AU736917B2

AU736917B2 - Long-life egg-based product and preparative process

Info

Publication number: AU736917B2
Application number: AU28778/97A
Authority: AU
Inventors: Hans-Joachim Beyer; Jean-Pierre Bisson; Robert Petermann
Original assignee: Societe des Produits Nestle SA; Nestle SA
Current assignee: Societe des Produits Nestle SA
Priority date: 1996-07-22
Filing date: 1997-07-21
Publication date: 2001-08-09
Anticipated expiration: 2017-07-21
Also published as: DE69636281D1; CN1098653C; PL321202A1; EP0820704B1; DE69636281T2; MX9705512A; CN1171211A; BR9704052A; AU2877897A; PT820704E; EP0820704A1; ES2268698T3; PL187580B1; AR010728A1

Description

1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant/s: Actual Inventor/s: Societe Des Produits Nestle S.A.

Jean-Pierre BISSON, Hans-Joachim BEYER and Robert Petermann Address of Service: Invention Title: SHELSTON WATERS MARGARET STREET SYDNEY NSW 2000 "LONG-LIFE EGG-BASED PRODUCT AND PREPARATIVE

PROCESS"

The following statement is a full description of this invention, including the best method of performing it known to us:- (File: 19883.00) la- Long-life egg-based product and preparative process The invention relates to a sterilized egg-based product, with a functionality similar to that of a product of the same nature containing egg not having been subjected to heat treatment. It concerns in particular an egg-based product capable of being gelled by heat treatment and hence suitable for the preparation of gelled food products.

Eggs are often used for their excellent functional properties, for example of gelling, emulsification and suitability for beating, for their flavour and their colour. It is known that egg-based food products are not free from microbiological risks, from the fact that eggs may contain spore bearing germs and salmonella. Egg proteins usually lose their 10 functional properties, in particular their ability to gel under conditions of heat treatment which would be necessary for the elimination of salmonella and resistant spores. This is why industrial egg products are generally pasteurized which does not eliminate all the risks. On account of the residual risks, the use of eggs is limited, for example in longlife refrigerated desserts.

15 It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

Various processes are known for making egg-based products hygienic. According to EP-A-179946, for example, egg yolks are diluted with water, the dispersion is acidified to pH 1 A.

19883-00.DOC -2- 2-5.7, and it is then sterilized at an ultra high temperature (UHT), under conditions preventing any apparent coagulation.

According to EP-A-281431, a custard is prepared by mixing milk, a pasty concentrate of whole egg, sugar and stabilizers, and the mixture is then sterilized at 100-160 0 C, cooled by reducing the pressure, homogenized aseptically and aseptically packaged.

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common 0 0o 0 o general knowledge in the field.

i According to a first aspect the invention provides a long shelf life sterilized egg-based 6 oo 10 oven cooked custard, which is gelled by heat treatment, which does not contain any 0o added emulsifier or thickening agent, which is microbiologically stable and which comprises: a milk base rich in casein representing 55 to 80 wt%; ~carbohydrates representing 3 to 20 wt% egg; and a sterilized food quality calcium salt.

According to a second aspect the invention provides microbiologically and physically stabilized long-life expanded or emulsified foodstuff, which does not contain any added emulsifier or thickening agent, containing a mixture of egg, milk proteins rich in casein and carbohydrates and in that the milk proteins replace the functional properties of egg to expand and emulsify in its applications.

Unless the context clearly requires otherwise, throughout the description and the claims, the words 'comprise', 'comprising', and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of"including, _w/but not limited to".

19883-OO.DOC/LL 2a In particular, the product according to the invention may be gelled by heat treatment in the presence of calcium.

Within the context of the invention, the expression "physically and microbiologically stable" means that the product, both as it is as well as in a finished product, for example a gelled product, is stable microbiologically over a long period and in that there is no separation of phases or settling during intermediate storage.

In a particular embodiment, the product according to the invention contains a sterilized food quality calcium derivative, in particular an inorganic or organic salt, for example lactate, gluconate, chloride or a mixture of these salts, at a rate of 0.05 to 3 wt.%, preferably from 0.1 to 0.8 wt.%.

The invention also concerns a process for preparing the preceding product, characterized in that a milk base rich

"D

o •oi5 19883-00.DOC/SSPL in casein is mixed with carbohydrates and liquid egg and in that the mixture is then sterilized by ultra high temperature treatment.

Within the context of the invention, a milk base rich in casein means any raw material of milk origin containing milk proteins, rich in casein. Any raw material containing casein may be used, provided that the casein is able to react with calcium on heating to form a gel. The casein is o.

10 preferably native, that is to say essentially in the form of an intact micelle. As a preferred raw material oo reference may be made to powdered milk, enriched with a milk protein concentrate, obtained in particular by .oo o ultrafiltration of skimmed milk followed by diafiltration (ultrafiltration with water washing) or by microfiltration of skimmed milk, optionally dried, for example, by eooe spraying. As a variant, use may be made of buttermilk as the source of casein, preferably sweet buttermilk, subjected to ultrafiltration or not, or a caseinate other than calcium caseinate. The milk base advantageously represents 55 to 80 wt.% and the milk proteins 1 to preferably approximately 6 wt.% of the mixture.

The liquid egg which can be used in the process of the invention may be egg yolk, egg white, a mixture of yolk and white or a whole egg in liquid form having been previously pasteurized. Use may be made of freshly run egg or matured egg, that is to say kept at refrigeration temperature for example at approximately 4 0 C for a period of as long as several days. Use may be made of a mixture of egg white and yolk having been matured separately. According to the egg content of the mixture, from 1 to 45 preferably to 30 the gel obtained after hot reaction with calcium will have a smoother texture but one which is less firm and an improved flavour, as this content increases.

The carbohydrates which can be used in the process of the invention are in particular sucrose and lactose when it is desired to use the product according to the invention for manufacturing a sweetened food or, if a salted food is concerned, maltodextrin, preferably with a low dextrose equivalent, for example 20, alone or in a mixture.

.*.Carbohydrates represent 3 to 20 and preferably approximately 10 wt.% of the mixture.

In order to put the process into practice, the solid :0 components are mixed in whole milk or milk skimmed to a varying extent, with stirring until complete solubilization is achieved, the pH is adjusted where necessary to a value :°•eoo of 6.5 to 7.5, and the mixture is then preheated with the aid of a plate exchanger to a temperature less than or equal to 95 0 C, preferably to a temperature of less than or :°•ooe 0..0 equal to 70 0

C.

UHT sterilization treatment can be carried out by direct S"20 steam injection or in an indirect manner, for example by 00 0 means of a plate exchanger. The apparatus may comprise, for example, an in-line positive pump, a steam injection nozzle, a stand-by tube, a pressure release valve, a cooler using pressure reduction and a plate cooler with iced water circulation.

Sterilization takes place preferably at 138 0 C-150 0 C for 4the lowest temperature being generally associated with the longest duration and the highest temperature with the shortest duration.

After cooling by pressure reduction, preferably under vacuum, the mixture may be homogenized in a homogenizer with 1 or 2 stages, preferably, for a stage at a pressure of 75 to 300 bar (P1) or for two stages from 75/15 bar to 300/60 bar (Pl/P2 with a P2/Pl ratio equal to close to 0.2) followed by cooling to room temperature. Of course all the operations following sterilization are carried out in an aseptic manner. Homogenization may be optional in relation to the applications. For example, in the case where heat treatment takes place by direct steam injection, a sonic effect is produced which may prove insufficient for the desired homogeneity and it is then preferable to carry out a homogenization.

According to a preferred embodiment of the process, an 10 aqueous solution of a previously sterilized calcium derivative is introduced into the cooled mixture. Any calcium derivative of food quality may be used for this purpose, in particular an inorganic or organic salt, for example lactate, gluconate, chloride or a mixture of these salts, at a rate of 0.05 to 3 preferably 0.1 to 0.8 The solution may be sterilized by direct or indirect heat treatment or by microfiltration.

The sterile mixture thus obtained may be packaged in an aseptic manner in previously sterilized packages and constitute a ready-to-cook gelling foodstuff, for example, for domestic or industrial preparation.

For industrial preparation, calcium salt may also be added to the sterilized product in an effective amount with a view to subsequent gelling treatment.

As a variant, the mixture in question may be dried, for example by spraying in a drying tower under moderate conditions not causing gelling of the milk proteins. It is also possible to dry the mixture of milk proteins/eggs separately and then mix the calcium salt or salts and optionally other dehydrated components in the dry state.

Once dried and with the optional addition of the other dehydrated ingredients of the recipe, the mixture may be reconstituted with an aqueous medium, and then subjected to a gelling heat treatment.

The invention also concerns a process for manufacturing a gelled foodstuff or comprising a gelled garnish, characterized in that, after having optionally added a calcium salt, the preceding product is heat treated so as to form a gel, optionally in the presence of other components by way of a receptacle, inclusions, supplements or flavouring ingredients.

Thus, the process according to the invention may be used as 0 10 a basic ingredient in any foodstuff comprising the use in a mixture of milk, eggs and carbohydrates with the aim of forming a gel by cooking. Reference may be made to salted culinary preparations for flans, omelettes, quiches or ~sauces or sweetened culinary preparations for pastry, in particular for cakes, creams or custard tarts.

*S oso 00 ~The product according to the invention may be used in liquid form or in a dehydrated powder form, which can be reconstituted in the presence of liquid.

09 In a particular embodiment, the manufacture of a baked dessert for storage in the refrigerated state, the product according to the invention, used in a liquid form, serves as an egg base to which is added a suitable quantity of calcium salt, for example in a dynamic mixer.

After filling pots, these may be presealed, leaving the possibility for gases to escape, and they are baked, for example in an infrared oven with convection or in a water bath between 100 and 250 0 C for 20 to 90 min and they are finally sealed and cooled.

The sterilization heat treatment of eggs mixed with milk proteins destroys the functional properties of egg proteins. However the preparation of a foodstuff, for example a custard or a mousse remains possible by virtue of the exploitation of the gelling properties or the expansion and emulsification ability of milk proteins which take the place of egg proteins. In the special case of a gelling foodstuff, the milk proteins replace the egg proteins through their ability to gel in the presence of calcium and with the addition of heat.

The following examples illustrate the invention. In these, parts and percentages are by weight, except where indicated to the contrary.

.~o Example 1 Freshly run liquid egg and skimmed milk were mixed in a vessel with stirring, and sucrose was then introduced thereto and optionally skimmed milk powder or a total milk protein concentrate with 60 proteins obtained by ultra centrifuging and drying, a turbine mixer being used until a solution was obtained. The mixture was then pumped by means of a positive pump to a plate exchanger where it was preheated to a temperature less than or equal to 70 0

C.

After directly injecting steam, the liquid was held at 145°C for 8 seconds and then cooled, first of all by reducing the pressure under vacuum at 70 0 C and then by means of a plate exchanger with circulation of iced water 15 at 4-6°C, and the liquid was then temporarily stored in a sterile vessel, the operations following the heat treatment taking place in an aseptic manner.

The proportions of ingredients and the pH of the 20 mixture before sterilization are shown in table 1 below.

oo Table 1 a a Egg Whole Egg Sucrose Skimmed Total Skimmed pH white egg, yolk milk milk milk before white/ powder protein sterilyolk concen- ization 70/30 trate 26 9 3 62 6.89 26 9 3 -62 6.78 13 9 3 75 6.65 26 9 3 62 7.00 26 9 -5 60 6.75 26 13 5 56 6.40 26 9 3 5 57 6.64 26 11 3 60 6.57 26 11 7 57 6.56 S 13 11 5 71 6.63 32 11 5 52 6.82

I

In to all any the cases, the sterilization treatment did not lead visible coagulation or physical destabilization.

The products were free from mesophilic germs after 3 days at 30 0 C and free from mesophilic spores after 3 days at As a comparison, the same products which had not been subjected to a sterilization treatment possessed mesophilic and coliform germs at a concentration of 2 102 to 2 108 germs/ml. The same products pasteurized at for 10 min had 4 102 to 1 10 5 mesophilic spores/ml.

The products served as a base for manufacturing sweetened foods.

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*4 Example 2 The procedure was as in example 1, but with liquid eggs matured for 5 days at 4 0 C. The ingredients and their proportions as well as the pH of the mixture before sterilization are given in table 2 below.

Table 2 Egg Whole egg, Egg Sucrose Total milk Skimmed pH white white/yolk yolk protein milk before 70/30 concen- steriltrate ization -32 11 5 52 6.88 22.4 9.6 11 5 52 6.90 The physical properties and the microbiological quality of the products were similar to those obtained in the case of example 1.

15 Example 3 The procedure was as in example 1, starting from a mixture containing 26 whole egg, 11 sucrose, 5 total milk protein concentrate (containing 60 proteins) and 58 skimmed milk, the pH of the mixture before UHT treatment being 6.8. The UHT heat treatment conditions were varied and, after cooling by pressure reduction under vacuum at 0 C, homogenization was optionally carried out at 70 0

C.

The operating conditions of the process are given in the table 3 below.

12 Table 3 UHT Duration of UHT 1-stage 2-stage homogenization treatment treatment homogeniza- (1st stage/2nd stage, temperature tion pressure in bar) (OC) (pressure in bar) 140 140 143 143 143 10 143 10 150 143 10 250 143 10 75/15 143 10 -150/30 143 10 -250/50 The microbiological quality of the products was similar to 5 that obtained in the case of example 1. The gelling power was in addition improved in the case where homogenization was carried out.

Example 4 .0 The procedure was as in example 1, except that the products served as bases for salted foods. The ingredients and their proportions are given in the table 4 below.

13 Table 4

S

*5 Whole Concen- Concen- Sodium Malto- Malto- Skimmegg trate with trate chloride dextrin dextrin ed milk total with 75% (with a (with a milk total dextrose dextrose proteins milk equi- equiproteins valent of valent of 19) 12) 32 5 0.88 7 55.12 32 5 11 52 32 5 0.88 5 55.12 32 5 7 56 The physical properties and the microbiological quality of the products were similar to those obtained in the case of example 1.

The products obtained were used as a base for manufacturing a quiche Lorraine by adding 0.07% of Ca in the form of a gluconate/lactate solution just before cooking. The texture and flavour of the quiche were similar to those of a traditional quiche.

Example A powder was manufactured from a mixture prepared according to example 1 by spray drying in a drying tower with a turbine under the following drying conditions air inlet temperature 180-200 0

C

air outlet temperature 85-900C.

Once reconstituted in water from the selected dry extract, the mixture could be used as in example 1.

Example 6 To a mixture prepared according to example 3, sterilized at 143 0 C for 15 seconds, not having undergone homogenization, 1.8% of a 10% aqueous solution of calcium chloride previously sterilized by microfiltration was injected inline, in a sterile manner, and was then temporarily stored in a sterile vessel with a view to subsequent use.

Egg custards were then manufactured by metering the 15 preceding preparation into pots, by partially sealing the -pots, by baking them in a hot air oven at 110 0 C for 75 min and then finally sealing the pots. After cooling, the firmness of the gel was examined by penetrometry with a model TAXT 2® texture analyser (TA instruments), analysis 20 of the compression curve giving the value of Young's modulus (firmness of the gel expressed in Pa). The value obtained was 1638 Pa.

Example 7 The procedure was as in example 6, except that the necessary effective quantity of calcium chloride solution was metered into the pots just before baking in the oven.

The custard obtained was entirely comparable to that obtained according to example 6. The gel had a firmness which depended on the quantity of calcium added.

Example 8 The procedure was as in example 7, except that the sterilization conditions were 140 0 C/10s. As the calcium salt, the chloride was used or a gluconate/lactate mixture (Gluconal-CalO, Akzo Nobel) at various concentrations as indicated in table 5 below. After baking, the gels had the firmness values indicated in table 5 below.

0.0* *0 Table Calcium salt Concentration Firmness of the gel (Pa) CaCI 2 (10% aqueous 2.2 2581 solution) CaCI 2 (10% aqueous 2.6 3532 solution) CaCI 2 (10% aqueous 3 4916 solution) CaCl 2 (10% aqueous 4 6460 solution) Mixture of Ca 2.2 2094 gluconate/lactate (27.5% aqueous solution) Mixture of Ca 2.6 3136 gluconate/lactate (27.5% aqueous solution) Mixture of Ca 3 3643 gluconate/lactate (27.5% aqueous solution) Mixture of Ca 4 5294 gluconate/lactate (27.5% aqueous solution) Example 9 A sterilizable expandable base was prepared consisting of a mixture of milk proteins, sugar, whole egg, chocolate and cocoa with a view to manufacturing a long-life chocolate 17 mousse, from the ingredients and in the proportions indicated in table 6 below.

Table 6 Ingredients Whole milk or skimmed milk or water 47.8 Whole egg Sucrose 14.6 Total milk protein concentrate with 60 4.6 proteins, in powder form Dark chocolate and alkalinized chocolate 21 Cocoa powder 2 The ingredients were mixed, their pH was optionally adjusted to neutral, they were preheated to 700C and they were treated by UHT with direct steam injection at 1430C/ 10 s. After cooling by reducing the pressure under vacuum at 70 0 C, and then by a plate exchanger at 10 0 C, the mixture was aerated in a Mondomix® aerator until an overrun of 100% by volume was achieved.

Claims

2. Products according to claim 1, which can be gelled by heat treatment containing a sterilized food quality calcium salt.
3. A product according to claim 2, wherein the calcium salt is a lactate, gluconate, chloride or mixture thereof A product according to claim 2 or 3, wherein the calcium salt is present in an amount ofO0.05 to 3 wt%. A product according to any one of claims 2 to 4, wherein the calcium salt is 15 present in anamount of 0.1toO.8wt%.
6. Products according to any one of the preceding claims, wherein the milk base represents 55 to 80 wt% and the milk proteins I to 15% of the mixture. A product according to claim 6, wherein the milk proteins represent 6 wt% of the mixture.
8. A process for the preparation of a product according to any one of claims i to 7, which comprises mixing a milk base rich in casein with carbohydrates and liquid egg, sterilizing the mixture by UHT, cooling it, adding a previously sterilized calcium derivative and heat treating to effect gelling. ,neo, an ntCIprflfl, -19-
9. Process according to claim 8, wherein as a milk base rich in casein, a raw material is used containing casein able to react with calcium on heating to form a gel. A process according to claim 9 wherein as a milk base, powdered skim milk enriched with a milk protein concentrate is used.
11. Process according to any one of claims 8-10, wherein the milk base represents to 80 wt% and the milk proteins 1 to 15% of the mixture.
12. A process according to any one of claims 8-11, wherein the milk proteins represent 6 wt% of the mixture.
13. Process according to any one of claims 8-12, wherein use is made of egg yolk, egg white, a mixture of yolk and white or a whole egg in liquid form having been previously pasteurized and optionally matured, at a rate of 1 to 45 wt% of the mixture.
14. A process according to any one of claims 8-13, wherein use is made of egg yolk, •egg white, a mixture of yolk and white or a whole egg in liquid form having been previously pasteurized and optionally matured, at a rate of 10 to 30 wt% of the mixture. 15 15. Process according to any one of claims 8-14, wherein the carbohydrates used represent 3 to 20 wt% of the mixture.
16. Process according to any one of claims 4 to 15, wherein the carbohydrates used represent 10 wt% of the mixture.
17. Process according to any one of claims 8 to 16, wherein the carbohydrates used are 20 sucrose, lactose, a polymer of glucose and mixtures thereof when the product is for use in manufacturing a sweetened food. IQLOR-n nnr/CTm
18. Process according to any one of claims 8 to 16, wherein the carbohydrate used is maltodextrin, alone or in a mixture when the product is for use in manufacturing a salted food.
19. Process according to claim 18, wherein the maltodextrin has a low dextrose equivalent. Process according to claim 19, wherein the maltodextrin has a dextrose equivalent
21. Process according to any one of claims 8 to 20, wherein the solid components are mixed in milk, with stirring, until complete solubilization is achieved, the pH is adjusted where necessary to a value of 6.5 to 7.5, the mixture is preheated to a temperature of less than or equal to 70 0 C, it is sterilized by UHT and that it is cooled by reducing the pressure. j: 22. Process according to claim 21, wherein the sterilization by UHT is by direct injection of steam. 15 23. Process according to claim 21, wherein the sterilization by UHT is in an indirect manner.
24. Process according to claim 23, wherein the sterilization is by means of a plate exchanger.
25. Process according to any one of claims 21-24, wherein sterilization takes place at S20 138 -150C for 4-25 20 138 0 C -15 0 °C for 4-25s. 0 .noo~M ~TYl~mnl -21-
26. Process according to any one of claims 8-25, wherein, after cooling by reducing the pressure, the mixture is homogenized in a 1- or 2-stage homogenizer and is then cooled to room temperature, all the operations following sterilization being carried out in an aseptic manner.
27. Process according to any one of claims 8-26, wherein an aqueous solution of a previously sterilized calcium derivative is introduced into the cooled mixture at a rate of 0.05 to 3 wt% and in that the whole is sterilized in an aseptic manner in previously sterilized packages.
28. Process according to claim 27, wherein the calcium derivative is a lactate, gluconate, chloride or mixture thereof.
29. Process according to claim 27 or 28, wherein the calcium derivative is introduced into the cooled mixture at a rate of 0.1 to 0.8 wt%.
30. Process according to any one of claims 8 to 26, wherein a calcium salt is added to the sterilized product in an effective amount at the time of subsequent gelling treatment. 15 31. Process according to any one of claims 8-30, wherein the mixture is dried, and the calcium salt or salts and optionally other dehydrated components are then mixed in the dry state. S: 32. Process according to claim 31, wherein the mixture is dried by spraying in a drying tower under moderate conditions not causing gelling of the milk proteins. o* o 20 33. Process for manufacturing a gelled foodstuff or a foodstuff comprising a gelled garnish, wherein after having optionally added a calcium salt, the product according to one of claims 1-7 is heat treated so as to form a gel. 1, Q o.R rv/.Tnw -22-
34. Process according to claim 33 wherein the product is heat treated in the presence of other components by way of receptacle, inclusions, supplements or flavouring ingredients. Microbiologically and physically stabilized long-life gelled foodstuff, obtained by putting the process according to claim 33 into practice.
36. Microbiologically and physically stabilized long-life expanded or emulsified foodstuff, which does not contain any added emulsifier or thickening agent, containing a mixture of egg, milk proteins rich in casein and carbohydrates and in that the milk Vi proteins replacing the functional properties of egg to expand and emulsify in its .10 applications. *e
37. Flavoured mousse dessert, according to claim 36.
38. A flavoured mousse dessert according to claim 37, wherein the flavour is chocolate. 15 reference to any one of the examples, excluding comparative examples. e 40. A procedure for preparing a long-life sterilized egg-based product substantially as herein described with reference to any one of the examples, excluding comparative examples. DATED this 29th day of May 2001 SOCIETE DES PRODUITS NESTLE S.A. Attorney: CHARLES W. TANSEY Registered Patent Attorney of The Institute of Patent and Trade Mark Attorneys of Australia of BALDWIN SHELSTON WATERS
19883-OO.doc/C W