UTILISATION D'ALKYL THIAZOLES COMME EXHAUSTEUR D'AROME

USE OF ALKYL THIAZOLES AS FLAVOR ADDITIVES

Abrégé anglais

ALKYL THIAZOLES AS FLAVOR ADDITIVES
Abstract of the Disclosure
2-Isopropyl-4methyl thiazole has been found useful in
impacting or enhancing fruit flavors to foodstuffs.
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Revendications

The embodiments of the invention in which an exclusive property
or privilege is claimed are defined as follows:
1. A flavoring composition comprising, in combination
with other organoleptically active components, an amount
effective to impart or enhance a fruity flavor of 2-isopropyl-4-
methyl thiazole.
2. A foodstuff to which has been added about .0001 to
5% based on the total weight of said foodstuff of 2-isopropyl-4-
methyl thiazole.
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Description

~icneL Case 3
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This invention relates to the use of a specific alkyl
thiazole as a flavor additive to impart a fruit flavor to an
otherwise non-$ruity, edible material or to enhance a fruit flavor
which is already present in a foodstuff.
The compound o~ this invention is 2-isopropyl-4-methyl
thiazole having the formula
CH -C - N
3 ~
H - C C-CH-CH
, \ / I
The thiazole useful in the present invention is not per
se novel. Thus, 2-isopropyl-4,5-dimethyl thiazole and
2-isopropyl-4-methyl-5-ethyl thiazole have been found in potatoes.
The 2-isopropyl-4-methyl thiazole has been identified in roast
meat extract. Additionally, U.S. patent 3,769,040, Swiss patent
548,166 and-German D.T. ~,262,471 have shown various other alkyl
thiazoles as additives for beverages such as coffee and cocoa,
meat products, soup, vegetable and cereals. They are even said
to be useful as flavor addltives for tobacco. U.S. patent
3,660,112 teaches that 2-alkyl thiazoles (3 carbon alkyl and up)
are useful as tomato flavor enhancers.
In accordance with this invention it has been found that
the addition of 2-isopropy-4-methyl thiazole causes significant
and highly desirable improvement or enhancement o~ fruit flavors,
and in particular, peach flavor. This additive is also use~ul
for the enhancement of grape, guave, black currant, grapefruit
and other fruit and berry flavors.
The amount o~ 2-isopropyl-4-methyl thiazole added to a
foodstuff need be only the amount sufficient to impart or enhance
`l~ the desired fruit flavor. Small amounts are effective, though
, the amount can be varied over a wide range depending upon the
flavor strength sought. The use o~ too great an amount is, of
course, economically undesirable and in some cases can unbalance
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the ~lavor and aroma, thus leading to less than optimum results.
Generally, the amount will be between about 0.0001 to about 5~ by
weight based on the foodstuff being flavored.
The novel flavoring agent of this invention can be em-
ployed to enhance the fruit tlavor ot various foodstuffs such as,
e.g., fruit juices or fruit flavored beverages, puddings, pastries
and ice cream. It can also be employed to enhance the fresh fruit
effect of canned and frozen fruits such as, in particular, canned
peaches.
It is very surprising to find that this compound, not
known to be present in fruits naturally, but known to be present
in materials having flavors totally different from fruits, could
be used to enhance fruit flavors.
Although the alkyl thiazole employed in this invention is
naturally occurring and can be isolated from its natural environ-
ment, it is normally more convenient to prepare it synthetically.
This is accomplished by known methods, e.g., 2-isopropyl-4-methyl
thiazole can be prepared by reacting mercaptoacetone with iso-
butyraldehyde in the presence of ammonia followed by oxidation of
the resulting thiazolidine to the thiazole.
Example 1
A. Preparation of 2,5-DihYdro-2-isopropyl-4-methyl Thiazole
A solution of ~00 g. (5.0 moles) of sodium hydroxide in
800 ml. of water was charged to a four-nec~ed 3000 ml. round-
bottomed flask provided with a mechanical stirrer, dropping
funnel, thermometer, gas inlet tube and gas outlet tube. The
; flask was cooIed to 0C. At that temperature the solution was
saturated with hydrogen sulfide and subsequently 416 G. (4.5
moles) of chloroacetone was added in a slow current over ~0
minutes. After the addition, stirring was continued for 2
hours. The li~uid layer was decanted and to the crude solid
mercaptoacetone ~dimer) was added 1000 ml. of water and 302 g.

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(4.2 moles) oL isobutyraldehyde. Gaseous a~monia was introduced
into the mixture for about 8 hours. During this time, the reac-
tion temperature was allowed to reach 60-70C. At the end of
the reaction, the temperature was about 25C. The oily layer
was separated and the water layer was extracted twice with 500 ml.
of water and dried over anhydrous sodium sulfate. The title
compound (460 g.) was distilled at 70-72C. at 12 mm. Hg.
refractive index at 20 1.4948.
B. Preparation of 2-Isopropyl-4-methyl Thiazole
A solution of 43 9. of para-chloranil in 2500 ml. ot
absolute benzene was charged to a four-necked 4000 ml. round-
bottomed flask provided with a mechanical stirrer, dropping
funnel, thermometer and reflux condenser. The mixture was heated
to reflux temperature and at that temperature, 250 g. (1.75
moles) of 2,5-dihydro-2-isopropyl-4-methyl thiazole was added
over a 30 minute period. After the addition, the mixture was
refluxed for 3 hours. The cooled reaction mixture was poured
into 2500 ml. of a 5% sodium hydroxide solution. The organic
layer was separated and the water layer was extracted 3 times
Z0 with 500 ml. of benzene. The combined extracts were washed with
300 ml. of a 5~ sodium hydroxide solution and dried over
anhydrous sodium sulfate. The title compound (197 g.) was
distilled at 56-57C.- at 12 mm. Hg., refractive index at 20
~ 1,4989.
-I Example 2
. f
' f ' Grapefruit Flavor
Grapefruit flavor 60 parts
Ethyl butyrate 8 parts
Ethyl acetate 4 parts
Lemon oi] 8 parts
Orange oil 8 parts
Ethyl alcohol 12 parts

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When about 0.05 to 0.5 part o~ 2-isopropyl-4-methyl
thiazole is added to the above grapefruit flavor, a well-roùnded,
more juicy and peel-like flavor is obtained. When this flavor is
added to a 15~ sugar solution in water, a good tasting, peely,
juicy grapefruit taste is obtained.
Example 3
Peach Flavor
delta-Decalactone 5.0 parts
Ethyl acetate 50.0 parts
Orange oil 2.5 parts
Linalool 2.5 parts
Octyl acetate 2.5 parts
Caproic acid 2.5 parts
Ethyl alcohol 35.0 parts
i When 0.05 to 0.4 part of 2-isopropyl-4-methyl thiazole
is added to the above peach flavor, a peach skin note is imparted
and a generally nice fresh peach flavor is obtained. A 15~ sugar
solution containing 0.25% of the flavor, which includes the 2-
isopropyl-4-methyl thiazole, was made and tested. A fresh, well
rounded peach taste was obtained.