Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

226 > Fruits & Vegetables: Quality & Shelf Stability > Flashcards

Fruits & Vegetables: Quality & Shelf Stability Flashcards

1
Q

EXTRINSIC

A

Temperature
Relative humidity
Gases
Packaging materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

INTRINSIC

A

Respiration rate
Transpiration
Ethylene production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Temperature affects

A

Physiological responses
Starch-sugar balance
Shelf stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

van’t Hoff rule

A

An increase of temp by 10 °C increases respiration
rate by 2-3 folds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Temperature effects on physiological responses-A low temp causes reduction in the

A

respiration rate of fruits, hence slows the metabolic process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Temp > 86 °F (30 °C)

A

the enzymes activity in fruits and veggies reduces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Temp ≥ 95 °F (35 °C)

A

Many enzymes still active, but
at this temp the metabolism of fruits is abnormal
(disruption of cellular organization, rapid
deterioration of produce)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Some produces are susceptible to chilling injury, thus
cooling < 50 °F (10 °C)

A

may not be a good option for
storage stability of produces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Normal ripening process:

A

10-30 degree celcius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Low temps may lead to

A

metabolic abnormalities
causing localized cell collapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Temperature eeefects on starch sugar balance

A

Generally, starch-sugar balance is at equilibrium
Some sugars degrade during respiration:

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

For some produces like potato and sweet potato:

A

At ambient temp: tend towards accumulation
of starch
Below critical temp: tend towards
accumulation of sugar
potato (≤ (10 °C))
sweet potato (≤ (15 °C))

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Temperature eeefect on shelf stability

A

Susceptibility of certain crops toward injury when stored at
temp <55 to 60 F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

during chilling injury, The cell structure of produces degrades

A

and metabolites such as amino acids, sugars, minerals are released: provides substrates for
microbial growth esp fungi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Freezing Injury

A

Occurs due to susceptibility of plant tissues to temp below freezing points, 25-30 °F (-4 to -1 °C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What will happen during freezing injury

A
  1. Crystal puncture cell membranes : turgor loss
  2. Crystal breaks up the cell wall structures :
    tissue breakdown, release of degenerative enzymes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Rapid cooling (pre-cooling) is important to increase the producesʼ shelf
life:

A

reduces respiration rate
reduces sensitivity to ethylene
reduces water loss
inhibits/slow down microbial growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Among main factors for the selection of the pre-cooling techniques;

A

The physiological properties of the produce (the nature of the
produce)
The desired shelf life of the produce
Package design
Room design

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Room Cooling

A

Simple, inexpensive method
Less efiicient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Forced-Air Cooling

A

An efficient method compared to room cooling
Using fans in addition to cool air
The use of forced air fans hsould be stopped oncethe priduce has reached its opt temp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Vacuum Cooling

A

Highly dependent on the surface to
volume ratio

22
Q

Hydrocooling

A

Faster heat removal (15X than air), not
energy efficient
Not suitable for produce that cannot
tolerate wetting

23
Q

Direct contact with ice

A

Efficietn for produces of high respiration rates
suitable for produces that are not chilling sensitive

24
Q

Relative Humidity

A

High humidity (90-95%) is recommended to
retain fruits/vegetables freshness

25
Q

However, high humidity may

A

y promote microbial
growth
In the case that dew point (moist a

26
Q

In the case that dew point (moist air) is cooled, a temp is reached.

A

At this temp, the vapor pressure
of water reaches its maximum: fog, condensation

27
Q

Fog causes the package of the produce

A

becomes unappealing

28
Q

Condensation can promote

A

microbial growth,
integrity loss for the package

29
Q

Respiration Rate-senescence

A

Senescence of fresh produces is
proportional to respiration rate

30
Q

respiration rate is

A

Temperature dependent and affected by modified atmosphere

31
Q

Respiratory quotient (RQ) is

A

the ratio of CO2 produced to
O2 consumed (assumed=1)

32
Q

RQ<1 when

A

reduced lipids are used for respiration

33
Q

RQ>1 when

A

organic acids are used for respiration

34
Q

Transpiration

A

The loss of water from fruits or vegetables (living cells) in a form of vapor

35
Q

transpiration is esential because

A

i) ʻcreates suction force and helping in ascent of sapʼ
ii) ʻaffects water and minerals absorption through roots
iii) ʻtranslocation of plant food from one part to another
iv) ʻdissipates excess solar energy received by plantʼ and etc

36
Q

Factors influencing transpiration:

A

Temperature
Surrounding gases (type and level)
Cultivar
Relative humidity (minimize VPD)
Light
Air movement
Nature of surface coatings
Physical injury, etc

37
Q

Gases-CO2 -help to

A

inhibit microbial growth

38
Q

co2 known to

A

increase firmness in certain fresh produces

39
Q

Higher composition (>15%) of co2 has known to

A

induce off-flavor development (fermentative metabolism)

40
Q

Nitrogen help to

A

inhibit microbial growth
Retain package from being collapsed
Prevent oxidation
Replace air

41
Q

Oxygen-reduced lvl was reported ot help in

A

delaying the
softening and pigment development

42
Q

ethylene

A

s used to control ripening process of fruits

43
Q

Produces high in ethylene MUST BE STORED
SEPARATELY

A

than produces low in ethylene

44
Q

climacteric Fruits

A
  1. Ripening process continues after
    harvest
  2. Some produces large amount of ethylene
45
Q

Non-climacteric Fruits

A
  1. Must ripen on the plant
  2. Exposure to ethylene after harvest can
    deteriorate the quality faster
46
Q

Acetylene-an alternative to ethylene

A

Economical alternative to ethylene and commonly used
in less developed countries

47
Q

Combination of CO2 and O2 is

A

s common for active modified atmosphere applications

48
Q

Packaging Materials

A

help in prolonging
the shelf life of fruits and vegetables

49
Q

Provide protection and containment

A

for distribution purposes of
fruits and vegetables

50
Q

packaging material example

A

Vented corrugated boxes
Vented clamshell?

226 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions