as such co- reaction has been found to result in much better emulsifier-aerating agent properties . Thus, a preferred method of preparing the emulsifiers of the invention is to react a polyglycer¬ ol, optionally containing monomeric glycerol , with a fatty acid or a mixture of fatty acids or with a fatty acid glyceride or a mixture of fatty acid glycerides, the number of carbon atoms of the fatty acid or of the fatty acid moieties of the glyceride or the average number of carbon atoms of the fatty acids or the fatty acid moieties of the glycerides being in the range between 13.0 and 16.5.

The reaction may be performed in a manner known per se, normally by heating the polyglycerol product with the fatty acid or mixture of fatty acids or the fatty acid glyceride or mixture of fatty acid glyce¬ rides at a relatively high temperatu re, such as a temperature in the range of 200-270°C in the presence of an amount of a basic catalyst. Another special method for preparing polyglycerol partial fatty acid esters which may also be used for preparing the emulsifiers of the invention is a method wherein the esterification is performed by reacting a polyglycerol product with fatty acid glycerides in tertiary butyl alcohol as the solvent. This method is described in European Patent No. 0 038 347.

The ratio between the starting materials in the process of the inven¬ tion is suitably so selected that the resulting emulsifier product will be one in which the glycerol or polyglycerol moieties are predominant¬ ly mono- or diesterified and little or no higher esterified glycerol or polyglycerol molecules are formed. I n practice, a suitable weight ratio between the fatty acid component and the polyglycerol product com¬ ponent may be precalculated on the basis of the composition of the fatty acid component and the polyglycerol product component, based on the presumption that the degree of esterification will substantially correspond to the stoichiometric ratios in the starting reaction mix- ture. For most combinations of polyglycerol product and fatty acids, for example, the weight ratio between fatty acids and polyglycerol product will be of the order of less than 7:3, preferably less than 6:4, a preferred ratio often being of the order of 5.5:4.5. After the reaction , an excess of unreacted diglycerol may, if desired, be re¬ moved in a manner known per se. It is also possible to add monomeric glycerol to the product, if desired, in order to adjust the viscosity of the product.

The emulsifier of the invention is used in the same manner as known emulsifiers for the same purposes . Thus, for example, it may be added to the products or mixes to be emulsified or aerated in an amount of about 1 -4% by weight, such as 1 .5-3% by weight, such as about 2% by weight, calculated on the weight of the emulsifier relative to the weight of dry constituents of the products or mixes (i . e. , e. g . , for cake mixes, without the eggs and water added immediately before mixing) . The emulsifier may be added to such cake mixes and similar mixes at the time when the mixes are mixed with eggs and water, or it may be added to the dry mix .

The invention also relates to a food product, in particular a cake mix or a cake product made therefrom, containing an emulsifier as defined above in particular in an amount of 1 -4% by weight, calculated as stated above.

A preferred administration form of the emulsifier is as a free-flowing powder product.

It is known to prepare such free-flowing powder products by spray- drying or by application of the emulsifier on sucrose particles as a carrier. Thus, one known method for preparing such powders is to spray-dry an emulsion made from skim milk or whey and the emulsi¬ fier. However, a preferred administration form of the emulsifier is a substantially free-flowing emulsifier product in which the emulsifier is applied on a particulate carrier, preferably in an amount of at least 10% by weight, calculated on the weight of the product. The carrier is preferably of vegetable origin, and interesting carriers are carriers selected from flours, starches, mono- and disaccharides and pentosans and mixtures thereof, optionally with an admixture of material of vegetable fibre origin .

Such a type of product, and a method for its preparation, is described in Applicants's prior pending Danish patent application No. 1487/84 (International application No. PCT/DK85/00018, publication No. WO85/03846, European application publication No. 0153870) .

It is generally preferred that the carrier is one which contains or consists of starch .

As examples of such carriers which are of great interest in connection with surface-active substances for use in the food industry may be mentioned tuber starches or flours such as potato starch , batat starch and yam starch , sago starch, bean flour and pea flour, cereal starches or flours such as rice starch, wheat starch, rye starch, barley starch, oat starch , rice flour, wheat flour, rye flour, barley flour, oat flour, and maize starch, maltodextrins, dextrose, fructose, and mixtures thereof .

The particulate carriers are normally carriers, the particles of which have a particle size distribution with a major fraction having a size in the range of about 1 -20 μm, in particular 1 -10 ym. It is often pre¬ ferred that the carriers have very small particle sizes, for examples with major particle size fractions in the range of 1 -5 ym or less .

In the emulsifier products of the invention, the percentage of the emulsifier is normally in the range of 10-60%, such as 10-50%, and often preferably 15-50%, in particular 15-40%, calculated on the total weight of the emulsifier and the carrier.

The substantially free-flowing powder product having the above- described characteristics may be prepared by mixing the emulsifier with one or several particulate carriers and subjecting the resulting mixture to extrusion or an equivalent treatment to form a substantially free-flowing powder. When the emulsifier and a suitable particulate carrier, in particular a carrier which is able to become "wetted with" or to "sorb" (adsorb and/or absorb) the emulsifier under the conditions prevailing, is sub¬ jected to extrusion, it is possible to obtain an extrudate which, in- stead of having the form of an extruded string of the mixture, imme¬ diately disintegrates into a powder product with highly desirable pro¬ perties .

Suitable carriers are the ones mentioned above, in particular particu¬ late carriers which are starches or flours . While these preferred car¬ riers may be used as they are (with particle size distributions which often have a major fraction having a size in the range of about 1 -20 ym and preferably 1 -10 ym, but may also be somewhat larger, e. g . with major fractions of up to 20-50 ym or even 50-100 ym) , it is contemplated that it may be advantageous to secu re a very fine part- icle size of the carriers, such as 1 -5 ym or finer, by subjecting the carriers to additional comminution beyond the comminution which such products (for example flours or starches) have normally been sub¬ jected to. Such additional comminution may, e. g . , be performed in a circular-chamber jet mill or a blender type mill . A typical example of Blaine value for wheat starch useful as a carrier is about 2500 cm²/ g, and for rice starch about 6000 cmVg . When emulsifier has been ap¬ plied to such carriers , the Blaine values decrease somewhat, typically to, e. g . , about 1100 cmVg for a product containing 22.5% by weight of emulsifier and 77.5% by weight of wheat starch , and about 1700 cmVg for a product containing 35% by weight of emulsifier and 65% by weight of rice starch .

The vegetable flour or starch carriers may, if desired, be combined with fibrous materials to obtain a starch or flour/fiber combination carrier, provided that the fibrous materials in the final product have about the same "particle" size (e. g . fiber length) as the flour or starch particles, such as a size in the range of 1 -100 ym, in partic¬ ular 1 -20 ym, or less, such as explained above. The fibrous materials may be comminuted to such small sizes before they are added to the mixture, or they may be fibrous materials of such a brittle or weak character that they are comminuted to the small particle sizes men- tioned during the mixing process . Examples of suitable fibrous mat¬ erials for this purpose are brans such as wheat bran, rye bran , pea bran or bean bran . When finely divided fibrous materials are included in the carrier, it is preferred that they constitute at the most 50% by weight of the carrier material, preferably at the most 20% by weight of the carrier and most preferably at the most 5% by weight of the carrier.

The mixing of the constituents is suitably performed immediately prior to the extrusion in the mixing/transport means of the extruding equipment. This transport means is typically a screw mixer such as a double screw mixer. The temperature in the last part of the screw mixer (and hence approximately the temperature of the mixture sub¬ jected to extrusion) is normally in the range of 100-180°C, typically 110-150°C and often preferably 120-140°C . The orifice or each orifice through which the mixtu re is extruded will normally have a diameter of from about 1/2 to about 8 mm; often, a diameter of about 1 -4 mm, such as about 2 mm, is very well suited .

The mixture subjected to the extrusion will normally have a free water content (water which is not chemically bound) of 1 -30% by weight, especially 5-25% by weight. I n certain cases it may be found advantageous to add a small percentage of water, such as 0.1 -5% by weight, in particular 0. 1 -3% by weight, to the mixer together with the surface-active substance and the carrier.

EXAMPLE 1

An emulsifier product was prepared by heating 202.5 g of glycerol condensate mixture (comprising 15% of monomeric glycerol, 60% of di¬ glycerol and the remainder being higher glycerol condensates) , 247.5 g of a stearic acid product (containing about 70% by weight of stearic acid, 25% by weight of palmitic acid, and 5% by weight of myristic acid, average carbon atom number of the product: 17.2) and 2 g of sodium hydroxide to 230°C and keeping the mixture at 230°C for 20 minutes, whereafter the mixture was quickly cooled to just below 100°C. The resulting homogeneous, clear product was allowed to cool , whereby a yellow to light brown fat-like emulsifier product (in the following termed stearic acid diglycerol partial ester) was obtained .

Using exactly the same conditions and exactly the same amounts, but using, instead of the stearic acid product, myristic acid (99% by weight of myristic acid, carbon atom number: 14) , another, yellow to light brown fat-like emulsifier product (in the following termed myris¬ tic acid diglycerol partial ester) was obtained . The saponification number of the product was 135-140.

The stearic acid diglycerol partial ester was mixed with the myristic acid diglycerol partial ester in the weight ratios 90: 10 and 80: 20, respectively (by melting and mixing) , and the resulting mixtu res, as well as each of the stearic acid diglycerol partial ester and the myris¬ tic acid diglycerol partial ester per se, were applied on rice starch as follows :

To an extruder of the type BC 45 supplied by Creu sot- Loire, France, and comprising a double screw which rotates at a rotational speed of 200 r. p . m. , and two nozzles of a diameter of 2 mm, part of the double screw length being cooled by means of a water jacket and the part of the double screw being adjacent to the nozzles being heated by means of an induction heating jacket, rice starch was supplied through an inlet funnel comprising two screws conveying the starch , and the diglycerol partial ester or diglycerol partial ester mixture in molten form was supplied to the double screw through a tube. Through another tube to the extruder, 1 .5% of water (calculated on the same percentage basis as the diglycerol partial ester or mixture and the rice starch) was added . The weight ratio between the supply of di¬ glycerol partial ester or mixture and the supply of rice starch was 35% of diglycerol partial ester or mixture to 65% of rice starch . The total amount supplied per hour was 45 kg.

The temperature of the screw part was thermostated to 130°C.

As a start up phase, a surplus of the diglycerol partial ester or mix¬ ture and the water was added, and the product emerged as a semi- liquid or pasty liquid or paste-like string . When the water and di- glycerol partial ester or mixture supplied had been adjusted to the amounts referred to above, the product changed into a particulate free-flowing powder.

The product resulting from the extrusion was a free-flowing powder comprising the rice starch particles (or small agglomerates of partic- les) carrying the diglycerol partial ester or mixture.

Three further emulsifier products were prepared by esterification of the same glycerol condensate mixture in exactly the same manner as described above, but using, as the acid reactant, mixtu res of the stearic acid product and the myristic acid in the weight ratios 90: 10, 80:20, and 70:30, respectively. The resulting "co-reacted" products were applied on rice starch in exactly the same manner as described above.

57 g of each of the resulting rice starch-supported products was sub¬ jected to a whipping test in a layer cake mix of the following compo- sition :

405 g of granulated sugar 270 g of wheat flour 188 g of wheat starch 30 g of baking powder 50 g of milk powder

350 g of whole egg 350 g of water. The dry ingredients (i . e. all ingredients with the exception of egg and water) were mixed and sifted . The egg and water were stirred into the dry mixture on a Hobart-type planetary mixer for 1 minute at lowest speed setting, followed by whipping at 264 r. p.m. for 3, 5 or 10 minutes, at which times the bulk weight was determined . The results appear from Table 1 :

Table 1 Cake mix bulk weight, g/litre

Ratio myristic acid : Whipping time Stearic acid product Comment 3 min . 5 min . 10 min .

0:100 1030 1010 755

100:0 335 335 360

90:10 mixture 380 345 350

80:20 mixture 470 400 365

90:10 co-reacted 360 365 345

80:20 co-reacted 320 315 335

70:30 co-reacted 350 335 335

It appears from Table 1 that the emulsifier made with the stearic acid product has poor whipping properties whereas the emulsifier made with myristic acid gives excellent whipping . Also, the mixtu re of 90% of the emulsifier made with myristic acid and 10% of the emulsifier made with the stearic acid product results in good whippling proper- ties, whereas the whipping properties are somewhat inferior when the stearic acid emulsifier proportion of the mixture is increased to 20%. It also appears that the co-reaction tends to result in better whipping properties . Thus, the product co-reacted with 80% of the myristic acid and 20% of the stearic acid product has much better whipping properties that the 80:20 mixture. It will also be noted that while the mixture product starts to result in poor whipping results al ready at the ratio 80: 20, the co-reacted product gives excellent whipping properties at the ratio 70:30. EXAMPLE 2

In the same manner as described in Example 1 , mixtures of myristic acid and the stearic acid product were reacted with diglycerol to re¬ sult in co-reacted products . After the reaction, unesterified glycerol and glycerol condensate were removed from the reaction mixture. Each of the resulting emulsifiers was applied on icing sugar in an amount of 10% of emulsifier on 90% of the sugar by melting the emulsifier and adding the sugar. Then, each resulting coarse powdery product was passed through a sieve to yield a free-flowing powder. After standing for about 24 hours, each product was again passed through a sieve and was then subjected to the same whipping test in the same layer cake mixture as described in Example 1 . The results appear from Table 2:

Table 2 Cake mix bulk weight, g/litre

Ratio myristic acid : Whipping time stearic acid product, 3 min . 5 min . 10 min . co- reacted

100:0 360 315 355 90: 10 335 305 305 80:20 335 295 300 70:30 320 295 285 60:40 360 315 285 50: 50 350 305 275 40: 60 330 315 285 20:80 565 415 300 10:90 630 440 285

In the same manner, a co-reacted 50:50 myristic acid :fully hardened tallow fatty acids product was prepared and tested . The whipping re¬ sults were: 3 minutes: 350 g/litre, 5 minutes: 305 g/litre, and 10 minutes : 280 g/litre, in other words almost identical to the results stated above, although the tallow fatty acids product introduces a small extra amount of glycerol .

EXAMPLE 3

I n the same manner as described in Example 2, co-reaction emulsifiers were made with mixtures of the myristic acid and 99% palmitic acid. After the reaction , the unesterified glycerol and glycerol condensate were removed from the reaction mixture. The resulting products were applied on sugar as described in Example 2 and subjected to the whipping test in the same manner as- described in Example 1 . The results appear from Table 3.

Table 3 Cake mix bulk weight, g/litre

Ratio myristic acid : Whipping time palmitic acid, co-reacted 3 min . 5 min . 10 min .

100:0 350 310 355 90: 10 335 305 345 80:20 330 305 330 70:30 340 305 315 60:40 325 320 305 50: 50 335 315 305 40: 60 330 335 305 30: 70 325 320 290 20: 80 330 335 315 10: 90 330 335 305

EXAMPLE 4

An emulsified product was prepared by heating 19.92 kg of the same glycerol condensate mixture as in Example 1 , 0.33 kg of glycerine, 12.38 kg of lauric acid (99%) and 12.38 kg of the same stearic acid product as in Example 1 at 225-230°C for 40 minutes . During the heating, 1 .4 kg of reaction water was removed . (The reaction was obtained without addition of catalyst; the amount of catalyst present in the glycerol condensate mixture) . The mixture was then quickly cooled to just below 100°C. The resulting homogeneous, clear product was allowed to cool, whereby a yellow light brown fat-like emulsified product was obtained . The saponification value of the product was 141 .7, the acid number was 2.7, and the pH was 7.2. A melting point determination in capillary tube gave the following result: Clarification point 38.5°C, rising point 61 °C.

This co-reacted emulsifier product was applied on rice starch in an extruder in the same manner as described in Example 1 . In one experiment, 35% of the emulsifier was applied on 65% of rice starch with addition of 1 .5% of water. I n another experiment, 35% of the emulsifier was applied on 65% of rice starch without addition of water. I n a third experiment, 39.2% of the emulsifier was applied on 60.8% of rice starch without addition of water.

Each of the rice starch-supported products was subjected to the same whipping test in the same layer cake mixture as described in Example 1 . Each product was mixed with the other ingredients, and part of the resulting mixture was immediately whipped. Another part of the emulsifier-containing mix (dry) was stored for three months at room temperature, whereafter it was whipped . The results of the whipping tests appear from Table 4:

Table 4 Cake mix bulk weight, g/litre

Co- reacted 50: 50 Whipping time lauric acid : stearic 3 min . 5 min . 10 min . acid product

35% emulsifier, 65% rice starch , prepared using 1 .5% of water

Mix fresh prepared 335 335 355

After three months 340 355 380

35% emulsifier, 65% rice starch, without water

Mix fresh prepared 325 330 345

After three months 345 350 360

39.2% emulsifier, 60.8% rice starch , without water

Mix fresh prepared 350 330 340

After three months 335 340 365

It appears from the results that the emulsifier has excellent whipping properties , and that these excellent whipping properties are retained even when the emulsifier, mixed with the cake mix , is stored for a long period at room temperature.

EXAMPLE 5

I n the same manner as described in Example 4, a series of emulsifiers were prepared in large scale with four different acid reactants : 99% lauric acid; the stearic acid product described in Example 1 ; 99% my¬ ristic acid; and 99% palmitic acid . The glycerol condensate mixture was the same as in Example 1 . The weight ratio between the acid reactant and the glycerol condensate mixture was 55:45. As catalyst, 0.44% of sodium hydroxide was used, calculated on the reactants. Each of the resulting emulsifier products was applied in an amount of 35% on 65% of rice starch in the same manner as described in Example 1 , using 1 .5% of water and no water, respectively . The results of the whipping tests appear from Table 5.

Table 5

Emulsifier Whipping time product 3 min . 5 min . 10 min .

lauric acid product applied on rice starch , with water 665 730 710 applied on rice starch , without water 525 630 695 stearic acid product applied on rice starch , with water 900 750 475 applied on rice starch , without water 910 735 490 myristic acid product applied on rice starch , with water fresh mix 335 335 360 after th ree months storage in the cake mix 420 390 365 palmitic acid, applied on rice starch with water fresh mix 395 365 330 after three months 530 430 355

EXAMPLE 6

An emulsifier product was prepared by heating 57.8% of a glycerol condensate mixture having a viscosity of 1000 cps at 60°C and having the following average composition : Monomeric glycerol 21 .5%

Diglycerol 26.3%

Trimeric condensate 19. 1%

Tetrameric condensate 12.1%

Pentameric condensate 7.4%

Higher condensates 13.6%

The above product was esterified with myristic acid . The weight ratio between the glycerol condensate product and the myristic acid was 57.8:42.2. No catalyst was added (the small amount of catalyst pre- sent in the polyglycerol product was sufficient) . The mixtu re was kept at 265°C for 20 minutes whereafter it was quickly cooled to just below 100°C . The resulting homogeneous, clear product was allowed to cool, whereby a yellow to light brown fat-like emulsifier product was obtained . Unesterified glycerol and glycerol condensate were removed from the product. The data of the product were as follows : Before removal of un reacted glycerol and glycerol condensate: Saponification value 111 .5; acid number 0.9; pH 7.6. After removal of unreacted glycerol and glycerol condensate: Saponification value 150.5, acid number 9.2.

I n the same manner, another product was made using the same glyce¬ rol condensate mixture, but using a 80: 20 mixture of myristic acid (99%) and the stearic acid product described in Example 1 as the acid reactant. The data of the resulting emulsifier product were as follows : Before removal of unesterified glycerol and glycerol condensate: Saponification value 134.8; acid number 2.9; pH 8.5. After removal of unesterified glycerol and glycerol condensate: Saponification value 163.3; acid number 10.9.

Each of these emulsifier products (from which unreacted glycerol and glycerol condensate have been removed) was applied in an amount of 10% on 90% of icing sugar as described in Example 2, and the sugar- supported products were subjected to the same whipping tests in the same layer cake mixture as described in Example 1 . The results ap¬ pear from Table 6: Table 6 Cake mix bulk weight, g/litre

Whipping time

Product 3 min . 5 min . 10 min .

Prepared with myristic acid 500 465 465

Prepared with 80:20 mixture of myristic acid and stearic acid product 650 560 410

These results are much better than results obtained with the same glycerol condensate reacted in the same manner with the stearic acid product alone.

Claims

1 . A polyglycerol partial fatty acid ester emulsifier comprising poly¬ glycerol which is predominantly mono- and/or diesterified with satu r¬ ated fatty acid moieties and optionally monomeric glycerol which is predominantly mono- and/or diesterified with saturated fatty acid moieties, in which the fatty acid moieties are selected so that the average number of carbon atoms in the acid moieties is in the range between 13.0 and 16.5.

2. A polyglycerol partial fatty acid ester emulsifier according to claim 1 , in which at least 50%, preferably at least 60%, of the emulsifier consists of diglycerol partial fatty acid ester, and at the most 25%, such as at the most 20%, consists of partial fatty acid esters of mono¬ meric glycerol .

3. A polyglycerol partial fatty acid ester emulsifier according to claim 1 or 2, in which at least 60%, in particular at least 80%, more pre¬ ferably at least 90%, of the fatty acid moieties contain at least 12 carbon atoms .

4. A polyglycerol partial fatty acid ester emulsifier according to any of claims 1 -3, in which the average number of carbon atoms of the acid moieties is in the range between 14.0 and 16.0.

5. A polyglycerol partial fatty acid ester emulsifier according to any of claims 1 -4, in which the major proportion of the fatty acid moieties is selected from lau ric acid moieties, myristic acid moieties, palmitic acid moieties, and stearic acid moieties .

6. A polyglycerol partial fatty acid ester emulsifier according to claim 5, in which 40-60%, preferably about 50%, of the fatty acid moieties are lauric acid moieties, and 25-50%, such as 25-35%, are stearic acid moieties, 10-20% are palmitic acid moieties, and 0-3% are myristic acid moieties .

7. A method for preparing a polyglycerol partial fatty acid ester emulsifier, comprising reacting a polyglycerol, optionally containing monomeric glycerol, with a fatty acid or a mixture of fatty acids or with a fatty acid glyceride or a mixture of fatty acid glycerides, the number of carbon atoms of the fatty acid or of the fatty acid moiety of the glyceride or the average number of carbon atoms of the fatty acids or the fatty acid moieties of the glycerides being in the range between 13.0 and 16.5.

8. A method according to claim 7, in which at least 50%, preferably at least 60%, of the polyglycerol product consists of diglycerol molecules, and at the most 25%, such as at the most 20%, consists of partial fatty acid esters of monomeric glycerol .

9. A method according to claim 7 or 8, in which at least 60%, in par¬ ticular at least 80%, more preferably at least 90%, of the fatty acid moieties contain at least 12 carbon atoms .

10. A method according to any of claims 7-9, in which the average number of carbon atoms of the acid moieties is in the range between

14.0 and 16.0.

11 . A method according to any of claims 7-10, in which the major proportion of the fatty acid moieties is selected from lauric acid moie¬ ties, myristic acid moieties, palmitic acid moieties and stearic acid moieties .

12. A method according to claim 11 , in which 40-60%, preferably about 50%, of the fatty acid moieties are lauric acid moieties, 25-50%, such as 25-35%, are stearic acid moieties, 10-20% are palmitic acid moieties, and 0-3% are myristic acid moieties .

13. A substantially free-flowing emulsifier product, comprising an emulsifier according to any of claims 1 -6 applied on a particulate carrier, preferably in an amount of at least 10% by weight, calculated on the weight of the product.

14. A product according to claim 13, in which the carrier is selected from flours, starches, mono- and disaccharides and pentosans, and mixtures thereof, optionally with an admixtu re of material of vegetable fibre origin .

15. A method for preparing an emulsifier product as claimed in claim 13 or 14, comprising mixing the emulsifier with one or several par- ticulate carriers and subjecting the resulting mixture to extrusion or an equivalent treatment.

16. A method according to claim 15, in which the temperature of the mixture subjected to extrusion is in the range of 100-180°C, in par¬ ticular 110-150°C, preferably 120-140°C.

17. A food product, in particular a cake mix or a cake product made therefrom, containing an emulsifier as claimed in any of claims 1 -6 or an emulsifier product as claimed in claim 13 or 14, preferably in an amount of 1 -4% by weight, calculated on the weight of the emulsifier relative to the weight of dry constituents of the food product.