|MadSci Network: Agricultural Sciences|
Hello...The tongue has about 10,000 taste buds most of which are on the top of the tongue and some on the sides. It would be a good idea for you to find out where on the tongue we taste, sour, bitter, salty, and sweet.
The sour taste
This is the taste of acids. The more acidic the substance the more sour the taste. Acids include hydrogen ions in their chemical makeup. The intensity of the sour taste is approximately proportional to the logarithm of the hydrogen ion concentration.
The salty taste
Ionized salts are responsible for eliciting this taste perception. Different salts have slightly different tastes because they also contain other basic taste components.
The sweet taste
There is a long list of substances that yield the sweet taste. You will be familiar with sugars (e.g., sucrose, fructose, glucose, maltose, lactose) but glycols, alcohols, and aldehydes are also included. Nearly all are organic compounds. Sucrose is considered a basic comparison substance and is given a sweetness index of 1. Saccharin, by contrast, has an index of over 600.
The bitter taste
Like the sweet taste there is a long list of substances that elicit the bitter taste. Most are also organic. One significant group of organic substances which tastes bitter is the alkaloids. This may have survival value since many of the deadly toxins in poisonous plants are alkaloids and intense bitter tastes are normally rejected.
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