Importance of Salt in Dairy Products and Sodium Reduction Strategies in Food and Dairy Products

Abstract

Salt (sodium chloride, NaCl) is the oldest food additive known used for the enhancement of the sensory properties of the food, extending their shelf-life and maintaining food safety. Although salt is one of the components that is needed for human body to maintain the normal physiological activity, high intake of sodium found in the composition of salt leads especially to heart disease and high blood pressure, and therefore sodium intake is limited. Usually foods contain more sodium than human requirement and table salt, baking powder and baking soda are the richest sources of sodium. The majority of the consumed sodium comes not from the salt added to the food in dining table but from the processed foods. New salt reduction strategies have been developed for many food products including dairy products. In this review, purposes of using salt in food products and salt reduction strategies including the use of salt substitutes were discussed.

Full text

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Agro FOOD Industry Hi Tech - vol. 28(2) - March/April 2017
KEYWORDS: Dairy products, salt, sodium chloride, hypertension, salt reduction, human health.
Abstract Salt (sodium chloride, NaCl) is the oldest food additive known used for the enhancement of the sensory
properties of the food, extending their shelf-life and maintaining food safety. Although salt is one of the
components that is needed for human body to maintain the normal physiological activity, high intake of sodium found in the
composition of salt leads especially to heart disease and high blood pressure, and therefore sodium intake is limited. Usually foods
contain more sodium than human requirement and table salt, baking powder and baking soda are the richest sources of sodium. The
majority of the consumed sodium comes not from the salt added to the food in dining table but from the processed foods. New salt
reduction strategies have been developed for many food products including dairy products. In this review, purposes of using salt in
food products and salt reduction strategies including the use of salt substitutes were discussed.
Importance of salt in dairy products
and sodium reduction strategies in food and dairy products
these foods is decreasing signi cantly (5, 6). Although salt
gains importance in terms of preserving the microbiological
properties of foods as well as enhancing the sensory properties,
it has negative effects on the human health. In this review, the
importance of salt in food and dairy products were discussed
and the salt reduction strategies were explained.
THE ROLE OF SALT IN DAIRY TECHNOLOGY
Salt in cheese, in addition to taste-aroma and quality enhancing
functions in the product, has a preservative role. The preservative
effect of the salt is particularly related with its water activity (aw)
lowering mechanism. It is considered that water in cheese
which is not contributing to the vapor pressure is held by the
cheese matrix. This held water is thought be not available for
microbial activity. Additionally, salt increases the osmotic pressure
of the aquatic phase of the food and causes the dehydration
of the bacteria, thus eliminates them and/or prevents their
development. As NaCl directly maintains the salinity of the cheese
and affects the aroma, it is a desired ingredient.
Saltless cheese aroma is generally described as tasteless
and irriguous. It was mentioned that salt content should be
0.8% minimum (7-9).
Salt controls the microbiological and enzymatic activities and
indirectly affects the cheese aroma. These conditions are
the formation of aroma components as a result of lactose
metabolism, pH value of cheese, reduction of milk fat and casein,
formation of peptide, free amino acids and free fatty acids. In
addition to these functional properties, it affects pH and calcium
levels, paracasein hydration or aggregation, water-holding
capacity of the casein matrix, serum separation, rheological and
textural properties and cooking properties (7-9).
The salt used in concentrated dairy products neutralizes the
acidic taste of the product. There are concentrated fermented
ECEM AKAN, OKTAY YERLIKAYA*, ÖZER KINIK
*Corresponding author
Ege University, Faculty of Agriculture,
Department of Dairy Technology, Bornova-İzmir, Turkey
Oktay Yerlikaya
INTRODUCTION
Sodium chloride (salt) has been used as a preservative and
 avour enricher for years. It preserves food against microbial
spoilage, extends shelf-life and improves the  avor of food.
Sodium is largely consumed through chloride salt and
it is estimated that at least 75 % of sodium intake in
the industrialized diet originates from NaCl added to
manufactured foods (1). Nowadays, salt has gained much
signi cant role in terms of nutrition and public health.
Cardiovascular diseases are the most important public health
problems and they are the primary cause of death for humans.
Sodium is an ingredient in salt which is a potential health threat
especially affecting blood pressure. It has been reported
that excessive dietary sodium is associated positively with
hypertension, which in turn causes cardiovascular diseases (2).
The recommended daily intake for salt is 6 g NaCl (3) and
the average NaCl consumption is 18 g in Turkey. Both foreign
institutions and the government agencies in Turkey initiate new
action plans for reducing sodium in foods due to its adverse
effects on human health. Additionally, consumer demands
indicate foods with reduced sodium contents (4).
Dairy products comprise substantial part of total sodium intake
in the diet. Various types of cheeses, ayran and butter contain
varying levels of salt and particularly cheeses have high levels
of salt in their composition. It is crucial to decrease sodium levels
in foods but when reducing salt in foods, there will be some
problems such as acidity, proteolysis, water activity and bacterial
growth. Thus, using mineral salt substitutes become widespread
with regards to decreasing sodium level and maintain protective
effect of salt on foods. Combination of sodium chloride with
potassium chloride, calcium chloride and magnesium chloride
is a way to reduce sodium level in food. In several researches,
mixtures of sodium chloride with different mineral salt replacers
have been used successfully in various foods and salt level of
INGREDIENTS: SUGAR
AND SALT SUBSTITUTES

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second thought especially if you go through it quickly in baking!), so
 avor is much more important. Salted butter enhances the taste of
toasts and other foods as the salt bring out not only the butter  avor,
but the other  avors that are in the food. There is no need to add
salt in the food if you are cooking with salted butter. Therefore it is
probably not a good idea to use salted butter while baking (17, 18).
SODIUM REDUCTION STRATEGIES IN FOOD AND DAIRY PRODUCTS
Although sodium is an essential component in human diet, excessive
intakes have undesirable physiological effects. The most signi cant
physiological effects are hypertension and increased calcium
excretion which can lead to osteoporosis. The recommended daily
requirement of sodium for the adult human is approximately 2.4 s
Na+ that is equivalent to 6 gram NaCl per a day. Sodium intake in
Western diet is 2-3 fold higher than daily requirement. This situation
has caused to dietary Na intake reduction and increased demand
for reduced sodium foods including cheese. Various governments
and others take holders in the food industry are concerned about
salt reduction and these caused in modelling of various innovative
approaches for important reduction of salt intakes by consumers
and the improvement of proper methods which lead to no health
risks. These methods include initiatives on using ingredients like
potassium chloride, calcium chloride, extract from yeast and  avour
improvers which give similar sensorial attributes (19, 20).
A simplest view on sodium reduction is just tell consumers they
eat too much sodium and expect them to change their eating
behavior. Sodium reduced diets are dif cult to maintain as they
require a change in dietary behavior, for example choosing low salt
foods which there is limited level on market (21, 22). It is accepted
concept that sodium reduction might be more effectively by
decreasing the sodium content of processed foods and by applying
multisensory principles as enhancing aromas, to optimize the  avour
characteristics than by giving dietary advice (23).
Results from many studies suggest a role for minerals in blood
pressure regulation. Sodium may increase blood pressure,’
whereas the reverse has been reported for potassium and
magnesium. Several studies have shown a stronger relation of
the sodium to potassium ratio with blood pressure than sodium
or potassium alone. Hence dietary measures to reduce blood
pressure might be more effective when the intake of several
minerals is changed simultaneously (24).
Many methods of salt reduction have been developed, an ideal
situation could be the replacement of sodium with numerous
compounds that elicit a similar saltiness when consumed (25). They
claim to either enhance the salty  avour or replicate the function
of salt without affecting the sodium content whereas they do not
have the preservative effect of salt. Therefore producers need
to be cautious if using salt replacing ingredients in reduced salt
products. Strategies for reducing salt in cheese include mainly
the reduction of the salt sodium chloride and its replacement by
salt replacing agents such as potassium chloride (20). But, these
applications present many challenges such as adverse effects on
 avour, microbiological and rheological stabilities and functional
properties of the end product. When salt content is simply reduced
in cheese, proteolysis, water activity and bitterness all might be all
increased while hardness might be decreased. Also undesirable
fermentations could occur which may the desired characteristics
taste of the cheese etc. Potassium chloride can generally only
substitute up to 30 % of salt in majority of food products. At higher
using levels potassium chloride has caused to a noticeable  avour
which some consumers  nd unpleasant. Therefore to help reduce
the unpleasant taste, it is usually blended with chloride and other
milk products in Turkey and other countries added salt at different
levels. In Table 1 sodium contents of some dairy products are
given. Salt use in concentrated milk products including winter
yoghurt both extends the shelf-life of the product and provides a
unique taste. Ayran is a traditional dairy product. It is produced
by the fermentation of semi-skimmed or whole milk with yoghurt
bacteria, reconstitution of approximately 35% and salt forti cation
of approximately 1% (10-13). Salt is normally added to the
dairy products under aseptic conditions, if possible, before the
packaging. Salt has a negative effect on the stability of the
product, therefore it is added after the heating process applied
to the fermentate. Theoretically, pectin reacts with the proteins
before the forti cation with the salt (14).
Nilsson, Lyck and Tamime (14) mentions that the salt solution that
will be added to the product can be sterilized by passing through
a sterile  lter before aseptic  lling of the product. Yoghurt and
similar fermented milk products are used in the production of
drinks or beverages as the base component of the production.
These products are consumed by drinking from the glass or
directly from its container. Chemical composition and viscosity
of such fermented dairy drinks vary in a wide range. Consumers
in some markets may demand products with viscous drinking
while some prefer salty products with low viscosity. Adding a small
amount of salt to the fermented drink is very popular in most
Middle Eastern countries including Turkey and Pakistan (14).
Butter is mostly produced unsalted. However, taking
the consumer preferences and legal regulations into
consideration, salted butter production is carried out in many
countries. Particularly in times when raw milk cream is used for
butter production and cold chain could not be provided, salt
addition was a mandatory application.
If the butter produced for meeting the consumer demands
although it masks the characteristic taste and aroma of butter, it
should be carried out after washing application (15). Salted butter
is produced by adding salt in the unsalted butter in the butter-
making process. Salt, as wells as its role in the taste, preserves
the product and extends the shelf-life - the average shelf-life of
salted butter is  ve months when refrigerated while this period is
three months in unsalted butter. What is the exact amount of salt
in the salted butter? In comparison between four major butter
brands, it was found that the average salt content of sodium
per 10 g serving was 80 mg. This corresponds to 8 mg of sodium
for 1 g butter. These calculations were conducted using some
mathematical methods based on some approximations. If a
salted butter is used in a recipe using unsalted butter the amount
of additional salt should be reduced according to the amounts
mentioned above. If the recipe does not call for any salt, then
the  nished product will de nitely be saltier (16). Salt has two
roles in butter. It preserves the product and acts as a  avoring
agent. As the refrigeration is so reliable in today’s technological
conditions, most people don’t need to give butter spoilage a
Table 1. Sodium contents of some dairy products (27).

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mineral salt substitutes in order to reduce the metallic taste (20, 25).
Another way of the salt reduction is using to taste enhancers.
Sodium chloride affects the taste of specic foods by providing
the avor of saltiness, by enhancing of masking other avor,
and by controlling growth of microorganisms. Currently there
are no compounds that can effectively substitute for the avor
of sodium chloride in foods. Lithium compounds are salty
but they are toxic in amounts that would be needed as salt
substitutes. Calcium and potassium compounds have some
salty avor but, they also have off avours such as a metallic or
bitter taste. Taste enhancers include autolysed yeast extract,
monosodium glutamate, hydrolyzed vegetable proteins,
gluconoic acid-8-lactone, glycinamide hydrochloride, 5
ribonucleotides etc. These compounds are added into recipes
to encourage the avour. Especially the umami taste increases
the perceived salty taste without the high sodium content.
Whereas the taste enhancing ingredients provide a strong
avour, they have negative organoleptic and health problems
related to some of these ingredients. Especially mono sodium
glutamate is associated with possible health problems
covering sickness, migraines and hyperactivity etc. (26).
Salt reduces water activity in foods thereby acting as
a critical hurdle to control of pathogens and spoilage
organisms. If sodium chloride levels are decreased it can be
necessary to increase concentrations other antimicrobials
and more carefully control cooking or storage temperature
to ensure safety foods with a reasonable shelf life. So, if salt
levels are reduced, it may be necessary to use some other
compounds. Natural antimicrobials or organic acid are
becoming increasingly popular and to support this trend. Such
compounds are used as chemical preservatives to reduce pH
and can be used to ensure microbiological safety (23).
Currently also many methods of salt reduction strategies have
been developed which may gradual reduction by stealth,
modication of the structure of sodium chloride, reduction
of salt over period of time or emerging technologies in salt
reduction such as changing the food matrix, encapsulation of
salt in emulsions (20).
CONCLUSION
There is now conclusive evidence that high sodium intake is related
with elevated blood pressure and increased risk of cardiovascular
diseases. When all of the dietary nutrients such as salt, saturated
fat, etc. considered, the evidence for salt is robust and strong.
Thus National and International organizations are developing
programs to sodium reduction which cover educational and
labeling activities. Moreover the food industry is encouraged
to reduce sodium levels in processed foods including bread,
cheese, pickled oil, snacks etc. The consumer preferred saltiness
in products depends on the habitual salt intake and lifespan
changing. Therefore the industry is investigating strategies that
will maintain the salt intensity at lower levels. Currently applied
methods are resulting to the approximately 20- 30 % salt
reductions without affecting the sensory acceptability. Today
to achieve larger reductions it is studying on new technologies.
REFERENCES
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