‘Chandler’, ‘0.~0 Grande’ and ‘Sweet Charlie’ strawberries were forced-air precooled
after delays of 0 or 6 h at 30°C to study the effect of delaying precooling on physical
and chemical quality characteristics of strawberry fruit. Fruit pulp temperatures were
equilibrated to 30°C prior to the start of each experiment to minimise water loss differences
between treatments. Evaluations were made after storage for one week at 1°C plus one day
at 20°C. Delaying the start of precooling resulted in about 50% greater water loss than in
control fruit, which was evident as increases in superficial shrivelling. Tissue firmness values
were also 14-22% lower in fruit from the delayed treatment. Fruits were darker (lower L*
value), less bright (lower chroma) and apparently less red (lower a* value) with the cooling
delay, although hue angle was also lower, which may reflect the occurrence of browning. No
significant differences in pH were observed in these experiments, but titratable acidity was
slightly lower with the delay to cooling. Delaying precooling also caused increased losses of
ascorbic acid, soluble solids, fructose, glucose and sucrose compared to controls. In spite of
differences related to harvest time and the variability among cultivars, the general responses
were quite similar and illustrate the importance of rapid precooling and subsequent storage
at low temperature for maintenance of acceptable appearance, texture and nutritive value of
strawberries