CHAPTER 4: SENSORY PROPERTIES OF FOOD Flashcards
What is the study of sensory perception?
How the sensory organs–eyes, ears, nose, mouth and skin–detect and interpret the world.
What helps sensory organs “sense” the world around them?
It’s actually receptors on the organs that do all the work.
Examples of sensory receptors.
Taste buds, olfactory cells and nerve endings beneath the skin.
Sensory properties of food.
Appearance, flavor and texture.
Is evaluating food the same as eating for enjoyment? Why?
No, sensory evaluation takes practice and deliberate concentration, because the perception of food is complex.
An example of why sensory evaluation is important for chefs.
It helps determine whether or not a dish is properly balanced. Even if it is one you may not like.
Do genetics, gender and health contribute to an individuals ability to evaluate food? What is most important.
Yes but experience is most important.
What creates the first impression customers have of food?
Appearance
Why is it harder for humans to eat an ugly plate of food where as a dog has no problem?
Our sense of sight is more highly developed than the other senses. This is not the case with many animals. Dogs depend primarily on smell.
Why are messages received from other senses often ignored if they conflict with what we see? Example.
Because our sense of sight is so highly developed. Yellow candy is expected to be lemon flavored. If it is grape flavored, many people can not accurately identify the flavor.
Does strawberry ice cream tinted with red food coloring have a stronger strawberry flavor?
No, but that is our perception.
Besides color, or hue, what other important factors influence appearance?
Opacity, sheen, shape, size and a visual evaluation of texture.
What is opacity?
The quality of a product that appears opaque or cloudy.
What is the opposite of opacity?
Clarity or translucency.
Example of an opaque product.
Milk
Example of clear or translucent product.
Water
What is sheen?
The state of a product that appears glossy or shiny.
The opposite of glossy.
Matte or dull.
Example of product with sheen.
Honey
Example of dull product.
Shortbread cookie
What happens when light hits an object?
It is reflected (bounced off), transmitted (passed through), or absorbed by the object.
What must light do to be perceived as a sheen?
Only light that bounces off or passes through.
What three factors affect the perception of appearance?
The nature of the light source, the nature of the object itself, the nature of the surroundings (optical illusion).
What happens to light when it is absorbed by food?
Light energy disappears from sight because it is converted into another form–heat or kinetic energy.
Why are leaves perceived as green?
A green leaf contains chlorophyll that absorbs most light except green light. Only the green light is reflected of the leaves and reaches the eyes.
Do objects absorb light selectively?
Yes
Why are raspberries red?
Raspberries absorb most light but red.
Why are objects black?
They essentially absorb all light, leaving little or nothing to reflect.
Why are objects white?
They absorb almost no light.
What happens when you hold a prism up to white light?
You can see it separate into its component colors (the colors of the rainbow).
If the light hitting the object changes, what happens to its appearance? Why?
The objects appearance changes because it absorbs, reflects and transmits changes.
Both brightness and what type of light sources are important to consider?
Fluorescent, incandescent and halogen.
Bakeshops often have what type of lighting?
Fluorescent
Dining room lighting.
Dim, incandescent bulbs that have a warm, yellow cast, which tends to mute appearance.
Two main reasons objects may respond differently to light.
They differ in their chemical makeup or in their physical structure.
Why does chocolate icing look different than vanilla?
The added ingredient, chocolate, absorbs all the light.
Why would a pastry cream with dark yellow yolks be different than one with pale yellow yolks?
They are chemically different; the darker contain a higher amount of carotenoids, the yellow pigments in eggs that reflect yellow light and absorb the rest.
Why do beaten egg white appear opaque?
Light bounces off the tiny, rounded air bubbles and scatters in many directions; scattered light appears opaque.
What is lighter in color, a vanilla cake with fine or coarse crumb? Why?
A fine crumb has smaller, and more compact, air bubbles. This makes it harder for light to pass through causing it to bounce off the rounded air cells in different directions.
What’s lighter, an under-mixed or properly mixed chocolate cake? Why?
A properly mixed because it has more round and consistent air bubbles trapped inside.
What happens if fondant is melted above 100ºF (38ºC)? Why?
It cools to a rougher, grayer, duller surface because tiny crystals recrystallize above 100ºF to form jagged edges as the fondant cools.
What should fondant be warmed to before use?
Body temperature.
Why does the same white cake look so much whiter on a black plate instead of a white plate?
There is no difference, only the strong contrast between colors that is an optical illusion.
Appearance my be the first contact customers have with food but what do they remember?
Flavor
Everyday word for flavor.
Taste
What does flavor include to a scientist?
Includes the basic tastes, smell and trigeminal effects, or chemical feeling factors.
The three (scientific) sensations occur when what happens?
Food molecules–chemicals–stimulate receptors throughout the mouth and nose.
Are the components of flavor–smell, taste and trigeminal effects–distinctly different? How?
Yes, each is detected by different receptors and stimulated by different chemicals.
Why is sensory evaluation a challenge?
All the taste sensations occur simultaneously. They even occur at the same time the brain evaluates appearance and texture.
Examples of basic tastes.
Sweet, salty, sour, bitter and umami.
Where are basic taste receptors?
Throughout the mouth but concentrated on the tongue.
Nature of flavor chemical for basic tastes.
Most dissolve in water (saliva).
