WO1997013413A1

WO1997013413A1 - Aqueous dispersions with hydrolysed starch derivatives

Info

Publication number: WO1997013413A1
Application number: PCT/EP1995/004016
Authority: WO
Inventors: Charles Rupert Telford Brown; Malcolm Glyn Jones; Ian Timothy Norton; Jeffrey Underdown
Original assignee: Unilever NV
Current assignee: Unilever NV
Priority date: 1994-10-10
Filing date: 1995-10-11
Publication date: 1997-04-17
Anticipated expiration: 1998-04-11
Also published as: AU3841295A

Abstract

The invention provides an edible dispersion having less than 50 % by weight of an edible fat phase and a gelled aqueous phase containing a hydrolysed starch derivative with a Dextrose Equivalent of below 2 as a gelling agent. Preferably the hydrolysed starch derivative has a DE between 0.2 and 1.5, more preferably between 0.4 and 0.9. It is advantageous if the hydrolysed starch derivative is present together with at least one other gelling agent and that at least one of the gelling agents is present at a concentration at or above its critical gelling concentration. Especially good results are obtained if the hydrolysed starch derivative is present above its critical gelling concentration and the other gelling agent(s) below its/their critical gelling concentration(s).

Description

Aqueous dispersions with hydrolysed starch derivatives.

The invention relates to aqueous dispersions with hydrolysed starch derivatives. More in particular the invention relates to edible aqueous dispersions containing hydrolysed starch derivatives of low Dextrose Equivalent (DE) as a gelling agent.

Hydrolysed starch derivatives of Low Dextrose Equivalent have been described in US 4,510,166. In this document, the use of low DE starches as fat and/or oil replacers in various foodstuffs has been described. It is indicated that starches not having been modified are preferred. In European Patent Specification no. 554 818, also low DE starches have been described.

In EP-A-398 411 spreads comprising gelatin at 1-7.5 times its critical gelling concentration and optionally another gelling agent such as e.g. hydrolysed starch derivatives below the critical concentration are described. The hydrolysed starch described in particular is Paselli SA2, which is a maltodextrin having a DE of at least 2, and which is used e.g at 2% level, in combination with gelatin above its critical concentration of about 1 wt% on the aqueous phase. The products disclosed in these specifications still have a few problems to be solved. Most gelling agents as e.g. alginate and carrageenan yield elastic gels which are unfavourable in dispersions whereas plastic rheology is required for first quality dispersions and although such gels can be obtained with hydrolysed starch derivatives this usually leads to the complication that a starchy off- flavour becomes clearly noticeable when conventional hydrolysed starch derivatives such as Paselli SA2 , are used above their critical concentration. Other gelling agents like e.g. gelatin are not appreciated by certain groups of consumers like vegetarians. Consequently there has been a need for dispersions comprising gelling systems not suffering from the above disadvantages. The present invention therefore provides dispersions in which at least one of the above noted problems have been solved.

In a first embodiment the present invention provides a dispersion comprising an edible fat phase and an aqueous phase containing a hydrolysed starch derivative with a Dextrose Equivalent (DE) of below 2 and at least one gelling agent other than that, wherein the hydrolysed starch derivative is present at or above its critical concentration.

By hydrolysed starch derivatives are to be understood products obtained by the hydrolysis (using e.g. acid and/or enzymes as catalysts) of starch, but also similar gelling products obtained by synthesis e.g. by enzymatic synthesis in vitro catalysed by the enzyme phosphorylase. Gelling hydrolysed starch products obtained by hydrolysing vegetable starch are preferred. Sometimes it is preferred to remove glucose and/or di- and/or lower polysaccharides from the hydrolysate by fractionation.

The term derivatives also comprises chemically modified products e.g. obtained by esterifying some of the free hydroxyl groups with acetyl groups. Suitable starches are mentioned in, e.g., US 4,510,166 and/or EP 554 818. A hydrolysed starch derivative to be used according to the present invention suitably has a DE between 0.2 and 1.8, more preferably between 0.4 and 1.6 e.g. from 0.5 to 1.2. Hydrolysed starch derivatives which can be used in the practice of the present invention are e.g. product

4679: 35-3 , (sample 91455) having a DE of about 1, ex Natio¬ nal Starch & Chemical Co (NSCC) , Bridgewater N.J. USA;: Dextrin II and 78NN128, ex Staley Manufacturing Co (reported to have DE-values of 1 and 0.6 respectively) and AB 7436 ex Anheuser Busch, St Louis, Missouri, USA (reported to have a DE of 0.5) (Carbohydrate Polymers 6 (1986) 213-244) . The use of such hydrolysed starch derivatives in dispersions leads to improved properties because these starches have lower critical gelling concentrations of say 3% and that when comparing with Paselli SA2, which has a critical concentration of about 10% considerably less is required, resulting in a more cost-effective product having no (or a hardly noticeable) starchy off-flavour and a lower calorie content. This effect is in particular beneficial for fat-continuous spreads.

As with the dispersions of the present invention, the structuring of the dispersion is obtained when applied in amounts as set forth in the claims, the total amount of starch derivative can be kept relatively low, which, in addition to the advantages thereof for taste also provides cost advantages.

The DE-value of the hydrolysed starch derivatives can be determined by various method. The DE values quoted below have been determined by NMR-spectroscopy as described by Gidley, M J in Carbohydrate Research 139, (1985) 85-93 in an article entitled Quantification of the structural features of starch polysaccharides by NMR spectroscopy. It has been established that the data so obtained are in reasonable agreement with the classical "wet chemistry" method described by Nelson, N and Somogyi, M in Journal of Biological Chemistry, 153. 160 and 175 , 61. The NMR-method is the yardstick employed below.

The critical concentration of a gelling agent is the concentration at which that gelling agent will start to form a gel. When applied in a particular composition, the critical concentration is to be calculated from measu¬ rements of the shear modulus of a series of samples con¬ taining different concentrations of said gelling agent as described in Br. Polymer J. _.17 (1985) , 164. The critical concentration of a specific gelling agent in the aqueous phase of the present dispersion is determined in an aqueous system of a similar composition, with the proviso that no other gelling agents are present, and in which system concentration and water content are varied in order to establish the critical concentration.

The dispersion of the invention comprises a gelling agent other than the hydrolysed starch of DE <2. By the presence of such a gelling agent, a further reduced starchy mouth eel, improved flavour release and mouthfeel, ar.d improved melting behaviour is obtainable. Such gelling (not being hydrolysed starch derivatives) agents can be, e.g. gelatin, pectin, alginate, gellan, a carrageenan, fur- celleran etc. Also synergystic gels, i.e. components which are gelling agents when applied in the presence of particular other ingredients, e.g. xanthan, logust bean gum, in the presence of k-carrageenan, and gelling agents such as heat set protein gels are applicable. The use of alginate, gelatin and/or pectin in combination with a gelling hydrolysed starch of low DE-value is preferred. In a preferred embodiment of the invention at least one of the gelling agents is present at a concentration at or above its critical gelling concentration.

If the critical concentration of a combination of gelling agents is to be determined, this is done in a manner analogous to the procedure described outlined above, and whereby the composition of gelling agents considered as if it consisted of one single gelling agent. Accordingly, the composition of gelling agents is kept constant, and the weight concentration thereof is varied as if it consisted of one single gelling agent.

By the preparation of the dispersions according to this invention, a rapid formation of crystal structures can be obtained, and, hence, the preparation of these dispersions provide an advantage in the filling of the containers when compared to the prior art dispersions which crystallize slower. This rapid crystallization in its turn furthermore provides an improved product stability, as the conditions at which the products are set can be controlled better when compared to slower crystallizing dispersions. Accordingly, the invention allows to prepare products of a more constant quality when produced at commercial scale.

The present invention provides aqueous dispersions which are in particular advantageous when applied for the preparation of spreads, such as margarines and the like.

The term dispersion comprising an edible fat phase and an aqueous phase are to be understood as to comprise fat- continuous as well as water-continuous systems. The dispersion may be a fat continuous spread or a water continuous spreads. Dispersions such as very low fat spreads e.g. containing 20% or less of fat, zero fat spreads and spoonable dressings are particularly preferred. "Zero" fat spreads generally contain up to 7 wt% of fat, and are suitably water continuous dispersions. Preferably, the dispersion of the present invention comprises less than 70 wt% fat, and preferably less than 65 wt% fat. In an even more preferred embodiment, the level of fat in the dispersion of the present invention is equal or less than 45 wt% fat, and preferably less than 25 wt% fat. According to another preferred embodiment of the invention a dispersion is provided herein the level of fat is from 0 to 15 wt%, more preferred 0.5 to 10 wt% calculated on the dispersion. The rheological properties of spreads, in particular zero fat spreads are disclosed in detail in EP-A-0, 298 , 561 page 7, lines 46 to page 8, line 31. According to another preferred embodiment of the invention the dispersion provided is a dispersion which is water- continuous and has a fat-level of less than 20 wt%. Important dispersions according to the present invention are water-continuous, (very) low fat spreads containing 0.5 to 20 wt% of fat and dressings containing 0-10 wt% of fat.

The dispersion of the invention may very well contain an emulsifier at the levels of 0.01 to 2 wt% calculated on the weight amount of oil. A highly preferred embodiment of the present invention is a spread which contains an emulsifier at the levels of 0.01 to 2 wt% calculated on the weight amount of oil. The emulsifier system may e.g. comprise mono- diglycerides, citric acid esters of monogly¬ cerides, diacetyltartaric acid esters of monoglycerides, poly-glycerol esters of fatty acids, polyoxyethylene sorbitan esters of fatty acids, sucrose esters of fatty acids, stearoyl lactylates, sorbitan esters of fatty acids, lecithin and mixtures thereof.

The present invention is very useful in a specific group of water-continuous dispersions viz. "spoonable" creams and dressings and the preparation thereof, this type of products is well-known in the United Kingdom. Although the rheological parameters of creams, emulsions etc are defined in P. Sherman, Emulsion Science, Academic Press 1968, the term spoonable is not defined therein. According to our definition, a spoonable cream or dressing should display the following rheological behaviour at 5°C.

1) the yield value (also called yield stress) should be more than 50 Pa extrapolated from shear rates between 1-300 s^~l (Bingham) ;

2) the Bingham viscosity should be less than 500 mPas between shear rates of 100-300 s^"1;

3) the failure to stress should occur at a strain of less than 0.5 radians, preferably less than 0.1 radians. Yield values and Bingham viscosities are determined utilising the Carrimed Rheometer. Measurements are performed at 5°C, using 4° cone and plate geometry with a gap setting of 1 mm. The shear stress is increased from zero at a rate of 60 Pa/min, and shear rates are measured until values in excess of 600 s^'1 are achieved. The experiment is then terminated. A graph of shear stress vs shear rate is plotted, and a straight line fitted to the curve between the shear rates of 100-300 s¹. The slope of this line is the Bingham viscosity. The yield stress is determined by extrapolation of this line back to zero shear rate. The failure to stress measurements are determined utilising the Carri ed Rheometer. Measurements are performed at 5°C, using a 4° cone and plate geometry and a gap setting of 1 mm. The experiments performed are torque sweeps with the rheometer in oscillation mode. The samples are oscillated at a frequency of 1 Hz, as the torque is increased from 50- 5000 μNm in thirty steps. The measurement time at each torque value is 10 sec, and the time between measurements is 5 sec. The parameters measured are storage modulus (G') , loss modulus (G'') and strain in radians. A graph of G' and G'' vs strain is then plotted. At low strain values the samples may display solid-like characteristics, and G ' >G ' ' . At higher strain values G'' > G' and the failure to stress is defined as the strain at which G' = G' ' .

According to another preferred embodiment of the invention the dispersion provided is a spread wherein the fat phase is based on highly unsaturated vegetable oils.

Throughout this specification the terms (edible) oil and (edible) fat are used interchangeably. They are meant to include triglycerides of natural or synthetic origin such as soybean oil, sunflower oil, palm oil, fish oil, rapeseed oil, coconut oil, and hydrogenated, fractionated and/or interesterified triglyceride mixtures as well as edible substances that are physically similar to triglycerides such as waxes, e.g. jojoba oil and poly fatty acid esters of mono- or di-saccharides, and that can be used as replacement for or in admixture with triglycerides.

Preferably the zero fat spreads according to the invention are plastic in the sense that they can be spread onto bread without tearing the bread. Generally plastic spreads will have a stress strain relation with a maximum stress occurring at strain of 0.001-0.5, more preferred 0.01 to 0.3, the maximum stress at this strain being 0.01-100 kPa, more preferred 0.01 to 60 kPa and with a ratio of plastic stress and the maximum stress of 0.1 to 1. A suitable method for determining these values is given in EP 298 561.

In addition to the above mentioned ingredients, spreads of the invention may comprise a number of optional ingredients such as flavouring, salt, preservatives, acidifierε, vitamins, colouring materials etc.

Preferably the level of salt (sodium chloride) is from 0 - 4 wt%, more preferred 0.1 to 3 wt%, most preferred 0.2 to 2 wt%. Preservatives, especially in the case of spreads are preferably incorporated at a level of 0 - 4 wt%, more preferred 0.01 to 2 wt%, most preferred 0.05 to 0.15 wt%. Especially preferred is the use of potassium sorbate. A preferred colouring material is β-carotene; preferred levels of colouring material are from 0 - 1 wt%, more preferred 0.01 to 0.2 wt% . Acidifiers, especially in the case of dressings, may be incorporated to bring the pH of the product to the desired level, preferably the pH of the product is from 3 to 10, more preferred 3.5 to 7. A suitable pH-adjuster is for example lactic acid, citric acid or sodium bicarbonate.

Another optional ingredient for spreads and dressings according to the present invention which may be present in compositions of the invention are proteins. Preferably the protein level (including gelatin) in spreads of the invention iε from 0 to 15 wt%, more preferred, 2 to 6 wt%, most preferred 2.5 to 4 %. Another option is to include dairy proteins, specifically to improve and enhance flavour release and oral texture. In another preferred embodiment of the invention the protein is partially a vegetable protein, especially soy bean protein. For example if mixtu- res of these ingredients are used suitable weight ratios of animal protein to vegetable protein may for example be from 10 : 1 to 1 : 10.

Still very good dispersions of the present invention can be prepared without the use of any gelatin. As the dispersions comprising the hydrolysed starch and gelling agent as set forth in the claims, provide a good texture and mouthfeel, the present invention also allows for the preparation of so called kosher products, not comprising any products originating from animals.

The dispersion of the invention, for example a spread may further contain small particles such as herbs and vegetables. The total level thereof will generally be less than 10 wt%.

Spreads of the preferred invention will generally comprise fairly high levels of water, say from 30 to 88 wt% of the composition, more preferred 40 to 80 wt% , most preferred 50 to 70 wt% . Water may be incorporated as such, or as part of the other ingredients such as milk etc. Such spreads may be fat-continuous in the sense that they comprise a continuous fat phase. Fat-continuous spreads can readily be distinguished from water-continuous spreads by means of conductivity measurements.

Fat continuous dispersions of the invention can suitably be used as bread spreads to replace e.g. margarine or halvarine, but they can also suitable be used as flavoured spread, for example cheese spreads, meat spreads, nut spreads, sweet spreads or vegetable spreads.

Spreads of the invention may be prepared by any suitable method for the preparation of fat-continuous spread products. A preferred method however involves the mixing of the ingredients, optionally followed by pasteurisation followed by cooling in one or more scraped surface heat exchangers (A-units) to a temperature of 0 to 10 °C, optionally followed by processing through one or more

C-units. Pasteurisation is especially preferred for extending the keepability of the product. Generally, the initial mixture is water continuous, during cooling this may be inverted (generally under shear) to a fat-continuous product. Preferably, at least some of the polysaccharide in the aqueous phase is retrograded/gelled prior to phase- inversion to a fat-continuous product. After preparation the spreads are generally packed in wrappers or containers, generally tubs with a content of 2-1000 g will be used, especially 5, 10, 15, 250 or 500 g. Preferably the packed product is stored at refrigerator temperatures.

Dispersions according to the present invention can be prepared in a number of different manners which inter alia depend on the type of product desired.

Dispersions having a continuous fat phase and a dispersed gelled aqueous phase according to the present invention can advantageously be prepared by a process wherein a water- continuous composition, containing at least the hydrolysed starch derivative with a DE value below 2 and one or more other gelling agents is cooled from above the gel setting temperature of the water-continuous composition to below said gel setting temperature and subjected to such conditions of shear that the water-continuous composition is converted into small gelled aqueous pieces, after which a fat-continuous dispersion is formed while maintaining the temperature at below the gel melting temperature. Preferably this process is conducted in such a manner that the water-continuous composition is maintained at a temperature below the gel setting temperature for at least 100 seconds prior to the formation of the fat-continuous dispersion. More preferably cooling regime and residence time employed till the formation of the fat-continuous dispersion are such that under quiescent conditions a gel having a shear storage modulus of more than 50 Pa. , preferably of more than 70 Pa., is formed. The process can be conducted in such a way that the water-continuous composition is converted to small gelled aqueous pieces having a volume weighted mean diameter of less than 150 μm(microns) prior to the formation of the fat-continuous dispersion. Alternatively this process can be conducted in such a way that the water-continuous composition after having been converted to small gelled aqueous beads is combined with a separate fat-continuous stream to form a fat-continuous dispersion.

The invention will be illustrated by the following examples. All parts and percentages mentioned therein are on a weight basis unless indicated otherwise.

Example 1 A very low fat spread (water-continuous) was prepared as follows:

2.5 wt% gelatin (Geltec 250 Bloom) , 7.5 wt% hydrolysed starch derivative

(NSCC product 4679:35-3; sample 91455) , 1.0 wt% NaCl,

0.13 wt% K-sorbate,

0.05 wt% β-carotene (cold water soluble),

6 wt% of double cream, lactic acid to pH 5.0, the balance is water.

The hydrolysed starch derivative was added to water at 80°C, stirred for 10 minutes, then cooled to 60° and all other further ingredients were added. The mixture was passed into an A-unit having an exit temperature of 80°C to pasteurize; the mixture was then cooled down by passage (at 30 g/min) through a series of two A-units, passed through a C-unit and then another A-unit (exit temperature from each unit was 5°C) and finally packed into tubs. A very good starch-continuous product was obtained, which had a favourable texture and flavour perception together with a very low calorie content.

Example 2

A spoonable fat-free dressing was prepared from the following ingredients.

1.000 wt% low methoxy pectin (DE35)

0.250 wt% CaCl₃.2H,0

5.000 wt% hydrolysed starch derivative (NSCC product 4679:35-3; sample 91455)

0.130 wt% potassium sorbate

8.000 wt% sucrose

1.500 wt% NaCl

1.210 wt% flavours 0.009 wt% colour

0.650 wt% acetic acid

82.251 wt% water The pectin was dissolved in deionised water at 85°C. Calcium chloride solution was added to form calcium pectate, followed by the addition of hydrolysed starch derivative and then the remaining dry ingredients such as salt, sucrose and flavour followed. The pH was adjusted to 3.8 with acetic acid and the mixture was cooled through a MicroVotator® A-unit operating at a shaft speed of 3800 rpm, to an exit temperature of 12°C. The product was then cooled and sheared through further A- and C-units to a final temperature of 5°C. The throughput for the process was 50 g/min. A spoonable fat-free mayonnaise with a smooth texture was obtained. The product showed plastic rheology and was opaque/translucent due to the presence of hydrolysed starch derivative and no titanium dioxide needed to be incorporated. The product satisfied the required parameters for a spoonable cream/dressing set out above and had a calorie content which was extremely low.

Example 3

A spread containing 20 wt% of a continuous fat phase and 80 wt% of a dispersed gelled aqueous phase was prepared from a water-continuous emulsion obtained by admixing an oil phase and an aqueous phase of the following composition: Oil phase: fat blend containing 20% soya bean oil,

60% sunflower oil and 20% soya bean oil 19.6 wt% hardened to 44°C; monoglycerides (Hymono 8903) 0.3 wt% flavouring + β-carotene 0.1 wt% Aqueous phase: hydrolysed starch (NSCC product 4679:35-3; sample 91455) 2.0 wt%

Geltec gelatin (Bloom 250) 3.2 wt% NaCl 2.0 wt% potassium sorbate 0.13 wt% water 72.67 wt%

The water-continuous emulsion obtained after mixing of the above two phases at 50°C was pasteurized at 80°C and subsequently (at 50 g/min) passed through two scraped surface heat exchangers (A-units) and two crystallisers (C- units) provided with cooling jackets and filled into tubs. Inversion of the water-continuous emulsion to a fat- continuous dispersion was obtained in the second C-unit.

The fat-continuous spread obtained was found to have a conductivity at 5°C of 10^"5 mSiemen/cm, no starchy off- flavour was noted and the spreadability of the spread was found to be good. The conditions at which the various units were operated are tabulated below:

Exit temp. Rotation Residence (°C) speed (rpm) time

First A-unit 1 500 15 sec

Sec . A-unit 5 500 15 sec

First C-unit 8 1000 180 sec

Sec. C-unit 19 1400 180 sec

Claims

C L A I M S

1. Dispersion comprising an edible fat phase and an aqueous phase containing a hydrolysed starch derivative with a Dextrose Equivalent (DE) of below 2 and at least one gelling agent, wherein the hydrolysed starch derivative is present at or above its critical concentration.

2. Dispersion according to claim 1, wherein the hydroly¬ sed starch derivative has a DE between 0.2 and 1.8, preferably between 0.4 and 1.6.

3. Dispersion according to claim 1 or 2, wherein at least one of the gelling agents present is present at a concentration at or above its critical gelling concentration.

4. Dispersion according to any one of claims 1-3, wherein the dispersion comprises less than 70 wt% fat, and preferably less than 65 wt% fat.

5. Dispersion according to claim 4, wherein the level of fat is equal or less than 45 wt% fat, and preferably less than 25 wt% fat.

6. Dispersion according to claim 5, wherein the level of fat is between 0-15 wt%, and preferably between 0.5 to 10 wt%

7. Dispersion according to any one of the claims 1-6, wherein the dispersion contains an emulsifier at the levels of 0.01 to 2 wt% calculated on the weight amount of oil.

8. Dispersion according to any one of the claims 1-7, wherein the dispersion is a fat-continous spread.

9. Dispersion according to any one of the claims 1-7, wherein the dispersion is a water-continuous spread having a fat-level of less than 20 wt%.

10. Dispersion according to any one of the claims 1-9, wherein the fat is based on highly unsaturated vegeta¬ ble oils.