is the important things in our life. Food is acting as fuel to our body. Food
also supply protein and mineral to support body development and growth. Some
nutrients needed by body to recover the parts that are broken. Therefore, food
is very important to our life. One of the problems when talking about food is food preservation. As we know, food is containing
bacteria or microorganism. This microorganism in food causing the food begin to
rot or spoilage. The food that rotten can’t be consumed because it will harm
our body. The rotten food also decreasing the nutrients contained in food
itself. Since long ago, human kind has
conducted research about how to preserve food. The purpose to preserve food is
to extend shelf life, maintain sensory properties, maintain or improve
nutritive properties, ensure safety, make the food is easy to consume or easy
to digested by body and make the economic value increase. After so many
research and experiment, the scientist found the ways or methods to preserve
food and the methods has divided into 5 major different methods.
first methods is heating process. Heating process is a methods using high
temperature around 500 C-1500C to eliminates
microorganism that contained on food so the shelf life of the food product can
be extended. Sometimes, the nutrients inside the food will be damaged in
exchange. The example of this method is blanching and pasteurization. According
to (BAT in the Food, 2005) blanching operations
are designed to expose the entire product to high temperatures for a short
period of time, by using steam heating (with temperature above 1000C)indirectly
for fruit juices and directly for vegetables while pasteurization is the
process of heating a liquid to below the boiling point (900C-1000C)
to destroy microorganisms. Sometimes the pasteurization methods can use high
temperature above the boiling point but short time exposure, this process that
we called Ultra High Temperature or UHT. The example product is milk, yoghurt,
green beans porridge.
The second is low temperature treatment.
Low temperature treatment is a methods exposing food or saving food in the low
temperature below 40C. This methods divided into 2 that is
refrigration and freezing. Refrigeration is defined as the science of
maintaining the temperature of a particular space lower than the surrounding
space (Khemani, 2008) . Based on (Robinson, 2013) statement, freezing process is a
combination of the beneficial effects of low temperatures at which
microorganisms cannot grow, chemical reactions are reduced, and cellular
metabolic reactions are delayed. The difference between two methods is the
temperature. The temperature used in refrigaration is 00C- 40C
while the freezing methods using 00C to 40C below
freezing point. Both methods allow the food shelf life to be extended because
of the germ and microorganism inside food will be inactivated. This method
makes the food lost some nutritive value.
The next method is dehidration or
drying. Food dehydration is the process of removing water from food by
circulating hot air through it, which prohibits the growth of enzymes and
bacteria. It can makes food to be stored longer than usual. Based on International Journal of Food Nutrition and
Safety written by (Ahmed, 2013), dried foods can be
stored on room temperature until a month or longer because the water inside the food has been
reduced so the microorganism inside food can’t grow because lack of water. Some
food can’t be preserve with this method. Some fruit can’t be dried such as
water melon and pumpkin. The example product is fish, dried meats, dates.
The next is Acidification. According to
Journal that written by (Ekanayake, 2010) “Acidfication is process for
acidifying and preserving a food product. The process can include providing a
food product having an initial pH, acidifying the food product to a final pH to
produce an acidified food product”.
In simple, acidification methods is a method that makes food has pH below 7.
The acid makes microorganism can’t grow because microorganism only grow if the
pH is around 7. So, the process prevent the microorganism from multiplying. The
example of this method is pickling,
sugaring and salting. The question is why the sugaring and salting is concluded
into acidification method? Sugaring and Salting is method to prevent
microorganism from multiplying and they creates thin “layer” that has pH below
7 or above 7.
The next method is packaging. Packaging
is used to wrap food and separating food from the environtment. “Packaging
provides protection, tampering resistance, and special physical, chemical, or
biological needs” this statement is said by (Claudio, 2012) in his book. This prevent the bacteria
on the outside can’t get contact with the food. So the food shelf life can be
extended. Packaging method needs to be combined with other methods such as the
heating process so the microorganism inside the food can disappear. Some
packaging method also create vacuum space inside the package such as canning
Food preservation methods divided into
five groups which is Heat Treatment, Low Temperature Treatment, Drying,
Acidification, Packaging. Food Preservation is a way to make food shelf life
extended, safety to be consumed and makes the economic value rising up. This is
the main reasons why the food preservation research still studied until now.
Besides, the food preservation research still continue for the sake efficiency,
easy to comercialize, long shelf life food,and gaining more nutrition value.