CA1208966A

CA1208966A - Foodstuffs containing sweetness modifying agents

Info

Publication number: CA1208966A
Application number: CA000432334A
Authority: CA
Inventors: Ronald E. Barnett; Ronald G. Yarger
Original assignee: General Foods Corp
Current assignee: General Foods Corp
Priority date: 1983-07-13
Filing date: 1983-07-13
Publication date: 1986-08-05

Abstract

FOODSTUFFS CONTAINING SWEETNESS MODIFYING AGENTS ABSTRACT Food acceptable sweetness modifying compounds comprising certain aromatic hydroxy acids and food-stuff compositions containing the same.

Description

~Z~ 66 This invention relates generally to sweetness modification and more particularly to low-caloric compounds, particularly well suited as sweetness modifiers in edible foodstuffs.
Sweetness is one of the primary taste cravings of both animals and humans. Thus, the utilization of sweetening ayents in foods in order to satisfy this sensory desire is well establishedO
Naturally occuring carbohydrate sweeteners, ` such as sucrose, are still the most widely used sweetening agents. While these naturally occurring carbohydrates, i.e. sugars, generally fulfill the requirements of sweet taste, the abundant usage thereof does not occur without deleterious con-sequences, e.g. high caloric input, dental decay and nutritional imbalance. In fact, often times the level of these sweeteners required to satisfy taste in foodstuffs is far higher than that level of ~sweetener which is desired for economic, dietetic or other functional considerations.

., 3o 8~66 --2~

1 In an attempt to eliminate the disadvantages concomitant with natural sweeteners, considerable research and expense have been devoted to the pro-duction of artifical sweeteners, such as for example, saccharin, cyclamate, dihydrochalcone, aspartame, etc. While some of these artifical sweeteners satisfy ~he requirements of sweet taste without caloric input and have met with considerable com-mercial success, they are not, however, without their own ir~erent disadvantages. For example, many of these artifical sweeteners have the disadvantages of high cost of production, as well as delay in perception of the sweet taste, persistent lingering of the sweet taste~ and very objectionable bitter, metallic after-taste when used in food products.
Since it is believed that many of the dis-advantages of artificial sweeteners, particularly after-taste is a function of the concentration of the sweeteners, it has been previously suggested, that these effects could be reduced or eliminated by combining artificial sweeteners, such as saccharin, with other ingredients or natural sugars, such as pectin, sorbitol, dextxose, maltose, etc. These combined products, however, have not been entirely satisfactory eith~r. Some U.S. patents which dis-close sweetener mixtures include, for example, U.S.
Patent No. 4,228,198, U.S. Patent No. 4,158p068, U.S. Patent No. 4,154,862, U.S. Paten~ No. 3l717,477 More particularly, U.S. Patent No. ~,228,1g8 3 discloses a sweetening composition comprised of a protein sweetener, saccharin or cyclamate in com-bination with a-sweetness modifier, namely arabino-galactan. The patentee states that the arabino-12~3966 l galactan enhances the overall sweetness of thecomposition and reduces or eliminateS the after taste.
u.s. Patent No. 4,158,068 discloses a sweetener mixture having an improved saccharose-like taste consisting of acetosulfame and at least one sweet-ener from the group of aspartyl peptide ester, the sulfamate sweeteners, the sulfimide sweeteners and diydrochalcone sweeteners.
Mixtures of artificial sweetners, such as saccharin and the like, and neodiosmin are dis-closed, in U.S. Patent No. 4,154,862, to be of reduced bitterness and after taste.
U.S. Patent No. 3,717,477 discloses that the sweeteniny potency and taste of sodium saccharin are improved by the addition of small amounts of optic-ally active D-tryptophan.
The use of sweetening agents in foods to pro vide functions other than sweetening, such as to act as fillers, bulklng agents, antimicrobial agents, freezing point depressants, stabilizers, etc. is also well established. For example, U.S. Patent No.
3,5~7,235 discloses a composition, useful or pre servin~ the color of meat, comprising ascorbic acid and a compound selected from the group consisting of para-aminobenzoic acid, m-aminobenzoic acid, is-onicotinic acid and N-ethylnicotinamide, wherein dextrose is optionally employed as a carrier to provide a more unifonm distribution of the pre-serving composition in and on the meat.
U.S. Patent No. 2,752,332 and U.S. 2,709,657disclose 2~amino-3-hydroxy-benzoic acid or its esters as antioxidants and/or stabilizing agents for certain vegetables. Other U.S. patent including U.S. 3,876,814, U.S. 3,952,058, U.S. 3,845,225 and 12~B966 ~ .

1 U.S. 3,876,816 dlsclose certain aromatic amino compounds as sweeteners. That is, U.S. 3,876,814 and 3,952,058 disclose 3-amino-4~n-propylbenzyl alcohol as a non-nutritive sweetener for foods and beverages. U.S.3,845,225 discloses compounds of the formula O - ( CH2 ) nBr ~\ NH2 as O , sweetening agents for foodstuffs, while U.S. 3,876,816 discloses inter alia, 2-amino-4-nitrobenzoic acid as a sweetener.
Many times the amount of sweetening agent employed for these alternate functions provides an excessively sweet taste, thereby requiring a modi~ica~ion of ~he formulation to reduce the sweetener level with a concurrent reduction in providing the alternate function to the food pro-duct. One unsuccessful solution of the art was to add bitter or acidic ingredients to the food to reduce the sweetness pexception; however, the result-ant ood then had an undesirable bitter or acidic taste. W. Jakinovick, Jr. Science, Vol.219, p 408-410 (1983)- discloses methyl 4, 6-dichloro-4, 6-dideoxy-a-D-galactopyranoside to inhibit sweet taste response in gerbils when the compound is combined with sucrose or saccharin.
Accordingly, in view of the aforemention~d 3 disadvankages associated with the use of known sweeteners, i.e., naturally occurrin~g, artificial or combinations thereof, it be~omes readily apparent that it would be highly desirable to (a) provide a sweetness modifying agent which when added to food-stuffs can greatly reduce the level of deleterious sweetener normally required and concomitantly elimi-~Z~96~

1 nate or greatly diminish the numerous disadvantages associated with prior art sweeteners or (b) provide sweetness inhibiting agents which are non-caloric, which do not result ln off-tastes and which when 5 added to foodstu~fs reduce the level of sweetness perceived wlthout a concurrent reduction in the desirable properties of the foodstuff.
The present invention provides food-acceptable sweetness modifying compounds, i.e. sweet~ners or sweetness inhibitors, 10 which when added to a foodstuff and depending upon the particular compound employed, increases or inhibits the sweet taste perceived from the food-stuff, said food acceptable sweetness modifying compounds having the general formula:
(i) A (ii) A

R3 ~ Y or R2 $ Y

wherein:
A is an acid group of the structure ~ZOqHr or salt thereof wherein Z is an element selected from 25 the group consisting of carbon, sulfur, boron and phosphorus, q is an integer from 2 to 3 and r is an integer from 1 to 3;
Y is OH or salt thereof;
R~ R2 and R3 is independently selected from the group consisting of H, alkyl from 1 to 3 carbons, cyclopropyl, OH, OCH3, OCH2CH3, CH20CH3, CH2CH20H, .. CH(CH3)CH20H, CHO, COCH3, CH2CHO, COOH, CH2COOH, COOCH3, OCOCH3, CONH2, NHCHO, F, Cl, Br, I, CF3, 35 SCH3, SCH2CH3, CH2SCH3, S03H, S02NH2, S02CH3, SOCH3, CH2S03H and CH2SONH2; and with the provision that in ~2~6~;

l structure tii~ when A is COOH, Rl, R2 and R3 are not all hydrogen.
In accordance with the present invention, it has been surprisingly discovered that the sweet taste perceived in a food product can be greatly modified, i.e. sweetened or inhibited, by the addi-tion of the food product of a compound within cer-tain classes of compounds desribed in more detail hereinafter .
Thus, according to the present invention it has been unexpectedly found that certain compounds, described in more detail hereinafter, are effective sweetness modifiers with any of a number of known ; natural and/or artificial sweeteners including, for example, sucrose, fructose, corn syrup solids, dextrose, xylitol, sorbitol, mannitol, acesulfam, thaumatin, invert sugar, saccharin, cyclamate, dihydrochalconer aspartame (L-aspartyl-L-phenyl-~ alanine methyl ester) and other dipeptides, glycyr-rhizin, stevioside and the like.
Typical foodstuffs, including pharmaceuticalpreparations, in which the sweetness modifiers of thé present invention may be used are, for example/
beverages including soft drinks, carbonated bever-ages, ready to mix beverages and the like, infusedfoods (e.g. fruits or vegetables), sauces, condi-ments, salad dressings, juices, syrups, desserts, including puddings, gelatin and frozen desserts, like ice creams, shexbets, and icings, confections, toothpaste, mouthwashes, chewing gum, intermediate moisture foods (e.g. dog foods) and the like.
: More speGifically the' sweetn~ss modifying agents of this invention have the general formula:

1 (i) A (ii) A

R2 ~ or R2 ~ Y
R R

Wherein:
A is an acid group of the structure ~ZO~Hr or salt thereof wherein Z is an element selected from the group consisting of carbon, sulfur, boron and phosphorus, ~ is an integer from 2 to 3 and r is an integer from 1 to 3;
Y is OH or salt thereof;
Rl, R2 and R3 are independently selected from the group consisting of ~, alkyl from 1 to 3 car-bons, cyclopropyl, OH, OCH3, OCH2CH3, CH20cH3, CH2CH20H, CH(CH3)CH20H, CHO, COCH3, CH2CHO, COOH~
CH2COOH, COOCH3, OCOCH3, CONH2, NHCHO, F, Cl, ~r, I, CF3, SCH3, SCH2CH3, C~2SCH3, S03H, S02NH2, S02CH3, SOCH3, CH2S03H and CH2SONH2; and with the provision that~in structure (ii) when A is COOH, Rl, R2 and R3 are not all hydrogen.
Food acceptab7e non-toxic salts of the above-identified sweetness modifying agent of th epresent invention are contemplated. These salts include acid salts for example carboxylate as well as hydroxylate salts. Acid salts and/or hydrcxylate salts include, sodium, potassium, calcium, magnesium, a~ onium and the like and may be preformed or formed in the food stuff by reaction with typical buffering agents, such as sodium phosphate, potassium citrate, sodium acetate, calcium phosphate, such as mono-calcium phosp~ates and tricalcium phosphate, and the 6~

1 like which are also normally employed in foodstuffs to provide the desired pH.
Illustrative compounds with the above general formulas (i) and (ii) include:

2,3-dihydroxy benzoic acidi 2,4 dihydroxy benzoic acid;
2-hydroxy-4-amino benzoic acid;

3~hydroxy-4-methoxy benzoic acid;
3-hydro~y-4~amino benzoic.acid; and 3,5-dihydroxy benzoic acid Many of the compound withln the above formulas ~i) and (ii) are sweetness inhibiting agents while others are sweeteners. Identification of these properties for many of these compounds is found hereinafter.
A preferred sweetness inhibiting agent within the scope of the present invention is 3,5-dihydroxy benzoic acid; 3-hydroxy-4 methoxybenzoic acid; and 3-hydroxy-4-aminobenzoic acid.
Compounds within the above formulas (i) and (ii) which are sweeteners include 2,3 dihydroxy benzoic acid; 2,4-dihydroxybenzoic acid; and 2 hydroxy-4-aminobenzoic acid.
As is readily apparent, depending upon the paxticular set o~ substituents, a given compound within the above formula may be a sweetness inhibi-tor or may be a sweetener. In order to determine whether a compound within the above general formula is a sweetness inhibitor or is sweet itself, a . simple procedure is emp].oyed. This procedure in-volves making a 1% a~ueous solution of the selected compound adjusted to pH 7 .and a 0.2~ aqueous solu-tion of the selected compound adjusted ko a pH 3.

~2Q~3~66 1 The solutlon5 alone are tasted to determine whetherthe selected compound is a sweetener. To determine whether the compound is a sweetness inhibitor, solutlons made up as above which also contain 5%
sucrose are tasted and judged against 5% sucrose alone which has been adjusted to the same pH. If the compound has bitter, salty or sour tastes of its own, the bitter, salty or sour tastes are matched with urea, sodlum chloride or citric acid, respec-tively, and the compound plus .5% sucrose tastedagainst s% sucrose cont~ining urea, sodium chloride, or citric acid at a level to match the off-tastes of the compound.
` In accordance with the present invention, a sweetness inhibitor is defined to be a compound which, when mixed with a sweetener, reduces or eliminates the perceived sweehless without substan-tially conkributing to the bitter, salty or sour taste of the foodstuff product. If a compound has a bitter, salty or sour taste of its own, it must be shown that the bitter, salty or sour -taste is not sufficient to account for the substantial loss in sweetness perception.
Thus, one significant aspect of the present invention is that the inhibiting of the sweet taste of a food product by the sweetness inhibitors of the present invention i5 not due to the taste of the compound itself, but rather is due to an unexpected and highly surprising effect which results when the sweetness inhibitor is combined with a sweetener in the food product and tasted by th~e consumer. 3,5 dihydroxy benzoic acid is ajpreferred sweetness in-- hibiting agent within the scope of the present invention.

8~66 ~1.0-1 Accordingly, what ls readily apparent from the dlscovery herein is that the utillzation of even very small qua~tities of the inhibiting modifiers described herein can reduce or even eliminate the undesirable sweet and/or lingering aftertastes of certain sweeteners in food products containing natural and/or artificial sweeteners, without af-fecting the other desirable tastes and properties of the food.
In order to achieve the surprising modifying results of the present invent:ion, the modifying compounds described herein are generally added to the food products at a level which is effective to inhibit the sweetness perception of the food product or potentiate the sweetness of the food product.
More particularly, it has been found that the aston-ishing resul~s provided by the present invention occur when the sweetener or inhibiting agent is added to the food product (containing a sweetener) in an amount in the range of from about 0.001 to 2%
by weight based on the weight of the consumed pro-duct. Greater amounts are operable but not prac-tical. Preferred amounts are in the range of from about 0.01 to 1% and most preferably 0.1 to 0.5% by weight of the foodstuff.
Generally, the inhibiting or sweetening effect provided by the present compounds is experienced over a wide pH range, e.g. 2 to 10 preferably 3 to 7 and in buffered or unbuffered formulations.
3~ Many of the compounds within the scope of the present invention are known and 'can ~e readily s~lthesized according to conventional synthetic procedures or can be commercially obtained. Many of the compounds are commercially available. Notwith-standing, these compounds can be readily prepared, l ~or example, by (a) nltratlon of benzoic acid fol-lowed by reduction and dlazotlzation, (b) oxidation of substituted nitrotoluenes, (c) sulfonation of nitrobenzenes followed by reductlon or~ sulfonation of aniline or derivatives thereof and (d) nitration of benzenesulfonic acids followed by reduction and diazotization.
Compounds within formulas ~i) and ~ii), wherein A is SO2H can be prepared from .a. the co~responding substituted phenylsulfochlor-ide according to Gutmann, Zeitschrift fur Analy-tische Chemie 65, 251 or Gebauer-Fulnegg, Riesenfeld, Monatscheffe fur Chemie 47, 191, 194 or V. Braun, Kaiser, Berich~e, 56, 550 or Beilstein XI, 1st edition, 4;
b. the corresponding substituted phenylmagnesium bromide accordng to Gilman, Fothergill, JACS 51 3506;
c. the corresponding substituted thiophenyl or 29 diphenylsulfide accordiny to Lecher, Holschneider, Berichte _ 757;
d. the corresponding substituted benzene sulfonyl-phenyldisulfide according to Hubacher, Organic Synthesis 15, 1935 or Booker, Chiied, Smiles, J.
~5 Chemical Society London, 1927, 1386-7;
e. The corresponding substituted benzene sul~onlc acla accor~lng IO (lWlSe, ~mlleS, J~ Lonaon, 1~() ) .
~. The correspondlng substltuted dlazoanlllne accordlng to Kharash, et ai., JACS 43 612; and g. t:he corresponding substituted bénzene sulfonic acid chloride according to Child, Smiles, JCS 1926 2699 or Bere, Smiles Organic Synthesis, Vol. 1, 2nd edition, 1941, 7.

~ ~ .

~2~1396~

l Compourlds ~hereln h lS Po3H2 can be prepared from the corresponding nltrophenylhydroxyphosphOazo-benzene accordlng to seilsteln x~rI, 1st supplement page 427.
Compounds wherein A is P02H2 can be synthesized from the corresponding nltrophenyl phosphlne accord-ing to Beilstein XVI, 791 or nitrophenyldichlorophos-phlne as taught by Mlchaels, Ananow, Berlchte 7, 1688 and Michaelis, Annalen, 181, 303.
Compounds wherein A is B02H2 can be prepared as follows:
a. ~ydrolysls o~ the correspondlng nltrophenyl-borodichloride as taught by Michaelis, Behrens, Berichte 27, 248;
b. hydrolysis of the corresponding nitrophenylboro-diisobutylate as taught by Khotinsky, Melamed, serichte _, 3033;
c. from the nitrophenylborodifluoride as taught by Beilstein XVI, 2nd supplement, 638; or d. nitration of the appropriate substituted ben-zene boronic acid as taught by Beilstein XVI, 3rd supplement 1276 or JACS 53, 711, 714 or Seaman &
Johnson, JACS 53, 711, 716 followed by reduction to the corresponding amino compound.
For synthetic routes to R1, R~ and R3, many of the desired compounds are commercially available or can be made from commercially available compounds by the routes described above. Otherwise, the starting materials can be made by standard methods of electro-3o phili~ aromatic substitution.
In order that thosé skilled~ in the art may better understand how the present invention may be practiced, the following examples are given by way ; of illustration and not by way of limitation.
Unless otherwise indicated, all solutions are aqueous.

961~i Ex AMp LE 1 To a pH 3 . O buffered solutlon and a pH 7.0 buffered solutlon was added 0.2% of the sweetness agent. The sweetness of these solutions was then judged by a panel of experts against stock sucrose concentrations in ldentical buffered solutions.
Compound pH Tested Sweetness Judgement 2, 3-dihydroxy 3 2-3% sucrose benzoic acid 7 2-3% sucrose 2, 4,-dihydroxy 3 2-3% sucrose benzoic acid 7 2-3% sucrose 2-hydroxy-4-amino 3 2.0% sucrose benzoic acid 7 1.0% sucrose To a pH 3.0 buffered solution and a pH 7.0 buffered solution containing 5% sucrose was added 0.2% of the sweetness agent. The sweetness of these solutions was then judged by a panel of experts against stock sucrose solutions at pH 3.0 and pH
7Ø
Compound pH Tested Sweetness Judgement 2,3-dihydroxy 3 7-8% sucrose benzoic acid 7 7-~% sucros~
2, 4-dihydroxy 3, 7-8% sucrose benzoic acid 7 7-8% sucrose 2-hydroxy-4-amino 3 5.5 7.0% sucrose benzoic acid 7 5~5-7.0% sucrose 3o To a pH-7.0 buffered solution cont~ining 15 sucrose was added varying amounts of a sweetness modifying agent, 3-hydroxy-4-methoxy benzoic acid.

~896~

1 These solutlons were tasted agalnst stock sucrose solutlons ln pH 7.0 buffer. Tasters were asked to match sweetness of the test solutions and stock solu tlons .

Modifler ConcentrationSucrose Match 0 05% 15.0%
0.10% 14.0%
0.30~ 5%
1.00% 8.5%
2.00% 6.0%

To a pH 7.0 buffered solution cont~ining 5%
sucrose was added 1.0% of the sweetness modifying agent. These solutions were than tasted by a panel of experts and examined against a pH 7.0 bu~ered solution cont~ining only 5% sucrose. The tasters were then asked to judge the sweetness reduction of the sample cont~ining the modifying agent.
Compound ~ Reduction In Sweetness 3-hydroxy-4-amino 40-50%
benzoic acid 3, 5-dihydroxy 70-90%
benzoic acid 3o /

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A foodstuff composition comprising a sweetness modifying agent, said sweetness modifying agent having the structure selected from the group consisting of:

(i) (ii) wherein:
A is an acid group of the structure -ZOqHr or salt thereof wherein Z is an element selected from the group consisting of carbon, sulfur, boron and phosphorus, q is an integer from 2 to 3 and r is an integer from 1 to 3;
Y is OH or salt thereof;
R1, R2 and R3 are independently selected from the group consisting of H, alkyl from 1 to 3 car-bons, cyclopropyl, OH, OCH3, OCH2CH3, CH2OCH3, CH2CH2OH, CH(CH3)CH2OH, CHO, COCH3, CH2CHO, COOH, CH2COOH, COOCH3, OCOCH3, CONH2, NHCHO, F, Cl, Br, I, CF3, SCH3, SCH2CH3, CH2SCH3, SO3H, SO2NH2, SO2CH3, SOCH3, CH2SO3H and CH2SONH2; and with the proviso that in structure (ii) when A is COOH, R1, R2 and R3 are not all hydrogen.

2. The foodstuff composition of Claim 1 wherein A is COOH

3. The foodstuff composition of Claim 1 wherein A is SO3H.

4. The foodstuff composition of Claim 1 wherein R1 is H.

5. The foodstuff composition of Claim 1 wherein R2 is H.

6. The foodstuff composition of Claim 1 wherein R3 is H.

7. The foodstuff composition of Claim 1 wherein said sweetness modifying agent is present in an amount in the range of from about 0.001 to about 2%.

8. The foodstuff composition of Claim 1 wherein said sweetness modifying agent is present in an amount in the range of from about 0.1 to about 1%
by weight of the foodstuff.

9. The foodstuff composition of Claim 1 wherein said sweetness modifying agent is present in an amount in the range of from about .1 to about 0.5% by weight of the foodstuff.

10. The foodstuff composition of Claim 1 wherein said foodstuff composition comprises a sweetener in addition to said sweetness modifying agent.

11. The foodstuff composition of Claim 10 wherein said sweetener is selected from the group consisting of a natural sweetener and an artificial sweetener.

12. The foodstuff composition of Claim 10 wherein said sweetener is selected from the group consisting of sucrose, fructose, corn syrup solids, dextrose, xylitol, sorbitol, mannitol, acesulfam, thaumatin,`invert sugar, saccharin, saccharin salts, cyclamate, dihydrochalcone, aspartame, stevioside, glycyrrhizin, mixtures thereof and salts thereof.

13. The foodstuff composition of Claim 1 wherein the foodstuff is selected from the group consisting of beverages, sauces, desserts, con-fections, intermediate moisture foods and infused foods.

14. The foodstuff composition of Claim 1 wherein said sweetness modifying agent is a sweet-ness inhibitor.

15. The foodstuff composition of Claim 14 wherein said foodstuff comprises a sweetener.

16. The foodstuff composition of Claim 15 wherein said sweetener is selected from the group consisting of natural sweetener, an artificial sweetener and mixtures thereof.

17. The foodstuff composition of Claim 15 wherein said sweetener is selected from the group consistin of sucrose, fructose, corn syrup solids, dextrose, xylitol, sorbitol, mannitol, acesulfam, thamatin, invert sugar, saccharin, saccharin salts, cyclamate, dihydrochalcone, aspartame, stevioside, glycyrrhizin, mixtures thereof and salts thereof.

18. The foodstuff composition of Claim 15 wherein the foodstuff is elected from the group consisting of beverages, sauces, desserts, confec-tions, intermediate moisture foods and infused foods.

19. The foodstuff composition of Claim 15 wherein said sweetness inhibitor is present in said foodstuff in an amount in the range of from about 0.001 to about 2% by weight of the foodstuff.

20. The foodstuff composition of Claim 15 wherein said sweetness inhibitor is present in said foodstuff in an amount in the range of from about 0.1 to about 1% by weight of the foodstuff.

21. The foodstuff composition of Claim 15 wherein said sweetness inhibitor is present in said foodstuff in an amount in the range of from about 0.1 to about 0.5% by weight of the foodstuff.

22. The foodstuff composition of Claim 1 wherein the sweetness modifying agents is 2, 3-dihydroxy benzoic acid.

23. The foodstuff composition of Claim 1 wherein the sweetness modifying agent is 2, 4-dihydroxy benzoic acid.

24. The foodstuff composition of Claim 1 wherein the sweetness modifying agent is 2-hydroxy-4-amino benzoic acid.

25. The foodstuff composition of Claim 1 wherein the sweetness modifying agent is 3-hydroxy-4-methoxy benzoic acid.

26. The foodstuff composition of Claim 1 wherein the sweetness modifying agent is 3-hydroxy-4-amino benzoic acid.

27. The foodstuff composition of Claim 1 wherein the sweetness modifying agent is 3, 5-dihydroxy benzoic acid.

28. A process for modifying the sweetness perception in a foodstuff, said process comprising adding a sweetnes modifying agent to a foodstuff, said sweetess modifying agent having the structure selected from the group consisting of:

wherein:
A is an acid group of the structure -ZOqHr or salt thereof wherein Z is an element selected from the group consisting of carbon, sulfur, boron and phosphorus, q is an integer from 2 to 3 and r is an integer from 1 to 3;
Y is OH or a salt thereof;

R1, R2 and R3 are independently selected from the group consisting of H, alkyl from 1 to 3 car-bons, cyclopropyl, OH, OCH3, OCH2CH3, CH2OCH3, CH2CH2OH, CH(CH3)CH2OH, CHO, COCH3, CH2CHO, COOH, CH2COOH, COOHCH3, OCOCH3, CONH2, NHCHO, F, Cl, Br, I, CF3, SCH3, SCH2CH3, CH2SCH3, SO3H, SO2NH2, SO2CH3, SOCH3, CH2SO3H, and CH2SONH2; and with the provision that in structure (ii) when A is COOH, R1,R2 and R3 are not all hydrogen.