WO1998034494A1

WO1998034494A1 - Edible fat compositions

Info

Publication number: WO1998034494A1
Application number: PCT/NZ1998/000015
Authority: WO
Inventors: Richard Beyer; Patrick Joseph Silcock
Original assignee: University of Otago; Kiwitech Ltd
Current assignee: University of Otago; Fonterra Tech Ltd
Priority date: 1997-02-07
Filing date: 1998-02-09
Publication date: 1998-08-13
Anticipated expiration: 1999-08-07
Also published as: AU6007498A

Abstract

The invention relates to edible fat compositions in which the triglycerides have been partially hydrolysed, usually by treatment with a suitable base, to produce diglycerides and monoglycerides but not free fatty acids. The compositions are useful in food products such as butters.

Description

EDIBLE FAT COMPOSITIONS

This invention relates to edible fat compositions.

BACKGROUND

There is a need for edible fat compositions containing differing proportions of mono-, di- and triglycerides. Altering the relative proportions of these components can affect the physical properties (such as melting point) of a fat composition. Such compositions have application in the food industry.

Previous attempts have been made to produce fat compositions with modified properties. However, such approaches of which the applicants are aware generally involve lipases and have a tendency to release significant amounts of free fatty acids, including butyric acid. This is undesirable, particularly given the unpleasant odour of butyric acid even at very low concentrations.

It is therefore an object of the present invention to provide edible fat compositions which do not contain significant free fatty acids (and butyric acid in particular) which will at least provide the public and/ or food manufacturers with a useful choice.

SUMMARY OF THE INVENTION

Accordingly, in a first aspect, the present invention may be said to consist in an edible fat composition comprising triglycerides, diglycerides and monoglycerides, wherein said composition has been prepared by partial hydrolysis of a triglyceride- containing composition and wherein said composition contains no or substantially no free fatty acids.

In a second aspect, the invention provides an edible fat composition comprising triglycerides, diglycerides and monoglycerides, wherein said composition has been prepared by partial hydrolysis of a triglyceride-containing composition without significant release of butyric acid.

The triglyceride-containing composition can be an animal fat such as tallow. It can also be a milk fat such as Anhydrous Milk Fat (AMF). The triglyceride-containing composition can also be a vegetable oil such as palm oil.

It is preferred that the partially hydrolysed triglyceride-containing composition has a Solid Fat Index of about 7.1% by weight at 30°C.

It is also preferred that the partially hydrolysed triglyceride-containing composition includes from 34-37% by weight solids at 10°C.

In a further aspect, the invention provides a process of preparing an edible fat composition, which comprises the step of partially hydrolysing a triglyceride- containing composition under conditions such that a proportion of the triglycerides are converted to diglycerides and monoglycerides but under which the release of significant amounts of free fatty acid is avoided.

Preferably, the process comprises reacting the triglyceride-containing composition with a base at a sufficient temperature and for a sufficient time to allow partial hydrolysis of the triglycerides to occur, followed by neutralization of the partially hydrolysed triglyceride composition with a suitable acid.

Conveniently, the base is a strong base such as sodium hydroxide, lithium hydroxide or potassium hydroxide.

Conveniently, the reaction takes place at a temperature of between 55 and 90°C, more conveniently at a temperature of 80°C to 85°C.

Conveniently, the reaction is continued for a period of from 2 to 12 hours, more conveniently for a period of from 4 to 10 hours, and most conveniently for a period of from 5 to 7 hours.

Preferably, the acid for neutralization is lactic acid.

In a particularly preferred embodiment, the process comprises the following steps:

(a) heating AMF to a temperature of from about 78°C to about 84°C; (b) adding a base selected from sodium hydroxide, lithium hydroxide and potassium hydroxide, in an amount of from 0.2%-2% by weight of the anhydrous milk fat;

(c) maintaining the temperature of the resulting reaction mixture at about 55-90°C for a sufficient time to allow partial hydrolysis to occur; and

(d) preventing further hydrolysis of the reaction mixture.

Conveniently, the milk fat is heated to a temperature of about 80°C during step (a).

Conveniently, the base is added in an amount of about 0.4% by weight of the anhydrous milk fat.

Preferably, the base is sodium hydroxide.

Preferably, the temperature of the reaction mixture is maintained at about 80°C to about 85°C in step (c).

Conveniently, the temperature is maintained at about 82°C and the reaction time is about 6 hours in step (c).

It is preferred that the temperature is maintained at about 82°C and the reaction is continued until the partially hydrolysed AMF has a Solid Fat Index of about 7.1% by weight at 30°C.

It is also preferred that in step (c) the temperature is maintained at about 82°C until the partially hydrolysed AMF contains from 34-37% by weight solids at 10°C.

Conveniently, step (d) is effected through separation of the base from the remaining components of the reaction mixture.

Alternatively, step (d) comprises the step of cooling the partially hydrolysed AMF to about 50°C. It is however preferred that step (d) comprises neutralizing the partially hydrolysed AMF with a suitable acid such as lactic acid, preferably with a concentration of at least about 88% w/v.

In one form, the process includes the additional step of:

(e) treating the partially hydrolysed AMF to remove any free fatty acids present.

Step (e) can involve washing the partially hydrolysed AMF in distilled water, vacuum distillation or ion exchange.

The invention further provides an edible fat composition comprising triglycerides,

» diglycerides and monoglycerides but which contains no or substantially no free fatty acids which is the product of a process as defined above.

The invention also provides a food product which contains an edible fat composition as described above, particularly a butter.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

The invention consists in the foregoing and also envisages constructions of which the following gives examples.

Preferred embodiments of the present invention are described below in more detail.

DESCRIPTION OF THE INVENTION

The edible fat compositions of the present invention comprise triglycerides, diglycerides and monoglycerides. These compositions may conveniently be prepared by partially hydrolysing a triglyceride-containing composition, under conditions which avoid a significant quantity of free fatty acids (and in particular butyric acid) being released, and therefore avoid an unpleasant odour in the final product.

The initial triglyceride-containing composition from which the edible fat compositions are prepared can be animal fat such as tallow. It can also be vegetable oil such as palm oil. It is however preferred that the triglyceride- containing composition is milk fat, especially anhydrous milk fat (AMF).

The partial hydrolysis of the initial triglyceride-containing composition is desirably continued until the Solid Fat Index of the resulting partially hydrolysed triglyceride- containing composition is about 7. 1% by weight at 30°C (measured in accordance with IUPAC standard, 1979), or until the composition contains from 34-37% solids at 10°C (measured by low resolution NMR).

The presently preferred process for preparing the edible fat compositions of the present invention is a base-catalyzed hydrolysis of a triglyceride-containing composition, followed by neutralization of the reaction product using acid. In the preferred embodiment, the triglyceride-containing composition (preferably AMF) is heated to between about 78°C to about 84°C (preferably about 80°C) to liquefy it. Excess base, conveniently sodium hydroxide, lithium hydroxide or potassium hydroxide is added, preferably in an amount of 0.2 to 2% by weight (more preferably about 0.4% by weight) of the AMF. The resulting reaction mixture is preferably stirred continuously and maintained at a temperature of between about 55°C and 90°C (more preferably between 80°C and about 85°C, most preferably 82°C) for a sufficient time to allow partial hydrolysis to take place without releasing significant amounts of free fatty acids.

It has been found that a reaction time of from 2 to 12 hours will achieve a desirable degree of hydrolysis. It is however preferred that the reaction time be between 4 and 10 hours, more preferably from 5 to 7 hours and most preferably about 6 hours.

Following' the desired degree of hydrolysis being effected, the reaction is stopped. It is preferred that the hydrolysis is terminated when, or prior to, volatile fatty acids being detected by sensory means, when the Solid Fat Index at 30°C is 7.1% by weight (measured in accordance with IUPAC standard, 1979) or when the composition contains from 34-37% solids at 10°C (native AMF contains 46-55% solids at 10°C). The reaction can be stopped by removal of the base (for example by filtering), by lowering the temperature of the reaction mixture or, as is preferred, by neutralizing the reaction mixture by addition of a suitable acid.

Where this preferred step is employed, the partially hydrolysed fat is neutralized using a suitable acid, preferably lactic acid and more preferably lactic acid at a concentration of not less than about 88% w/v. The amount of acid required to neutralize the partially hydrolysed fat may be calculated using a simple titration. Conveniently, the titration may be carried out as follows: Mix vigorously 18g partially hydrolysed AMF, 90ml hot water and 1ml phenolphthalein solution, and titrate the mixture with a 0.88% w/v lactic acid solution to a colorless end point.

While the process of the invention will usually produce a hydrolysis product which contains no or substantially no free fatty acid, there may be instances where some free fatty acids are present in the mixture. In such instances, it is desirable for these to be removed. This additional although optional step of the process can involve washing in distilled water or vacuum distillation. It is however presently preferred that any free fatty acids be removed by an ion exchange process. The magnetic-bead ion-exchange separation process of EP 0522856 is particularly preferred.

Although it is preferred that the edible fat compositions of the present invention are prepared by partial hydrolysis of a triglyceride-containing composition (as described above), compositions which have been prepared by blending the triglyceride, diglyceride and monoglyceride components in appropriate proportions are not excluded.

The edible fat compositions of the present invention have applications in the food industry. If desired, although not essential, they may incorporate additional components to the fat, such as salt (as a preservative) and antioxidants. Alternatively, the edible fat composition may be used as a spread. For example, a spreadable fat composition may be obtained by combining partially hydrolysed anhydrous milk fat with water and, optionally, salt, to yield a composition having approximately the same water content as butter. Such a composition has been found to possess the advantage of easy spreadability at refrigeration temperatures. Additionally, weight for weight, it has a lower energy content than butter, which is advantageous for those wishing to restrict their calorific intake. The preparation of such a spreadable fat composition is illustrated by the non-limiting examples provided below.

Example 1

Partially hydrolysed AMF (lOOOg) prepared by the preferred process described above was heated to 60°C + 2°C. Cold water (14°C) was added (190g) and mixed under low shear for 30 minutes until the temperature of the mixture was 24°C + 1 C. Mixing at a high shear rate was continued but the temperature was decreased to 13°C to 15°C (preferably 13°C). The mixture was rested overnight for 16 hours at 5°C. The following morning the mixture was brought to room temperature (about 20°C to 25°C) and cooled to 12°C to 15°C (preferably 13°C) with mixing, and packed into containers.

If a spreadable fat composition containing salt is desired, the procedure set out above may be followed, with the modification that salt is added to the water before mixing, conveniently in an amount of about 9.3% by weight. This will yield a final concentration of about 1.6% salt in the spreadable fat composition.

Example 2

Composition

Partially hydrolysed AMF (PHAMF) 35.00 kg Cream 1 1.00 kg

Salt 0.75 kg

Method

The salt was dispersed in the cream (T=20°C) with agitation; The cream and salt were blended with the PHAMF (T=60°C); The mixture was pumped to a scraped surface heat exchanger (churn); The conditons for the SSHE were: Inlet temperature 63°C Inlet pressure 2 bar

Rotor speed 600 RPM

Number of rotor blades 2

Exit temperature 10°C Exit coolant temperature • 10°C

This resulted in a buffer being prepared. The butter was pumped to the pin worker (Kombinator Crystalliser);

The conditions for the pin worker were:

Pin worker speed 300 RPM

Exit temperature 15° C

Pin worker arrangement 3 rows of pins in both stator & barrel

The butter was filled into tubs and rested at 5°C.

Example 3 - reduce fat spreads

Composition Sample 1 Sample 2 25% -water 50% tυater Partially hydrolysed AMF 25.00 kg 10.00 kg Cream 15.00 kg 30.00 kg Salt 0.85 kg 0.65 kg

Sample 1 was produced exactly as per the method of Example 2. The only difference for Sample 2 was the pin worker speed - this was increased from 600 RPM to 750 RPM.

These products produced a stable emulsion with good spreadability.

Example 4

Both AMF and tallow were treated with 0.4%. pearl NaOH for 7 hours at 80°C. The resultant partially hydrolysed fats exhibited a reduction in Slip Melting Point (SMP) of 1.5 to 2°C as well as a significant reduction in percentage solids (by weight) across a range of temperatures.

The results were: SMP°C Percent solids at

10°C 20°C 30°C 40°C

Milk Fat before Treatment 35 46.91 24.87 7.99 ND Milk Fat after Treatment 33.5 36.55 16.53 7.30 0.80

Tallow before Treatment 45.2 44.46 22.7 13.89 5.09 Tallow after Treatment 43.2 35.57 18.06 11.71 3.69

ND means Not Determined

Example 5

AMF, tallow and palm oil were treated with 0.4% pearl NaOH at 80°C for 5 hours. This yielded the following results:

Blend/ 'Oil Type SMP NMR

10°C 20°C 30°C 40°C

AMF before NaOH 36 49.05 19.52 7.46 0.36

AMF after NaOH 29 35. 16 28.2 0.88 0.35

TALLOW before NaOH 44 50.55 29.59 15.91 4

TALLOW after NaOH 41 41.75 22.83 11.39 1.31

PALM OIL before NaOH 39 57.28 31.23 13.23 4.99

PALM OIL after NaOH 38 50.07 24.31 9.53 2.5

GLC analysis was performed on the AMF samples and gave the following results:

AMF

Before After

C6:0 1.4 1.2

C8:0 1 1

C 10:0 2.5 2.5

C 12:0 3 3.1

C 14:0 10.3 10.4

C 14: l 1.2 1.3

C 16:0 29.3 2.8

C 16: l 1.3 1.5

C 18:0 13.4 11.6 C 18: l 24.3 28.3

C 18:2 2.2 2.5

C 18:3 0.9 0.9

C20:0 1.5 1.1

C20: l 0.3 0.2

The treated product had a lower content of palmitic (C 16:0) and stearic (C 18:0) acids, and a higher content of oleic (C 18: 1) acid.

INDUSTRIAL APPLICATION

It is believed that the edible fat compositions according to the present invention will find widespread acceptance in the food industry. The spreadable fat composition, for example, has a reduced solids content at refrigerator temperatures when compared to native non-hydrolysed triglycerides, which makes the composition readily spreadable directly from the refrigerator. In addition, the composition is believed to have a reduced calorific content.

Other applications of the edible fat compositions include use in the preparation of ice creams, and in reduced calorie dairy products such as reduced fat cheeses.

The compositions will also find application in the baking and confection industries.

It will be appreciated that the above description is provided by way of example only and that the precise steps and ingredients used can be modified or replaced without departing from the scope of the invention.

Claims

1. An edible fat composition comprising triglycerides, diglycerides and monoglycerides, wherein said composition has been prepared by partial hydrolysis of a triglyceride-containing composition and wherein said composition contains no or substantially no free fatty acids.

2. An edible fat composition comprising triglycerides, diglycerides and monoglycerides, wherein said composition has been prepared by partial hydrolysis of a triglyceride-containing composition without significant release of butyric acid.

3. A composition according to claim 1 or claim 2 wherein the triglyceride- containing composition is or contains an animal fat.

4. A composition according to claim 3 wherein said animal fat is tallow.

5. A composition according to claim 1 or claim 2 wherein the triglyceride- containing composition is milk fat.

6. A composition according to claim 5 wherein the milk fat is anhydrous milk fat.

7. A composition according to claim 1 or claim 2 wherein the triglyceride- containing composition is or contains a vegetable oil.

8. A composition according to claim 7 wherein the vegetable oil is palm oil.

9. A composition according to claim 1 or claim 2 wherein the partially hydrolysed triglyceride-containing composition has a Solid Fat Index of about 7. 1% by weight at 30°C.

10. A composition according to claim 1 or claim 2 wherein the partially hydrolysed triglyceride-containing composition includes from 34-37% by weight solids at 10°C.

1 1. A process of preparing an edible fat composition, which comprises the step of partially hydrolysing a triglyceride-containing composition under conditions such that a proportion of the triglycerides are converted to diglycerides and monoglycerides but under which the release of significant amounts of free fatty acid is avoided.

12. A process according to claim 1 1 wherein the triglyceride-containing composition is or contains animal fat.

13. A process according to claim 12 wherein the animal fat is tallow.

14. A process according to claim 11 wherein the triglyceride-containing composition is or contains milk fat.

15. A process according to claim 14 wherein the milk fat is anhydrous milk fat.

16. A process according to claim 11 wherein the triglyceride-containing composition is or contains vegetable oil.

17. A process according to claim 16 wherein the vegetable oil is palm oil.

18. A process according to claim 1 1 which comprises reacting the triglyceride- containing composition with a base at a sufficient temperature and for a sufficient time to allow partial hydrolysis of the triglycerides to occur, followed by neutralisation of the partially hydrolysed triglyceride composition with a suitable acid.

19. A process according to claim 18 wherein the base is a strong base.

20. A process according to claim 19 wherein the base is sodium hydroxide, lithium hydroxide or potassium hydroxide.

21. A process according to claim 18 wherein the reaction takes place at a temperature of between 55 and 90°C.

22. A process according to claim 21 wherein the reaction takes place at a temperature of 80°C to 85°C.

23. A process according to claim 18 wherein the reaction is continued for a period of from 2 to 12 hours.

24. A process according to claim 23 wherein the process is continued for a period of from 4 to 10 hours.

25. A process according to claim 23 wherein the process is continued for a period of from 5 to 7 hours.

26. A process according to claim 18 wherein said acid for neutralization is lactic acid.

27. A process according to claim 11 which comprises the following steps:

(a) heating anhydrous milk fat to a temperature of from about 78°C to about 84°C;

(b) adding a base selected from sodium hydroxide, lithium hydroxide and potassium hydroxide, in an amount of from 0.2%-2% by weight of the anhydrous milk fat;

(d) preventing further hydrolysis of the reaction mixture.

28. A process according to clai 27 wherein the milk fat is heated to a temperature of about 80°C during step (a).

29. A process according to claim 27 wherein the base is added in an amount of about 0.4% by weight of the anhydrous milk fat.

30. A process according to claim 29 wherein the base is sodium hydroxide.

31. A process according to claim 27 wherein the temperature of the reaction mixture is maintained at about 80°C to about 85°C in step (c).

32. A process according to claim 27 wherein the temperature is maintained at about 82°C and the reaction time is about 6 hours in step (c).

33. A process according to claim 27 wherein the temperature is maintained at about 82°C and the reaction is continued until the partially hydrolysed anhydrous milk fat has a Solid Fat Index of about 7.1% by weight at 30°C.

34. A process according to claim 27 wherein in step (c) the temperature is maintained at about 82°C until the partially hydrolysed anhydrous milk fat contains from 34-37% by weight solids at 10°C.

35. A process according to claim 27 wherein step (d) is effected through separation of the base from the remaining components of the reaction mixture.

36. A process according to claim 27 wherein step (d) comprises the step of cooling the partially hydrolysed fat to about 50°C.

37. A process according to claim 27 wherein step (d) comprises neutralizing the partially hydrolysed anhydrous milk fat with a suitable acid.

38. A process according to claim 37 wherein the acid is lactic acid.

39. A process according to claim 38 wherein the lactic acid has a concentration of at least about 88% w/v.

40. A process according to claim 27 which includes the additional step of:

(e) treating the partially hydrolysed milk fat to remove any free fatty acids present.

41. A process according to claim 40 wherein step (e) involves washing the partially hydrolysed milk fat in distilled water.

42. A process according to claim 40 wherein step (e) removes any free fatty acids present by vacuum distillation.

43. A process according to claim 40 wherein step (e) removes any free fatty acids present by ion exchange.

44. An edible fat composition comprising triglycerides, diglycerides and monoglycerides but which contains no or substantially no free fatty acids which is the product of a process as claimed in any one of claims 1 1 to 43.

45. A food product which contains an edible fat composition as claimed in claim 1, claim 2 or claim 44.

46. A butter which contains an edible fat composition as claimed in claim 1, claim 2 or claim 44 and which has a Solid Fat Index of about 7. 1 by weight at 30°C.

47. A butter which contains an edible fat composition according to claim 1, claim 2 or claim 44 which contains from 34% to 37% by weight solids at 10°C.