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- Physical and chemical quality characteristics of strawberries after storage are reduced by a short delay to coolingPublication . Nunes, M. C. N.; Brecht, J. K.; Morais, A. M. M. B.; Sargent, S. A.Chandler’, ‘Oso 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.
- Effects of delays to cooling and packaging on strawberry qualityPublication . Brecht, J. F.; Sargent, S. A.; Morais, A. M. M. B.; Nunes, M. C. N.
- Quality evaluation of tomato (cv. Bufalo) stored under controlled atmospherePublication . Nunes, M. C. N.; Morais, A. M. M. B.; Brecht, J. K.; Sargent, S. A.
- Controlling Temperature and Water Loss to Maintain Ascorbic Acid Levels in Strawberries During Postharvest HandlingPublication . Nunes, M. C. N.; Brecht, J. K.; Morais, A. M. M. B.; Sargent, S. A.Chandler’, ‘Oso Grande’ and ‘Sweet Charlie’ strawberries were stored for 8 days at 1 or 10°C, or 4 days at 20°C, either unwrapped or wrapped in PVC film to retard were conducted during the 1 water loss. Total ascorbic acid (AA) content was expressed on a dry weight basis to correct for water loss differences between treatments. Loss of AA was low and did not differ between wrapped treatments at 1 and 10°C, but was much greater at 20°C. Wrapping reduced AA loss by 5-fold at 1 and 10°C and by 2-fold at 20°C. The effect was not due to modification of O2 and CO2 levels in wrapped treatments, which was minimal. The results indicate that water loss had a greater effect on AA levels than temperature. Combining wrapping with storage at 1 or 10°C reduced AA loss by 7.5-fold compared to unwrapped strawberries stored at 20°C.
- Prompt cooling reduces incidence and severity of decay caused by Botrytis cinerea and Rhizopus stolonifer in strawberryPublication . Nunes, M. C. N.; Morais, A. M. M. B.; Brecht, J. K.; Sargent, S. A.; Bartz, J. A.Delays in initiating the cooling of freshly harvested `Chandler' strawberries (Fragaria xananassa) were compared with prompt cooling to determine how such handling affected development of postharvest decays during subsequent storage and marketing. Strawberries at the three-quarter to full red ripeness stages were harvested four times between mid-June and late July, inoculated with Botrytis cinerea or Rhizopus stolonifer and then handled to simulate prompt or delayed precooling prior to storage. This was done by incubating fruit at 35 °C (95.0 °F) and 70% to 80% relative humidity (RH) for 1 or 6 hours. The fruit were then forced-air cooled to 5 °C (41.0 °F) in 1 hour and stored for 7 days at 2 °C (35.6 °F) and 85% to 95% RH, plus displayed in a simulated market at 20 °C (68.0 °F) and 85% RH for 1 day. Decay incidence increased as the season progressed. For non-inoculated fruit, prompt cooling reduced the incidence of decay by an average of 25% and the decay severity by ~24%. With inoculated fruit, prompt cooling resulted in 15% and 29% decreases in the incidence and severity, respectively, of rhizopus rot compared to delayed cooling, and 5% and 22% decreases in the incidence and severity, respectively, of botrytis rot. Overall, the incidence of botrytis and rhizopus fruit rot averaged 60% and 85% in the prompt and delayed cooling treatments, respectively. Although prompt cooling is important for minimizing postharvest decay of strawberries, temperature management alone may not sufficiently control postharvest decay when decay pressure is high.
- Effects of delay to cooling and storage on postharvest decay of strawberry (cv. chandler)Publication . Nunes, M. C. N.; Morais, A. M. M. B.; Brecht, J. K.; Sargent, S. A.
- Quality of pink tomatoes (cv. buffalo) after storage under controlled atmosphere at chilling and nonchilling temperaturesPublication . Nunes, M. C. N.; Morais, A. M. M. B.; Brecht, J. K.; Sargent, S. A.Greenhouse-grown pink tomatoes (cv. Buffalo) were stored in air or in a controlled atmosphere (CA) of 4% O2 plus 2% CO2, to study the effect of CA at chilling and nonchilling temperatures on fruit quality characteristics. Tomatoes could be stored in CA at 12C for three weeks with no major changes in fruit appearance. CA was effective in delaying color development and ripening at this temperature. The soluble solids content was lower after CA storage, but no significant differences in firmness, pH or titratable acidity were observed between storage in air or CA. Storage in CA at 12C was also effective in reducing decay. However, at 6C, fruit showed high incidence of decay after both air and CA storage. CA did not alleviate chilling injury symptoms relative to air-stored samples and may have caused CO2 injury. Water loss was greater under CA at both temperatures.
- Quality of strawberries after storage is reduced by a short delay to coolingPublication . Nunes, M. C. N.; Morais, A. M. M. B.; Brecht, J. K.; Sargent, S. A.The effects of delay to cooling and storage were evaluated on postharvest quality and decay of fresh harvested strawberries. 'Chandler' strawberries were forced-air precooled after delays of 0 or 6 hours at 30°C to study the effect of delaying precooling on decay, and physical and chemical characteristics of strawberries. For decay experiments the fruits were previously inoculated with Botrytis cinerea and Rhizopus stolonifer. Fruit pulp temperature was equilibrated to 30°C prior to the start of each experiment to minimize 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 greater water loss than in control fruits. Tissue firmness values were also lower in fruit from the delay treatment. Fruits were darker, less bright and apparently less red. No significant differences in pH were observed, 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, and also resulted in more decayed fruits. This illustrates the importance of rapid precooling and subsequent storage at low temperature for maintenance of an acceptable appearance, texture, flavor and nutritive value of strawberries.
- Effects of delays to cooling and wrapping on strawberry quality (cv. Sweet Charlie)Publication . Nunes, M. C. N.; Brecht, J. K.; Sargent, S. A.; Morais, A. M. M. B.'Sweet Charlie' strawberries were wrapped with PVC polymeric film, and forced-air precooled after delays of O, 6 or 8 hours at 30°C to study the effect of delaying precooling on physical and chemical quality characteristics of the strawberry. Non-wrapped fruits were used as a control. Evaluations were performed after storage for one week at 1°C plus one day at 20°C. Delaying the precooling resulted in less attractive fruits and loss of quality characteristics. Wrapped strawberries maintained better appearance and quality than nonwrapped berries.