Evaluation of Properties of Foods

Essay by cindyleyUniversity, Bachelor'sA, November 2014

download word file, 9 pages 0.0

Practical 1: Evaluation of Properties of Foods 1

A) pH


To determine the pH value of orange juice.


pH is a measure of the acidity or basicity of an aqueous solution. pH is an important aspect that is being inspected in food processing and food preservation. pH control method is one of the method used by food manufacturers to prevent growth of microorganisms in food that will eventually cause early food spoilage and food contamination. Most foodborne pathogens cannot grow below pH 4.4 (Montville, Matthews & Kneil, 2012). Most microorganisms grow best in the pH range of 6.5 to 7.5 (Ministry of Agriculture, Food and Rural Affairs of Ontario 2013). Hence, pH level of food is being monitored during food processing to prevent microbial growth. pH levels also affect the appearance, taste, quality as well as the shelf-life of food products. It is also under the food safety issues.

One example of pH control requirements is in the manufacture of fruit jelly. The gel formation brought about by pectin takes place over a narrow pH range, which is further complicated by sugar concentration. High pH value results in an unacceptable liquid. Too low pH causes the mixture to gel prematurely, resulting in an overly hard product. Continuous pH adjustment using acids such as citric acid yields the optimal gel consistency. Another example of pH control would be in the making of cheese. The enzymes used are particularly sensitive to pH. variations of ± 0.1 pH will affect the enzymatic reaction activity by as much as 50 per cent. However, modern technologies allow cheese ageing process to be accurately monitored by using the puncture probe. pH meter with resolution of 0.1 pH unit is the most common equipment that is used in food industry to measure the pH levels...