Food or edible material: processes – compositions – and products – Products per se – or processes of preparing or treating... – Foam or foamable type
Reexamination Certificate
2000-03-09
2003-05-20
Bhat, Nina (Department: 1761)
Food or edible material: processes, compositions, and products
Products per se, or processes of preparing or treating...
Foam or foamable type
C426S101000, C426S656000, C426S660000
Reexamination Certificate
active
06565908
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The invention relates to novel ice confections. In particular the invention relates to novel ice confections containing an antifreeze protein.
BACKGROUND TO THE INVENTION
It is highly desirable to be able to manufacture ice confections having novel shapes, properties and/or textures. Until now, however the ability to provide such a high degree of novelty and interest to the products has been limited. In particular products have to be manufactured with the ability to survive packaging, storage and distribution.
We have now shown that inclusion of specific antifreeze proteins into selected ice confections results in the formation of a strong, close-packed continuous network of ice crystals within the ice confection. As a result the ice confection is provided with specific defined mechanical properties. Such ice confections have novel textures and/or properties. The novel features can be retained during packaging, storage and distribution.
WO 98/04146 (Unilever) discloses that AFPs can be incorporated into frozen food products such as ice confections to provide desirable product properties providing that the product and processing conditions are varied such that the ice crystals provided in the product have an aspect ratio of more than 1.9, preferably from 1.9 to 3.0. The specific examples given are all aerated ice cream compositions. As shown by comparative Examples A to C below, the addition of antifreeze proteins to aerated ice cream does not significantly change the mechanical properties of the ice cream. WO 98/04146 does not teach that it is possible to provide specific ice confection products having novel mechanical properties.
WO 96/39878 (The Pillsbury Company) discloses a method for making a frozen composition for storage, the method not requiring a hardening step prior to storage. The frozen composition contains an antifreeze protein, in particular Type I AFP. Examples show the preparation of an aerated ice cream and an aerated frozen yogurt. As shown by comparative Examples A to C below, the addition of antifreeze proteins to aerated ice cream does not significantly change the mechanical properties of the ice cream. WO 96/39878 does not teach that it is possible to provide specific ice confection products having novel mechanical properties.
U.S. Pat. No. 5,118,792 (Warren et al) discloses the addition of fusion proteins, and in particular the fusion protein protein A-Saf5 into foods which are to be consumed frozen, for example, ice cream, frozen yogurt, ice milk, sherbet, popsicles and frozen whipped cream. No examples are given where a final ice confection product is provided containing such fusion proteins. It is shown in Example 3B that when a popsicle formulation is used within the “splat assay”, growth of the ice crystals is restricted.
Surprisingly we have now found that the addition of specific antifreeze proteins to defined ice confections, for example to water ices, ice milks, and unaerated ice cream, results in the formation of a strong, close-packed continuous network of ice crystals within the ice confection providing significant, advantageous changes to the mechanical properties of the ice confection.
DISCLOSURE OF THE INVENTION
Accordingly the invention provides an ice confection comprising an antifreeze protein, wherein
&Dgr; modulus/original modulus ≧0.4, and/or
&Dgr; strength/original strength ≧0.4, providing that when
&Dgr; modulus/original modulus ≦6.0, &Dgr; modulus ≧50 MPa, and/or when &Dgr; strength/original strength ≦2.0,
&Dgr; strength ≧0.2 MPa.
Preferably &Dgr; modulus/original modulus ≧0.4; providing that when &Dgr; modulus/original modulus ≦6.0, &Dgr; modulus ≧90 MPa. Most preferably &Dgr; modulus/original modulus ≧1.0; providing that when &Dgr; modulus/original modulus ≦6.0, &Dgr; modulus ≧100 MPa.
Preferably &Dgr; strength/original strength ≧0.7. Most preferably &Dgr; strength/original strength ≧1.5.
By modulus is meant the apparent elastic modulus (E) as determined using a four point bend test. Example 1 gives the standard procedure for performing a four point bend test.
Therefore &Dgr; modulus (&Dgr;E) means the change in modulus between two ice confections whose formulation and process of manufacture are identical in all respects except that the first ice confection includes in its composition an antifreeze protein, and the second ice confection has no antifreeze protein included in its composition (the control composition). Original modulus (E
orig
) is the modulus measured in the control composition.
By strength is meant the flexure strength (&sgr;
u
) which can be defined as the maximum stress that a material can withstand, under the particular conditions. The flexure strength is given by the stress at a point of maximum force on the force versus displacement curve recorded during a four point bend test.
Therefore &Dgr; strength (&Dgr;&sgr;
u
) means the change in strength between two ice confections whose formulation and process of manufacture are identical in all respects except that the first ice confection includes in its composition an antifreeze protein, and the second ice confection has no antifreeze protein included in its composition (the control composition). Original strength (&sgr;
u orig
) is the modulus measured in the control composition.
In addition to changes in the apparent elastic modulus and flexure strength, an increase in product hardness is provided by the ice confections according to the invention. For ice confections frozen with agitation, for example in an ice cream freezer (such as a scraped surface heat exchanger), the increase in hardness can be measured using the Vickers hardness test. Details of the Vickers hardness test are given in Example 3.
The degree to which the Vickers Hardness (H
v
) of the ice confection is increased by the addition of the antifreeze protein depends in part on the ice content of the ice confection.
However, generally &Dgr;H
v
/H
v orig
≧0.3, providing that when &Dgr;H
v
/H
v orig
≦5.0, &Dgr;H
v
≧0.3.
Preferably &Dgr;H
v
/H
v orig
≧1.0, providing that when &Dgr;H
v
/H
v orig
≦5.0, &Dgr;H
v
≧1.25.
Most preferably either &Dgr;H
v
/H
v orig
≧6.0 or &Dgr;H
v
/H
v orig
≦6.0 and &Dgr;H
v
≧2.0.
Where &Dgr;H
v
is the change in Vickers Hardness between two ice confections whose formulation and process of manufacture are identical in all respects except that the first ice confection includes in its composition an antifreeze protein, and the second ice confection has no antifreeze protein included in its composition (the control composition). H
v orig
is the original Vickers Hardness measured in the control composition.
By close-packed continuous network of ice crystals is meant that any given ice crystal is connected to at least one other ice crystal.
In unaerated ice confections which have been frozen with agitation, the degree of network formation can be measured as contiguity. Contiguity is defined as the ratio of the particle to particle interface area divided by the total interface area. It is thus a measure of the degree of network formation of the particle phase. Example 4 shows a method for the measurement of contiguity.
Unaerated ice confections according to the invention have a contiguity of at least 0.2, as measured by the test given in Example 4, for an ice content of from 50-90%, preferably 54-85% by weight, when measured at −18° C.
In unaerated ice confections which have been frozen by any means, the degree of network formation can be measured as the Euler-Poincare characteristic of the ice phase. The Euler-Poincare characteristic is a measure of the degree of network formation of a particular phase. The lower and more negative the value of the Euler-Poincare characteristic, the greater the continuity of the phase in question. Example 5 shows a method for the measurement of the Euler-Poincare characteristic.
Unaerated ice confections according to the invention have an ice phase Euler-Poincare characteristic of less than −150 mm
−2
as measured by the test
Daniel Adrian
Hoddle Andrew
Jones Anabela
Oldroyd Jon Richard
Singleton Scott
Bhat Nina
Good Humor-Breyer's Ice Cream, division of Conopco, Inc.
McGowan, Jr. Gerard J.
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