Preservatives in food (salt, sugar or vinegar)
With focus on salt
Preservatives in food (salt, sugar or vinegar)
Preserving food has been part of human culture and a way to store food since ancient times.
Our ancestors used different techniques or processes for food preservation so that they could protect
food from microorganisms, bacterial growth for future consumption. The main natural preservatives
used were and continue to be (among others): salt, sugar and vinegar by the method of pickling, curing
and sugaring. Salt speeds the drying process by osmosis and prevents the growth of bacteria. For
pickling, as an example we use vinegar which kills and inhibits bacteria and other microorganisms.
Whereas earliest civilizations used to preserve fruits by immersing them in honey.
For our project the main focus is going to be salt and its characteristics, as well as its history and impact
on human health.
CLUSTER A: Element Profile
|Number of Isotopes||20|
Sodium is an Alkali Metal. When it becomes an ion it loses an electron and becomes a cation with a
charge of +1. It can be part of polyatomic Ions such as NaOH. It has 20 isotopes and 2 radioisotopes,
22Na and 24Na. Sodium is a soft silvery white metal which is a good conductor of electricity. It can float
on water. It has low ionization energy. It is the 6th most abundant element in the earth crust. It is used
in road de-icing, producing glass, paper, soap and textiles.
CLUSTER B: Compound Profile
Sodium Chloride (NaCl) – Salt
Sodium chloride or salt is an ionic compound made up of 1 sodium and 1 chloride ions which is small,
transparent, and colorless to white cubic crystal. It is solid at room temperature and odorless as well.
The melting point for solid sodium chloride is 800.70C and a boiling point of 1465oC. The molecular
weight is 58.4428. The weight percentage of Na+ is 39.34% whereas Cl- is 60.66% in the compound .The
ions of Na+ and Cl- are very strongly attracted to each other that only highly polar solvents such as
water can dissolve NaCl well, otherwise it is insoluble or slightly soluble in most other liquids. When
dissolved in water, sodium chloride disintegrates into Na+ and Cl- ions surrounded by polar water
molecules. The pH of NaCl is approx. 7 which makes it a neutral compound.
CLUSTER C: Connections
Both, the element of sodium and the molecule sodium chloride are integral part of salt. Basically
salt is sodium chloride and vice versa. Sodium on the other hand as an element is widely known as a
component of salt and in many instances people mistakenly use them interchangeably.
Other elements and chemicals that are part of the topic are:
a) sugar C12H22O11, also known as sucrose (saccharose, a saccharide) which is made in different
plants such as beets and sugarcanes,
b) vinegar, which consist of acetic acid CH3COOH created from fermentation of ethanol by bacteria.
Among these substances, salt is my favourite as it has, in my opinion, a simple yet elegant and powerful
formula as a compound which can be used to explain atomic bonding as well as other chemical
processes in clear, easy to understand fashion.
That is the reason why we’re focusing more on Na and NaCl for the purpose of explaining and providing
information about salt.
CLUSTER 1: History of Salt
Salt has been part of human life and history since ancient times. Salt can be obtained either
Through mining or evaporation of seawater. Over millions of years rain, rivers and streams have washed
over rocks containing salt or sodium chloride compound and carried that to the sea, which is the
explanation as to why the sea and ocean water is salty. Salt’s history with humans goes as far back as
6050 BC, it has been recorded 4700 years ago in ancient Chinese writings which described more than 40
types of salt and two methods of extracting salt which are similar to what we still use today. Humans
have used salt for thousands of years from food preservation, which was a founding contributor to the
development of civilization, to seasoning.
Early civilizations understood the importance of salt and its availability was crucial to their prosperity.
Every empire throughout history has sought to control it and even use it as currency, sometimes worth
more than gold . The Natron Valley supported the Egyptian empire by supplying it with a kind of salt that
came to be called natron. The Phoenicians proved themselves to be masters in extraction and trading of
salt. It was the Romans that took all of that to a higher level of production and trade through a
worldwide network. Ships bearing salt crisscrossed the Mediterranean Sea, caravans crossed the dessert
from Morocco to Timbuktu, then to Libya and beyond. Venice become wealthy by trading salt with
spices from Asia in Constantinople. The Latin roots of words such as “salary”, “soldier” are connected to
salt as related to giving or receiving it. In the early years of the Roman Republic, roads were built to
make transportation of salt to the capital easier, notably Via Salaria (Road of Salt), which connected
Rome to Adriatic Sea as it had higher salinity than the Tyrrhenian Sea, much closer to Rome. Salt was
such a precious commodity that Greeks and Romans used salt to buy slaves which spawned the phrase
for when someone is not worthy then that someone is “not worth his salt”.
During the Middle Ages, various superstitions surfaced around salt. Spilling salt was considered bad
omen, so the spiller had to throw a pinch of salt over his left shoulder because the left side was
considered sinister, where the bad spirits congregated. We see this in Leonardo Da Vinci’s masterpiece
“The Last Supper” where Judas is shown with a dropped saltcellar in front of him.
The gabelle, the French tax on salt from 1286 -1790, was widely hated and was one of the main
contributors to the French Revolution. Whereas in the 16th century a Dutch revolt against King Philip II of
Spanish Empire was successful when they blockaded the Iberian salt works which led to Spanish
bankruptcy. It is also recorded that thousands of Napoleon’s troops died during their retreat from
Moscow as they wounds would not heal due to lack of salt.
Moving closer to home, salt has played an important role in North American history as well. The Erie
Canal, opened in 1825, was mainly built to ease salt transportation, which made many refer to it as “the
ditch that salt built”. In the American Civil War, salt was so important that The Union Army fought a
fierce battle in 1864 to capture Saltville, Virginia from the South, which created a salt shortage in the
Confederate states. In Canada, Windsor Salt is more than a century old.
CLUSTER 2: Reaction Profile
In this part we going to have a brief look at various reaction profiles of our compounds.
2 Na (S) + 1 Cl2(G) → 2 NaCl (S)
Sodium chloride’s formed through a chemical reaction called synthesis
Sodium chloride is a strong electrolyte as it completely ionizes when dissolved in water.
When it comes to sugar, dissolving it in water is a physical reaction as we have no chemical change in
In terms of vinegar, an interesting chemical reaction to mention is with baking soda, as it occurs in two
In general we have,
NaHCO3(s) + CH3COOH(l) → CO2(g) + H2O(l) + Na+(aq) + CH3COO–(aq) or another way of writing it:
NaHCO3 + HC2H3O2 → NaC2H3O2 + H2O + CO2 which goes through
a)NaHCO3 + HC2H3O2 → NaC2H3O2 + H2CO3 —- here we have double displacement reaction to form
sodium acetate and carbonic acid
b) H2CO3 → H2O + CO2 —– Carbonic acid being unstable, undergoes decomposition reaction and
produces carbon dioxide gas
CLUSTER 4: Implications for Human Health
As we mentioned before, salt has been part of human life since ancient times. It helped our
ancestors preserve food, cure hides and heal wounds. There has been a lot of debate regarding salt and
its health effects on human health. Lately salt has been cast as villain when it comes to hypertension and
heart disease. But evidence shows that salt can be both beneficial and harmful depending on use
When it comes to its harmful side, too much salt can raise blood pressure (which the leading
cause for cardiovascular disease), increase chance of a heart attack or stroke. Studies have shown that
high salt intake might be responsible for stomach cancer, also known as gastric cancer, as well as
damage to stomach lining and growth of bacteria which in turn might lead to inflammation and stomach
ulcers. That’s why many health authorities recommend a daily amount of no more than 2300 mg of
sodium a day.
But what happens if we take to little salt? There is some evidence that shows that might be harmful as
well. Low salt intake has negative health effects such as:
- High LDL (bad) Cholesterol and triglycerides.
- Increased risk of dying from heart disease and increase risk of dying for people with heart failure.
- Increases insulin resistance.
- Increase risk of death in people with Type 2 diabetes.
- Reduced hydration, especially in athletes.
- Muscle cramps.
- Headache & Weakness.
Salt is an excellent source of electrolytes and helps prevent muscle cramps. It helps thyroid function
properly. It is a good remedy for gum disease, infections, mouth sores. That’s why when we go to the
dentists they recommend salt water rinses as they promote healing and help with tissue inflammation.
Recently, some researchers are recommending that health authorities not issue blanket guidelines for
the general population as the salt intake recommended levels vary from people to people. For example,
the traditional Japanese diet is very high in salt intake, but the Japanese have low rates of cardiovascular
disease and the highest longevity in the world.
However the debate regarding salt and its health implications goes, salt will remain with us for a long
time, giving flavor to our daily meals.
Food preservatives are important to our daily lives, as they’ve been to the lives our ancestors.
They have helped human civilization evolve and progress, as well as make our food tasty. This project
helped me learn a lot more about the science behind them, the history and health implications on
humankind. This paper is by no means an exhaustive treatment of the topic, but rather a brief insight
into it with a main focus on salt as a food preservative.
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