How to perfectly boil eggs?

A method has been developed to cook eggs more perfectly. It is a cooking technique that not only improves the texture of the eggs but also increases the polyphenol content, which is an antioxidant.

According to the health media 'Health.com', Professor Emilia Di Lorenzo's research team at Federico II University in Naples, Italy, conducted an experiment to make perfectly cooked eggs without overcooking the yolk.

Egg whites cook at 85°C, while yolks cook at 65°C. Professor Di Lorenzo said, "Top chefs cook the yolk and white separately to achieve their optimal textures."

The research team conducted an experiment boiling medium-sized eggs (approximately 68g each) at different temperatures and times, developing a computer model capable of simulating cooking methods that preserve taste and texture.

The research team discovered that alternating cooking eggs in water at 100°C and 30°C is the optimal method. This cooking technique, called "periodic cooking," requires transferring the eggs between containers of water at different temperatures every 2 minutes for a total of 32 minutes.

The research team compared fully cooked, soft-boiled, and sous-vide eggs (a cooking method that involves vacuum-sealing food and cooking it in low-temperature water). They analyzed texture and quality, and investigated chemical properties using nuclear magnetic resonance and high-resolution mass spectrometry.

'Periodic Cooking' eggs had a soft yolk and white that were between sous-vide and soft-boiled eggs. The whites were fully cooked, and the yolk was very creamy. The yolk was maintained at a constant 67°C, while the whites ranged from 27°C to 100°C.

Chemical analysis results showed that the yolk contained more polyphenols, trace nutrients that protect against cell damage and inflammation, compared to other cooking methods. The research team was unable to determine the reason why periodic cooking increases polyphenol levels. It was hypothesized that temperatures close to the protein denaturation temperature prevent nutrient loss. Generally, cooking at high temperatures destroys some nutrients in ingredients.

The U.S. Department of Agriculture recommends boiling medium-sized eggs for 12 minutes, large eggs for 15 minutes, and extra-large eggs for 18 minutes for safety. Experts say this cooking method maintains the yolk at 67 degrees Celsius, which is sufficient to kill pathogenic bacteria such as Salmonella.

The research team gently scraped the top of the egg with a knife to increase the porosity of the shell and took care to prevent the shell from cracking when placed in hot water. They also gently stirred the eggs while in cold water to prevent the yolks from falling due to gravity. To reduce cooking time, they recommended raising the cold water temperature to 40 degrees and shortening the cycle, encouraging each person to find their optimal method.