In addition to the pleasant feeling, and even if it sounds strange, that we enjoy eating crispy food there is science-based. Frying-up is the most common process to obtain crispy food, however, frying the food involves a risk that we must avoid.
Everybody likes crispy food. Golden French fries, crispy fish and chips… even vegetables are more appealing when fried in tempura batter. When food is crunchy, it triggers a positive response in our brain, while if it’s tough or chewy we usually reject it
The point is that our draw to crispy food is not only matter of taste; it’s an evolutionary fact that defines the human relationship with food since the time of our ancestors. As explained by the anthropologist John S. Allen, from the University of Southern California, choosing crispy food is since the dawn of time the way to distinguish between safe-to-eat food and food going off. A chewy carrot is not the same as a crunchy one when we bite in it, as it gives us give us a sign of freshness. We’ve always preferred the most crunchy fruits and vegetables, as its texture reveals to us if it’s fresh or rancid food.
Furthermore, crispy food has another characteristic that appeals to us not only to our palates but to our hearing. Spencer’s research in multisensory perception of food, demonstrated that the sound produced by food when chewed affects the way we perceive its taste. Indeed, the range of frequency in which we like to hear the crunch is between 90 to 100 decibels.
To obtain the crispy texture we use the frying oil. When the oil is heated, this causes the change which makes the food crispy, but the disadvantage is that during this frying process dangerous changes occur in the oil compositions. Reactions of hydrolysis, oxidation and polymerization generate polar compounds due to the water content present in the food that comes into contact with the oil, the oxygen in the atmosphere and the high temperatures (320-390 oF).These polar compounds can be harmful for human health and raise the risk for cancer according to the FDA, raise the blood pressure, cause intestinal damage and change the organoleptic properties of the food. Therefore, European countries such as Spain, Portugal, France, Germany, Belgium, Switzerland, Italy and the Netherlands, have established legislations to control the quality of frying oil in restaurants and all kind of establishments dedicated to food manufacturing.
How do I know when I have to change the frying oil?
It’s necessary to change the frying oil with regularity due to the accumulation of these polar compounds. The legislations of most European countries establish that the parameter to take into account to change the oil is the percentage of polar compounds which must not equal or exceed a value in the range of 24-27%, depending on the country. To verify the presence of toxic substances in oil periodic revisions of the oil quality are necessary. Now, this is easy with OleoTest , a rapid and economic method which determines the oil alteration degree and that can be used by the establishment staff. In less than 2 minutes you will know the percentage of polar compounds and if your frying oil is ready to use or must be changed.