Topics In This Section
1. Introduction
2. General Rules of Frying
3. Temperature Control
4. Preparation of Food
5. Fat Absorption and Topping Up
6. Choice of Frying Medium
7. The Spoilage of Fats and Oils
8. Cleaning
9. Frying Specific Foods
10. Recommended Frying Temperatures
11. The Basic Chemistry of Fats and Oils
12. The Chemistry of Fat Spoilage
13. The Visible Effects of Chemical Spoilage
14. The Role of the Oil Refiner
15. The Role of the Fryer
16. Fire Hazards
Reproduced with permission from Pura Food Products Limited
15 The Role of the Fryer
A number of spoilage reactions were described in section 12, and their effects were discussed in section 13. It doesn't matter how carefully the frying process is conducted,
all these spoilage reactions will be going on in the fryer to some extent.
However, if good fats and good frying practices are used, some of the effects can be minimised. This is why the food should be as dry as possible, why cleaning both the oil
and the equipment should be carried our regularly, and why the oil should not be overheated. The hotter the oil, the faster will be the rate of all these reactions. However,
frying must be carried out at a certain minimum temperature, or the fried food will be greasy and the fat usage (by absorption) will go up. Therefore, a watchful eye should be
kept on the temperature, and thermostats should be checked regularly to make sure they are working correctly.
In a more optimistic vein, there is a tendency for the heat and steam generated during frying to drive off some of the breakdown products that are formed. Also, if the fryer
is regularly topped up with fresh fat, the effect of these spoilage reactions may be damped down so that they might not get out of hand. Because of this last point, it is advisable
to fry the correct proportion of food to fat. In general, the best ration appears to be to fry one part of food in six parts of fat.
It is not necessarily wise to economise by only filling the fryer, say, half full of oil or fat. The specific surface area of the frying medium, is the surface area of the medium
divided by its volume. The specific surface area of a half full fryer is twice that of a full fryer. That is to say, twice the proportion of frying medium is on the surface if the
fryer is half full. Reference to the first table in section 13 will show that oxidation is one of the most common breakdown reactions in frying. Oxidation is a result of the oxygen
of the air attacking the frying medium, and common sense will indicate that oxidation occurs at the surface of the fat or oil. It can therefore be argued that, the shallower the oil
in the fryer, the bigger proportion of it will be at the surface, and the more important oxidation becomes.
Remember, that as soon as an oil is heated, it will begin to break down, however good it is. It is best to keep the oil as busy as possible.
Never heat three fryers when two will do.