CHAPTER 4: SENSORY PROPERTIES OF FOOD Flashcards
(132 cards)
1
Q
What is the study of sensory perception?
A
How the sensory organs–eyes, ears, nose, mouth and skin–detect and interpret the world.
2
Q
What helps sensory organs “sense” the world around them?
A
It’s actually receptors on the organs that do all the work.
3
Q
Examples of sensory receptors.
A
Taste buds, olfactory cells and nerve endings beneath the skin.
4
Q
Sensory properties of food.
A
Appearance, flavor and texture.
5
Q
Is evaluating food the same as eating for enjoyment? Why?
A
No, sensory evaluation takes practice and deliberate concentration, because the perception of food is complex.
6
Q
An example of why sensory evaluation is important for chefs.
A
It helps determine whether or not a dish is properly balanced. Even if it is one you may not like.
7
Q
Do genetics, gender and health contribute to an individuals ability to evaluate food? What is most important.
A
Yes but experience is most important.
8
Q
What creates the first impression customers have of food?
A
Appearance
9
Q
Why is it harder for humans to eat an ugly plate of food where as a dog has no problem?
A
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.
10
Q
Why are messages received from other senses often ignored if they conflict with what we see? Example.
A
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.
11
Q
Does strawberry ice cream tinted with red food coloring have a stronger strawberry flavor?
A
No, but that is our perception.
12
Q
Besides color, or hue, what other important factors influence appearance?
A
Opacity, sheen, shape, size and a visual evaluation of texture.
13
Q
What is opacity?
A
The quality of a product that appears opaque or cloudy.
14
Q
What is the opposite of opacity?
A
Clarity or translucency.
15
Q
Example of an opaque product.
A
Milk
16
Q
Example of clear or translucent product.
A
Water
17
Q
What is sheen?
A
The state of a product that appears glossy or shiny.
18
Q
The opposite of glossy.
A
Matte or dull.
19
Q
Example of product with sheen.
A
Honey
20
Q
Example of dull product.
A
Shortbread cookie
21
Q
What happens when light hits an object?
A
It is reflected (bounced off), transmitted (passed through), or absorbed by the object.
22
Q
What must light do to be perceived as a sheen?
A
Only light that bounces off or passes through.
23
Q
What three factors affect the perception of appearance?
A
The nature of the light source, the nature of the object itself, the nature of the surroundings (optical illusion).
24
Q
What happens to light when it is absorbed by food?
A
Light energy disappears from sight because it is converted into another form–heat or kinetic energy.
25
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.
26
Do objects absorb light selectively?
Yes
27
Why are raspberries red?
Raspberries absorb most light but red.
28
Why are objects black?
They essentially absorb all light, leaving little or nothing to reflect.
29
Why are objects white?
They absorb almost no light.
30
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).
31
If the light hitting the object changes, what happens to its appearance? Why?
The objects appearance changes because it absorbs, reflects and transmits changes.
32
Both brightness and what type of light sources are important to consider?
Fluorescent, incandescent and halogen.
33
Bakeshops often have what type of lighting?
Fluorescent
34
Dining room lighting.
Dim, incandescent bulbs that have a warm, yellow cast, which tends to mute appearance.
35
Two main reasons objects may respond differently to light.
They differ in their chemical makeup or in their physical structure.
36
Why does chocolate icing look different than vanilla?
The added ingredient, chocolate, absorbs all the light.
37
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.
38
Why do beaten egg white appear opaque?
Light bounces off the tiny, rounded air bubbles and scatters in many directions; scattered light appears opaque.
39
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.
40
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.
41
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.
42
What should fondant be warmed to before use?
Body temperature.
43
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.
44
Appearance my be the first contact customers have with food but what do they remember?
Flavor
45
Everyday word for flavor.
Taste
46
What does flavor include to a scientist?
Includes the basic tastes, smell and trigeminal effects, or chemical feeling factors.
47
The three (scientific) sensations occur when what happens?
Food molecules--chemicals--stimulate receptors throughout the mouth and nose.
48
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.
49
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.
50
Examples of basic tastes.
Sweet, salty, sour, bitter and umami.
51
Where are basic taste receptors?
Throughout the mouth but concentrated on the tongue.
52
Nature of flavor chemical for basic tastes.
Most dissolve in water (saliva).
53
Examples of smell.
Vanilla, butter, thousands more.
54
Examples and location of smell receptors.
Olfactory cells on the olfactory bulb at top of the nasal cavity.
55
Nature of flavor chemicals (smell).
Must evaporate to reach the olfactory bulb and dissolve in water (mucous membranes); must be volatile.
56
Examples of trigeminal effects.
Pungency, burn, numbing, cooling and others.
57
Trigeminal receptors and location.
Nerve endings underneath the surface of the skin, throughout the mouth and nose.
58
Nature of flavor chemicals for trigeminal sensors.
Must absorb through skin; must be volatile to be perceived in nasal cavity.
59
Once at the site of the receptors, flavor chemicals do what?
Interact with, or stimulate, receptors in some way, by bonding to them, for example. This generates electrical impulses that travel through nerve cells to the brain, where the info is processed.
60
What is the organ that actually perceives flavor?
The brain, not eyes, mouth, ears, nose or skin.
61
To get an idea of umami what can you do?
Dissolve MSG on your tongue.
62
Who first presented the idea of umami? When did this occur?
Japanese scientists did in the early 1900s when MSG was purified from dried seaweed.
63
Taste cells are clustered where?
On taste buds.
64
How many taste cells are on a taste bud? Do they perceive all basic tastes?
Around 100 a piece. Each able to perceive 1 or more of the basic tastes.
65
What are papillae?
Small bumps on the tongue which contains taste buds hidden in crevices beneath them.
66
Is saliva mostly water?
Yes
67
Why is saliva important to taste perception?
It carries molecules into the crevices and taste buds.
68
What easier to identify, sweet and salty or sour and bitter? Why?
Sweet and salty because most things sour are also bitter.
69
Smell is also called what?
Aroma
70
What is often considered the most important component of flavor?
Aroma which is the most predominant and most complex.
71
Is there a single coffee molecule?
No, it consists of hundreds of separate chemicals.
72
What is meant by a product being volatile?
It must evaporate and escape from food.
73
To reach the olfactory cells at the top of the nasal cavity, molecules must travel where?
Either directly from food through the nose (orthonasal pathway), or up the bak of the throat (retronasal pathway), as food is warmed and chewed through the mouth.
74
What is a super taster?
Have the highest number of taste buds.
75
How can taste buds be measured?
Swabbing a tongue with blue dye and measuring the bumps--papillae--that stand out in relief on the tongue as pink spots.
76
On average, how many taste buds are located around one papillae?
5 or 6.
77
Who is Linda Bartoshuk?
A researcher at Yale University that studies taste perception.
78
Three categories of tasters and their percent of population.
Supertasters (20%), normal tasters (60%), non-tasters (20%).
79
Are supertasters especially sensitive to bitterness?
Yes
80
Does being categorized as a "taster" influence taste buds and aroma?
No, only taste buds.
81
How is bitterness perceived in your mouth?
Bitterness is often slightly delayed and tends to linger as an aftertaste. It also seems to to be perceived toward the back of the throat.
82
How is sourness perceived in your mouth?
It's perceived almost instantly, as soon as food is placed in the mouth. It is also perceived more on the sides of the tongue.
83
How does your mouth perceive a product that is very bitter and sour?
It will be perceived throughout the mouth as a combo.
84
A third sensation that is sometimes confused with bitterness and sourness.
Astringency
85
While sourness causes the mouth to water, astringency leaves a ________ sensation that makes the tongue feel rough.
drying
86
Astringency is often described as having a mouth full of what?
Cotton balls.
87
Is astringency a taste sensation?
No, the drying is from tannins in foods binding with proteins in saliva.
88
Three foods that are predominantly sour.
Buttermilk, pickles, yogurt.
89
Three foods that are predominantly bitter.
Strong black coffee, strong dark beer, unsweetened chocolate.
90
Foods that are predominantly astringent.
Strong black tea, unripe persimmons, grape skins.
91
Is cranberry juice sour, bitter or astringent?
All three.
92
By some estimates, what % of flavor is smell?
80%
93
Best way to evaluate food tastes. Why?
Hold your nose so it's focused on your tongue.
94
What part of flavor is it that best differentiates and describes food?
Smell
95
True or False: Smell is so important to taste it is why we say, "I can't smell anything" when sick.
True
96
Although the receptors for smell are at the top of the nasal cavity, it often seems smell takes place where? Explain.
In the mouth. Because our brains sense the food is there, it perceives the smell is coming from there as well.
97
Helpful hints for evaluating smells.
Take several small "bunny sniffs." This pulls flavor molecules up to the olfactory cells. Block your briefly while you chew food. Then, release your nose and breathe in deeply. Your olfactory cells will be bombarded will smells as flavor molecules are pulled up the back of your throat. Move the food around as you chew it well. This gives it time to warm up. Give your ode frequent breaks and breathe fresh air. Your olfactory cells--and brain--are easily fatigued; breaks will improve sensitivity.
98
Do nutmeg and mace smell similar?
Yes
99
Do allspice and cloves smell similar?
Yes
100
Why do pleasant smells bring tears to our eyes?
The connection between smell, memory and emotion. As signals are transferred to our brains there is often a crossing of wires with nearby regions, especially those related to memory and emotion. That is what makes perfume so powerful and why smells from a bakeshops are good marketing tools.
101
The word trigeminal refers to what?
The nerve that carries the signal of certain sensations from nerve endings in the mouth and nose to the brain.The same nerve carries signals of temperature and pressure.
102
It is hard to name a spice where the flavor isn't dependent on what?
Trigeminal effects.
103
Trigeminal effects often go by what other names?
Chemical feeling factors, pungency, chemical irritation, chemosensory irritation, or chemesthesis.
104
Are trigeminal effects a part of flavor?
Yes
105
What triggers trigeminal effects?
Chemicals in food trigger these sensations.
106
What triggers the cooling sensation of mint?
Menthol
107
What triggers the hot, pungent sensation of chili peppers?
Capsaicin
108
Flavor chemicals must do what to reach the nerve endings?
Be absorbed by the skin, evaporate, etc.
109
Do different sweeteners provide different qualities of sweetness?
Yes
110
Aspartame is also called what?
NutraSweet
111
Explain sweetness of aspartame. Compare to sucrose.
This high-intensity sweetener may be sweet but has a different sweetness than sucrose (table sugar). Sucrose tastes sweet almost immediately while aspartame lingers much longer as a sweet aftertaste, and it tastes bitter to many people.
112
Name one of the main acids in apples.
Malic acid.
113
Is malice acid different than citric and acetic acid? Can their flavor be substituted for one another?
Malic acid has a different sour taste than citric acid in lemons or acetic acid in vinegar. This is why adding lemon juice or vinegar to mild-tasting apples will not provide the same flavor impact as using apples that are naturally sour.
114
Does products temperature affect flavor perception?
Yes
115
What happens to the perception of saltiness as a products temperature rises?
It decreases.
116
What will taste less salty, warm biscuits or room temperature biscuits?
Warm biscuits.
117
What happens to sweetness as product temperatures rise?
It increases when heated.
118
Will a sorbet mix taste properly sweetened at room temperature be sweet enough frozen? Why?
No, because sweetness decreases as temp drops.
119
Why do aromas typically increase as temperatures rise?
Molecules evaporate more readily at higher temperatures, more reach olfactory cells.
120
Because flavor perception changes with product temperature, when should you evaluate it?
At serving temp.
121
Why should you be careful adding gelatin to bavarian creams and chiffon pie fillings?
Not only does too much gelatin in these products produce a tough, rubbery dessert, but it also reduces the release of flavor.
122
How does a hard and firm or thick and viscous product affect flavor perception?
It takes a few moments for flavor molecules to be dissolved in saliva, or evaporate to the nasal cavity, or to be absorbed through skin; if flavor molecules cannot reach receptors, they cannot be perceived.
123
What happens when you add a small amount of acid to a sweet product? Why?
It tastes less sweet because acid changes the perception of sweetness. Likewise, sugar decreases the perception of sourness in the mix.
124
Do bitterness and sweetness have the same relationship as sourness and sweetness?
Yes, sweetness helps balance many trigeminal effects.
125
What else changes the perception of smell besides temperature? Why?
Salt and sugar affect the perception of smell, probably by changing the rate at which molecules evaporate.
126
How much salt or sugar does it take to affect the aroma of food?
Sometimes it only take a small amount of salt or sugar to change and improve the aroma and overall flavor of food.
127
Why are low-fat and fat-free foods notorious for having an unappealing taste?
Fat affects flavor perception because many flavor molecules dissolve in fat, so when fat is eliminated, there is a change in the release of flavor molecules to the taste buds, olfactory cells, and nerve ending below the skin; this is why low-fat foods require extra time and effort to flavor properly.
128
Is texture often ignored unless it's extreme?
Yes, the texture of breakfast cereal, for example, might go unnoticed until unpleasantly soggy.
129
The main way texture is evaluated.
By touch: how food feels against the skin, how it feels as it melts in the mouth, and how it responds to touch as food is squeezed, bitten and chewed.
130
When it comes to a evaluating crispness, what is a response to pressure?
Sound - the louder, higher-pitched and more frequent the sound, the crispier it is.
131
Is sound just as important as touch?
Yes
132
The first--although not necessarily the most accurate--info about texture is based on what?
Appearance or sight.
