Browsing by Author "Carvalho, Susana"
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- Biochemical basis of CO2-related internal browning disorders in pears (Pyrus communisL. cv. Rocha) during long-term storagePublication . Deuchande, Teresa; Larrigaudière, Christian; Giné-Bordonaba, Jordi; Carvalho, Susana; Vasconcelos, Marta W.This study aimed at understanding the biochemical basis of internal browning disorders (IBDs) in 'Rocha' pear. For this purpose, the effects of storage under normal controlled atmosphere (CA) (3 kPa of O2 + 0.5 kPa of CO2) and IBD-inducing CA (1 kPa of O2 + 10 kPa of CO2) on the antioxidant and fermentative metabolisms and polyphenol oxidase (PPO) activity and phenolics concentration were studied. The higher IBD incidence in high CO2-stored fruits was positively correlated with fermentative metabolites and negatively with ascorbate and H2O2 concentrations, and it was linked to PPO activation. These results indicate that both the antioxidant and fermentative metabolisms are involved in the occurrence of IBD in 'Rocha' pear. From the integration of the biochemical and enzymatic data, a schematic model illustrating the effects of high CO2 and low O2 in 'Rocha' pears during long-term storage was constructed.
- Dynamic controlled atmosphere for prevention of internal browning disorders in ‘Rocha’ pearPublication . Deuchande, Teresa; Carvalho, Susana; Guterres, Umbelina; Fidalgo, Fernanda; Isidoro, Nelson; Larrigaudière, Christian; Vasconcelos, Marta W.This study aimed to evaluate the potential of two dynamic controlled atmospheres, DCA-CF (chlorophyll fluorescence sensor) and DCA-EtOH (ethanol sensor) when compared to controlled atmosphere (CA), in the prevention of internal browning disorders (IBD) in ‘Rocha’ pear stored under commercial conditions. Pears harvested at optimal maturity were stored for 145 days at 0.5 C and 95% relative humidity, under three atmospheres: (1) CA (3 kPa O2 þ 0.5 kPa CO2), (2) DCA-CF and (3) DCA-EtOH. At the end of storage, fruits in DCA-CF did not develop IBD while fruits in DCA-EtOH had an IBD incidence of 15 and 20% after 125 and 145 days of storage, respectively. The higher incidence of IBD under DCA-EtOH may be related to the higher levels of fermentative metabolites and to the lower ascorbate content. In contrast, the higher levels of ascorbate in DCA-CF showed that this technology contributes to maintaining the fruit's antioxidant potential. Collectively our results suggest that DCA-CF is an effective strategy to prevent IBD in ‘Rocha’ pear. On the contrary, the DCA-EtOH is not suitable to prevent the induction of fermentation and IBD development. The results also suggest that the IBD development in ‘Rocha’ pear is related to fermentative metabolism.
- Dynamics of stomatal adaptation in rose leaves exposed to long-term high relative air humidityPublication . Fanourakis, Dimitrios; Carvalho, Susana; Heuvelink, Ep
- Effect of processing and storage on nutritional and functional quality of strawberryPublication . Pereira, Maria João Valle; Amaro, Ana; Carvalho, Susana; Vasconcelos, Marta; Pintado, M. E.
- Evaluation of natural antimicrobial agents against pseudomonas syringae p. actinidiaePublication . Silva, M. Nunes da; Nascimento, B.; Correia, A.C.; Teixeira, Paula; Balestra, G.M.; Vasconcelos, Marta W.; Carvalho, Susana
- Evaluation of natural antimicrobial agents against pseudomonas syringae p. actinidiaePublication . Silva, M. Nunes da; Nascimento, B.; Correia, A.C.; Teixeira, Paula; Balestra, G.M.; Vasconcelos, Marta W.; Carvalho, Susana
- Fresh-cut melon nutritional and functional quality throughout the production processing line and during storagePublication . Pereira, Maria João; Amaro, Ana Luísa; Carvalho, Susana; Pintado, Maria ManuelaFruits processing conditions can be described through representative flowcharts with the identification of the process variables. However, integrated information about the effect of each processing step on phytochemical properties of the processed fruits is still lacking. This study aims at development of a system to audit postharvest handling systems and processing lines for the preservation of health-promoting phytochemicals and to optimize processing conditions to maintain fruit quality. A nutritional and functional audit of postharvest handling systems and processing lines of a fresh-cut fruits enterprise was performed and the effects of the production process upon the nutritional and phytochemical composition of melon were determined. Three replicated samples were collected at each step of the production flowchart of fresh-cut cantaloupe melon: at fruit reception, after washing and decontamination and after processing. All samples were frozen with liquid nitrogen and stored at -80 °C until analyzed for nutritional characterization. Total antioxidant activity was assessed by the ABTS method, total phenolics by Folin Ciocalteau´s method and phenolic compounds and carotenoids were analyzed by high performance liquid chromatography (HPLC-DAD). Throughout cantaloupe melon processing, a significant decrease in total phenolic compounds and antioxidant capacity was observed, while total carotenoids levels were relatively maintained. Contrarily, as processing advanced, ascorbic acid concentration increased significantly after decontamination step. After the nutritional audit to the process and to evaluate nutritional quality during storage, simulating the company´s commercial conditions and product´s shelflife, fresh-cut cantaloupe samples were placed in polypropylene clamshells (236 mL) or in packages heat sealed with a low oxygen transmission rate film (78 mL) and stored at 5 °C for 6 days. Except for ascorbic acid concentration, which was better maintained in filmed packages, overall nutritional quality of fresh-cut melon is better maintained during storage in clamshell packages.
- Impacts of Flavescence dorée on growth, production and quality of Vitis vinifera cv. Loureiro in the portuguese ‘Vinho Verde’ regionPublication . Rebelo, M.J.; Castro, S.C.S.; Bertaccini, A.; Vasconcelos, Marta W.; Carvalho, Susana
- Impacts of Flavescence dorée on growth, production and quality of Vitis vinifera cv. Loureiro in the portuguese ‘Vinho Verde’ regionPublication . Rebelo, M.J.; Castro, S.C.S.; Bertaccini, A.; Vasconcelos, Marta W.; Carvalho, Susana
- Modeling the effect of oxygen availability and storage temperature on fresh-cut strawberry respiration ratePublication . Amaro, Ana Luísa; Pereira, Maria João; Carvalho, Susana; Vasconcelos, Marta; Pintado, M.Fresh-cut commodities shelf-life is limited by minimal processing operations and storage conditions. Wound damage is sensed by sensors/receptors that recognize increased concentrations of endogenous molecules or their fragments, and tissue response involves an increase in respiration rate. Respiration behavior of fresh-cut strawberries is affected by wounding, storage temperature and oxygen availability. Modified atmosphere packaging and refrigerated storage are frequently used to reduce the respiration rate without negatively affecting the physiology of the fruit and to increase shelf life. Mathematical models have been proposed to correlate the respiration rate with different storage parameters such as gas composition and temperature, but the two factors have rarely been considered simultaneously and the systematic approach to modified atmospheres packaging design involves the knowledge of respiration rate kinetics at different temperatures. The objectives of this study were to determine respiration rate of fresh-cut strawberries as a function of oxygen and temperature conditions during storage and to develop and validate mathematical models for predicting respiration rate. Freshly harvested strawberries were processed into wedges and placed in 750 mL glass jars. The glass jars containing fresh-cut strawberries were then flushed with different oxygen concentrations (2.5; 5; 10 and 20% O2) and stored in three different temperatures (0, 5 and 10 °C), for 5 days. The experiments were performed in three replicates. Oxygen and carbon dioxide concentrations inside the glass jars were analyzed throughout refrigerated storage with a gas analyzer, measuring at two hours intervals in the first 48 hours and then in 12 hours intervals until the end of the 5 days. Initial oxygen partial pressure and temperature had significant effects on fresh-cut strawberry respiration rate with significant decreases with lower initial oxygen levels and lower temperature. The models developed are useful for supporting decision on fresh-cut strawberry optimal storage conditions based on physiological response.