explanation of rancidity
Answers
Answer:
It refers to the spoilage of food in such way that it becomes undesirable (and usually unsafe) for consumption. When people say that a food has "gone bad," what they're usually talking about is rancidity.
Explanation:
Rancidity is one of the major problems in relation with use of vegetable oils. Time, temperature, light, air, exposed surface, moisture, nitrogenous organic material, and traces of metals are known to be factors responsible for rancidity. In salad dressing and mayonnaise products, the oil is subjected simultaneously to most or all of these adverse conditions.
Salad dressing and mayonnaise are emulsified, thus increasing the exposed surface of the oil.
Air is incorporated, with the average mayonnaise containing from 10% to 12% air by volume, although in many cases an inert gas such as nitrogen replaces some of the air.
Moisture is present; nitrogenous organic material is dispersed in films surrounding the oil globules; the products are packed in glass jars that are exposed to light; and in some plants traces of metal may be dissolved out of the equipment by the vinegar, although in the modern plant the use of stainless steel equipment reduces this to a minimum.
The temperature at which salad dressing and mayonnaise are kept may be as high as 38 °C (100 °F) or higher in midsummer, and it may take 3–6 months before these products are consumed.
It is for these reasons that the oil used by the salad dressing industry must be of the highest quality.
The industry has adopted purchase specifications for oil that call for a bland and neutral odour, flavour, and taste. The free fatty acid content should be less than 0.05% expressed as oleic acid, and the oil should respond negatively to the Kreis test for incipient rancidity. The higher-melting-point fractions should be removed from the oils.
The most common vegetable oils used are soybean, canola, and olive, with cottonseed and corn oil used to a lesser extent.