Production Practices and Quality Assessment of Food Crops. Vol. 1

10 R. M. Madakadze and J. Kwaramba
Table 3. Vegetables susceptible to chilling injury.
Commodity Time/temperature °C Potential chilling injury symptoms
conditions for symptoms
Asparagus 10 days at 0 Darkened and water-soaked areas at the tips
followed by bacterial-soft rot.
Beans, snap 3 days below 4.5 Russeting and surface pitting
Cucumbers 2 days below 5 °C Surface pitting starting at lenticel area followed by
secondary pathogen rots.
Eggplant
Melons
3–4 days below 5 °C Scald-like browning, surface pitting, flesh browning
and secondary pathogen rots.
Muskmelons 15 days at 0–2.5 °C Water-soaking of rind, softening and surface
Honey Dew 15 days at 0–2.5 °C becomes soft and sticky resulting in increased decay.
Watermelons 7 days at 0 °C Surface pitting, loss of flavour and fading of red colour.
Okra 3 days at 0 °C
Peppers, bell 3–4 days at 7.5 °C Water-soaked appearance, sheet pitting, darkening and
pre-disposition to rots.
Potatoes 20 weeks at 0–1.5 °C Mahogany browning and sweetening.
Summer squash 4 days at 5 °C Severe surface pitting and slight decay.
Pumpkins and
winter squash
Rots
Sweet potatoes 4–7 days at 7.5–10 °C Flesh discolouration, internal breakdown, increased
decay, off-flavours, hard-core when cooked.
Tomatoes 6 days at 0 °C Rubbery texture, watery flesh, irregular ripening and
9 days at 5 °C seed browning.
Adapted from: Lutz and Hardenburg (1986) and Skog (1998).
prior to storage at 2.5 °C for 1, 2 or 3 weeks had less electrolyte leakage than did
untreated fruits indicating an increase in chilling tolerance in the fruits. In sweet
pepper, however, treatment at 50 °C for 45 minutes resulted in severe membrane
damage (Mencarelli et al., 1993). Alternating temperature can prevent symptom
development under certain time/temperature regimes. The beneficial effects of
warming after a period of exposure to chilling may be related to either, the restoration
of normal metabolism so that potentially toxic compounds accumulated during
chilling can be removed or the availability of some essential factor that became
deficient can be re-supplied (Lyons and Breidenback, 1987) or to repair of damage
incurred to membranes, organelles or metabolic pathways before degenerative
changes occur.
Intermittent warming is warming the commodity to room temperature at intervals
during storage before permanent injury has occurred and will allow the product to
recover and prevent chilling injury symptom development. Intermittent warming
plays a role in the control of chilling injury that occurs in the field prior to the harvest
of fall grown tomatoes. Lyons and Breidenback (1987) showed that accumulation