ESTER METHYLE DE L-ASPARTYL L-PHENYLALANINE EMPLOYE DANS LES BREUVAGES STABLES DURANT L'EMMAGASINAGE

METHYL ESTER OF L-ASPARTYL L-PHENYLALANINE IN STORAGE-STABLE-BEVERAGES

Abrégé anglais

ABSTRACT OF THE DISCLOSURE
The dipeptide sweetener, APM, is stabilized in liquid
comestibles over a pH flavor range of 2.3-7.0 by concentrating
the ester in a solution while freezing the solution to produce
discrete water ice crystals, thereby providing a stable water-
based edible concentrate having a storage stability in terms of
sweetness retention and avoidance of undesirable reactions in
excess of 16 weeks when the composition is maintained under frozen
storage.

Revendications

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:
1. An aqueous comestible of pH 2.3 to 7.00 in frozen form
containing as sweetener methyl ester of L-aspartyl-L-phenylalanine
wherein there are two phases of frozen material one of which has
a greater concentration of ester than the other.
2. A comestible according to claim 1, wherein the pH is
from 2.3 to 5.9.
3. A comestible according to claim 2, wherein the pH is
3.0 to 4.4.
4. A comestible according to any one of claims 1 to 3,
which is a fruit flavored beverage.
5. A method of producing a stabilized aqueous comestible
of pH 2.3 to 7.00 containing in solution as sweetener a methyl
ester of L-aspartyl-L-phenylalanine, wherein the solution is
cooled at a rate which crystallizes part of the aqueous system
to a solid with lower concentration of ester than the solution to
increase concentration of ester in the unfrozen phase and there-
after the entire solution is frozen and is stored at below freez-
ing point.
6. A method according to claim 5, wherein the pH is from
2.3 to 5.9.
7. A method according to claim 5, wherein the pH is from
3.0 to 4.4.

Description

~l~S~ 2
This invention relates to frozen aqueous comestibles.
The dipeptide sweetener APM, that is, ~he methyl
es~er of L-aspartyl L-phenylalanine i8 a most attractive
æweetening compound having advantages over the more conven-
tional sweeteners, for example saccharine or cyclam~tes. The
sweetness impact which would be of use dictates the desirabili-
ty o using such an ester in a beverage, typically a fruit
flavored beveragel having an acid pH. The prior art workers
~ave suggested that APM would have utility and stability in
aci aif iea solutions part-cala~ly ~he~ stored u~der r~frigera~e~
conditions, i.e. 35F. However, the stability aforded is
limited. Ester solutlons at e~en an optimum pH reported,
namely, 2.0-4.0, undergo a distinct loss in sweetness with
or without the decomposition of the ester as measured by
the presence of diketopiperazine ~KP) or other decomposition
products such as the amino acids, aspartic acid and phenyl-
alanine; the prior art workers have generally associated de-
composit~on with the aatual assay for DKP and have measured
the presence of methanol as a means for measurement thereof.
Nevertheless, refrigera~ed storage stability is
quit~ limited being in the order of less than a few months
and more typically in the order of about 4-5 weeks.
Accordingly, workers prior to the invention have viewed the
stability o APM to be such as to require its use in comes-
tibles having a reduced moisture content.
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The present invention is founded on the discovery
that an aqueous solution of the APM estl_r in beverage comes-
tibles, ranging from normal consumable concentrations to di-
lutable concentrates, is stabilized by causing the solution
to undergo a gradual temperature reduction to the point whereat
discrete water ice crystals are formed and ultimately the
beverage composition is converted into a solid or semi-solid
form.
According to the invention there is provided an
aqueous comestible of pH 2.3 to 7.00 in frozen form containing
as sweetener methyl ester of L-aspartyl-L-phenylalanine
wherein there are two phases o frozen material one of which
has a greater concentration o ester than the other.
There is also provided a method of providing a
stabilized aqueous comestible o pH 2.3 to 7.00 containing
in solution a5 swPetener a methyl ester of L-aspartyl-L-
phenylalanine wherein the solution is cooled at a rate which
crystallizes part of the a~ueous system to a solid with lower
concentration o ester than the solution to increase concen-
tration of ester in the unfrozen phase and thereater the
entire solution is rozen and is stored at below freezing
point.
The APM ester is stabilized almost indefinitely
so far as present experimental evidence indicates provided
tempera~ures are maintained below the freezing point of the
solvent phase in the beverage composition. Experiments to
date indicate that fruit flavored bever~ge compositions,
optimally having a pH in the range of 3.0-4.4, and generally
in the range of 2.3-5.9 are advantageously stabilized for
0 periods of a year when such compositions are stored at tem-
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peratures below 0C.; a broad operable range is believed to
range upwardly to pH 7. a.
The mechanism whereby this stabilization occurs i~
not understood. It is theorizdd that the equilibrium of the
ester is maintained by causing the a~ueous solution in which
it is present to undergo a form of freeze concentration in
that the water ice crystals thereof that are formed produce
an ever increasing enriched concentrate in terms of the ester
content; equilibrium stability occasions a minimal cleviation
from the intended form of the ester, i.e. the methyl ester
of aspartyl phenylalanine with a minimum generation of de-
composition products.
The invention has a number of applications ranging
from slush concentrates which normally would contain sucrose
but which have substituted therefor concentrations of APM
providing equivalent sweetnesses and such slush beverage com-
positions may have a number of freezing point depressing
agents added thereto inclualng the natural or artificial
acidulents typically in the conventional beverage food acids,
phosphoric acid, citric acid, malic acid which serve to
depress the freezing point. The invention does not require
any speciic critical observance of a formulation to achieve
a freezing point so far as is presently determined.
Moreover, the means whereby the ester concentrati~n
in the solute phase is affected does not appear to call for
any criticality and thus any means may be employed which
result in a partial crystallization of the water to discrete
water ice crystals with a resultant ester concentration in
the unfrozen aqueous solvent; the ester content will be con-
0 siderably increased over that in the solute phase initially--4--
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~s~
generated upon reezing. So far as is presently known, the
preservative effects of freezing are provided in slush con-
centrates as well as solid or semi-solid foxms such as pops
and spoonable beverayes.
The most preferred and economical uses of the in-
vention will involve the complete substitution of the e~ter
for the sweetening saccharides that are normally used in the
beverage and thus will provide the ability to reduce caloric
values of the beverage.
It is important in retaining the stability of the
ester-containing solution that it be maintained during storage
in packaging, distribution or preparatory to home consumption
at a temperature substantially below 0C., depending upon the
freezing point of the solution.
The number of applications in which this invention
will find use range from single to multi strer.gth concentrates,
either carbonated or non-carbonated, gelatin-containing solu-
tions useful as dessert gels, sherbets and even shakes which
are based on milk or other proteinacPous by products. Like-
wise other compositions such as jams and jellies may be
similarly formulated and take advantage of the present inven-
tion with a total or partial substitution of the saccharide
by the ester.
Accordingly, it will be:understood in accordance
with thi~ invention that the term comestible is intended
to apply to a wide range o~ alimentary compositions adapted
to be consumed in a liquid or semi-liquid state and wherein
the ester is a sweetening part o~ the aqueous phase.
EX~MPLE
A spoonable beverage concentrate is formulated as
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~ollows
PREMIX
Ingredient Per cent
Water 90,73
Colloidal Thickener 4.5Q
Cottonseed Oil 2.90
Color 0.10
Vitamin A 0.03
Orange Flavor 1.74
100.00
DRY BLEND
~, _
Ingradient Per cent
Citric Acid 70.61
Citrate/Phosphate Buffer (1=1) 15.64 ::
Vitamins (A,B,C) 6.78
Sodium Carboxymethyl Cellulose 3.30
APM 3.67
100.00
FINAL MIX
Ingredient Per Cent
Sugar Syrup 18.33
Corn Syrup 7.50
Water 37.40
Orange Pulp 8.37
Premix 22.16
Dry Blend 6.24
100.00
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PREPARATION PROCEDURE
1. Weigh out premix ingredients.
2. Make thorough blend of premix ingredients and
homogenize at 3500 psi~
3. Weigh dry blend ingredients. Mix in until
thoroughly blended.
4. Weigh ingredients for final mix.
5. Mix the dry blend into part of the water from the
final mix, then combine all remaining ingredients.
6. Freeæe finished concentrate at a rate initially
permitting formation o ice crystals, then grind
in commercial meat grinder, Speed No. :L, using
3/8" plate opening. Fill into cans, seal and place
in freezer.
Thus, the premix ingredients were thoroughly blended
and then homogenized at 3500 psi. The dry blend was then
mixed into part of the water for the final mix and then all
of the remaining ingredients including the premix were com-
bined until an essentially stabilized emulsified solution
was produced. This solution was a concentrated oxange
flavored sweet preparation. The concentrate was frozen at
the specified rate and then ground and charged to cans and
sealed. The frozen concentrate was stored for 12 months
and evaluated after storage at 0F. and 15F. The product~
versus the control was found to possess an acceptable flavor
and did not evidence any substantial loss in swee~ness
despite the extended storage under refrigerated conditions.