What characteristic distinguishes a trans fat from other types of fats?

Trans fats are primarily distinguished by their process of production, which involves partial hydrogenation. This process alters the chemical structure of unsaturated fats, converting them into trans fats. The partial hydrogenation increases the shelf life and stability of the oil, making it a popular choice in processed foods. Unlike naturally occurring fats, which typically have a cis configuration, trans fats have a trans configuration, leading to different physical properties and health effects.

The other characteristics mentioned do not accurately define trans fats. For instance, while some fats can be derived from fruits, trans fats are typically industrially created and not derived from natural sources. Additionally, while certain types of fats can be liquid at room temperature, trans fats can exist in both solid and liquid forms depending on the level of hydrogenation. Lastly, trans fats do not consist solely of saturated fatty acids; they can contain a mix of saturated and unsaturated fatty acids, with their defining feature being the presence of the trans isomer after hydrogenation.