The human mouth is equipped with taste receptors that detect five primary tastes. These are:

• Sweet: Typically associated with sugars and some artificial sweeteners. It's perceived as pleasant and often indicates energy-rich foods.
  
• Sour: Associated with acids, such as citric acid found in lemons. Sourness can evoke a puckering sensation and is often associated with freshness.
  
• Salty: Detected by receptors sensitive to sodium ions. Saltiness enhances other flavors and is important for overall flavor balance.
  
• Bitter: Detected by receptors sensitive to alkaloids, often found in substances like caffeine, quinine, and certain vegetables. Bitterness can signal potential toxins but is also present in many foods and beverages.
  
• Umami: A savory taste associated with the presence of glutamate, an amino acid. Umami enhances the perception of other flavors and is found in foods like meat, cheese, and tomatoes.
  

These five taste sensations work together to create the overall flavor experience of foods and beverages.