ConcentrationâResponse Relationships of Sweeteners - American

Chapter 20

Concentration—Response Relationships of Sweeteners A Systematic Study Grant E . DuBois , D. Eric Walters , Susan S. Schiffman , Zoe S. Warwick , Barbara J. Booth , Suzanne D. Pecore , Kernon Gibes , B. Thomas Carr , and Linda M . Brands 1

1

2

1

1

1

2

1

1

The NutraSweet Company, Mt. Prospect, I L 60056 Department of Psychiatry, Duke University Medical Center, Durham, N C 27710

Downloaded by UNIV OF MINNESOTA on July 22, 2013 | http://pubs.acs.org Publication Date: December 31, 1991 | doi: 10.1021/bk-1991-0450.ch020

1

2

Sweetness intensity ratings were made by a trained panel for a range of concentrations of nineteen sweeteners. Panelists were trained to make sweetness ratings relative to six sucrose standards (2%-16%). The shapes of the concentration-response plots were sweetener-dependent. Sugars and sugar alcohols yielded linear concentration-response relationships for intensities up to that of a 16% sucrose standard. Highpotency sweeteners including aspartame, acesulfame-K and alitame yielded hyperbolic concentration-response plots. The purpose of this study was to utilize a systematic approach for determining concentration-response relationships for a broad range of sweeteners relative to a sucrose reference. Trained panelists evaluated sugars (sucrose, glucose, fructose, fructooligosaccharide sweetener), sugar alcohols (maltitol, lactitol, isomalt), terpenoid glycosides ( m o n o a m m o n i u m glycyrrhizinate, stevioside, rebaudioside-A), dipeptide derivatives (aspartame, alitame), a sulfamate (sodium cyclamate), a protein (thaumatin), a chlorodeoxysugar (sucralose), t w o N-sulfonyl amides (sodium saccharin, acesulfame-K), a dihydrochalcone (neohesperidin dihydrochalcone, a n d a n amino acid (glycine). Although concentration-response relationships have previously been obtained for s o m e o f t h e s e sweeteners (1-6), t h e p r e s e n t methodology expands u p o n prior work i n that: 1) a w i d e r r a n g e o f s t r u c t u r a l t y p e s i s e v a l u a t e d ; 2) the intensity ratings are referenced to s t a n d a r d s u c r o s e c o n c e n t r a t i o n s b y a t r a i n e d t a s t e p a n e l ; a n d 3) t h e m a t h e m a t i c a l forms of the concentration-response relationship are examined.

0097-6156/91/0450-0261$06.00/0 © 1991 American Chemical Society

In Sweeteners; Walters, D., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1991.

262

SWEETENERS:

DISCOVERY, M O L E C U L A R

DESIGN, A N D

CHEMORECEPTION


Method Subjects: Screening a n d training. T h e s u b j e c t s were s c r e e n e d for n o r m a l taste a n d o d o r a c u i t y a n d t h e a b i l i t y to recognize a n d d i s c r i m i n a t e a m o n g v a r i o u s t a s t e s t i m u l i (7). T h e f i n a l p a n e l p a r t i c i p a n t s were selected for their ability to: correctly identify t h e tastes sweet (2.0% sucrose), salty (0.2% NaCl), s o u r (0.07% citric acid), a n d b i t t e r ( 0 . 0 7 % caffeine); a c c u r a t e l y r a n k o r d e r a s e r i e s o f four concentrations of each taste s t i m u l u s ; successfully identify the o d d s a m p l e i n a series of triangle tests; a n d recognize a n d describe the a r o m a of s i x c o m m o n odorants. Five female a n d thirteen male s t u d e n t s a n d employees of D u k e U n i v e r s i t y , D u r h a m , N . C . , ( m e a n age 3 6 . 5 y e a r s + 13.3) w e r e t r a i n e d a c r o s s s e v e n w e e k s (17 o n e - h o u r s e s s i o n s ) i n a m o d i f i e d S p e c t r u m ™ d e s c r i p t i v e flavor p r o f i l e m e t h o d (8). T h e p u r p o s e o f the t r a i n i n g w a s to familiarize the p a n e l w i t h taste profiles of sweeteners. T h e p a n e l w a s trained i n techniques to recognize, describe a n d quantify the tastes a n d aromatic characteristics of sweeteners. T h e t r a i n i n g b e g a n w i t h a n overview of b a s i c taste a n d olfactory physiology as well as the p s y c h o p h y s i c a l principles of vocabulary development a n d scaling. T h r o u g h t h e u s e o f flavor a t t r i b u t e r e f e r e n c e s (e.g., m e t a l l i c = . 0 0 0 3 g F e r r o u s s u l f a t e i n 1 5 0 m L 5 0 0 p p m aspartame solution; licorice = 1 drop M c C o r m i c k anise extract in 100 m L 5 0 0 p p m aspartame solution), the panel learned standard flavor v o c a b u l a r y to describe tastes a n d odors of sweeteners. S i x c o n c e n t r a t i o n s of s u c r o s e (2%, 5 % , 7 . 5 % , 1 0 % , 1 2 % , a n d 16%) w e r e u s e d to s t a n d a r d i z e s w e e t n e s s i n t e n s i t y r a t i n g s o n a 1 5 c m l i n e s c a l e ( F i g u r e 1). T h e s e s u c r o s e s t a n d a r d s w e r e a s s i g n e d t h e i n t e n s i t y v a l u e s 2, 5, 7 . 5 , 1 0 , 1 2 , a n d 1 5 , respectively. T w o c o n c e n t r a t i o n s of caffeine were u s e d to standardize bitterness intensity ratings: 0 . 0 5 % (assigned a value of 2 bitter) a n d 0 . 0 8 % (assigned a value of 5 bitter). The panel evaluated seven sweeteners at various concentrations d u r i n g the training: acesulfame-K, aspartame, sodium cyclamate, sodium saccharin, sucrose, a n d t h a u m a t i n . T w o mixtures were also u s e d i n t r a i n i n g : a s p a r t a m e p l u s caffeine, a n d s u c r o s e p l u s caffeine. Stimuli. T h e stimuli, classification, dilution range, a n d n u m b e r of c o n c e n t r a t i o n s t e s t e d a r e g i v e n i n T a b l e I. S a m p l e s w e r e d i s s o l v e d i n deionized water at r o o m temperature w i t h i n twelve h o u r s of evaluation. Concentrations are reported o n a weight/volume basis, c o r r e c t i n g t h e w e i g h t f o r a n a l y z e d p u r i t y o f t h e s a m p l e (e.g., N a saccharin, Sigma, lot 76F0079, contained 1 4 . 3 % water according to t h e s u p p l i e r ) . P a n e l i s t s received 2 0 m L a l i q u o t s o f test s t i m u l i , served at r o o m temperature i n 3 0 m L odor-free p l a s t i c c u p s coded w i t h r a n d o m l y selected three-digit n u m b e r s . The panel was c o n d u c t e d u n d e r n a t u r a l lighting i n a quiet, odor-free room.


20.

Concentration-Response Relationships ofSweeteners

DUBOIS E T A L

FLAVOR PROFILE ANALYSIS


Sample # AROMATICS

J J

BASIC TASTES Sweet Bitter S

o

u

J

r

Salty

ι

ι

ι

ι

J

ι

ι

|

FEELING FACTORS Metallic Astringent Cooling Other(

)

L

TIME OF MAXIMUM INTENSITY (CIRCLE ONE): EARLY

MIDDLE

LATE

COMMENTS:

F i g u r e 1. P a n e l i s t r e s p o n s e s h e e t .


263

264

SWEETENERS:


T a b l e I.

DISCOVERY, M O L E C U L A R DESIGN, A N D C H E M O R E C E P T I O N

Sweeteners used i n this study

Compound

Classification

Acesulfame-K Alitame Aspartame Fructooligosaccharide sweetener Fructose Glucose Glycine Isomalt Lactitol Maltitol Monoammonium glycyrrhizinate Neohesperidin dihydrochalcone Rebaudioside-A

N-Sulfonyl amide Dipeptide Dipeptide Polyol*

Sodium cyclamate Sodium saccharin Stevioside

Polyol Polyol Amino acid Polyolf Polyol Polyol Terpenoid glycoside Polyketide Terpenoid glycoside Sulfamate N-Sulfonyl amide

Dilution Range (ppm) 100-1560 5-200 60-3000 13,000-100,000

No. o f cones. 10 10 28 6

6,400-35,000 9,600-50,000 13,000-200,000 13,400-300,000 20,000-500,000 6,500-500,000 200-3000

11 10 7 8 10 10 7

32-875 70-1500 500-9000 20-1200

70-1500 Terpenoid glycoside 19-1200 Sucralose Chlorosugar 16,000-160,000 Sucrose Polyol Thaumatin 2.8-60 Protein * Fructo-oligosaccharide sweetener is a mixture of kestose,

9 13 8 17 12 11 53 18

n y s t o s e , a n d Ι-Ο-β-D-fructofuranosyl-nystose. t I s o m a l t i s a 1:1 m i x t u r e o f 6 - O - o c - D - g l u c o p y r a n o s y l - s o r b i t o l a n d 6-O-a-D-glucopyranosyl-mannitol



20.

Concentration-Response Relationships of Sweeteners

DuBOIS E T AL.

265

D e i o n i z e d w a t e r a n d u n s a l t e d c r a c k e r s were available to clear the palate between stimuli. Procedure. The concentration-response data were obtained by p r e s e n t i n g f o u r c o n c e n t r a t i o n s of a s w e e t e n e r i n one s e s s i o n . A fifth s a m p l e c o n t a i n i n g s u c r o s e or a s p a r t a m e w a s p r e s e n t e d as a control. In each session, the panelists first tasted their sweet a n d bitter references: 2%, 5%, 7.5%, 10%, 1 2 % a n d 1 6 % sucrose, a n d 0. 0 5 % caffeine. T h e y t h e n t a s t e d t h e first of five test s a m p l e s , followed b y a w a t e r r i n s e . T h e p a n e l i s t s were i n s t r u c t e d to taste the s a m p l e s , h o l d i n g a n d s w i r l i n g i n the m o u t h for t e n s e c o n d s , a n d to rate the m a x i m u m i n t e n s i t y e a c h a t t r i b u t e r e a c h e d before discarding the sample. Intensity scores were recorded on a r e s p o n s e s h e e t i n d i v i d u a l l y c o d e d for e a c h s a m p l e . P a n e l i s t s rinsed w i t h water three times a n d waited approximately 6 0 seconds, or u n t i l a l l taste s e n s a t i o n s u b s i d e d , before p r o c e e d i n g to t h e n e x t s a m p l e . E v a l u a t i o n of the four r e m a i n i n g s a m p l e s w a s c o n d u c t e d i n a s i m i l a r f a s h i o n . T h e o r d e r of t h e five s t i m u l i w a s r a n d o m i z e d across subjects. Statistical treatment. E a c h data point on the concentrationr e s p o n s e p l o t s r e p r e s e n t s the average of a l l p a n e l i s t i n t e n s i t y responses within a session. While only sweetness a n d bitterness d a t a are p r e s e n t e d here, p a n e l i s t s p r o v i d e d a full s e n s o r y profile of each sweetener sample. T h i s i n c l u d e d q u a n t i f i c a t i o n of a n y a d d i t i o n a l tastes that were detected, s u c h as salty, sour, or metallic. A r o m a t i c notes a n d "feeling factors" s u c h as b u r n i n g , v i s c o u s or s m o o t h w e r e a l s o r a t e d for i n t e n s i t y . In a d d i t i o n , p a n e l i s t s j u d g e d t h e t i m e of m a x i m u m s w e e t n e s s i n t e n s i t y a s early, m i d d l e o r late i n onset. T h e s w e e t i n t e n s i t y p a n e l m e a n s for e a c h s w e e t e n e r w e r e t e s t e d for t h e i r fit to t h r e e different m a t h e m a t i c a l m o d e l s : (a) l i n e a r ; (b) B e i d l e r e q u a t i o n ; (c) e x t e n d e d B e i d l e r e q u a t i o n . E q u a t i o n 1 i s t h e B e i d l e r e q u a t i o n (9;), w h i c h i s a n a l o g o u s t o t h e M i c h a e l i s - M e n t e n e q u a t i o n for e n z y m e - s u b s t r a t e i n t e r a c t i o n . T h i s e q u a t i o n h a s often b e e n u s e d t o fit c o n c e n t r a t i o n - r e s p o n s e d a t a f o r t a s t a n t s . T h e t h i r d m o d e l w e u s e d ( e q u a t i o n 2) i s a m o d i f i c a t i o n o f t h e B e i d l e r e q u a t i o n w h i c h i s e q u i v a l e n t t o t h e H i l l e q u a t i o n (10) f o r a r e c e p t o r w i t h multiple sites. The Hill-type equation, w h e n the exponent η = 1, r e d u c e s t o t h e B e i d l e r e q u a t i o n .

R

=

l/K + C

(

1

)

where R is the observed response; R is the m a x i m a l response; C i s t h e s w e e t e n e r c o n c e n t r a t i o n ; a n d 1/K = c o n c e n t r a t i o n w h i c h y i e l d s h a l f - m a x i m a l response, equivalent to the r e c i p r o c a l of the receptor-sweetener a s s o c i a t i o n c o n s t a n t . m


266

SWEETENERS:

fin

^


* C

"" it /Trail -

CHEMORECEPTION

r

(1/K') + C n

DESIGN, A N D

v

r

'


w h e r e η is t h e a p p a r e n t n u m b e r of b i n d i n g sites p e r r e c e p t o r m o l e c u l e , a n d 1/K' i s s t i l l t h e c o n c e n t r a t i o n w h i c h y i e l d s h a l f m a x i m a l r e s p o n s e , b u t i t i s n o l o n g e r d i r e c t l y r e l a t e d to t h e b i n d i n g e f f i c i e n c y a s i t i s i n e q u a t i o n 1. If w e a s s u m e t h a t t h e o b s e r v e d r e s p o n s e t o s u c r o s e i n c r e a s e s w i t h c o n c e n t r a t i o n a c c o r d i n g to a B e i d l e r - t y p e r e l a t i o n s h i p , t h e n t h e p a n e l i s t s are b e i n g t r a i n e d to l i n e a r i z e a h y p e r b o l i c f u n c t i o n . The r e s u l t of t h i s is t h a t c o m p o u n d s w i t h a m a x i m a l response c o m p a r a b l e to t h a t of s u c r o s e w i l l p r o d u c e a l i n e a r c o n c e n t r a t i o n response r e l a t i o n s h i p (with slope greater t h a n 1 if the potency is greater t h a n t h a t of s u c r o s e , a n d l e s s t h a n 1 i f t h e p o t e n c y i s l e s s t h a n t h a t of sucrose). C o m p o u n d s w i t h m a x i m a l r e s p o n s e l e s s t h a n t h a t o f s u c r o s e w i l l p r o d u c e a h y p e r b o l i c c u r v e (of t h e s a m e f o r m a s t h e B e i d l e r m o d e l , e q u a t i o n 1). A m a n u s c r i p t showing the m a t h e m a t i c a l d e r i v a t i o n o f t h e s e r e l a t i o n s h i p s i s i n p r e p a r a t i o n (K. Gibes). Concentration-response data were analyzed by nonlinear regression modeling techniques u s i n g S A S Institute's P R O C N L I N (J J ) , w h i c h u s e s l e a s t s q u a r e s a s a f i t t i n g c r i t e r i o n . To test whether the Beidler model (equation 1) w a s s u f f i c i e n t (i.e. e x p o n e n t = l i n e q u a t i o n 2), a n F - t e s t w a s p e r f o r m e d b y t h e " e x t r a s u m o f s q u a r e s " p r i n c i p l e (12). In a d d i t i o n , for a s p a r t a m e a n d s u c r o s e , sufficient c o n c e n t r a t i o n r e p l i c a t i o n s w e r e d o n e to a l l o w f o r a n F - t e s t f o r " l a c k o f f i t " o f t h e m o d e l (13). F i n a l l y , f o r s u c r o s e a n a d d i t i o n a l t-test w a s p e r f o r m e d to d e t e r m i n e w h e t h e r the slope of t h e l i n e a r fit w a s e q u a l to 1 a s w o u l d b e e x p e c t e d since sweetness was measured o n the sucrose equivalency scale. Results Sugars and sugar alcohols. S u c r o s e gave a l i n e a r r e s p o n s e w i t h c o n c e n t r a t i o n (p = 0 . 1 0 4 3 , l a c k o f f i t F - t e s t ) . It c a n b e s e e n i n F i g u r e 2 t h a t t h e s l o p e o f t h i s l i n e i s c l o s e t o 1.0 (p = 0 . 2 8 3 3 , t - t e s t f o r e q u a l i t y w i t h 1.0). In other words, the m e a n panel responses c l o s e l y m a t c h e d the a c t u a l c o n c e n t r a t i o n s of t h e s a m p l e s . Since p a n e l i s t s h a d b e e n t r a i n e d to m a k e t h e i r i n t e n s i t y j u d g m e n t s b a s e d o n a s u c r o s e - r e f e r e n c e d scale, t h i s one-to-one c o r r e s p o n d e n c e of sucrose concentration a n d intensity rating confirms the reliability of the s c a l i n g methodology employed i n t h i s s t u d y . T h e o t h e r s u g a r s a n d s u g a r a l c o h o l s w e r e b e s t fit t o t h e l i n e a r model over the concentration ranges studied. T h e g r a p h for fructose h a s a n initial slope that is greater t h a n one, consistent w i t h i t s i n c r e a s e d p o t e n c y relative to s u c r o s e ( F i g u r e 3a). Glucose a n d fructo-oligosaccharide sweetener, however, e x h i b i t slopes of less t h a n one; t h i s i s i n d i c a t i v e of s w e e t n e s s p o t e n c i e s l o w e r t h a n



20. DuBOIS E T AL.


Sucrose

OH 0

•

•

•

•

1

•

•

•

•

5

1

10 Concentration

•

•

'

1

15

(%)

F i g u r e 2. Concentration-response d a t a for s u c r o s e . The e q u a t i o n for l e a s t - s q u a r e s fit of a s t r a i g h t l i n e to t h e d a t a i s R = 0 . 8 0 + 0 . 9 4 ( C ) ; R2 = 0 . 9 6 .


267

268


SWEETENERS:


DESIGN, A N D

CHEMORECEPTION

Glucose

0.0

10.0 Concentration

Fructo-oligosaccharide

15Ί

ο α

20.0

(%)

sweetener

10

CO V

4 6 Concentration

8

12

(%)

F i g u r e 3. C o n c e n t r a t i o n - r e s p o n s e d a t a for fructose, g l u c o s e , a n d fructo-oligosaccharide sweetener. F o r figures 3-8, large circles indicate sweetness response and small circles indicate b i t t e r n e s s response; error b a r s are L e a s t S i g n i f i c a n t Difference, [ ( 2 * s t d . d e v . ) ( V 2 / n ) ] , w h e r e η = n o . o f p a n e l i s t s , (a) F r u c t o s e , R = 0 . 0 4 + 1.27 C ; R = 0 . 9 7 3 . (b) G l u c o s e , R = - 0 . 0 2 + 0 . 6 0 C ; R = 0 . 9 7 4 . (c) F r u c t o - o l i g o s a c c h a r i d e s w e e t e n e r , R = - 0 . 0 3 + 0 . 2 7 C ; R = 0.949. 2

2


2


20. DUBOIS E T AL,


269

t h a t of s u c r o s e (Figures 3 b a n d 3c). S u g a r a l c o h o l s w e r e a l s o f o u n d to b e less p o t e n t t h a n s u c r o s e . Isomalt, l a c t i t o l a n d m a l t i t o l a l l h a v e s l o p e s o f s u b s t a n t i a l l y l e s s t h a n o n e ( F i g u r e 4). H i g h potency sweeteners. T h e s h a p e of the c o n c e n t r a t i o n r e s p o n s e f u n c t i o n s o b t a i n e d for h i g h p o t e n c y s w e e t e n e r s differs s u b s t a n t i a l l y f r o m t h o s e o b t a i n e d for t h e p o l y o l s d i s c u s s e d above. Aspartame exhibited a concentration-response function w h i c h was h y p e r b o l i c o n t h e s u c r o s e r e f e r e n c e s c a l e (p = 0 . 7 8 3 2 , l a c k o f f i t F-test). The other high potency sweeteners evaluated i n this study behaved similarly, asymptotically approaching m a x i m a l responses. The Beidler equation (equation 1) g a v e t h e b e s t f i t t o t h e e x p e r i m e n t a l d a t a except i n the cases of s o d i u m c y c l a m a t e , s o d i u m s a c c h a r i n , a n d sucralose. F o r these three c o m p o u n d s , the Hill-type e q u a t i o n ( e q u a t i o n 2 ; η = 1.8, 1.4, 1.4, r e s p e c t i v e l y ) g a v e a s l i g h t l y b e t t e r fit, b u t i n e a c h c a s e a s i n g l e d a t a p o i n t w a s r e s p o n s i b l e f o r t h e b e t t e r fit of t h e H i l l - t y p e e q u a t i o n . W h i l e w e c a n n o t r u l e o u t t h e p o s s i b i l i t y t h a t a H i l l - t y p e e q u a t i o n m a y be r e q u i r e d for s o m e c o m p o u n d s , o u r d a t a indicate that the s t a n d a r d Beidler equation is a n a d e q u a t e m o d e l of the s w e e t e n e r - r e c e p t o r i n t e r a c t i o n s for the high-potency compounds. A s s h o w n i n F i g u r e 5, t h e h i g h e s t m a x i m a l r e s p o n s e s w e r e o b s e r v e d for the d i p e p t i d e sweeteners a s p a r t a m e a n d a l i t a m e (16.0 a n d 14.6, respectively) a n d for s u c r a l o s e (13.0). These three c o m p o u n d s have the lowest i n c i d e n c e of n o n - s w e e t tastes a m o n g the h i g h - p o t e n c y sweeteners. T h e r e m a i n i n g h i g h - p o t e n c y s w e e t e n e r s ( F i g u r e 6-8) h a d R values less t h a n 12. These c o m p o u n d s all h a d significant concentrationdependent non-sweet tastes (acesulfame-K, sodium cyclamate, m o n o a m m o n i u m glycyrrhizinate, neohesperidin dihydrochalcone, rebaudioside-A, s o d i u m s a c c h a r i n , stevioside) or l i m i t e d s o l u b i l i t y (glycine) w h i c h m a y h a v e p r e v e n t e d a t t a i n m e n t of h i g h e r s w e e t n e s s i n t e n s i t i e s . T a b l e II l i s t s t h e v a l u e s f o r m a x i m a l r e s p o n s e (Rm) a n d a p p a r e n t r e c e p t o r - s w e e t e n e r a s s o c i a t i o n c o n s t a n t s (1/K) f o r a l l o f the h i g h - p o t e n c y sweeteners o b t a i n e d f r o m f i t t i n g to t h e B e i d l e r equation. m

Discussion T h e l i n e a r i t y of t h e s u c r o s e r e s p o n s e w i t h c o n c e n t r a t i o n i s a r e s u l t of the p a n e l t r a i n i n g . T h e l i n e a r i t y observed for the other s u g a r s a n d sugar alcohols indicates that they s h o u l d exhibit a m a x i m a l s w e e t n e s s s i m i l a r t o t h a t o f s u c r o s e . I n s o m e c a s e s (e.g., f r u c t o oligosaccharide sweetener a n d isomalt) the potency and/or s o l u b i l i t y i s too l o w to e v e r a c t u a l l y a c h i e v e t h e s a m e s w e e t n e s s i n t e n s i t y as t h a t of a c o n c e n t r a t e d s u c r o s e s o l u t i o n . T h e a b i l i t y of t h e B e i d l e r e q u a t i o n to fit c o n c e n t r a t i o n - r e s p o n s e d a t a for t h e high-potency sweeteners is consistent w i t h a one-to-one s w e e t e n e r - t o - r e c e p t o r i n t e r a c t i o n for t h e s e c o m p o u n d s . It i s l e s s c l e a r h o w to i n t e r p r e t t h e a p p a r e n t l y i m p r o v e d fit of t h e H i l l - t y p e


270

SWEETENERS:


Isomalt

15η


10

30

20

Concentration

(%)

Lactitol

10

30

20

Concentration

(%)

Maltitol

10 Concentration

F i g u r e 4. maltitol. Lactitol, R 0.71 C; R 2

C o n c e n t r a t i o n - r e s p o n s e d a t a for i s o m a l t , lactitol, a n d (a) I s o m a l t , R = - 0 . 6 3 + 0 . 4 3 C ; R = 0.996. (b) = - 0 . 8 2 + 0 . 4 1 C ; R = 0 . 9 9 0 . (c) M a l t i t o l , R = 0 . 0 5 + = 0.990. 2

2


20.

DuBOlS E T XL

Concentration—Response Relationships of Sweeteners

271

Alitame

a


Concentration (ppm)

Aspartame

0

1000 2000 Concentration (ppm)

3000

F i g u r e 5. C o n c e n t r a t i o n - r e s p o n s e d a t a for a l i t a m e , a s p a r t a m e , a n d sucralose (Hill-type equation). F o r figures 5-8, the c a l c u l a t e d B e i d l e r (or H i l l - t y p e ) c u r v e a r e s h o w n . (a) a l i t a m e : R = ^ 2 8 ^ 0 ^ ^ . _ (13.0)(C)i>4 (c) s u c r a l o s e : R = i.4 i.4 ;

a

s

P

a

r

t

a

m

e

:

R

=

^56(f+C^

n

1 1 Q

+

c


:

272

SWEETENERS:


Acesulfame-K

1500


500 1000 Concentration (ppm)

Sodium

2500

Cyclamate

5000

10000

7500

Concentration (ppm)

Glycine

15-|

a ο α en

5"

20

10 Concentration

(%)

F i g u r e 6. C o n c e n t r a t i o n - r e s p o n s e d a t a for a c e s u l f a m e - K , s o d i u m cyclamate (Hill-type equation), a n d glycine, (a) a c e s u l f a m e : (11.6)(C) ι τ. (11-3)(C) , > , . 470 + C ( ) cyclamate: R = i . 8 + i.8 (c) g l y c i n e : 1 8

D

=

R =

;

b

1

8

Q

Q

c

;

(11.3)(C) 12.0+ C



20. DUBOIS E T AL.

15-|

Monoammonium

Glycyrrhizinate

3 io ο CO

&

5-


/f 1000

3000

2000

Concentration (ppm)

15η

Neohesperidin

Dihydrochalcone

G Ο CO

5"

250

500

750

1000

Concentration (ppm)

Rebaudioside-A

15

S

1 0

- H — I

o £

5

I

τ ι ι

ι

J II

500

ι 1000

I 1500

Concentration (ppm)

F i g u r e 7. C o n c e n t r a t i o n - r e s p o n s e d a t a for m o n o a m m o n i u m glycyrrhizinate, neohesperidin dihydrochalcone, and rebaudioside-A. (a) m o n o a m m o n i u m glycyrrhizinate: (7.3)(C) (9.8)(C) R = (b) n e o h e s p e r i d i n d i h y d r o c h a l c o n e : R = 210+ C 53+ C (c) r e b a u d i o s i d e - A :

R =

(10.0HC) 200+ C


273

274

SWEETENERS:

15

DISCOVERY, M O L E C U L A R DESIGN, A N D

Sodium Saccharin

a 10

il

Ο

α CO

&

5

τ

ι

t

1t I


CHEMORECEPTION

250

500 Concentration

750 (ppm)

I

_ I

1

1

ι

I

1000

Stevioside

500 Concentration

15n

1500

1000 (ppm)

Thaumatin

S ίο Ο CO

« fi 20 40 Concentration (ppm)

60

F i g u r e 8. C o n c e n t r a t i o n - r e s p o n s e d a t a for s o d i u m s a c c h a r i n (Hill-type equation), stevioside, a n d t h a u m a t i n . (9.9)(C) (9.0)(C)i-4 (a) s a c c h a r i n : R = 961.4 (b) s t e v i o s i d e : R = 1.4 410+ C (ÎO.D(C) (c) t h a u m a t i n : R = 3.6+ C +

C


20. DuBOIS E T AL.


275


T a b l e II. B e i d l e r e q u a t i o n (or H i l l - t y p e e q u a t i o n ) p a r a m e t e r s derived from the concentration-response data Compound Acesulfame-K Alitame Aspartame Glycine Monoammonium glycyrrhizinate Neohesperidin dihydrochalcone Rebaudioside-A S o d i u m cyclamate Sodium saccharin Stevioside Sucralose Thaumatin a

1/K

Rmax 11.6 14.6 16.0 11.3 7.3

470 p p m 28 p p m 560 p p m 12% 210 p p m

9.8

53 p p m 200 p p m 1800 p p m 96 ppma a

410 p p m 110 p p m 3.6 p p m a

10.0 11.3 9.0 9.9 13.0 10.1

V a l u e l i s t e d i s f o r 1 / K ( e q u a t i o n 2) r a t h e r t h a n 1/K.

e q u a t i o n (with n o n - i n t e g r a l exponents) for three of t h e c o m p o u n d s . A r i e n s points o u t that interactions w h i c h appear to have a higher order t h a n one-to-one are often t h e r e s u l t of a s e q u e n t i a l series of interactions (14). Multiple receptor types and receptor cooperativity are hypotheses w h i c h could be considered. A l l of the s u g a r s a n d s u g a r alcohols have i n c o m m o n a large n u m b e r of hydroxyl groups (hydrogen b o n d donors/acceptors) a n d a r e q u i r e m e n t for h i g h concentrations i n order to elicit sweet taste. It i s c o n c e i v a b l e t h a t t h e s e c o m p o u n d s a c t i v a t e r e c e p t o r c e l l s i n some n o n - s p e c i f i c w a y (e.g., b y o s m o t i c o r c o n f o r m a t i o n a l p e r t u r b a t i o n of cell membranes) rather t h a n b y direct i n t e r a c t i o n w i t h receptor protein(s). High-potency sweeteners, o n the other h a n d , might interact specifically w i t h some subset of the receptor p o p u l a t i o n . T h i s w o u l d a c c o u n t for the lower m a x i m a l sweetness levels for these c o m p o u n d s . Alternatively, h i g h p o t e n c y sweeteners a n d polyol sweeteners m a y a l l activate the same receptor protein where the polyols are full agonists a n d the h i g h potency sweeteners are partial agonists. M e d i a t i o n of sweet taste b y more t h a n one receptor protein or more t h a n one cellular activation system cannot b e a s c e r t a i n e d b y a n a l y s i s o f t h e d a t a p r e s e n t l y i n h a n d . It a p p e a r s clear, however, that polyol sweeteners as a group are distinct i n their behavior from h i g h potency sweeteners. T h u s it is tentatively c o n c l u d e d t h a t a t least two r o u t e s to receptor cell a c t i v a t i o n m u s t exist.


276

SWEETENERS: DISCOVERY, MOLECULAR DESIGN, AND CHEMORECEPTION


Literature Cited

1. Stone, H.; Oliver, S.M. J. FoodSci.1969, 34, 215-222. 2. Moskowitz, H.R. Perception Psychophys. 1970, 7, 315320. 3. Moskowitz, H.R. Perception Psychophys. 1970, 8, 40-42. 4. Frijters, J.E.R.; Oude Ophius, P.A.M. Perception Psychophys. 1983,12,753-767. 5. Hoppe, K.; Gassman, B. Lebensmittelind. 1985, 32, 227231. 6. Schiffman, S.S.; Lindley, M.G.; Clark, T.B.; Makino, C. Neurobiol. Aging 1981, 2, 173-185. 7. Guidelines for the Selection and Training of Sensory Panel Members. ASTM STP 758 (1981). 8. Meilgaard, M.; Civille, G.; Carr, B.T. Sensory Evaluation Techniques, Vol II; CRC Press: Boca Raton, FL, 1987; pp 822. 9. Beidler, L.M. J. Gen. Physiol. 1954, 38, 133-139. 10. Segel, I.H. Enzyme Kinetics: Behavior and Analysis of Rapid Equilibrium and Steady-State Systems; John Wiley & Sons: New York, 1975; pp 360-361. 11. SAS User's Guide: Statistics, Version 5; SAS Institute Inc Cary, NC, 1985; pp 575-606. 12. Draper, N. R.; Smith, H. Applied Regression Analysis; John Wiley & Sons: New York, 1966; pp 67-69. 13. Draper, N. R.; Smith, H. Applied Regression Analysis; John Wiley & Sons: New York, 1966; pp 26-30. 14. Ariëns, E.J.; Simonis, A.M.; van Rossum, J.M. In Molecular Pharmacology: The Mode of Action of Biologically Activ Compounds, Ariëns, E.J., Ed.; Academic: New York, 1964; p 146. RECEIVED August 27, 1990


ConcentrationâResponse Relationships of Sweeteners - American

Recommend Documents

ConcentrationâResponse Relationships of Sweeteners - American