Lecture 17: Quality and Maturity Indices Harvesting Methods Flashcards
(40 cards)
define quality
combination of various physicochemical and nutritional characteristics that give them value as a food item
what are components of food quality?
- appearance or visual factors
- texture or mouth feel
- flavor
- nutritive value
- safety or antinutritional factors
what are types of defects?
- morphological: sprouting, seed germination
- physical: shrivelling and wilting
- mechanical: punctures, cuts, abrasion
- physiological: chilling and freezing, internal breakdown
- pathological: fungal and bacterial
- entomological: damages by insects and pests
what are the perceptions and priorities or quality in the produce chain?
everybody: appearance factor
plant breeders and farmers: yield and resistance to disease
consumer: appearance, firm, good flavor, nutrition
what are quality factors imp for?
setting standard specifications
what genetic factors influences quality?
cultivars
rootstocks
selection of specific varieties
GMO
what are environmental factors that influences quality?
climate (temp, light, rainfall, irrigation, wind)
cultural (soil type, water supply, pruning, thining, pesticides, growth regulators)
what is TR?
tolerance range
within the TR, higher temp = ____ growth = ____ harvest
faster growth and earlier harvest
what is temp summation
indicator of harvest maturity (degree day - heat unit)
what can heat units be expressed as?
degree hour or degree days
define a degree hour
accumulated heat unit equivalent to the exposure of the crop to one degree above the reference temp for one hour
define a degree day
exposure at one degree above the reference temp for one day
what temperatures for day and nights are ideal for plant growth?
what climates is this?
warm days ( greater photosynthetic activity and better storage of food reserves)
and cool nights (lower resp; lower depletion of stored reserve)
temperate climates
describe how tropic climates is diff than temp climates. what does this cause?
in tropic climates, night temp is around the same as day temp
causes diff fruit quality (higher accumulation during the day and higher depletion of stored reserves during night)
how does duration of light affect quality?
longer day and shorter nights = more photosynthetic activity = less depletory activity = better
how does intensity of light affect quality
higher intensity = higher sweetness = lower acidity
higher intensity also causes fading of colors
how does canopy shading affect tomatoes and cucumbers?
deeper colors
how does density of planting influence light intensity?
high intensity planting = lower exposure to light = lower photosynthetic activity = lower sweetness
quality of light is imp for what?
pigmentation
how do purple cabbage or eggplant derive their color rom?
what if they have direct exposure to light?
exposure to blue and violet light
direct exposure = green color
what are other environmental factors that affect quality?
rainfall
soil texture
wind factors
what kind of effects does pesticides have on quality?
undesirable (low TSS and high acid)
what is abscission preventing for?
to control fruit drop
includes 2,4,5 T, NAA, CPA, Alar