What is the process called where a viscous liquid is transformed into a solid using a narrow opening?

The process of transforming a viscous liquid into a solid using a narrow opening is known as extrusion. This technique is commonly used in food technology to shape and form various products by forcing a thick material through a specially designed die, which creates the desired shape as the material solidifies.

In extrusion, the heat, pressure, and shearing forces applied during the process contribute to the cooking or setting of the material, allowing it to retain its new form after emerging from the opening. This method is often used in the production of snacks, pasta, and other food items, as it allows for the creation of uniform shapes and textures.

Other processes listed serve different functions: filtration is about separating solids from liquids or gases; fermentation involves the conversion of sugars into acids, gases, or alcohol using microorganisms; and emulsification is the mixing of two immiscible liquids, such as oil and water, to form a stable mixture. Understanding these distinct processes helps clarify why extrusion is the correct answer in this context.