EP0963162A1

EP0963162A1 - Composite ice confections

Info

Publication number: EP0963162A1
Application number: EP97936639A
Authority: EP
Inventors: Donald Reginald Biggs; David Robert Graham Cox; Susan Elaine Jones; Paul Harvey Richardson
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1997-01-08
Filing date: 1997-07-10
Publication date: 1999-12-15
Also published as: GB9700231D0; IN183717B

Abstract

An ice confection comprising a mass of milk containing ice confection and a discrete element of water ice, wherein the water ice is essentially non-sticky and has a composition which in the form of a water ice solution has a rheometry value of more than about 1.0. The ice confection provided has a soft water ice element. The ice confection is provided by a process wherein (i) a mass of milk containing ice confection is contacted with a water ice solution having a rheometry value of more than about 1.0 to cause the water ice solution to adhere to the mass of milk containing ice confection, at least in part in the form of water ice; and (ii) the adhering water ice solution is rapidly cooled to -15 °C or below.

Description

COMPOSITE ICE CONFECTIONS

Technical Field of the Invention

The invention relates to ice confections and their method of preparation. In particular the invention relates to ice confections which comprise a mass of a milk containing ice confection, for example ice cream, with at least one discrete element of water ice which is preferably present as a surface layer covering the mass of milk containing ice confection.

Background to the Invention

A well known ice confection on the market is a traditional split product comprising an ice cream core and an outer layer of water ice on a stick. These products are produced by filling a mould with a water ice solution, cooling the mould such that a layer of water ice is frozen to the mould, removing the still liquid water ice solution from the centre, filling the centre with ice cream, inserting a stick and final cooling to fully freeze the product.

Traditional split products, however, have a number of disadvantages. Primarily the quality of the water ice layer provided is poor. The quiescently frozen water ice layer has large ice crystals which result in a hard icy texture. Furthermore the shape of the product which can be achieved is limited because the product must be able to be removed from the mould, the quality of the ice cream is poor because in order to dose the ice cream into a mould the ice cream must have a sufficiently low viscosity and thus an overrun of greater than 80% is not suitable, in order to de-mould the final product, the product has to be warmed then re-cooled which further lowers the final product quality.

In particular the consumer desires a soft water ice layer of high quality.

To overcome the problems of the traditional split,

WO 95/20883 proposes to produce the water ice layer via a dipping process, whereby the surface of the ice cream core is pre-cooled to -15°C or below to effect the quick freezing of the water ice layer, the water ice layer is then hardened. This method indeed results in products of good quality having a soft water ice layer texture.

However a problem with the process disclosed in WO 95/20883 is that it is generally necessary to dip the ice-cream core more than once in order to achieve a water-ice layer of appropriate thickness.

Furthermore the essential requirement in WO 95/20883 to pre-cool the surface of the ice cream core to -15°C or below prior to dipping in the water ice solution, raises the production costs.

EP 500 940 (Kanebo) discloses a process to provide a two component ice confection having a rugged surface . An ice confection core is dipped into a semi-frozen ice mixture.

EP 560 052 (Nestle) discloses a process for coating a frozen confectionery product which comprises applying a gelatin sol to the confectionery product. The gelatin sol may contain up to 10% gelatin and preferably contains from 1.5 to 3% by weight based on the total weight of the gelatin sol. The gelatin sol is applied by a dipping process, the temperature of the sol being from 10 to 25°C during this dipping process. The coated product may advantageously be re- frozen in a freezing tunnel to complete the setting process if necessary.

The levels of gelatin taught by EP 560 052 for the gelatin sol results in a number of well known disadvantages as described by, for example, US 2,360,559 namely;

(i) The gelatin sol must be at a relatively high temperature during the dipping process which results in some melting of the ice confection core, providing a loss of quality.

(ii) The finished coating has a tendency to become sticky and adhere to the paper in which the ice confection is packaged.

(iii) The product has undesirable eating characteristics

Surprisingly it has been found that if the properties of the water ice solution are carefully selected this significantly widens the possible processing conditions to produce products of high quality having a water ice which is soft, non-icy and has a substantially reduced tendency to stick. Furthermore, the product has excellent eating characteristics.

In particular it has been found if the rheology of the water ice solution is chosen in a specific range, this results in a good quality product which can be produced via a single application step. Disclosure of the Invention

Accordingly the invention relates to a process for producing an ice confection comprising a mass of milk containing ice confection and a discrete element of water ice, wherein;

(i) a mass of milk containing ice confection is contacted with a water ice solution having a rheometry value of more than about 1.0 to cause the water ice solution to adhere to the mass of milk containing ice confection; and

(ii) the adhering water ice solution is rapidly cooled to -15°C or below.

Preferably the water ice solution has a rheometry value of 1.1 to 1.8, more preferred 1.2 to 1.6. A suitable method of measuring the rheometry value is described in the examples .

It is well within the ability of the skilled person to vary the composition and processing of the water ice solution such that the required rheometry value is obtained.

Suitable measures may for example be selected from variation of type and amount of solids, use of thickeners or gelling agents, inclusion of other phases e.g. aeration etc, and mixtures thereof.

Generally speaking the rheometry value will increase if the solids content of the water ice solution increases. For example a low amount of sugar in the formulation will provide low rheometry values, while an increase in sugar level will increase this parameter. Also the inclusion of high levels of fruit puree or other solids result in an increase .

Specific minor ingredients can also be used for increasing the rheometry value. In particular one or more thickeners or gelling agents can be used. Examples of suitable ingredients are for example locust bean gum, xanthan, agar, guar, carrageenan, alginate, pectin, microcrystalline cellulose, gelatin, maltodextrin etc. Levels of these ingredients may be selected to obtain the desired rheometry values. For gelling agents suitable levels are from 0.5 to 1.5 wt%, more preferred 0.65 to 1.2 wt% .

Also the processing conditions of the water ice solution can be adapted to influence the rheometry index. For example aeration of the water ice solution may lead to a higher rheometry value .

The water ice solution is preferably maintained at a temperature at or below 8°C, preferably at or below 5°C. The maintenance of a low temperature has two advantages . Firstly any melting of the surface of the mass of milk containing ice confection on application of the water ice solution is minimised and thus a high quality product is provided. Secondly it is hygienically advantageous to process at cooler temperatures.

In a gelled system the requirement to maintain the water ice solution at a temperature of at or below 8°C, whilst still being able to apply the water ice solution to the mass of milk containing ice confection, is achieved by producing a smooth paste of the gel . The smooth paste is provided by shearing the water ice mixture either during or after gelation. Examples of suitable shearing devices include scraped surface heat exchangers, stirred vessel, spray driers followed by rehydration, static mixers and colloid mills.

Preferably the total soluble solids level of the water ice solution is between l and 70 wt%, most preferred 2-60 wt%. Low soluble solids levels may for example advantageously be used for the formulation of isotonic water ice solutions. While higher soluble solids levels result in more traditional water ice solutions.

Preferably the water ice solution is chosen such that it forms a smooth layer on the mass of milk containing ice confection. For example preferably the water ice solution is substantially liquid and does not contain ice crystals. Typically the water ice solution will be at a temperature above its freezing point. The smooth layer formed on the mass of milk containing ice confection preferably has a thickness of 0.5 to 6 mm, more preferred 1 to 5, most preferred 2 to 4 mm. Also preferably the layer is a single layer and not a composite layer e.g. produced by multiple applications.

The mass of milk containing ice confection contains proteins and this class of products includes, ice cream, frozen yoghurt, sherbet, sorbet, ice milk and frozen custards. The usual form of protein will be animal milk, but vegetable sources e.g. soy milk are also usable. The level of fat in the mass of milk containing ice confection may vary in a broad range, for example 0-3 wt% for zero to low fat products, 3 to 6 wt% for medium fat, 6-10 wt% for creamy products and above 10wt% for super- premium products.

Preferably the mass of milk containing ice confection is aerated to an overrun of 30 to 300%, more preferred 40 to 200%, most preferred 50 to 150%. As stated above, a problem of known ice confection coatings (for example as described in EP 560 052) is that they have a tendency to become sticky and adhere to the inner surface of the wrapper in which the ice confection is packaged. Thus the consumer of the product has difficulty unwrapping the product for consumption.

It is an advantage of the present process that a product is provided that has both excellent eating characteristics and an essentially non-sticky water ice.

In order to achieve the desired water ice properties of softness and reduction of stickiness, it is essential that after contact with the water ice solution, the adhered water ice solution is subjected to a rapid cooling step such that a temperature of -15°C or below is achieved throughout the water ice. By rapid cooling is meant that the cooling environment has a temperature of -50°C or below (inclusive of wind chill factor) , preferably -60°C or below (inclusive of wind chill factor) , most preferably -70°C or below (inclusive of wind chill factor) . Such rapid cooling may be achieved by for example dipping in a liquid cryogen, such as liquid nitrogen, or cooling in a blast freezer. Preferably the rapid cooling is achieved by dipping in liquid nitrogen.

The wind chill factor may be calculated using the following formulation (as used by the US National Weather Service) ;

= 0.045 (5.27.V^0*-^* + 10.45 - 0.28.V).(T - 33) + 33

where T_ωc is the wind chill (°C) , T is the actual temperature (°C) and V is the wind speed (km/hr) . This formula is only applicable at wind speeds above about

7km/hr. Below this speed the actual temperature should be used .

Accordingly the invention also provides an ice confection comprising a mass of milk containing ice confection and a discrete element of water ice, wherein the water ice is essentially non-sticky and has a composition which in the form of a water ice solution has a rheometry value of more than about 1.0.

Preferably the surface of the mass of milk containing ice confection has a temperature of less than -5°C when contacting with the water ice, more preferred less than -8°C, most preferred less than -10°C. Generally the temperature will be more than -40°C, more preferred more than -25°C. Especially preferred for low cost production are temperatures of more than -14 °C, more preferred more than -12°C.

The mass of milk containing ice confection can be contacted with the water ice solution in any convenient manner, for example spraying, dipping, smearing, rolling etc. Most preferred is the dipping of the mass of milk containing ice confection into the water ice solution. Also preferably the core is provided with a stick which can act as a grip during the dipping operation. The discrete element of water ice is preferably present as a layer, most preferably as a surface layer. It is particularly preferred that the water ice solution is contacted with the mass of milk containing ice confection in such a way that a water ice layer is produced which predominantly covers the mass of milk containing ice confection without leaving substantial uncoated areas .

Ice confections according to the invention may contain a number of optional ingredients normally present in ice cream or water ice. Examples of such ingredients are flavouring materials, emulsifierε, stabilisers, colorants etc .

Examples

The invention will now be illustrated by means of the following examples:

Example I

A water ice solution having the following composition was prepared by mixing the ingredients into water at 60°C under gentle stirring:

Ingredient wt%

tropical fruit puree 40 sucrose 17.5 glucose 3.9 additives see below colouring 0.1 citric acid 0.2 water balance

The pick-up (in grams) of various formulations was tested by cooling a shaped block of ice-cream of 52 grams to -34 °C and dipping it for 5 seconds in the mix which was kept at 2°C.

Generally a higher pick-up is indicative of a higher rheometry value. Thus pick-up amounts of approximately 20 to 50g, more preferably approximately 25 to 40g, typically correspond to rheometry values according to the invention. In order to provide a definite answer as to whether a composition has the required rheometry value, the rheometry value can be measured as shown in Example II.

The following additives were tested: Test addit ves weight total pickratio amount up (g) wt%

1 LBG/Carrageenan 3 :1 0.4 15

2 LBG/Carrageenan 1 :1 0.4 15

3 LBG/Carrageenan 1:3 0.4 -

4 LBG/Carrageenan 3 :1 1.0 31

5 LBG/Carrageenan 1:1 1.0 28

6 LBG/Carrageenan 1 :3 1.0 36

7 LBG/Xanthan 3 :1 0.01 10

8 LBG/Xanthan 1 :1 0.01 10

9 LBG/Xanthan 1 :3 0.01 10

10 Xanthan - 0.01 11

11 Pectin - 0.01 16

12 LBG - 1.0 28

13 LBG/Carrageenan 1:2 1.0 35

14 LBG/Carrageenan 1 :5 1.0 43

15 LBG/Carrageenan 1 : 7 1.0 43

16 Carrageenan - 1.0 48

17 LBG/Xanthan 1 :1 0.05 10

18 Guar - 1.0 24

19 Agar - 1.0 11

20 gelatin - 1.0 22

21 Pectin - 1.0 12

22 LBG/Xanthan 1 : 1 0.2 16

23 LBG/Carrageenan 1 :5 0.8 46

24 LBG/Carrageenan 1 :7 0.8 38

25 Carrageenan - 0.8 30

26 LBG/Xanthan 1 :1 0.6 -

27 LBG/pectin 1 :1 1.5 31

28 LBG/Carrageenan 1 :7 0.75 37

29 LBG/Carrageenan 1 :7 0.75 44

30 LBG/Carrageenan 1:7 0.75 34

31 LBG/Xanthan 1 :7 0.6 31

32 Xanthan - 0.6 17

33 Guar/Xanthan 1:7 0.6 18

Notes : test 11 high methoxy pectin; test 21 medium methoxy pectin test 27 low methoxy pectin Example II

The rheometry value can be determined as follows:

A solid stainless steel cylinder having a length of 80mm and a diameter of 38 mm was provided with 1.2 pitch diamond knurl grooves of depth 0.5mm extending for 40mm along the length of the cylinder. A 1.2 pitch knurl defines that the distance between the grooves is 1.2mm. The diamond knurl defines that the grooves intersect to form a diamond pattern. The included angle at the top and bottom apex is 60°, whilst the included angle between is 120° The grooves are at an angle of 30° to the vertical. The cross-section of the groove is triangular, w th a right angle at the tip. The total depth is 0.5mm The remaining 40mm length of the cylinder was smooth.

The cylinder was cooled to 2°C and the patterned end of the cylinder was dipped into the water ice solution at 2°C for 5 seconds. The depth of dipping was 40 mm (i.e. for the full extent of the grooves) . The bottom surface was wiped clean and the cylinder was weighed to determine the amount of water ice solution adhered to it From the surface area of the cylinder (exclusive of grooves), the weight of pick-up and the density of the water ice solution, the average layer thickness adhering to the cylinder is calculated in mm's. This is the rheometry value.

Example Calculation

For a 38mm diameter cylinder of height 40mm, the surface area (excluding the grooves) is 4780mm². If 7g of water ice solution of density 1.1 g cm³ is adhered, the volume of water ice is 6360mm"'. Therefore the rheometry value is

1 3 Example III

An ice cream formulation was prepared of the following composition:

Ingredient wt%

skimmed milk powder 7.7 sucrose 15.3 butter 8.1 flavour/colour 0.1

Cremodan SE019

(ex Daniεco) 0.4 whey powder 2.5 water balance

The ice cream was prepared with an overrun of 60% and extruded through a shaped nozzle to give a cylinder of 52g and a stick was inserted. The ice cream was frozen in a blast freezer such that the surface temperature was -10°C.

The ice cream was then dipped for 5 seconds into water ice solutions at 2°C having the following formulations;

Formulation ( %wt) A B C

Fruit puree 40 .0 45.0 40.0 sucrose 18 .0 18.0 17.5 glucose monohydrate 4. .0 4.0 3.9 locust bean gum 0, .3 0.09 0.14 carrageenan 0. .1 0.66 - guar gum - 0.06 citric acid 0. .2 0.25 0.2 sodium citrate - 0.05 - water - balance ^■ Formulation B was gelled at 2°C. Therefore a smooth paste was produced prior to dipping by shearing the gel in a domestic food blender for approximately 30 seconds.

The adhering water ice solution was then rapidly cooled in a blast freezer operating between -32°C and -34°C (wind speed factor of 5 ms^"1) for 15 minutes (cooling environment of the blast freezer was therefore -5l°C inclusive of wind chill factor) .

The pick-up of the formulations was measured as in Example I. For formulation A the pick-up was 16 g, for formulation B this was 34 g, and for formulation C this was 8g.

The rheometry value for each formulation was measured as in Example II. For formulation A the rheometry value was 0.8, for formulation B 1.4, and for formulation C 0.8.

Formulation B resulted in highly preferred products having a smooth appearance, good thickness of the single water ice layer and with a soft attractive texture.

Formulations A and C resulted in a layer which was too thin after the single dip in water ice solution.

Example IV

Example III was repeated except that the ice cream was cooled to -12°C prior to dipping in the water ice solution.

The pick-up of formulation A (measured as in example I) was 11 g, while for formulation B this was 32 g and for formulation C this was I2g. Formulation B resulted in highly preferred products having a smooth appearance, good thickness of the single water ice layer and with a soft attractive texture.

Formulations A and C resulted in a layer which was too thin after a single dip in the water ice solution.

Example V

A water ice solution of formulation B in Example III was produced and cooled to 2oC. The water ice solution provided was a soft gel -type substance. This gel was sheared for approximately 30 seconds in a domestic blender to form a smooth flowable paste.

Ice cream prepared as in Example III was frozen in a blast freezer such that the surface temperature was -9°C. The ice cream was then dipped for 5 seconds in the water ice solution at 3°C. The adhering water ice solution was then rapidly cooled by immersion in liquid nitrogen for 12 seconds. The product was then wrapped in a waxed paper wrapper and stored at -25°C.

The product did not significantly adhere to the wrapper.

Comparative Example A

Example V was repeated except that the product was not rapidly cooled after immersion in the water ice solution but cooled in a cold store at -25°C.

The resulting product adhered to the wrapper making it difficult to remove the product from its packaging.

Claims

1. A process for producing an ice confection comprising a mass of milk containing ice confection and a discrete element of water ice, wherein;

(ii) the adhering water ice solution is rapidly cooled to -15°C or below.

2. A process according to claim 1, wherein the discrete element of water ice is a layer.

3. A process according to claim 1 or 2 , wherein during step (ii) the mass of milk containing ice confection is dipped in the water ice solution.

4. A process according to any preceding claim, wherein the rapid cooling of the water ice element is achieved either in a blast freezer or by contact with a liquid cryogen.

5. A process according to any preceding claim, wherein the temperature of the water ice solution is at or below 8°C.

6. A process according to any preceding claim, wherein the temperature of the water ice solution is at or below 5°C.

7. A process according to any preceding claim, wherein the rheometry value of the water ice solution is from l.l to 1.8, preferably from 1.2 to 1.6.

8. A process according to any preceding claim, wherein the water ice solution comprises from 0.5 to 1.5 wt%, preferably from 0.65 to 1.2 wt% gelling agent.

9. A process according to any preceding claim, wherein the surface of the mass of milk containing ice confection has a temperature of below -5°C prior to contact with the water ice solution.

10. A process according to any preceding claim, wherein the surface of the mass of milk containing ice confection has a temperature of from -8°C to -14°C, preferably from -8°C to -12°C, prior to contact with the water ice solution.

11. A process according to any preceding claim, wherein the element of water ice is a smooth layer having a thickness of from 0.5 to 6mm, preferably from 1 to 5mm, formed by a single application of the water ice solution.

12. An ice confection comprising a mass of milk containing ice confection and a discrete element of water ice, wherein the water ice is essentially non-sticky and has a composition which in the form of a water ice solution has a rheometry value of more than about 1.0.

13. An ice confection according to claim 12, wherein the water ice has a composition which in the form of a water ice solution has a rheometry value of from l.l to 1.8, preferably from 1.2 to 1.6.

14. An ice confection according to claim 12 or 13, wherein the water ice comprises from 0.5 to 1.5 wt%, preferably from 0.65 to 1.2 wt% gelling agent.

15. An ice confection according to claim 12, 13 or 14, wherein the element of water ice is a single smooth layer having a thickness of from 0.5 to 6mm, preferably from 1 to 5mm.

16. A wrapped water ice confection comprising a mass of milk containing ice confection and a discrete element of water ice, the water ice having a composition which in the form of a water ice solution has a rheometry value of more than about 1.0, wherein there is substantially no adherence between the inner surface of the wrapping and the water ice.

17. An ice confection within a non-adhering wrapping, the ice confection comprising a core mass of milk containing ice confection and thereon a smooth layer of rapidly frozen water ice, the water ice having a composition which in the form of a water ice solution has a rheometry value of at least about 1.0.