IES63990B2 - A low fat spread - Google Patents

Abstract

A relatively low fat spread which has a relatively low stabiliser content is prepared using a margarine process from a fat phase which includes a fat liquid at room temperature and a fat firm at room temperature and an aqueous phase. The aqueous phase is dispersed in the fat phase to form a water-in-oil emulsion which is subsequently pasteurised and cooled to a temperature of approximately 10°C to 14°C. The water-in-oil emulsion is then subjected to vigorous shearing in a high speed pin mixer at a mixer speed of approximately 700 rpm for a period of 13 secs. prior to packaging. By subjecting the water-in-oil emulsion to vigorous shearing, it has been found that the spread can be stabilised with a significantly lower level of stabiliser than is required for relatively low fat spreads known heretofore.

Description

A low fat spread The invention relates to a method for preparing a water-in-oil emulsion with a relatively low stabiliser content, and in particular, though not limited to a method for preparing such an emulsion with a relatively low fat content. The invention also relates to a method for preparing a spread with a relatively low stabiliser content, and in particular, though not limited to a method for preparing a relatively low fat spread. The invention also relates to a water-in-oil emulsion and a spread prepared according to the method.

Low fat spreads of the water-in-oil emulsion type, such as, for example, spreads of fat content not exceeding 60%, which are suitable for spreading on bread, in general, require a stabiliser to be added to the aqueous phase of the water-in-oil emulsion prior to the preparation of the water-in-oil emulsion. The stabiliser is required to stabilise the spread against phase inversion and/or dispersed phase coalescence during storage. A wide range of stabilisers may be used, and these include hydrocolloides, proteins, starch derived products and vegetable fibres. However, the use of such stabilisers, and in particular, their use in the proportions necessary to adequately stabilise the spread, in general, result in undesirable S6399Q side effects. For example, it has been found that the use of such stabilisers in the quantities required in low fat spreads to prevent phase inversion, in general, retard the meltdown rate and phase inversion of the spread in the mouth. This, thus retards and in some cases prevents release of the flavour components which are included in the aqueous phase. Accordingly, in many cases, the flavouring of the spread can only be vaguely tasted, and in some cases the flavouring is not tasted at all. In order for the flavouring in the aqueous phase to be adequately tasted, it is essential that meltdown of the fat phase should readily occur in the mouth and the emulsion should invert. The presence of stabilisers in the quantities required, in general, delays or prevents meltdown and phase inversion of the emulsion in the mouth. Accordingly, such spreads tend to taste bland, and in many cases leave an unpleasant gummy after-sensation in the mouth.

There is therefore a need for a spread, and a water-inoil emulsion, and indeed, a method for preparing such a spread and water-in-oil emulsion which overcomes these problems, and in particular, permits the preparation of a water-in-oil emulsion in which the stabiliser content required to stabilise the emulsion is sufficiently low to permit relatively rapid meltdown and phase inversion of the emulsion in the mouth. In particular, there is a need for a spread and a water-in-oil emulsion of relatively low fat content in which the stabiliser content required to stabilise the emulsion is also sufficiently low to permit relatively rapid meltdown and phase inversion of the emulsion in the mouth.

The present invention is directed towards providing such a method for the preparation of a water-in-oil emulsion, a method for preparing a spread prepared from the water-in-oil emulsion, and the invention is also directed towards providing a water-in-oil emulsion and a spread prepared according to the method of the invention.

According to the invention there is provided a method for preparing a water-in-oil emulsion with a relatively low stabiliser content using a margarine process, the method comprising the steps of preparing a water-in-oil emulsion by dispersing an aqueous phase in a fat phase, and subjecting the water-in-oil emulsion to vigorous shearing in a high shear mixer.

The advantages of the invention are many. It has been found that by subjecting the water-in-oil emulsion to vigorous shearing in a high shear mixer, a water-in-oil emulsion is provided, which with a relatively low stabiliser content is stable at room temperature, and furthermore, the stabiliser content of the water-in-oil emulsion is sufficiently low to permit relatively rapid meltdown and phase inversion of the emulsion in the mouth. Indeed, it has been found that the stabiliser content required is significantly lower than would be required had the water-in-oil emulsion not been subjected to vigorous shearing. In general, it has been found that the stabiliser content required to stabilise the emulsion using the method according to the invention may be lower by more than 50% of the stabiliser content required to stabilise emulsions prepared using known methods. This is a particularly important advantage where the water-in-oil emulsion is prepared as a relatively low fat spread, typically, a spread, the fat content of which does not exceed 60%, and in particular, spreads in which the fat content does not exceed 40%. It has been found in the past that in order to stabilise such spreads, a relatively high stabiliser content is required which impairs flavour release of flavourings in the aqueous phase, while use of the method according to the invention in preparing such spreads enables the stabiliser content to be reduced sufficiently to permit relatively rapid meltdown and phase inversion in the mouth, thereby permitting the release of flavourings in the aqueous phase. Furthermore, reduction in the stabiliser content avoids an unpleasant gummy after-sensation in the mouth.

It is preferable that the water-in-oil emulsion should be subjected to the vigorous shearing by operating the high shear mixer at a speed of at least 500 rpm.

Preferably, the speed of the high shear mixer should be in the range of 500 rpm to 2,000 rpm, and ideally, the speed of the high sheer mixer should be in the range of 500 rpm to 1,000 rpm.

It has been found, in general, that the water-in-oil 10 emulsion should be subjected to the vigorous shearing for a time period of at least 5 secs., and advantageously, for a time period of at least 8 secs. Ideally, the water-in-oil emulsion is subjected to the vigorous shearing for a time period in the range of 8 secs, to 16 secs. In general, preferred results are achieved when the water-in-oil emulsion is subjected to the vigorous shearing for a time period of approximately 13 secs.

In general, the water-in-oil emulsion is partly crystallised prior to being subjected to the vigorous shearing, and further crystallisation may take place after the vigorous shearing.

In order that the water-in-oil emulsion is at the desired level of part crystallisation prior to being subjected to the vigorous shearing, the temperature of the water-in-oil emulsion is reduced to a temperature in the range of 6°C to 20°C prior to being subjected to the vigorous shearing, and advantageously, the emulsion is cooled to a temperature in the range of 10°C to 18°C. Ideally, the water-in-oil emulsion is cooled to a temperature in the range of 10 °C to 14 °C prior to being subjected to the vigorous shearing.

In general, during the vigorous shearing the temperature of the water-in-oil emulsion will rise, and may rise by as much as 18°C over the temperature of the water-in-oil emulsion just prior to being subjected to the vigorous shearing. In such cases, as the water-inoil emulsion cools subsequent to the vigorous shearing further crystallisation may take place. Where the temperature rise of the water-in-oil emulsion during the vigorous shearing is sufficiently great to require a relatively high temperature drop subsequent to the vigorous shearing, the level of crystallisation occurring during this cooling of the water-in-oil emulsion may require that the water-in-oil emulsion be subjected to further shearing.

It is desirable that the water-in-oil emulsion is cooled to a temperature in the range of 10°C to 16°C after the vigorous shearing.

Preferably, the water-in-oil emulsion is subjected to pasteurisation prior to being subjected to the vigorous shearing.

In general, the water-in-oil emulsion may be subjected to the vigorous shearing in any suitable high shear mixer, however, it has been found that desirable results are achieved by subjecting the water-in-oil emulsion to the vigorous shearing in a pin mixer, and preferably, a high speed pin mixer.

Advantageously, the fats of the fat phase are raised to a temperature at which all the fats are liquid prior to dispersing the aqueous phase therein. Preferably, the aqueous phase is dispersed slowly into the fat phase. Ideally, the fat phase is continuously stirred during dispersion of the aqueous phase therethrough.

While it has been found that by subjecting the first water-in-oil emulsion to the vigorous shearing, the stabiliser content required to stabilise the emulsion is significantly lower than that required using known methods, nonetheless, a stabiliser is still required.

In general, any suitable stabiliser may be used, although, it has been found that desirable results are achieved when the stabiliser is selected from any one or more of the following stabilisers: Sodium Alginate, Low D.E. Maltodextrine, Inulin, Microcrystalline Cellulose, and Pectin.

It has been found that, in general, the stabiliser content required need not exceed the following percentages by weight of the water-in-oil emulsion when only one of the following stabilisers is used: Sodium Alginate 0.7% Low D.E. Maltodextrine 5.0% Inulin 5.0% Microcrystalline Cellulose 1.0% Pectin 0.5% In general, the stabiliser content need not exceed the following percentages by weight of the water-in-oil emulsion when only one of the following stabilisers is used: Sodium Alginate 0.5% Low D.E. Maltodextrine 4.0% Inulin 4.0% Microcrystalline Cellulose 0.75% Pectin 0.4% Indeed, the stabiliser content may be considerably less 5 than those set out above, depending on the other ingredients in the aqueous phase and the fat content of the emulsion.

Additionally, where one or more than one stabiliser is used in the water-in-oil emulsion, the total stabiliser content is selected so as to be sufficiently low to permit relatively rapid meltdown and phase inversion in the mouth, while at the same time being sufficient to stabilise the water-in-oil emulsion.

The aqueous phase may include many ingredients, and some typical ingredients which may be included in the aqueous phase may be any one or more of the following: Proteins, Salt Preservatives Acidulants, and Flavouring Agents.

Generally, the fat phase comprises a fat which is liquid at room temperature and a fat which is relatively firm at room temperature.

Any suitable fat which is liquid at room temperature may be used, however, desirable results are achieved when the fat which is liquid at room temperature is selected from any one or more of the following fats: Rapeseed Oil, Canola Oil, Soya Bean Oil, Olive Oil, Sunflower Oil, Safflower Oil, Fish Oil, and Lower melting point fractions of harder fats.

Any suitable fat which is relatively firm at room temperature may be used, however, desirable results are achieved when the fat which is relatively firm at room temperature is selected from any one or more of the following fats: Hydrogenated Soya Bean Oil, Hydrogenated Rapeseed Oil, Hydrogenated Palm Oil, Hydrogenated Coconut Oil, Hydrogenated Palmkernal Oil Hydrogenated Fish Oil, Coconut Oil, Palmkernal Oil Palm Oil Tallow or Lard Milk Fat, and Fractions of any of the above fats and/or interesterified blends of one or more of the above fats.

The fat phase may also include any one or more of the following ingredients: Emulisifiers, Anti-oxidants, Colourings Vitamins, and Flavouring Agents.

In general, the method is used for preparing a waterin-oil emulsion which has a relatively low fat content, and preferably, the fat content of the water-in-oil emulsion does not exceed 60% by weight of the water-inoil emulsion.

The method according to the invention may be used for preparing a water-in-oil emulsion in which the fat content does not exceed 40% by weight of the water-inoil emulsion, and furthermore, the method may be used in the preparation of a water-in-oil emulsion in which the fat content does not exceed 35% by weight of the water-in-oil emulsion. In general, the method is used for preparing a water-in-oil emulsion in which the fat content is in the range of 30% to 40% by weight of the water-in-oil emulsion, and in particular, where the fat content is in the range of 30% to 35% by weight of the water-in-oil emulsion.

Additionally, the invention provides a method for preparing a spread in which the spread is derived from the water-in-oil emulsion prepared by the method according to the invention.

Further, the invention provides a water-in-oil emulsion prepared according to the method of the invention, wherein the water-in-oil emulsion has a relatively low stabiliser content, and preferably, the stabiliser content of the water-in-oil emulsion is such as to permit relatively rapid meltdown and phase inversion of the emulsion in the mouth, while at the same time, is sufficient for stabilising the water-in-oil emulsion. Ideally, the water-in-oil emulsion is of relatively low fat content.

Preferably, the fat content of the water-in-oil emulsion does not exceed 60% by weight of the water-inoil emulsion. Advantageously, the fat content of the water-in-oil emulsion does not exceed 40% by weight of the water-in-oil emulsion.

In one aspect of the invention the fat content of the water-in-oil emulsion does not exceed 35% by weight of the water-in-oil emulsion.

In another aspect of the invention the fat content of 10 the water-in-oil emulsion is in the range of 30% to 35% by weight of the water-in-oil emulsion.

Additionally, the invention provides a spread prepared from the water-in-oil emulsion according to the invention.

The invention will be more clearly understood from the following description of a non-limiting example.

Example A spread is prepared from a water-in-oil emulsion comprising a fat phase and an aqueous phase prepared using a margarine from the ingredients set out below in the proportions by weight of the water-in-oil emulsion.

Fat phase Rapeseed Oil (liquid at room temperature) 26.6% Hydrogenated Soya Bean oil (firm at room temperature) 12.9% Emulsifier mono and di-glycerides 0.5% Colour beta carotene 0.003% Aqueous phase Water 57.9% Sodium Alginate (stabiliser) 0.5% Salt 1.5% Potassium Sorbate 0.1% The ingredients of the fat phase are placed in a container and raised to a temperature of approximately 45°C to 50°C for melting the hydrogenated soya bean oil, and the ingredients of the fat phase are thoroughly mixed. The ingredients of the aqueous phase are thoroughly mixed in the water and the temperature of the aqueous phase is adjusted to a temperature of approximately 45°C to 50°C to substantially correspond with the temperature of the fat phase.

A water-in-oil emulsion is prepared by slowly dispensing the aqueous phase at a temperature of 45°C to 50°C through the fat phase also at a temperature of between 45°C and 50°C while continuously stirring the fat phase. The water-in-oil emulsion is then pasteurised at a temperature of approximately 80°C by pumping the water-in-oil emulsion through a scraped surface heat exchanger in which the temperature of the water-in-oil emulsion is raised to approximately 80°C. After pasteurisation the water-in-oil emulsion is cooled to a temperature in the range of 10°C to 14 °C in two stages. Initially, the temperature is reduced to approximately 40°C by passing the pasteurised water-inoil emulsion through a water jacketed tubular heat exchanger. The water-in-oil emulsion is then passed through a scraped surface heat exchanger which reduces the temperature from 40°C to between 10°C and 14°C. At this stage the water-in-oil emulsion is partly crystallised, and before further crystallisation can take place, the water-in-oil emulsion is subjected to vigorous shearing in a high shear mixer, which in this example is a high speed pin mixer which is supplied by Gerstenberg and Agger A/S of Denmark under model number Labo Inverter Type 3 Ltr. The water-in-oil emulsion is subjected to the vigorous shearing at a mixer speed of approximately 700 rpm for a time period of approximately 13 secs.

During the vigorous shearing the temperature of the water-in-oil emulsion rises between 6°C and 8°C to a temperature of approximately 20°C. The water-in-oil emulsion is thus subjected to further cooling in a scraped surface heat exchanger which cools the waterin-oil emulsion to a temperature of approximately 12°C. In this particular case, the water-in-oil emulsion is subjected to further shearing after cooling to 12°C in a suitable shear mixer. The water-in-oil emulsion is then suitable for use as a spread and is packed in foil or other suitable packaging.

The spread prepared according to this example was tasted and was found to have a desirable mouth feel, good flavour and left no unpleasant gummy aftersensation in the mouth.

The spread according to the example was compared with a spread which was prepared using identical ingredients to those of the above example and in the proportions of the above example, with the exception that the sodium alginate accounted for 1.2% of the water-in-oil emulsion by weight in order to stabilise the spread.

The method for preparing this spread was identical to that described with reference to the above example with the exception that the water-in-oil emulsion was not subjected to the vigorous shearing in the high speed pin mixer. Rather, after pasteurisation the water-inoil emulsion was cooled to 11°C and subsequently packed. This spread which was not subjected to vigorous shearing was found to lack flavour, and to be rather bland, and also left an unpleasant gummy aftersensation in the mouth when tasted. Further tests have indicated that at levels of sodium alginate below 1.2% the spread is unstable unless subjected to the vigorous shearing in the high speed pin mixer.

In certain cases, depending on the fat blend used in the fat phase, it may be advantageous, and indeed, necessary to further process the water-in-oil emulsion in a conventional pin mixer just prior to packaging for approximately 1 minute at a speed of 100 rpm. It is also envisaged that in many cases shearing after the vigorous shearing imparted by the high speed pin mixer may not be required.

Claims (5)

1. A method for preparing a water-in-oil emulsion with a relatively low stabiliser content using a margarine process, the method comprising the steps of preparing a 5 water-in-oil emulsion by dispensing an aqueous phase in a fat phase, and subjecting the water-in-oil emulsion to vigorous shearing in a high shear mixer.

2. A method as claimed in Claim 1 in which the waterin-oil emulsion is subjected to the vigorous shearing 10 by operating the high shear mixer at a speed in the range of 500 rpm to 2,000 rpm.

3. A method as claimed in Claim 1 or 2 in which the water-in-oil emulsion is subjected to the vigorous shearing for a time period of at least 5 secs. 15

4. A method as claimed in any preceding claim in which the water-in-oil emulsion is cooled to a temperature in the range of 6°C to 20°C and is partly crystallised prior to being subjected to the vigorous shearing.

5. A water-in-oil emulsion prepared according to the 20 method as claimed in any preceding claim, the water-inoil emulsion having a relatively low stabiliser content and a relatively low fat content.