The measure of the molar
concentration of hydrogen ions in the solution is called as “pH”. The ph shows
that acidity and basicity of the solution. The numerical value is defined as
the negative base 10 logarithm of the molar concentration of hydrogen ions:[1]
pH = -log10[H+]
The measurement of the pH of a sample can be done by measuring the cell
potential of that sample in reference to a standard hydrogen electrode. (pH,
n.d., para. 1)The pH can be measured by ph meter or the method of titration.
The measurement of pH is very important
in food industry because of some reasons. For example, in milk and dairy products, in
processes such as sterilization, pH is checked since a lower value helps to
speed up the process. However, lower pH levels can indicate that the cattle
carried leukocyte infections such as mamites. The pH value of milk which is used for cheese
manufacturing contributes to whether the cheese will be soft or hard. pH is
also checked during cheese preparation, souring of milk and cream maturation.
Pathogen multiplication of the fresh and soft variety is slowed down
considerably by ensuring that the pH stays in the 4.1 to 5.3 region. With yogurt production, the cooling of cultured milk can
start only when acidification has reached a pH value of 4.4 to 4.6. In
drink industry, in making fruit juices, the pH of
sugar extracts as well as those of juices during purification and refining are
checked. pH plays an important role in the production of beer. For
example the pH value of crushed malt is around 5.8 whereas its ideal value for
protein decomposition is around 5.5. To ensure a consistent quality, the pH of
brewed beer prior and after bottling is regularly monitored. pH
of wine normally ranges from 2.8 to 3.8 with the pH influencing various stages
of the process including fermentation and conservation. With the pH exceeding
3.5, certain bacteria can attack the wine. However, taste of wine also depends
largely on its pH value with acidic wines becoming dry. In the meat industry, the
typical pH value ranging from 5.4 to 7.0, can also provide an indication of
whether fresh meat was properly stored as varies in different parts of the
animal based on the muscular mass, for example, the loin has a lower pH value.
Too high a pH value induces a loss of aroma and a visibly darker meat resulting
in a lower market value.[2]
Citric
acid affects sour flavor, preservative
quality, and ability to act as a pH buffer. For these reasons, citric acid is
found on the ingredient list of many food products today. The acidic pH of
citric acid also makes it useful as a preservative. Since many bacteria are
unable to grow in an acidic environment, citric acid is often added to jams,
jellies, candy, canned foods,beverages and even meat products as a
preservative. Citric acid is sometimes used to create an acidic environment and
facilitate the ripening process when making cheese, particularly mozzarella. [3]
Citric acid is also used to adjust the pH of solutions when brewing both
beer and wine. Citric acid is a primary organic acid in orange juice.The
reaction between sodium hydroxide and citric acid gives citric acid content in
sample.
Ascorbic acid (vitamin C) is a powerful reducing agent and also widely used as a food additive, to prevent oxidation. Ascorbic acid (vitamin C) is used extensively in the food industry, not only for its nutritional value but for its many functional contributions to product quality . .Acting as an antioxidant, ascorbic acid can improve the color and palatability of many kinds of food products. The problem of Vitamin C is that it breaks down easily. Vitamin C in fruits and vegetables is often lost in cooking. Vitamin C can also be lost simply through storing fruits or vegetables before consumption.[4]
- (n.d.) pH.Retrieved March 15, 2013 from http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/ph.html
- (2008). The Importance of pH in Food Quality and Production . Retrieved March 15, 2013 from http://www.mbhes.com/ph_&_food.htm
- Moncel B. (2013). What Is Citric Acid?. Retrieved March 15, 2013 from http://foodreference.about.com/od/Food-Additives/a/What-Is-Citric-Acid.htm
- Takeda Canada Vitamin & Food, Inc.(2011). Vitamin C in Food Processing.Retrieved March 15, 2013 from http://www.mratcliffe.com/images/vcb.pdf
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