white granule powder, MP121.5-123.5ˇăC,
Application: antiseptic,anti-microorganism agent
Chemical Name: C6H5COOK, F.W.: 160.21
CAS No.: 582-25-2
Potassium Benzoate is the potassium salt of benzoic acid. 1 gram of the salt is soluble in 2 ml of water, in 75 ml of alcohol, and in 50 ml of 90% alcohol. The salt is insoluble in ether. Potassium Benzoate is used as a food preservative. Potassium benzoate offers an alternative to sodium benzoate for products that require a low-sodium content. Potassium benzoate may be employed in a wide range of preservative applications because of its antimicrobial action and low taste. It is also generally recognized as safe (GRAS) by the FDA. It is most suitable when used in foods and beverages with a pH of 4.5 and below and is not recommended for use when the pH exceeds 4.5.
The lower the pH level, the greater the effectiveness of potassium benzoate on yeast, molds and bacteria. To maximize its effectiveness against enzyme formation, it is recommended that it be added at the earliest processing step possible.
The use of potassium benzoate as an alternative to sodium benzoate is becoming more popular for applications where a low sodium content is desirable. It is used in a number of the products we consume every day. Potassium benzoate is used in both carbonated and non-carbonated beverages, fruit and fruit juices, syrups, jams and jellies, prepared salads, tomato-based products, margarine, olives, pickles, and other condiments.
Potassium Benzoate is the potassium salt of benzoic acid. 1 gram of the salt is soluble in 2 ml of water, in 75 ml of alcohol, and in 50 ml of 90% alcohol. The salt is insoluble in ether. Additional solubility data (from the literature) for the salt in water is as follows:
Grams Potassium Benzoate
Per 100 Grams Sturated Solution
Potassium benzoate is a slightly hygroscopic, white, odorless or nearly odorless product. A typical aqueous solution of potassium benzoate will be slightly alkaline with a sweetish astringent taste. It is offered for sale in a densified granular form. The bulk density of potassium benzoate is ~ 45 # / ft3. Potassium benzoate contains 76.2 % of available benzoic acid.
Potassium Benzoate application:
1. FOOD AND BEVERAGE PRESERVATIVE:
Food and beverage spoilage has been a problem throughout history. Most food
spoilage is due to enzyme action upon the food. Enzymes are complex organic
compounds that may act as catalysts and cause a chemical change to occur.
Most enzymes that cause food to spoil are produced by living microorganisms,
e.g., bacteria, molds, and yeast. Fresh foodstuffs may have some of these
microorganisms present and others may be encountered by exposure to air or in
The enzymes that cause spoilage may be generally described as two types which
are (1) "endoenzymes" which exist within the microorganism and (2)"exoenzymes" which are released by the microorganism. The quantity of
microorganism enzymes causing food to spoil is directly related to the amount of
the microorganism present, its species, and its general activity.
By its general nature, food cannot resist the action of enzymes which may lead to
food spoilage. Thus, the elimination of food spoiling enzymes is accomplished
most easily by either (1) destroying or (2) inhibiting the source of the enzymes
which are the microorganisms themselves.
There are basically four generally accepted methods for preserving foodstuffs
and these methods rely on one or the other of these above mentioned methods of
microorganism control. Sterilization by heat or radiation destroys the
microorganisms; refrigeration reduces or stops the activity of the
microorganisms; drying reduces or stops the activity of the microorganisms by
removing essential water; and chemical preservatives reduce or inhibit the
activity of the microorganisms.
The addition of chemical preservatives to food is not new and has been practiced
for centuries. Some of the most familiar preservation methods; those of brining,
pickling with vinegar, smoking, and preserving with sugar solutions, depend upon
chemical preservatives. These methods inhibit microorganism activity and retard
microorganism growth and multiplication. These methods act in one of two
generalized ways-. (1) by physically increasing the density of the microorganism's
environment (raising osmotic pressure) or (2) chemically, by a direct inhibiting
action on the microorganisms themselves.
Consequently, chemical preservatives which perform by a direct inhibiting action
on the microorganisms themselves are not new. Potassium Benzoate is a
chemical preservative, which in very low concentrations inhibits the activity of the
The effectiveness of potassium benzoate as a preservative increases with
decreasing pH (increasing acidity). This is because the ratio of undissociated
benzoic acid (free benzoic acid) to ionized benzoic acid increases as the pH
decreases. It is generally accepted that the undissociated benzoic aid is the active
antimicrobial agent. Although no definite theory has been yet proposed to explain
this antimicrobial effect, it is believed to be related to the high lipid solubility of
the undissociated benzoic aid which allows it to accumulate on the cell
membranes or on various structures and surfaces of the bacterial cell, effectively
inhibiting its cellular activity.
Potassium benzoate has activity against yeast, mold, and bacteria. Although
several studies have been performed on the antimicrobial activity of benzoic acid
on these species, it is difficult to obtain substantial evidence on relative activities
against specific members of those general species. Actual field application trials
are recommended for assurance of satisfactory antimicrobial activity against the
species in question.
At low pH values, potassium benzoate may impart a slight tang in taste
attributable to the undissociated benzoic acid. If this effect is undesirable, it may
be overcome by using other applicable approved preservatives in conjunction
with potassium benzoate to lower the concentration of potassium benzoate below
the taste threshold.
An important consideration in preserving with potassium benzoate is the addition
of the preservative as early as possible in the food processing. The early addition
of potassium benzoate will prevent the microorganisms from forming enzymes
which may continue to cause deterioration, even though the microorganism
growth will be inhibited at the later stage in processing.
One of the most important considerations in preserving with potassium benzoate
is the maintenance of absolute cleanliness. It should be clearly understood that
although preservatives such as potassium benzoate serve a very useful purpose
in foods, they cannot take the place of cleanliness in food processing. Products
that have already spoiled will not benefit from the use of potassium benzoate as a
Potassium benzoate may be added conveniently and efficiently in the form of a
concentrated stock solution in water. A simple stock solution may be prepared by
dissolving one pound of potassium benzoate in one gallon of water. One fluid
ounce of this solution when added to one gallon of beverage gives a concentration of about 0. 1 % potassium benzoate. If the specific gravity of the
beverage is significantly higher than water after potassium benzoate is added in
processing, and an acidic pH adjustment is needed with the addition of a strong
acid such as citric acid, sufficient agitation should be available to prevent
localized precipitation of benzoic acid, which has a solubility of about 0.3 % in
water at 20'C. This processing step is important because the relatively water
insoluble benzoic acid may precipitate inside the processing vessels and lines
causing plugging problems and loss of essential preservative in the total batch
Potassium benzoate may be used in carbonated and still beverages, syrups,
cider, salted margarine, olives, sauces, relishes, jellies, jams, preserves, pastry
and pie fillings, low fat salad dressing, fruit salads, prepared salads, and in
storage of vegetables. Keep in mind that both federal and state regulations may
apply to specific applications. These regulations should be reviewed and verified
as applicable or non-applicable for each specific use application.
Potassium benzoate may be used in carbonated beverages with 0.03 to 0.08 %
typically used for the finished products. Potassium benzoate may also be used to
preserve the flavor syrup prior to the addition of the beverage acidulant. Noncarbonated
beverages normally require somewhat higher concentrations of 0.05
to 0.1 % potassium benzoate in the finished products.
The shelf life of un-pasteurized cider can be greatly extended by adding
potassium benzoate as soon as the juice is pressed. A slight tang, which many
tasters apparently prefer, may be imparted to the cider by concentrations of
potassium benzoate as low as 0.04 %.
METHODS OF ANALYSIS:
General methods of analysis for potassium benzoate (as benzoic acid) in food and drug
products are described in Official Methods of Analysis of the Association of Official
Potassium benzoate is slightly hygroscopic and should be stored in sealed containers.
Exposure to conditions of high humidity and elevated temperatures should be avoided.