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Food Chemistry II > FInal Exam > Flashcards

FInal Exam Flashcards

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1
Q

Difference sorbate and benzoate explain

A

Sorbate, active in salt form, used to inhibit mold growth and benzoate, active in free acid form, used to inhibit bacterial growth.

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2
Q

melted or frozen ice cream sweeter

A

Melted will taste sweeter since the cold from the frozen ice cream will numb taste buds and lessen the sweetness sensation.

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3
Q

differences between lactic acid and lactose and if there’s a relationship

A

Lactic acid is made from the fermentation of sucrose, potato starch, etc. and is doesn’t originate from dairy products. Lactose is the sugar found in dairy products that breaks down into galactose and glucose. It is the least sweet natural sweetener. Lactic acid is often found in fermented products as well as many dairy products.

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4
Q

purpose of using acidulants and applications 4 uses and examples (2 questions)

A
  1. Enhance taste in desserts and confectionnaries. Subthresholds amount of sour compounds
    decreases saltiness). Vinegar gives piquancy and aromatic flavors to pickles.
  2. Inhibit enzymatic activity ex. Enzymatic browning
  3. Inhibit microbial growth. Vinegar is used as a preservative for pickles.
  4. Increase gel­strength in pectin­based jams and jellies
  5. Activate antioxidant activity ex. Fumaric acid in mushrooms and rice products.
  6. Used in processing of wine to have a stable product.
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5
Q

drinking cold water to relieve black pepper

A

The cold will numb the taste buds temporarily to cause relief. Water does not stay in the mouth very long though so the relief will be short.

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6
Q

air and water do they both have the same affect and enzymatic browning

A

They do not. Water will temporarily inhibit enzymatic browning by restricting the amount of oxygen that comes into contact with the food item. The barrier is not present in air therefore enzymatic browning will proceed more quickly.

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7
Q

L or D amino acid sweeter

A

Usually, D amino acids taste sweet and L amino acids taste bitter. There are some exceptions such as L­ Ala which tastes sweet and D­Ala which tastes bitter.

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8
Q

2 examples of texturizers, water ­binding agent, emulsifying, foaming agents

A

Texturizers: thickener/thixotropic agents (gums, pectin, starch, sugars, whey protein, CMC), and emulsifying agents (mono­diglycerides, mustard powder and lecithin).

Water­ Binding agents: Humectants (phosphates, polyphosphates, glycerol), anti­caking agents (silicates, cornstarch)

Emulsifying agents: mono and diglycerides, mustard powder, lecithin

Foaming agents: egg whites, milk powder

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9
Q

2 amino acids in alitame

A

Aspartate and alanine

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10
Q

triangle test: panel how to chose from each corner

A

False. You Have 3 products. Two are identical. Pick the odd one out.

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11
Q

explain difference and preference tests

A

Preference tests are useful for the development of new products. Subjects are asked to choose the product that they prefer due to the overall taste. Tests include paired comparison, hedonic test and ranking. Difference tests are used to identify differences between products. One can identify certain attributes to a food and see if an improvement should be made. The sensory quality can be assessed. These test include simple paired comparison, scheffe paired comparison, ranking, multiple comparison, due trio, and triangle test.

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12
Q

Why would you chose synthetic over natural components

A

Natural colors do not give as vibrant of a color, it is more susceptible to changes in heat and light so the color can vary, can add flavor to food since more must be used and is much more expensive.

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13
Q

glucose vs fructose why is fructose sweeter

A

Fructose is sweeter due to its 5 membered ring, vs the 6 membered ring of glucose.

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14
Q

difference between high fructose corn syrup and corn syrup

A

In high fructose corn syrup glucose isomerase is added to regular corn syrup in order to convert glucose in fructose. Since fructose has a higher relative sweetness than glucose, the final product, in the same amounts, is sweeter than corn syrup.

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15
Q

3 things bitter tasting: xylitol, naringin, .. (false)

A

False: alkaloids (caffeine, theobromine, quinine), glycosides (naringin, coniferin, sinigrin, hesperidin), and certain amino acids.

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16
Q

What imparts sour sensation

A

H+ions.

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17
Q

What is ADI

A

Acceptable Daily Intake. It is the highest amount of a compound (weight/kg of body weight) that has not caused any harmful effects in the experiment animal divided by 100.

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18
Q

How do we perceive taste

A

Taste perception comes from the tongue and the nose and is interpreted by the brain to result in the overall sensation. Taste, mouthfeel and odor/olfaction play a role.

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19
Q

3 groups of food additives

A

Food Colors, Incidental (pesticides, PCBs, asbestos, etc.), Intentional (Processing aids, quality enhancers and preservatives)

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20
Q

what is sweetness equivalent

A

Sweetness comparison with sucrose (given value of 1)

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21
Q

MSG and mannitol are they flavour enhancers

A

only MSG

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22
Q

2 factors that affect mouthfeel (or necessary for)

A

tactile sensation (astringency, texture, consistency), temperature and pain

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23
Q

sour taste: tartiric, sorbic and citric (T or F) are organic not inorganic

A

T organic

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24
Q

3 characteristic of flavor

A

taste, odor, mouthfeel

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25
Q

do quinones impart a bitter taste

A

yes

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26
Q

hedonic scale is it part of the ranking test t/f

A

t

27
Q

3 purpose for adding food colorants

A

∙ offset color loss due to exposure to light, air, temperature extremes, moisture and storage conditions
∙ correct natural variations in color
∙ enhance colors that occur naturally
∙ provide color to colorless and “fun” foods

28
Q

what makes something sour

A

H+ ions

29
Q

what makes a molecule sweet

A

electronegative N and O

30
Q

theobriomine and bitter taste

A

It is an alkaloid that is structurally similar to caffeine and often found with caffeine in certain plants such as cola nuts.

31
Q

selection of sweetners

A

carcicogenicity, solubility, heat of solution, hygorscopicity

32
Q

Cariogenicity

A

Plaque­formation. Food fermented by Strep. Mutans pyruvate­>formic, acetic or lactic acid which erodes tooth enamel. Polyols are not fermented by these bacteria and therefore do not cause enamel erosion.

33
Q

Hygroscopicity

A

Water uptake ability. High values= soggy product and harder to preserve.

34
Q

Solubility

A

Solubility should ideally be similar to that of sugar. Changes in solubility can have an impact on onset of sweetness sensation, duration of sensation and mouthfeel.

35
Q

Heat of Solution

A

Heat reabsorption. If is low there is a cooling effect. This effect is found in polyols which is desired for certain products such as mints, lozenges, tablets, etc.

36
Q

Sweetness equivalent

A

Alternative sweetener should be sweeter or isosweet to sucrose. Sucrose is given a value of 1 in relative sweetness in order to compare it to other sugars.

37
Q

Criteria for Food additives

A

Must be to consumer’s advantage, must not deceive consumer, and must be safe to use continuously

38
Q

t/f

quinine and threobomine are alkaloids

A

t

39
Q

t/f

Acetic acid is the main component of vinegar

A

t

40
Q

t/f

Is multiple test also named hedonic scale

A

f

41
Q

t/f

frozen ice cream sweeter than melt ice cream

A

f

42
Q

t/f

Food flavor is determined by texture, astringency and consistency

A

f

43
Q

t/f

Temperature affects mouthfeel

A

t

44
Q

t/f

Air and immersion in water have the same effect on enzymatic browning

A

f

45
Q

Which is sweeter between L and D form

A

D

46
Q

t/f

Quinine, threobromine, narigin in alkaloids

A

F (Naringin is a glycoside­ naringenin is the aglycone and D­rhamnoglucose is the sugar)

47
Q

t/f

Tartaric, phosphoric, citric acid in acidulants

A

T (citric and tartaric acid are GRAS general purpose acidulants but

48
Q

Threshold value

A

Minimum amount of a substance for the sensation to be felt by the individual. Subthesthold amount of comopounds can have an overall effect on taste though. Subthreshold amounts of salt can decrease sourness and vice versa, etc.

49
Q

What causes astringency

A

Precipitation of proteins in the cheeks from saliva

the dry sensation in cheeks

50
Q

What are the factors that affect mouthfeel

A

tactile sensation, pain, temperature

51
Q

How do you detect mouthfeel

A

sensed by jaw teeth and mouth

52
Q

How does temperature affect taste perception

A

It affect mouthfeel which is a factor that determines taste.

53
Q

How do we perceive bitterness?

A

Organic and inorganic compounds

54
Q

Comparison: Taste modification VS Taste inhibition

A

Gymnemic acid makes taste buds insensitive to sweet and bitter. Taste modification: temperature increases solubility. Miraculin from miracle fruit makes sour and bitter taste sweet. Subthreshold levels of salt decreases sour taste, acids enhance saltiness, sugars reduce saltiness and sweet and salty reduces bitter.

55
Q

Xylitol is isosweet to

A

sucrose

56
Q

Flavor inhibitor and flavor enhancer

A

Flavor inhibitor examples include subthreshold amount of salt which reduce sour taste. Flavor enhancer examples include acids that enhance taste of deserts and confectionaries. Includes nucleotides (IMP (fresh meat, fruits and vegetables) and GMP), MSG, Maltol.

57
Q

t/f Xylitol is isosweet to other aspartame and lactose

A

F Xylitol is isosweet to sucrose. It is sweeter than lactose and less sweet than aspartame (200x sweeter than sucrose and xylitol).

58
Q

t/f

Astringency is caused by sucralose

A

(false, it is tannins) F­ caused by precipitation of proteins in cheeks from saliva

59
Q

Triangle evaluation

A

place three samples in each of the corner of the triangle

60
Q

Maltitol and Aspartame

A

Maltitol is a polyol, second sweetest after xylitol therefore less sweet than sucrose. It is very expensive.

Aspartame is a dipeptide that, under heat, becomes aspartate, phenylalanine and methanol. Methanol, with O, becomes formaldehyde=cross­linking agent. Phenylalanine and aspartate can affect mood by affecting CNS. Phenylalanine is converted to Tyrosine by PAH but without enzyme it accumulates and causes brain damage.
It is 200x sweeter than sucrose.

61
Q

Define texture and mouthfeel

A

Mouthfeel is how the food feels in the mouth and is sensed by
jaw, teeth and tongue. Texture is a component that determines mouthfeel.

62
Q

t/f

Ranking test may be used to evaluate the way food feels in mouth

A

T We can ask individuals to

rank a product based on a certain mouthfeel­related characteristic such as texture or consistency.

63
Q

t/f

Threobromine, quinine and xylitol are bitter tasting compounds

A

(false cause xylitol is a sugar)

64
Q

Additives of sulfites and acids to foods destroys “something” food components

A

Thiamin (vitamin B1)

Food Chemistry II (8 decks)

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