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- Effects of controlled atmosphere (ca) storage on pectinmethylesterase (PME) activiy on texture of "Rocha" pearPublication . Galvis-Sanchez, A. C.; Morais, Alcina M. M. B.
- Effects of controlled atmosphere (CA) storage on pectinmethylesterase (PME) activity and texture of ‘Rocha’ pearsPublication . Galvis-Sánchez, Andrea C.; Morais, Alcina M. M. B.Firmness and pectinmethylesterase (PME) activity were evaluated in pears (cv Rocha) after 9 months of storage in controlled atmosphere (CA) followed by various periods of exposure to air at room temperature. The free calcium content was also evaluated in tissues. Fruit firmness decreased with increasing time of air exposure for all four different CA storage conditions tested. After 9 days of air exposure, fruits stored in 2% O2 + 1.5% CO2 were less firm than control fruits (stored in air) and showed higher PME activity. In spite of normal textural changes being observed with increasing time of exposure to air at room temperature, the underlying metabolism might have been affected by CA storage.
- 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.
- Microstructural changes of 'rocha' pear following storage under controlled atmospherePublication . Fonseca, S. C.; Malcata, F. X.; Galvis-Sánchez, A. C.This research effort was aimed at evaluating the influence of storage (for 4 mo at 2°C), under various controlled atmospheres (viz. 1.9 kPa O2 + 4.9 kPa CO2, 1.9 kPa O2 + 0.5 kPa CO2 and 1.9 kPa O2 + 0 kPa CO2), on the microstructure of ′Rocha′ pear. Toward this goal, the morphology of cellular disassembly, as well as the quantity of granules and intercellular space using scanning electron microscopy (SEM), were tentatively correlated with sensory and instrumental firmness, by 1, 6 and 8 d of exposure to air, at room temperature, after storage. A specific methodology, based on panel evaluation of SEM images, was developed and statistically validated. The degree of cellular disassembly increased throughout exposure time to air at room temperature. Pears stored under 1.9 kPa O2 + 0.5 kPa CO2 yielded a degree of cellular disassembly similar to that of the control.
- Effects of preharvest, harvest and postharvest factors on the quality of pear (cv. "Rocha") stored under controlled atmosphere conditionsPublication . Galvis-Sánchez, Andrea C.; Fonseca, Susana C.; Morais, Alcina M. M. B.; Malcata, F. XavierPears (cv. Rocha’) grown at two locations and picked up at various times during the harvest season were assessed for firmness and colour, following 9 mo of storage under air or under controlled atmosphere conditions. A second-order polynomial was able to accurately fit the effect of time of harvest on pear’s quality, in an essentially empirical modelling effort; the best estimates of the parameters therein depend on the growing location, as well as on the atmosphere gas composition prevailing during storage.
- Sensorial and physicochemical quality responses of pears (cv Rocha) to long-term storage under controlled atmospheresPublication . Galvis-Sánchez, Andrea C.; Fonseca, Susana C.; Morais, Alcina M. M. B.; Malcata, F. XavierPears (cv Rocha) kept under controlled atmospheres (CA) and air were evaluated after longterm storage in terms of sensory attributes and physicochemical parameters, namely colour, firmness, polyphenoloxidase (PPO) activity and concentration of hydroxycinnamic compounds. The CA conditions were all combinations of 2 and 4% (v/v) O2 with 0.5 and 1.5% (v/v) CO2. Storage under CA conditions produced a beneficial effect on ‘Rocha’ pears in maintaining their quality and, consequently, in extending their shelf life and acceptability. Clear differences in sensorial attributes, colour parameters and PPO activity were found between CA- and air-stored pears. The effect provided by the CA conditions persisted throughout the time of exposure to the open air. The 2%O2 concentration produced amore beneficial effect than its 4%counterpart on the sensorial and physical characteristics of the pears.The former concentration of O2 prevented yellowing and allowed regular softening, hence keeping a high flavour quality. No clear effects could be associated with CO2 levels. Empirical models were developed that describe the effects of O2 and CO2 concentrations, as well as time at room temperature on physicochemical parameters pertaining to ‘Rocha’ pears.
- Effect of CA-storage on the physical and sensorial quality of ‘Rocha’ pearPublication . Galvis-Sánchez, A. C.; Fonseca, S. C.; Morais, A. M. M. B.; Malcata, F. X.