Topic 4 Flashcards

1
Q

Food processing

A

conversion of raw animal & plant tissue into forms that are convenient and practical to use

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2
Q

what is the purpose of food processing?

A

To make the food palatable

Make it more convenient

Improve taste (ex: strawberry jam vs. strawberries)

To increase shelf-life

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3
Q

food preservation

A

the use of specific thermal and non-thermal processing techniques to minimize the number of spoilage

increase the shelf-life of a food

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4
Q

spoiled

A

no longer palatable

physical appearance changes, moisture is lost

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5
Q

are all spoiled foods no longer edible or safe?

A

no

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6
Q

what are the 3 classes of food preservation?

A

physical

chemical

biological

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7
Q

physical food preservation techniques involved

A

asepsis

drying

heating

cooling

irradiation

blanching

heat

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8
Q

what type of preservation doesn’t include chemicals or microbes?

A

physical

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9
Q

what is goal of physical preservation?

A

to prevent the food from changing its physical properties (ex: moisture loss)

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10
Q

describe the affect cooling has on food

A

decreases growth rate of microbes

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11
Q

describe the affect freezing has on food

A

stops growth of microbes

frozen water is unavailable to microbes

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12
Q

blanching

A

heating followed by immediate freezing deactivates indigenous enzymes of the food that reduce the food’s quality (ex: enzymes that oxidize vit C)

enzymes can change colour of food

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13
Q

colour of blanched food is ____ than food that isn’t blanched

A

brighter

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14
Q

irridiation

A

methods of killing microbes

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15
Q

chemical food preservation

A

addition of sugar, salt or chemical preservatives

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16
Q

preventing oxidative rancidity is what type of food preservation?

A

chemical

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17
Q

preventing browning of apples is what type of food preservation?

A

chemical

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18
Q

what effect does salt have as a food preservative?

A

causes osmosis killing microbes, increases water holding capacity

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19
Q

what effect does sugar have as a food preservative?

A

hydroscorbicity making water unavailable to microbes

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20
Q

biological food preservation

A

fermentation

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21
Q

what effect do microbes have on food?

A

produce enzymes that produce compounds in foods- may or may not be harmful

can make the food unpalatable

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22
Q

what occurs when microbes break down food?

A

release ammonia

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23
Q

many foodborne illnesses are caused by what type of microbes?

A

aerobic

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24
Q

oxidative rancidity

A

rxn with oxygen & unsaturated FA

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25
Q

chemical oxidative rancidity

A

production of synthetic enzymes

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26
Q

biological oxidative rancidity

A

enzymes produced by microbes

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27
Q

aspesis

A

practice to keep micro-organisms out of food, protective coverings around food

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28
Q

what are the coverings used in aspesis?

A

Shells of nuts

Die skins of fruits & vegetables

Shells of eggs

Skin or fat on meat or fish

(also includes packaging - wraps, polythene covers, canning etc.)

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29
Q

what are the benefits of asepsis?

A

prevents moisture loss

prevents entrance of microbes

prevents oxidation

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30
Q

drying

A

removal of water from foods

inhibits growth of microbes

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31
Q

how was drying accomplished in ancient times?

A

sun drying

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32
Q

plate drying

A

puts the food in a single layer & puts it in the dehydrator

Dehydrator will have: Heat source & fans (push out moist air)

Moisture will leave food & remain in the air, when the moisture in the air is equal to the food, the food can longer be dried (no gradient is established). When this happens, new air is established by the fans pushing out the moist air

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33
Q

what is a negative & positive effect of plate drying?

A

Food that undergo this process lose most of their vit C

cheap

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34
Q

drum drying

A

dry liquids to make powders, drum is hot & rolls, as it rolls the liquid food is coated on it & the food dries out

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35
Q

spray drying

A

spray liquid food into a hot chamber, liquid droplets immediately dehydrate when introduced into the hot chamber. There is a vacuum pump that moves out the moist air

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36
Q

how is milk dehydrated?

A

spray drying

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37
Q

does drum or spray drying work better?

A

spray

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38
Q

is drum or spray drying cheaper?

A

drum

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39
Q

freeze drying

A

based on sublimation, put food in freeze drier that has vacuum pumps attached, moisture will escape as a vapour, the vacuum takes out the moist air causing the food to constantly lose its moisture & dry

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40
Q

what needs to occur to the food after freeze-drying & why?

A

When you remove the food product & place it into moist air, the food will regain moisture vacuum packed immediately after treating

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41
Q

what is a positive effect of freeze drying?

A

Doesn’t require heating - no vits or minerals destroyed, method of least nutrient loss

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42
Q

what drying method results in the least nutrient loss?

A

freeze drying

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43
Q

what is the problem with drying by heat?

A

loss of heat sensitive nutrients including vit C, riboflavin & niacin

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44
Q

drying by heat

A

Heat is applied to remove water to kill microbes, not to kill microbes directly

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45
Q

what envr factors are important in drying?

A

temp & moisture level

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46
Q

the longer the heating process =

A

the more vit & mineral loss

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47
Q

thermal processing

A

Food shelf life can be extended if sufficient heat is applied killing microorganisms & inactivating the present enzymes in food

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48
Q

pasteurization

A

• Heating foods to a specified high temp for a short time kills most disease-causing microbes

slightly extends shelf-life by killing most food spoilage & pathogenic organisms

Kill most microbes
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49
Q

sterilization

A

a more severe process which destroys all microorganisms & may change the organoleptic qualities of the product

Kill all microbes

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50
Q

canning

A

food is held at a high temp for several minutes

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51
Q

what is the closest form to sterilization in the industry ?

A

canning

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52
Q

Batch pasteurization (LTLT)

A

product is held in a specific temp range for a long time, low temperature, long time

Ex: 62-36C for 30-35 mins

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53
Q

High temp, short time (HTST) pasteurization

A

product is heated to a higher temp but for a shorter time

Ex: 72C for 15 secs for milk, using a plate heater

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54
Q

what method of pasteurization is more common?

A

HTST

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55
Q

ultra-high temp pasteurization

A

heats at very high temp under pressure

kills almost all microbes

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56
Q

what type of pasteurization do unrefrigerated milk products use?

A

ultra-high temp pasteurization

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57
Q

the longer the food is heated =

A

the more vits are lost

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58
Q

what form of pasteurization causes the most nutrient loss?

A

LTLT

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59
Q

sterilization

A

complete destruction of microbes

Food is exposed to wet heat (vapour) for 15 min at 121C

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60
Q

what type of microbes are killed in sterilization?

A

Pathogenic & toxin-producing organisms

Spoilage microorganisms

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61
Q

what temp is used in sterilization?

A

over 100 C

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62
Q

pressure cooking

A

atm pressure is increased to increase the BP of water (hotter), destroys spores & microbes

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63
Q

incres BP =

A

more destructive to microbes & spores

&

food cooks faster

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64
Q

how can pressure cooking result in food poisoning?

A

If correct temp isn’t reached, there is a possibility that the spores will germinate & could lead to poisoning

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65
Q

ultraheat treatment of ultrahigh temp (UHT)

A

Continuous process & product is packaged after sterilization into sterile containers

product is moving continuously rather then being stationary

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66
Q

how does sterilization & UHT differ?

A

UHT - shorter time & higher temp

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67
Q

canning

A

food is held for a number of mins at a high temp

above 110C & under pressure

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68
Q

what does canning kill?

A

Kills harmful or spoilage-causing microbes & their spores

69
Q

what effect does canning have on nutrient loss?

A

there will be some nutrient loss

70
Q

Time for which the food is held at high temp depends on several factors including: (canning)

A

Microbial population in the food product

Size of the food product

pH of the product

Size of container - when placing a can in boiling water, the can will not begin to boil instantly

71
Q

what effect does canning have onw ater soluble vits?

A

Water soluble vits may be lost when food is canned in water, especially if the water is discarded before consumption

72
Q

convection

A

heat is transferred by movement

73
Q

radiation

A

waves will hit something, will swirl & produce heat

74
Q

conduction

A

heat transferred via touch

75
Q

induction

A

heat is transferred by magnetic E

76
Q

how is canning determined to be finished?

A

due to the location of the cold spot

Use probes to determine what part of the can was heated last & for how long

77
Q

incres viscosity of food = ____ of heating

A

incres length

78
Q

does a low pH food require a higher or lower temp?

A

lower temp

79
Q

what needs to occur properly to prevent the growth of microbes?

A

heat

vacuum

seal

80
Q

traditional canning

A

food is heated & held at a high temp while already inside packaging material

81
Q

aseptic packaging

A

food can be batch heated in a sterile fashion & then placed in a sterilized container

82
Q

what are the 2 methods of aspetic packaging?

A

boiling water canning

pressure canning

83
Q

boiling water canning is used in what foods?

A

used for high acid foods

100C

84
Q

pressure canning is used in what foods?

A

used for low acid foods

can also be used for high acid foods, but will result in a softer texture

85
Q

what foods are high acid foods?

A

all fruits besides: figs, tomatoes & melons

rhubarb

fermented pickles

acidified foods

86
Q

what type of foods require pressure canning?

A

low acid foods

87
Q

what foods are low acid foods?

A

all vegetables except rhubarb

meats

poultry

seafood

soups

mixed canned foods

88
Q

processing schedules

A

Length of time at a specific temp that a food must be processed

89
Q

what affects processing schedules? (7)

A

pH value of the food

Composition of the food

Viscosity

Tightness of pack

Convection vs. conduction transfer of heat

Starches, fats & bones

Size of jar/can conduction

90
Q

what affects the processing time?

A

whether food heats by convection, conduction or a combo of both

91
Q

what must the cold spot do to ensure target pathogens are destroyed?

A

The “cold spot” in the food must reach the correct temp for the correct length of time to destroy target pathogens

92
Q

how is heated transferred in solid foods?

A

mostly by conduction

93
Q

what gets heated last in canned foods?

A

the cold spot

94
Q

where does the cold spot tend to situated? & why?

A

in the middle of the can

Due to convection – the heated liquid at the bottom will move upwards & the colder liquid at the bottom will move downward

95
Q

refrigeration

A

storing food at cold temp

Causes retardation of microbial growth, but doesn’t mean that pathogens are gone or not multiplying

96
Q

freezing

A

in contrast to refrigeration at warmer temps, cause liquid water within the food to become solid ice

Microbe growth & enzyme activity (degrades quality of food) ceases almost completely

97
Q

fermentation

A

Encourages growth of beneficial bacteria to inhibit the growth of pathogenic bacteria

used in preserving & providing a source of probiotics

98
Q

what foods have fermentation promoted?

A

yogurt, prosciutto, bread, cheese, wine & chocolate

99
Q

microwaves

A

Create heat through the movement of high frequency radio waves that energize some molecules within food & heats up the food

100
Q

irradiation

A

exposure of food to ionizing radiation in the form of gamma rays, x-rays or electron beams

101
Q

what are the functions of irradiation?

A

o Controls microbial growth
o Extends shelf life
o Preserves food by causing the formation of free electrons, ions & free radicals

102
Q

Irradiation is approved in Canada for the following foods: (6)

A
o	Onions 
o	Potatoes
o	Wheat 
o	Flour 
o	Whole wheat flour 
o	Whole or ground spices & dehydrated seasonings
103
Q

what symbol do irradiated foods display?

A

“radura”

Symbol must be accompanied with the words “treated by irradiation” or “treated with irradiation”

104
Q

• Vitamin composition & mineral retention can be affected by: (5)

A
o	pH 
o	Light 
o	Oxidation 
o	Water solubility 
o	Other applications
105
Q

vit C can be damaged by:

A

o Heat
o Oxidation
o Drying
o Enzymatic action of inherent enzymes when the food tissue us cut

106
Q

• Thiamin can be destroyed by:

A

o High heat

o Nonacidic conditions

107
Q

what vits are sensitive to heat treatment? (4)

A

Riboflavin, niacin, vit B6 & folate

108
Q

high pressure

A

• food is placed under uniform pressure of up to 100,000 lbs. per square inch

109
Q

what methods are included in high pressure food preservation ?

A

high-hydrostatic pressure processing or ultra-high pressure (UHP) processing

110
Q

ultraviolet food preservation

A

non-thermal treatments to eliminate or reduce microbes in food

111
Q

what methods are included in UV food preservation (3)

A

irradiation, pulsed light & ultrasound technology

112
Q

high pressure/high temp

A

called pressure assisted thermal sterilization (PATS)

combines pressure & heat

kills C. botulinum

113
Q

non thermal food preservation

A

includes UV radiation, pulsed light & ultrasoundn

114
Q

continuous microwave food preservation

A

ipuree is passed through a tube & the microwaves are directed towards the center of the food, heats the food inside out

ex: sweet potato puree

115
Q

what are the newer technologies in food preservation?

A

UV

high pressure

high pressure/high temp

non-thermal

continuous microwave process

116
Q

paper

A

made from pulped cellulose fibers derived from wood

transformed into paperboard for direct food contact

used as an outer package or shipping package

is waxed or laminated with a plastic polymer (polyethylene) to improve resistance to water & oils

117
Q

plastic

A

polyethylene terephthalate (PTE) is widely used in items like carbonated drink bottles b/w it is clear & impermeable to the carbonation gases

118
Q

metals

A

includes aluminum & other metals like steel

often lined with plastic to prevent a rxn

119
Q

glass

A

made from heated silica, sodium carbonate & stabilizers

120
Q

what was believed to be the 1st package?

A

glass

121
Q

what is an advantage & disadvantage of glass?

A

biodegradable

heavy & brittle

122
Q

what is health canada’s advice on PBA?

A

o Current dietary exposure to BPA through food packaging uses is not expected to pose a health risk to the general population, including newborns & infants

recommend to apply ALARA (as low as possible)

123
Q

modified atmosphere packaging (MAP)

A

respiration rates are decreased & shelf life is increased by modifying the air inside a package to MAP

kills microbes which require oxygen to survive

prevents oxidation of vit C & E

prevents oxidation of unsaturated FAs

124
Q

edible films

A

coatings are applied to foods for its beneficial properties

prevents exposure to oxygen

can combine with antimicrobial chemicals

125
Q

intelligent & active packaging

A

“smart” packaging that interacts with the external or internal envr of the package

o Has sensors & indicators that inform the processor, distributor, seller or consumer about the envr of the package

o Can close in the presence of gas or if the food is exposed to a new atmosphere then it will cause a colour change indicating its efficacy

126
Q

what is the cheapest preservative?

A

salt

127
Q

what is an envr effect of packaging?

A

source of municipal solid waste (MSW)

can be solved by using less packaging

128
Q

what family is coffee?

A

Rubiaceae

129
Q

what is the genus of coffee?

A

coffea

130
Q

what species of coffee is used in global coffee production?

A

coffea arabica

coffeae canephora

131
Q

what species of coffee is used on a smaller scale production?

A

coffea liberica

coffea deweveri

132
Q

what type of fruit is coffee?

A

berry - 1 berry has 2 coffee beans

133
Q

coffee - processing

A

removal of the bean from the fruit followed by drying

134
Q

what are 2 methods of processing coffee?

A

dry

wet

135
Q

dry processing in coffee

A

fruit is picked & placed in the sun to dry which takes 10 days - 3 weeks, the husk of the fruit is removed by a machine & the beans are revealed

136
Q

wet processing in coffee

A

outer skin & pulp of the fruit are removed by a machine immediately following the harvest of the berries, after fermenting & washing tanks they’re dried for several weeks after which milling machines remove the skin

137
Q

what is the most important factor affecting the taste of coffee?

A

roasting

138
Q

pulping

A

removal of the outer skin

139
Q

roasting

A

Beans are heated up to 900F for 16-17 mins where the coffee oil (caffeol) is released, the sugars within the bean caramelize & the beans develop a slightly burnt flavour

caramelizing triggers the darkening & flavour effects

oil contain caffeine

140
Q

more the coffee is roasted or at a higher temp = ___ bitter & tangy taste & ____ caffeine

A

more

less

141
Q

what are the 2 main roast types?

A

medium: delicate flavour & aroma
dark: bitter taste

142
Q

what are the 4 types of roasts identified?

A

Light/pale

Medium

Dark/full roast

Darkest roast

143
Q

decaf coffee

A

Caffeine is removed from green coffee beans by solvent extraction, water extraction or steam extraction

144
Q

extraction solvent in decaf coffee

A

methylene chloride (organic)

145
Q

American style coffee

A

coffee grinds placed in brew filters & pass through the unit of the pot

Grounds remain in the upper unit
146
Q

turkish style coffee

A

made in a small copper pot with a long handle with 2 tsps of finely ground coffee & 1 tsp of sugar added to a cup of water & then brought to a boil

147
Q

french

A

coarse, ground coffee is placed in the pot, hot water is added & steeps for 3-5 mins. The plunger is pushed down which separate the coffee grounds from the brew

plunger method, perforated method

148
Q

coffee what method extracts the most flavour?

A

plunger method

149
Q

what method is similar to the french method of making coffee?

A

turkish

150
Q

italian

A

espresso is made on a stove-top espresso maker, utilizes pressure as the hot water is forced through very finely ground, dark roasted coffee to produce the espresso brew

151
Q

what is the original maker of italian cofee?

A

Moka

152
Q

describe the acidity of coffee

A

pleasant tartness, low acidity exhibits a soft, smooth & mellow taste

153
Q

describe the mouth feel or body of coffee

A

heaviness, tactile richness & thickness when coffee is swished in the mouth

texture: oily, buttery or thin

154
Q

coffee - aroma

A

termed fragrance & is attributed to the gases of the aromatic oils which are released when roasting

155
Q

coffee - finish

A

refers to the immediate sensation after the coffee is swallowed, such as a chocolate finish, whereas others exhibit berry tones

156
Q

coffee - flavour

A

accounts for:

Sweetness because of caramelization after roasting

Bitterness which results from products during roasting

157
Q

camellia sinesis

A

evergreen & grown in tropical & subtropical regions

158
Q

where are the finest teas grown? & why?

A

above sea level

Cooler temps & harsher conditions encourage the leaves to mature more slowly which optimizes the flavour

159
Q

the smaller the leaf = ____ flavour

A

more

leaves don’t grow as long in colder conditions

160
Q

herbal teas

A

infusions of: leaves, roots, bark, seeds or flowers of other plants

161
Q

processing tea stages

A
  1. Withering: removes leaf moisture, breaks down into AAs & simple sugars & increases caffeine & polyphenols (provides brownish colouring)
  2. Rolling: leaves are crushed & broken
  3. Fermentation: polyphenols in leaves oxidize & become a copper colour (oxidation)
  4. Drying: uses heat & inactivates polyphenol enzymes, dries leaves & caramelizes sugars (oxidation rxn seizes)
162
Q

what are 2 ways to prepare tea?

A

tea can steep

tea perforator

163
Q

amora of tea

A

brisk or flowery tates

164
Q

what do?es the tastes of tea depend on?

A

processing, growing region, weather, additives/flavourings, soil type, leaf age, length leaves oxidize & type of wood used in the drying process

165
Q

what is responsible for the colour in tea?

A

polyphenols

166
Q

what is reponsible for the fragrance & flavour in tea?

A

aromatic oils

167
Q

what is the purpsoe of fair trade coffee?

A

to provide farmers access to international markets & fair wages for their labour

Protection needed due to boom & bust cycles

Farmers are poor & don’t have any savings to support themselves when their wages are poor
168
Q

boom cycle

A

production is poor & prices are higher

169
Q

bust cycle

A

too much production, prices are lower