Lab 4- Sensory Evaluation of Food
Be able to name the five basic qualities of taste sensation and list the chemical
substances that elicit them.
Be able to explain the perceptions and adaptation of tastes.
Be able to name factors that influence the appreciation of food.
Examine the cultural and genetic influences of food preferences.
After reading these guidelines, students should be able to answer the following
What is flavor versus taste?
What are the 5 tastes perceived by the brain?
What is sensory evaluation used for?
What are the typical tests used in sensory evaluation?
We know that food and the nutrients provided by food are essential for life.
However, our choice of foods is not determined by just nutritive value.
food choices or preferences are quite complex and are influenced by psychological
variables, cultural traditions or foodways (family, friends, and ethnic traditions) and the
sensory characteristics of food (taste, color, texture and odor).
Food quality is thought to include factors such as the appearance, flavor, texture
and nutritive content.
Food scientists use food quality as a reference for the sensory
qualities of food, which can be evaluated by the human sensory organs.
The taste and odor of foods, which are components of the flavor, have significant
effects on the perception of hunger, food preferences and intake.
We rely on our
senses of taste and smell to make decisions about what to eat.
In addition, we depend
on mouthfeel sensations to detect temperature (hot or cold), pain (spicy foods),
astringency (unripe fruit, such as a banana) and metallic characteristics.
and detection of some tastes are considered to be largely culturally and genetically
determined. Such is the case with the chemical phenylthiocarbamide (PTC), a well-known
taste variation in humans that is a genetic trait.
A large percentage of the population
perceives the chemical to be relatively tasteless, whereas some individuals perceive it as
In addition to enhancing the enjoyment of food, the sensory capabilities of
taste and odor have survival value. For example, when an individual tastes something
bitter, a rejection is often triggered causing gagging to protect against the ingestion of
The brain perceives sensations of taste and odor.
Taste is detected by
thousands of taste buds on the surface of the tongue.
In general, five distinct tastes
can be perceived: sweet, salt, sour, bitter and umami.
The ability to detect or seek out
salty foods (sodium chloride = NaCl) is thought to be protective since sodium is an