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5) Post-Harvest Fruit and Vegetable Technology > Lecture 1 > Flashcards

Lecture 1 Flashcards

1
Q

describe harvesting

A
  • separating from the mother plant

- beginning of the deteriorate process

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2
Q

what happens to quality after the crop is harvested?

what is an exception?

A

the longer the crop awaits before being used, the lower will be the quality

except some fruits which have optimal quality after a ripening period

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3
Q

what are main differences between characteristics of durables and perishables?

A

durables

  • low moisture content
  • small unit size
  • low resp rate
  • low generation of heat
  • hard texture (not easily damaged)
  • stable( natural shelf life of several years)
  • losses mainly caused by external agents (eg. molds, insects, rodents)

perishables

  • high moisture content
  • large unit size
  • high resp rate
  • high heat production
  • soft texture (easily damaged)
  • perishable (short natural shelf life)
  • losses caused by external agents and endogenous factors
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4
Q

what is the moisture content of durables?

A

low (10-15%)

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5
Q

what is the moisture content of perishables?

A

high (50-90%)

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6
Q

compare the unit sizes of durables and perishable

A

durables: small unit size (less than 1g)
perishables: large unit size (5g to 5kg)

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7
Q

compare the respiration rate and heat generation of durables and perishables?

A

D: low resp rate; low heat generation

P: high resp rate, high heat prod

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8
Q

compare the texture of durables and perishables

A

D: hard texture, not easily damaged

P: soft texture, easily damaged

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9
Q

compare the shelf life of durables and perishables

A

D: stable; natural shelf life of several years

P: natural shelf life of a few days to months

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10
Q

what mostly causes losses in durables?

A

external agents (molds, insects, rodents)

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11
Q

what mostly causes losses in perishables?

A

external agents and endogenous factors (respiration, senescence, sprouting)

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12
Q

what are average estimated losses of produce?

why is this?

A

24-40%

because produce loss is inevitable

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13
Q

what are ways to counteract produce loss?

A

grow more food by:

  • cultivating more land
  • intensifying agricultural production
  • using high density planting
  • using growth promoters
  • using new fertilizers
  • GM foods
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14
Q

what are advantages of minimizing post-harvest losses?

A
  • nutritional (remaining food is usually more nutritious)
  • economic
  • excessive food loss creates the initiative to produce more food due to fear of greater losses
  • environmentally friendly
  • consumer satisfaction
  • increasing food supply without using more resources (land, energy, water, capital)
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15
Q

describe the economic incentive to decreasing post-harvest losses

A
  • wastage represents an economic loss

- loss increases as the food moves down the food pipeline (cost of food and of handling, transportation, storage, etc…

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16
Q

how do we reduce post-harvest losses?

A
  1. understanding causes of post-harvest losses
  2. determine factors which affect them and how
  3. effectively use conditions which control the factors and minimize the spoilage
17
Q

what are 7 primary causes of post-harvest losses?

A
  1. biological and microbiological
  2. chemical and biochemical
  3. mechanical
  4. physical
  5. physiological
  6. psychological
  7. foreign substances
18
Q

describe how biological and microbiological factors cause post-harvest losses?

A

by consumption or damage by insects, pests, animals, microorganisms (fungi,bacteria)

19
Q

describe how chemical and biochemical factors cause post-harvest losses?

A

due to undesirable rxns between chemical compounds present in the food, such as browning, rancidity, enzymatic and chemical changes

20
Q

describe how mechanical factors cause post-harvest losses?

A

spillages and damages caused by abrasion, brusing, crushing, etc…

21
Q

describe how physical factors cause post-harvest losses?

A

improper environmental and storage conditions (temp, relative humidity, air speed, light…)

22
Q

describe how physiological factors cause post-harvest losses?

A

sprouting
senescence
respiration
transpiration

23
Q

describe how psychological factors cause post-harvest losses?

A

human aversion or refusal due to personal/religious reasons

24
Q

what are 5 secondary causes of losses?

A
  1. improper harvesting and handling
  2. inadequate storage facilities
  3. inadequate transportation
  4. inadequate refrigeration
  5. inadequate marketing system
25
Q

what are 7 produce related causes of post-harvest spoilage?

A
  1. respiration
  2. transpiration
  3. ethylene production
  4. compositional changes
  5. growht and development
  6. physiological breakdown
  7. other factors (eg. bruising, microbial)
26
Q

what are 5 keys to success in post-harvest handling of F and veg?

A
  1. initial quality
  2. maturity at harvest
  3. careful handling at harvest to minimize physical damage
  4. proper management of environmental conditions
  5. proper santiation

5) Post-Harvest Fruit and Vegetable Technology (2 decks)

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