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Chapter 3 Sensory Evaluation: The Human Factor
Chewiness refers to how well one part of a food slides past
another without breaking. Taffy would rank high in chewiness and
pudding would rank very low.
Graininess refers to the size of the particles in a food product. Cream
is very smooth with microscopic particles. Grits, which are commonly
served in the South, have a grainy or gritty feel, as their name implies.
Senses and Aging
When you touch
something, you sense
texture. When you taste,
there is fl avor. When you
smell, there is odor. All
these senses have different
names. However, the brain perceives them in
the same way. Whether you touch, taste, or
smell, you are stimulating nerve endings to
send a message to the brain. When the right
particle touches a nerve fi ber, an electric
impulse is sent to the brain. The location
in the brain that receives the impulse and
memories of similar experiences determines
the sensation. These factors control whether
you smell hot cocoa, feel its heat, or taste the
bittersweet chocolate fl avor.
Olfactory nerve cells at the ends of the
neurons die and are replaced every 60 days.
They are the only nerve cells the body remakes.
However, there is a point at which smell nerve
fi bers become damaged and the body cannot
repair them. The ability to taste bitter, salty,
savory, sour, and sweet remains. What people
lose is the ability to identify the difference
between the sour of vinegar and the sour
of lemon.
The nerve endings in the nose are very
sensitive and easily damaged. There appears
to be a loss of olfactory function as a result
of aging. Studies indicate that as many as
50% of people over age 65 are experiencing
olfactory loss.
People experiencing olfactory loss taste
the sweet and sour of fruits without perceiving
the orange, lemon, or strawberry fl avor. They
consume fewer fruits, vegetables, and other
foods because their ability to enjoy food is
reduced. When people start to lose their
sense of smell, they are less likely to want to
cook or eat. This may result in malnutrition
if not corrected.
Studies at the University of Connecticut
found another problem with olfactory loss.
Older women with a reduced sense of taste
and smell were more likely to be obese. They
tended to eat more to get enough satisfying
fl avor. They also tended to choose foods that
had a creamy mouthfeel (texture). These foods
were often high in fat and sugar. Researchers
believe such foods help people compensate
for loss of fl avor.
To help someone with olfactory loss
increase his or her interest in a balanced diet,
use the following tips:
• Serve fruits in sweet syrups. Most people
prefer sweet tastes.
• Vary texture and color. Concentrate on
the visual display.
• Increase the fl avor of bland vegetables by
adding olive oil, herbs, and/or spices.
• Increase cooking smells in the home by
simmering foods the person can still smell.
• Make meals a social event. People eat
poorer diets when they are alone.
• Make sure the person gets regular fl u
shots. Viral infections appear to damage
the olfactory bulb.