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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.
- Quality of 'Royal Gala' cut apple during osmotic dehydrationPublication . Bernardo, Alcina Maria Miranda; Pieters, Bert; Assis, Fernanda Rosa; Morais, Rui Manuel Santos CostaThe present work aimed to evaluate quality parameters of 'Royal Gala' apple cubes during osmotic dehydration (OD). We investigated the following OD conditions: osmotic agent, pressure, and temperature. The osmotic agent, being lower after OD with sorbitol than sucrose solutions, mainly influenced the water activity of the product. The color changes increased with increased temperature and were higher in vacuum experiments than at atmospheric pressure. In general, we recommend OD at 25 °C and atmospheric pressure for the preservation of the total phenolic content (TPC) and antioxidant activity (AA) of apple cubes during the process. Peleg's model was found to provide the best fit of TPC and AA data.
- Physicochemical and Sensory Evaluation of ‘Rocha’ Pear Following Controlled Atmosphere StoragePublication . Galvis-Sánchez, A. C.; Fonseca, S. C.; Morais, A. M. M. B.; Malcata, F. XavierThe effects of several processing factors (storage time, time in the open air at room temperature, and overhead concentrations of O2 and CO2) on color, firmness, polyphenol oxidase (PPO) activity, and sensory attributes of pears (cv. Rocha) grown in 2 locations were studied using a multiple linear regression model. Backward elimination (F ≥ 0.005) was used to assess the significant factors. Extended storage time, long-time exposure at room temperature, and high O2 concentration played major roles on color changes assessed instrumentally and further confirmed by a sensory panel. Firmness was strongly affected by storage time and by time in the open air at room temperature. Finally, PPO activity was dependent on the growing location.
- 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.