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Food Flavors Flashcards

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1
Q

What is sweet flavour elicited by/due to?

A

electronegative elements of organic molecules (ex. O & N)

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2
Q

What type of molecules obtain a sweet flavour due to oxygen? What are examples of each?

A
  1. alcohols (glycerol, glucose, xylitol)

2. aldehydes (cinnamic aldehyde)

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3
Q

What type of molecules obtain their sweet flavour due to nitrogen? what is an example?

A

certain amino acids (D-Histidine)

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4
Q

Relative sweetness of sugars uses what molecule as a reference? What number is it assigned?

A

sucrose: 1

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5
Q

What is the relative sweetness of:

  1. Sucrose
  2. Lactose
  3. Maltose
  4. Glucose
  5. Galactose
  6. Sorbitol
  7. Mannitol
  8. Glycerol
  9. Fructose
  10. Aspartame
A
  1. 1
  2. 0.27
  3. 0.5
  4. 0.5-0.7
  5. 0.6
  6. 0.5
  7. 0.7
  8. 0.8
  9. 1.1-1.5
  10. 100-200
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6
Q

Glucose and Fructose have the same molecular formula, so why is fructose sweeter than glucose?

A

Exam question

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7
Q

What is the definition of flavour?

A

sensations produced by a food in the mouth and nose

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8
Q

What are the 3 components of food flavour?

A
  1. taste
  2. odor or smell
  3. mouthfeel
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9
Q

What are the 5 different tastes sensed in taste buds?

A
  1. sweet
  2. sour
  3. salt
  4. bitter
  5. umami
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10
Q

What are the 7 different odors received in nasal epithelial?

A
  1. ethereal (nutty/earthy)
  2. pungent
  3. putrid (rotten/decomposed)
  4. floral
  5. minty
  6. musky (really strong/sweet)
  7. camphoraceous (woody)
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11
Q

What 3 things is mouthfeel perceived with?

A
  1. tongue
  2. teeth
  3. jaws
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12
Q

What are 3 examples of mouthfeel?

A
  1. pain
  2. temperature
  3. tactile sensations
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13
Q

What are the two groups of amino acids? What are these two groups based on? How do they differ in taste?

A

Two groups based on optical activities.

  1. L-isomers
  2. D-isomers: sweeter
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14
Q

What is the difference in taste between the L and D isomers of the amino acids:

  1. Asp-NH?
  2. Glu
  3. His
  4. Ile
  5. Try
A
  1. L: tasteless; D: sweet
  2. L: meaty; D: tasteless
  3. L: tasteless to bitter; D: sweet
  4. L: bitter; D: sweet
  5. L: bitter; D: very sweet
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15
Q

In that 3 ways are flavours from food perceived by our brain?

A
  1. smell signals from the nose
  2. taste signals from the tongue
  3. mouthfeel from teeth, jaws and tounge

Interactions with molecules in mouth

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16
Q

What are 5 examples of traditional sweetners?

A
  1. sugar (sucrose)
  2. invert sugar
  3. conventional corn syrup
  4. high fructose corn syrup
  5. maltodextrin
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17
Q

What two monosaccharides is sucrose made up of? what is the bond between them?

A

glucose + fructose

beta 1-2 bond

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18
Q

What happens if you add the ________ enzyme to sucrose?

A

Invertase.

Cleaves beta(1-2) bond between fructose and glucose - making a mixture even sweeter than sucrose

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19
Q

What is invert sugar?

A

solution of glucose and fructose created from applying invertase to sucrose

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20
Q

Steps and enzymes to break down corn starch into high fructose corn syrup

A
  1. add amylase –> glucose hydrolysate (conventional corn syrup)
  2. add glucose isomerase –> glucose + fructose hydrolysate (high fructose corn syrup)
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21
Q

Maltodextrin

A

white powder - super processed

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22
Q

Honey:

  1. Texture?
  2. Made by?
  3. Mixture of (%)?
  4. Contains a significant content of?
A
  1. sweet syrupy liquid
  2. honeybees
  3. fructose (33-40%) + glucose (32-42%) + water (15-20%)
  4. phenolics
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23
Q

How do honey bees produce honey?

A

suck nectar and take it to their hive. Pass it mouth to mouth one bee to another (massaging it and treating it with enzymes). When the honey stomach of bees is full they release the honey into the honeycomb

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24
Q

Is all honey that manufactures obtain sweet? What might manufacturers add and what might this be considered?

A

No, therefore manufacturers may add sugar which may be considered adulteration unless they are adding the sugar to make a uniform material

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25
Q

How many stomachs do bees have?

A

2, regular and honey stomach

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26
Q

What 4 things is maple syrup a mixture of?

A
  1. glucose
  2. fructose
  3. sucrose
  4. pigments
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27
Q

How is maple syrup obtained? What produces the brown color?

A

by boiling the sap of the sugar maple tree. Brown color due to boiling and polyphenolic compounds in the tree

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28
Q

What is molasses? What 2 plants does it come from?

A

the dark syrupy liquid left after recovery of sugar from either sugar cane or sugar beet. Has variable composition

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29
Q

How is molasses obtained in processing?

A

sugar cane or sugar beet crushed to obtain juice, then heated to concentrate it. The sugar crystals are separated from syrup, then the syrup is further reduced. Repeat separation step

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30
Q

Sugar cane and molasses have a high content of what 6 nutrients?

A
  1. Vitamin B6
  2. Potassium
  3. Iron
  4. Calcium
  5. Manganese
  6. Magnesium
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31
Q

What are the 8 different criteria for selecting alternate sweetners?

A
  1. carcinogenicity
  2. sweetness equivalent
  3. solubility
  4. hygroscopicity
  5. heat of solution
  6. viscosity
  7. laxative effect
  8. cost
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32
Q
  1. What is carcinogenicity of alternate sweeteners dependent on?
  2. What group of alternate sweeteners are resistant to fermentation? Therefore?
  3. How does this compare to common sugars?
A
  1. susceptibility of fermentation by oral microorganisms
  2. polyols, therefore formation of cavity causing fermentation plaque acids by mouth bacteria is minimal, therefore pH remains at normal. A declined pH would result in decay of tooth enamel
  3. Common sugars (glucose, fructose, sucrose) are all metabolized by mouth bacteria to produce lactic acid that causes decline in pH which solubilized tooth enamel
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33
Q

What are the two main requirements in terms of the sweet taste of synthetic sugars?

A
  1. Sweetness Equivalence to sugar (sucrose)

2. no aftertaste

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34
Q
  1. What 3 things can solubility influence?
  2. It is desirable for alternate sweeteners to have similar _______ profiles as traditional sugar.
  3. Alternate sweeteners with ____ solubility result in products with a ______ mouthfeel.
  4. What is the requirement for replacement/synthetic sugars in terms of solubility?
A
  1. mouthfeel, texture, and onset of sweetness perception of the product
  2. solubility
  3. low; chalky
  4. must be soluble in water and be able to dissolve at the same rate as common sugars
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35
Q
  1. How may synthetic sweaters alter the texture/characteristics of a product? Is this desirable?
  2. _______ is less viscous than sugar (sucrose) which could yield a poor bodying effect
  3. ________ has a higher viscosity than sucrose
  4. Combinations of _______ with _______ help to produce desired viscosity?
A
  1. may add body which increases texture/viscosity in comparison to common sugar - not desirable
  2. xylitol
  3. polydextrose
  4. xylitol + polydextros
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36
Q

What is todays challenge in terms of artificial sweeteners?

A

provide good tasting sugar free products (low calorie, non carcinogenic sweetners)

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37
Q

What are 3 examples of groups of sugars that are approved for food use?

A
  1. Pylyols: xylitol, mannitol, sorbitol, Maltitol, lactitol
  2. polydextrose
  3. fruit juices
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38
Q

What is hygroscopicity?

A

molecules tightly absorb water

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39
Q

What can hygroscopicity affect?

A

shelf-stability

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40
Q

_______ are considered to be fairly hygroscopic, but ______ and ______ are non-hygroscopic

A
  1. Polyols
  2. mannitol
  3. isomalt
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41
Q

Shelf life of products from ____ hygroscopic materials is relatively short

A

high

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42
Q

How are highly hygroscopic products wrapped in order to increase shelf-stability?

A

individually wrapped

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43
Q

What sensation do we get in our mouth when we ingest crystalline polyols?

A

They dissolve - the relatively lower heat of the solution (versus sugar) produces a pleasant cooling effect in the mouth

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44
Q

What is an example of a product that contains crystalline polyol?

A

Mint flavours - cause heat from inside our mouth to do into the sugars, making it seem like a sharp cooling feel

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45
Q

Which synthetic/common sugars produce:

  1. the highest cooling effect?
  2. significant cooling effect?
  3. marginal cooling effect?
  4. limited cooling effect? Which is similar to the cooling effect of what other sugar?
A
  1. xylitol
  2. mannitol, sorbitol
  3. isomalt
  4. sucrose - similar to Maltitol
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46
Q

What products take advantage of this cooling effect?

A

chewing gum, tablets, mints, lozenges, coatings, fondants, hard candies, some chocolates

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47
Q

What two synthetic sugars produce a laxative effect? Why?

A

Polyols and poly dextrose because they are incompletely digested and slowly absorbed

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48
Q

Foods that provide ____ amount of sorbitol/day, ____ mannitol/day or ____ polydextrose/day are required to pose a label warning statement concerning the potential laxative effect.

A

> 50g

> 20g

> 15g

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49
Q

What is the price of Maltitol relative to corn syrup?

A

5x more expensive

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50
Q

What is the price of sorbitol relative to sugar?

A

2 to 3 times

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51
Q

What 4 synthetic sugars are extremely expensive relative to sugar?

A
  1. mannitol
  2. xylitol
  3. isomalt
  4. Maltitol
52
Q

What group of sugars are commonly used as alternate sweetners?

A

polyols (polyhydric alcohols)

53
Q

put these 5 sugars in order from most to least sweet:

sorbitol, polydextrose, mannitol, Maltitol, xylitol, isomalt

A

xylitol > maltitol > mannitol > sorbitol > isomalt > polydextrose

54
Q

Why are alternate sweeteners mixed in food production? What two sweetness are commonly mixed?

A

formulation benefits: by using blends of the polyols, we obtain combinations that are similar to sucrose in sweetness and viscosity

Xylitol (less viscous than sucrose) and polydextrose (more viscous than sucrose)

55
Q

A ________ effect is obtained by blending different alternate sweeteners.

A

synergistic

56
Q

What are 3 favourable characteristics of xylitol?

A
  1. sweetest of polyols
  2. isosweet to sugar
  3. without discerning aftertaste
57
Q

Why can xylitol be used in diabetic foods?

A

metabolized independently of insulin

58
Q

How does xylitol react with oral bacteria?

A

resistant to fermentation by oral bacteria (ex. Streptococcus mutans). Therefore it does not cause pH decline (as with sucrose) to demineralize tooth enamel and cause decay.

59
Q

What are 5 technical characteristics of xylitol?

A
  1. high thermal stability
  2. high microbiological stability
  3. inhibits many food-spoilage organisms
  4. does not react with amino acids
  5. moderate hygroscopicity
60
Q

What are 4 applications of xylitol?

A
  1. chewing gum and other confectionery
  2. pharmaceuticals (syrups, chewable tablets)
  3. oral hygiene products (toothpaste, mouthwash)
  4. diabetic foods
61
Q

What is a side effect of using too much polyols in foods in order to reach the same level as sucrose? (ex. adding a lot of polydextrose until you reach sucrose sweetness)

A

Polydextrose is less sweet than sucrose but heavier/denser. Therefore, there is high likelihood of using a lot of them to achieve the same sweetness as sucrose. However, because they are not readily metabolized, too much intake can lead to enhanced bowel movement

62
Q

What are the two different categories for high intensity sweeteners?

A
  1. natural

2. synthetic

63
Q

What are the 4 types of natural sweeteners?

A
  1. amino acids
  2. Miraculin
  3. Thaumatin
  4. stevia
64
Q

__-amino acids are generally sweeter. ___-amino acids are generally bitter. What are 2 exceptions?

A

D

D-Alanine (insipid taste)
L-Alanine (sweet)

65
Q

What common 5 amino acids tent to be sweet?

A 
D-His 
D-Leu
D-Try
D-Tyr
D-Gly
66
Q

How much sweeter than sucrose of D-Tyr?

A

35 times

67
Q

What is the synthetic derivative of D-Tyr? How many times sweeter than sucrose is it?

A

6-chloro-D-Try (via addition of 6 chloroform groups)

approx ~ 1000 times

68
Q

What are 2 special characteristics about glycine?

A
  1. has another chiral centre

2. Cannot have D or L

69
Q

Miraculin:

  1. What type of compound is it?
  2. What type of fruit?
  3. Where is it found?
  4. Commonly referred as?
  5. Under what conditions does it taste sweet?
  6. What is this an example of?
A
  1. glycoprotein
  2. berries
  3. west africa
  4. miracle fruit
  5. tastes intensely sweet in presence of acids
  6. taste modification
70
Q

Thaumatin:

  1. what compound(s) is this? What compound does it produce?
  2. What fruit / what country is it found in?
  3. How many times sweeter than sucrose?
A
  1. a mix of sweet-tasting proteins - produces a peptide rich in the hydrolysate thermalin
  2. katemfe / africa
  3. 1,500 - 2,500 sweeter than sucrose
71
Q

Stevia:

  1. what kind of fruit is it?
  2. where is it found?
  3. what is its active compound?
A
  1. shrub
  2. sub-tropical / tropical zones in South America
  3. steviol glycoside (an alcohol)
72
Q

What are the 6 high intensity synthetic sweetness?

A
  1. Saccharin
  2. Cyclamates
  3. Aspartame
  4. Acesulfame
  5. Sucralose
  6. Alitame
73
Q

Saccharin:

  1. Name brand?
  2. Available in what two forms?
  3. Found in the market as what form?
  4. Is its use permitted in CAD?
  5. It is used in products like ______ and _______ because it is _____ stable.
  6. used as a sweetener in _________ products.
A
  1. Sweet n’ Low
  2. Sodium or Calcium salts
  3. tablets
  4. Yes. Used to not be because proven to cause tumors in the bladder of rats
  5. cookies, candies; heat
  6. pharmaceutical
74
Q

Cyclamates:

  1. Name brand?
  2. Available in what two forms?
  3. Converted to ________ by what part of our body? What type of compound is this?
A
  1. Sugar Twin
  2. Na and Ca salts
  3. cyclohexylamine by gut bacteria in certain individuals. A carcinogen
75
Q

Aspartame:

  1. What is it a derivative of?
  2. How much sweeter than sugar?
  3. When was it approved? For use as what 3 things?
  4. brand name?
  5. Used in what 3 food products?
  6. Why is it not suitable in cooked products/baked goods? What does high heat do?
  7. Why is it dangerous for aspartame to break down into its components via heat?
A
  1. a methyl ester of the dipeptide (L-aspartyl–L-PHE)
  2. 200x
  3. 1980’s. Table-top sweetener, dry beverage mixes, in foods that are not heat processed
  4. Equal / NutraSweet
  5. gums, yogurt, beverages
  6. heat-liable. High heat causes aspartame to break down into its components (PHE, aspartic acid, methanol)
  7. methanol=harmful. Individuals with rare defective genes for PHE hydroxylate, PHE formed can not be utilized and will accumulate. Condition is called PKU - can cause mental disorders
76
Q

Acesulfame-Potassium:

  1. What are its 3 shelf names?
  2. What is it?
  3. how much sweeter than sugar?
  4. Stability relative to other synthetic sweeteners?
  5. What are two characteristics about its sweet taste?
  6. How is it required to be used in food? products/processed/packaged goods? Who is allowed to incorporate the compound?
  7. Stability to heat? Therefor?
A
  1. Ace-K, Sunett, Sweet One
  2. K-salt of methyl-oxathiazine-dioxide
  3. 200 times
  4. more stable
  5. clean, does not linger
  6. in combination with other sweetness in food products, processed and packaged foods. Only the Manufacturers.
  7. heat stable so does not undergo flavour changes when used in cooked products or backed goods
77
Q

Sucralose:

  1. _________ derivative of __________.
  2. How much sweeter than sucrose?
  3. stability relative to sugar?
  4. Very suitable for what?
  5. found in supermarkets in what two forms?
  6. Why does it not supply calories as sugar?
A
  1. trichloro; glucose-fructose (sucrose)
  2. 6000x - so just need tiny amount to reach desired sweetness.
  3. more stable
  4. food uses b/c heat stable (beverages, baked goods, candies) & pharmaceuticals
  5. sachets or granulated
  6. not metabolized in the gut
78
Q

Alitame:

  1. Derivative of what?
  2. how much sweeter than sucrose?
  3. brand name?
  4. Heat stability?
A
  1. dipeptide L-alpha-aspartyl-alaninamide
  2. 2000-3000x
  3. aclame
  4. stable to heat
79
Q

What is sour taste due to?

A

H+ ions from acids

80
Q

What are examples of acids that release H+ ions - giving a sour taste?

A
  1. lactate
  2. pyruvate
  3. acetate
  4. malate
81
Q

What does the concentration of H+ determine? What does it not determine?

A

Determines degree of sourness, not total acidity

82
Q

What happens to the taste of the food if the acids inside are not in their ionizable form?

A

less sour

83
Q

What are other contributory factors to the sour taste of foods?

A
  1. nature of acidic group, buffering capacity, presence of other compounds
84
Q

The majority of the acids used in foods are ______ acids.

A

organic

85
Q

What are the two inorganic acids used in foods?

A

H3PO4 (phosphoric acid)

HCl (Hydrochloric Acid)

86
Q

What are 8 different reasons acids are used in foods?

A
  1. optimum acidity in deserts, sugar confectionery, and fruit flavoured beverages enhances flavour of product
  2. Acid milieu curtails microbial activity / metabolism and prevents spoilage
  3. acid milieu slows down / stops action of several enzymes - preventing food spoilage by autolysis
  4. enhance the action of natural antioxidants
  5. Important to have the right acidic pH during wine processing to obtain stable product
  6. pectin-based jams and jellies, gel strength depends on the use of correct acidity
87
Q

Ascorbic acid (an antioxidant) is stable at what pH? What happens if this pH is not met and it is in its reduced form?

A

low pH

reduces activity

88
Q

Acids with carboxylic groups (citric acid) act as what?

A

metal ion chelators, further enhancing antioxidant activity

89
Q

Acids naturally present in food material is used to _______ food products made from the ______ material.

A

acidulate; raw

90
Q

What are the 11 common organic acids?

A
  1. acetic acid
  2. adipic acid
  3. citric acid
  4. fumaric acid
  5. lactic acid
  6. magic acid
  7. propionic acid
  8. sorbic acid
  9. succinic acid
  10. succinic anhydride
  11. tartaric acid
91
Q

What is an example of an inorganic acid?

  1. characteristics?
  2. commonly used in the form of what?
  3. concentration?
A

Phosphoric acid

  1. colorless, crystalline solid
  2. a clear, syrupy liquid
  3. 75-85%
92
Q

Why is phosphoric acid able to blend in really well with non-fruit flavours?

A

because it has a flat taste

93
Q

What 3 things is phosphoric acid used to make?

A
  1. cola drinks
  2. cheese making
  3. brewing for pH control
94
Q

What is salty taste due to?

A

salt ions (Na+, K+, Cl+)

95
Q

What is salty taste dependent on? How do small and large ions differ in saltiness?

A

size of ions

Smaller = saltier
Larger = more bitter
96
Q

What are 4 examples of salts that have a salty taste?

A
  1. LiCl
  2. LiBr
  3. NaNO
  4. NaCl
97
Q

What are 3 examples of salts that have a bitter taste?

A
  1. CsCl
  2. KI
  3. MgSO4
98
Q

What are 2 examples of salts that have a sweet taste?

A
  1. PbAc

2. BeAc

99
Q

What are 4 functions of sodium chloride (NaCl)?

A
  1. salty taste
  2. preservation
  3. digestive stimulant
  4. flavour enhancer
100
Q

Most individuals can tolerate up to __% salt as NaCl in their diets. What happens if people intake salt past this concentration?

A

2%. Beyond this concentration, NaCl may render the resulting product indigestible or nauseating

101
Q

What are 2 approaches to reduce NaCl levels in foods?

A
  1. add spices
  2. salt substitues
    - Mineral based substitutes of ions other than Na+
    - Vegetized salt substitutes powdered dehydrated vegetables (onion, garlic, celery) as base
102
Q

What can Na compounds be replaced with in food products? What is an example?

A

Compounds of other cations. Ex. KHCO3 may be substituted for NaHCO3 in baking

103
Q

What are 4 examples of commercial salt substitutes?

A
  1. NH4Cl (from 4-50%)
  2. KCl (9-95%)
  3. Citric acid & citrates, starch (1-25%)
  4. Glutamic acid & glutamates
104
Q

What is bitter taste in foods due to?

A
  1. various organic and inorganic compounds
105
Q

Bitter compounds in foods are mostly of ______ origin.

A

plant

106
Q

What 3 classes of compounds are responsible for bitterness in foods?

A
  1. alkaloids
  2. glycosides
  3. certain amino acids/peptides
107
Q

What are alkaloids? What taste do they have?

A

nitrogenous compounds widely distributed in plants as salts with acetic acid or a carboxylic acid

bitter

108
Q

What are 3 examples of alkaloids?

A
  1. quinine
  2. caffeine
  3. theobromine
109
Q

Quinine:

  1. What is it?
  2. Solubility?
  3. Bitterness?
  4. Used in what?
A
  1. white amorphous powder
  2. limited solubility in H2O, although the sulphate and hydrochloride salts areH2O soluble
  3. one of the most bitter substances known
  4. beverages
110
Q

Caffeine

  1. What it is?
  2. Where is it found (3 + %)?
  3. Solubility?
  4. GRAS status?
A
  1. a crystalline purine derivative
  2. found in coffee beans (1.5%), tea leaves (5%), and cola nuts (2.5%)
  3. solubility in H2O is 1:50 @ 25C or 1:2 @ 65C
  4. powerful stimulant - GRAS status
111
Q

What is special about theobromine? What two plants is it found in?

A

structurally related with caffeine, and often found together with caffeine in various plants

  1. cocoa beans (2%)
  2. cola nuts (0.02%)
112
Q

What are glycosides? What are 4 examples?

A

aglycones esterified with various sugars

  1. naringin
  2. hesperidia
  3. conifers
  4. sinigrin
113
Q

In what foods is naringin found? What is its relative bitterness?

A

grapefruit and bitter orange. one of the most bitter substances known?

114
Q

What 2 substances does hydrolysis of naringin yeild?

A
  1. D-rhamnoglucose

2. aglycone - naringenin

115
Q

In what foods is Hesperidin found in?

What 2 substances does hydrolysis of hesperidin yeild?

A

sweet orange and other citrus fruits

  1. rutinose
  2. aglycone hesperetin
116
Q

Where is coniferin found? What substance does it produce upon hydrolysis (which then may be oxidized to what)?

A

in conifer wood

coniferyl alcohol which may be oxidized to vanillin

117
Q

What is sinigrin? What two substances does it yield upon hydrolysis?

A

a black mustard seed - yields glucose and allyl isothiocyanate upon hydrolysis

118
Q

What type of acid makes taste buds insensitive to sweet and bitter?

A

gymnemic acid

119
Q

What does “Miracle fruit” do?

A

makes bitter and sour compounds taste sweet

120
Q

what are the 2 criteria for taste sensitivity?

A
  1. solubility

2. concentration

121
Q

Sub-threshold levels of salt reduces ______ in foods.

A

sourness

122
Q

Sub-threshold levels of acids enhances ______ in foods.

A

saltiness

123
Q

Sub-threshold levels of sugars reduces ______ in foods.

A

saltiness

124
Q

What are flavour enhancers?

A

compounds that improve or intensify flavour / quality in foods

125
Q

What are 3 example of flavour enhancers?

A
  1. monosodium glutamate (MSG)
  2. nucleotides (IMP, GMP)
  3. maltol (3-hydroxyl-2-methyl-pyrone)

Food Chemistry 2 (6 decks)

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