Cooking potatoes is not as easy as you might think.
Potatoes are an important part of the Finnish dinner table. Adobe Stock / AOP
Cooking potatoes is one of the eternal topics that should be returned to at regular intervals. In principle, cooking potatoes should be easy, but even that has its pitfalls.
You will realize it at the latest when the long-ripened potato is still hard. How is that possible?
Research professor of food development at the University of Turku, familiar with molecular gastronomy Anu Hopia can give an answer.
He has written about the same phenomenon in his work A pinch of science (Gaudeamus 2017).
The reason lies in the enzymes of the vegetable cells, more specifically pectin methylesterase.
– If it gets to work, it hardens the pectin of the plant cell walls to such an extent that it no longer dissolves no matter how much you heat it. This is a natural reaction between calcium and pectin, says Hopia on the phone.
The enzyme is particularly active at a temperature of 40–60 degrees, when it hardens quickly. On the other hand, at 70 degrees, the enzyme is destroyed.
– Every now and then I have come across people’s stories about how the potatoes don’t seem to ripen at all, Hopia states.
In these cases, Hopia suspects that the enzyme was free to run amok. When the conditions are right, potato like potato hardens.
If the potato cell has been broken a lot, for example by grating or slicing with a dull knife, the enzyme can be released and come into contact with the pectin.
An ideal situation is also when the temperature of the cooking water for the potatoes rises slowly, in which case the cooking water has a suitable temperature for the enzyme to function for a long time.
Professor Anu Hopia thinks about food and chemistry both at work and in her free time. Arché Photography/Andi Balogh
So is it better to put the potatoes to be boiled in boiling rather than cold water?
Hopia does not have an absolute position on this.
– I don’t have one right answer. Hardening of the potato is a phenomenon that begins to have an effect under certain conditions. However, today’s stoves are so efficient that the water quickly heats up to the boiling point, destroying the enzyme.
Hopia wants to highlight that this reaction can also be used to innovate completely new potato products.
– This phenomenon can also be used. My favorite is the frozen wok fries, which are very thin potato strips. Even if the potatoes are in the oven for an hour, they still have a chewy feel and are not soggy, Hopia describes.
The product only contains 100 percent potato, so in order to achieve the desired end result, the chemical reactions of the potato have been utilized and a new product has been developed with them.
– I think it’s great that such inventions are made, in which an unpleasant phenomenon turns into something good, Hopia thanks.