ORGANOLEPTIC SCENSORY TASTE PROFILES
CITRIC ACID
TARTNESS
MALIC ACID
TASTE RETENTION
MASKING EFFECT OF MALIC VS CITRIC WHEN USED WITH HIGH INTENSITY
SWEETENERS
Saccharin
Malic Acid
Taste Strength
Citric Acid
Bitter After Taste
Time
The lingering tartness of malic acid outlasts and masks the bitter after taste
Reference: Riken Kagaku Co. Ltd, Japan (or intense sweetness) of many high intensity sweeteners.
Comparison of Molecular Weights of Food Acids
One mole = 602, 000, 000, 000, 000, 000, 000, 000 molecules
Weight in grams of a mole = numerical value of the molecular weight
One mole of Fumaric Acid
= 116 grams
One mole of Malic Acid
= 134 grams
One mole of Citric Acid (Anhydrous)
= 192 grams
One mole of Citric Acid (Monohydrate)
= 210 grams
Therefore the same number of molecules are in
134 grams of Malic Acid
192 grams of Citric Acid
Malic Acid molecules are smaller than Citric molecules; therefore you get
more molecules per kilogram with Malic than Citric.
CHEMICAL REACTIONS OR INTERACTIONS DEPEND ON THE
NUMBER OF MOLECULES - NOT THE NUMBER OF KILOGRAMS
INVOLVED.
Such as: - pH; buffer capacity; chelation capacity; and sourness.
The acid levels to lower pH to 3.5 - [0.0005N NaOH solution]
Lactic, 80%
Citric
Malic
Tartaric
SAS, 93%
% w/v acid required
Fumaric
Phosphoric, 85%
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
These acid strength values are of course not an exact prediction of what would happen in a
beverage system. A typical beverage contains hydrocolloids, salts, or other buffering ingredients
that influence the level of acid required to lower pH to a specific value.
0.2
Estimated Sourness (units from ratio scales of H. Moskowitz)
Sourness of Acids at 0.2% w/v vs pH
8
Malic
Citric
4
0
3
3.5
4
4.5
pH
Sourness models fitted to sensory data at pH 3.5, 0.4-0.7% acid
(Noble et al.,) and at pH 3.5, 4.5, 0.2% acid (Hartwig & McDaniel)
5
Malic Acid
-
Malic acid, or hydroxysuccininic acid, is a dicarboxylic acid. Malic acid is
an organic food acid.
-
Malic acid is a naturally occurring acidulant and can be found in a wide
range of fruits and berries - much more common than citric acid in nature.
-
Malic acid is essential for respiratory metabolic cycles in plants and
animals and is formed in living cells.
-
Malic acid provides the cell with energy and the carbon skeletons for the
formation of amino acids - this takes place in the Krebs cycle.
-
Malic acid was introduced to the food industry in 1923 but only became
commercially available in the mid-1970’s.
-
With the building of new plants, malic acid has become a fast growing food
acidulant, gaining market share universally.
Where is Malic Acid found in nature?
FRUIT
MALIC ACID as % of total acid
Watermelon
100
Quince
100
Plum
97
Apple
95
Lychee
95
Cherry
94
Pear
77
Rhubarb
77
Prickly Pear
75
Peach
73
Banana
73
Apricot
70
Orange Peel
70
Nectarine
60
Grape
60
Tomato
48
Gooseberry
45
Kiwi Fruit
17
Mango
17
Pineapple
13
Strawberry
10
Grapefruit
5
Lemon
4
Malic Acid versus Citric Acid
MISTAKEN PERCEPTION THAT CITRIC IS A “NATURAL ACID”
Certain citric vendors claim that because
citric is fermented from starch broth it is
a “natural product”
* Malic acid is far more abundant in nature
* Both Citric and Malic are made commercially in chemical plants
* Citric Acid has not been extracted from the juice of limes and
lemons since the 1920’s
* Both Citric and Malic form part of the Krebs Cycle (metabolic
pathway of living organisms)
* Generally fermentation processes result in more side streams
and (undesirable) by-products than a pure chemical synthesis
* Malic is considered to be GRAS by the FDA
* Both Malic and Citric are specified in all food codices and
pharmacopoeias
What is “natural”? Both Malic and Citric are fruit acids
Malic Acid versus Citric Acid
CITRIC ACID HAS BEEN AROUND FAR LONGER THAN MALIC ACID WHICH ACCOUNTS FOR THE
MAIN REASON WHY IT IS A MORE COMMONLY USED FOOD ACID THAN MALIC ACID
CITRIC ACID
First large commercial production in 1927
MALIC ACID
mid-60’s ICI and Allied Chemicals (not successful)
1972 Allied Chemicals ceased (ICI even earlier)
Early-70’s
- Fuso Chemicals (Japan)
mid-70’s
- Butakem (South Africa)
- Croda (UK) - ceased in 1983
- Bartek (Canada)
- Alberta Gas (USA) - Later H & R
* New Entrants - Lonza (Italy), Yong San (Korea),
Thirumalai (India), two plants in China
*
*
*
*
* 2003
- Isegen South Africa - unique granular
technology
• Malic acid is becoming far better known and more widely available, but most producers
still only concentrate on the existing malic market.
• Isegen has earnestly looked at replacing Citric with Malic acid in many niche applications,
where Malic clearly has an advantage.
Malic Acid versus Citric Acid
MISTAKEN PERCEPTION THAT CITRIC IS A “NATURAL ACID”
Certain citric vendors claim that because
citric is fermented from starch broth it is
a “natural product”
* Malic acid is far more abundant in nature
* Both Citric and Malic are made commercially in chemical plants
* Citric Acid has not been extracted from the juice of limes and
lemons since the 1920’s
* Both Citric and Malic form part of the Krebs Cycle (metabolic
pathway of living organisms)
* Generally fermentation processes result in more side streams
and (undesirable) by-products than a pure chemical synthesis
Synthesised products versus natural products
* It is now widely accepted that the highly sophisticated human
body is able to develop the enzymes to deal with both l- and dlenantiomorphs of Malic acid, as with lactic acid
* The lactic acid fermentation gives a range of pure dl-Lactic to
l-lactic acids. Infants of 2-4 weeks easily handle dl-Lactic acid
* Synthetic dl-Amino Acids have greater dietary value than
“natural” l-Amino Acids
* Malic is considered to be GRAS by the FDA
* Both Malic and Citric are specified in all food codices and
pharmacopoeias
What is “natural”? Both Malic and Citric are fruit acids
Malic Acid versus Citric Acid
MISNOMER THAT CITRIC IS A BETTER FOOD ACIDULANT THAN MALIC ACID
“Citric has three acid groups,
therefore is a better food
Acidulant”
* Not so! The third carboxyl group plays not role in the
“gustatory titration”. (Only 2/3 of the citric is neutralized
below a pH of 7.0)
* Less Malic is required for the same tartness level
* Citric is hydroscopic; Malic acid is not (and does not cake)
* Malic (130oC) has a lower melting point than Citric (150ºC)
resulting in lower and less degrading process temps.
* Malic is a better buffer (3.26 index) than citric (2.46)
* Both Malic and Citric are highly soluble
* Malic and Citric are both equally good chelating agents
* Malic has a longer lasting tartness than citric
* Malic acid masks the intense sweetness or bitter after taste
of synthetic sweeteners
* Malic acid is able to meld very effectively with flavourants
because of its smooth tartness profile
The above are only some of the advantages of using Malic instead of citric in food uses
Malic Acid versus Citric Acid
MISREPRESENTATION THAT CITRIC ACID HAS A BETTER TASTE
Citric has the “correct” flavour for
Orange drinks
* None of the food acids have any flavour notes, let alone
a citrus flavour
* Tartness is perceived, not flavour. Tartness or
sourness is linked to the availability of H3O+ ions
* No acid flavour links citric acid to the orange, malic acid
to the apple, or tartaric acid to the grape
* What is important is the melding together of the correct
quantity of acid + flavour + sweetness
Taste trials by a trained panel indicate that the “burst” of acidity claimed for Citric Acid is somewhat
exaggerated, and is more than compensated for by the longer lasting tartness of malic acid.
Malic Acid versus Citric Acid
MALIC ACID WAS PREVIOUSLY NOT EASILY AVAILABLE AND WAS RELATIVELY HIGH PRICED
Despite the savings in usage (+/- 10%), Malic
was priced (+/- 15-20%) higher than Citric
* Improved technology has resulted in lower
costs of Malic acid
* Improved availability of Malic is a result of
more producers and larger plants
* Isegen Malic aid is back-integrated with the
basic raw material with resultant synergy
Isegen has already implemented the next expansion of its Malic acid facility
MALIC ACID VERSUS CITRIC ACID - Buffering Indices
Comparison of the Buffering indices of Malic and Citric
acids.
Buffering index
Citric Acid
Malic acid
2.46
3.26
Note:
The higher the buffering index, the more effective is the acid as
a “food acidulant”.
Malic Acid versus Citric Acid - Adsorption Isotherm
Adsorption Isotherm
Malic Acid vs Citric Acid
18
16
Water Content (%)
14
12
Malic Acid
10
8
Citric
6
4
2
0
0
15
32
52
75
90
98
Relative Humidity
Results from actual trials run by the Council of Scientific and Industrial Research (CSIR)
Malic Acid versus Citric Acid - pH Profiles
Ph Profiles
2.6
2.4
2.2
pH
2
1.8
1.6
1.4
1.2
1
0.25%
0.50%
0.75%
1.00%
Concentration
DL-malic
Citric (Anhydrous)
Only at higher concentration (far too high for use in foodstuffs) does citric reduce the pH
more than malic acid.
In the 0.1% to 0.3% range (used in foods) less malic is required than citric for the equivalent
pH level.
Malic vs. Citric Solubility in water
120
Concentration % m/m
100
80
60
40
20
0
0
10
20
25
30
40
50
60
Temperature deg.C.
Citric
Malic
70
75
80
90
100
MALIC VS CITRIC - Equi-acid concentrations
Equi-acid concentrations of malic acid compared to 0.2% citric
acid
(Done by the CSIR in an independent test)
Units of acid required to achieve similar tartness
Citric acid (Monohydrate)
Malic acid
100.0 parts Citric acid (Anhydrous) 100.0 parts
78.5
Malic acid
85.8
Article on Acidulants by Townsend J. Sausville
Substituting one acid for another
At equal concentrations, the acidulants vary in their ability to
depress pH and in the degree of acidic taste produced, or
intensity of tartness.
The following replacement percentages using citric anhydrous
as equal to 100% based on experience:Citric anhydrous
100%
Fumaric
67-72%
Tartaric
80-85%
Malic
89-94% (in citrus flavours)
Malic
78-83% (in fruit flavours)
Adipic Acid
110-115%
Phosphoric (85%)
55-60%
Extracts from
Encyclopedia of Food Technology, Johnson & Petersen: - In a
discussion of one acid for another:“From 10% to 20% less malic acid gives approximately the same degree of
tartness as citric acid”.
This is confirmed on page 239 - Handbook of Food Additives:“It is stated that malic has a much stronger apparent acidic taste than citric
although the ionization of the two acids is much the same”.
Article by Allied Chemical Corporation, USA titled “Choosing and
Acidulant” states:“Malic acid differs from other food acids in its effect on taste sensations. It
has a stronger apparent acidic taste than citric acid in water and in
aqueous solutions containing other taste stimulating materials. Thus,
only 80 to 90 per cent by weight compared to citric is required in many
formulations.”
Article by University of California in American Journal of
Enologists and Viticulture
Results of sensory evaluation of equi-sourness between citric acid and
dl-malic acid in distilled water solutions at three levels of acidity
Fixed citric conc.
(g/100ml)
0.10
0.20
0.30
Varied dl-malic conc. % of judges
(g/100ml)
reporting malic as
more sour
0.05
4.17
0.06
4.17
0.07
16.67
0.08
33.33
0.09
75.00
0.06
0
0.10
0
0.14
25.00
0.18
87.50
0.22
100
0.12
0
0.16
4.17
0.20
12.50
0.24
75.00
0.28
91.67
Calculated equi-sour
level (g/100ml)
0.079
0.152
0.221