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- Microstructural, physicochemical and sensorial effects of pears (cv. Rocha) stored under controlled atmosphere conditionsPublication . Galvis-Sánchez, Andrea C.; Teixeira, Claudia; Fonseca, Susana C.; Malcata, F. Xavier
- Food safety and quality profile of Alheira de Vitela, Chouriço de Carne and Salpicão Serra D’Arga: traditional Portuguese sausages produced in the North of PortugalPublication . Noronha, Lúcia; Almeida, Ana Luísa; Freixo, Ricardo; Jácome, Samuel; Fonseca, Susana; Vaz-Velho, Manuela; Almeida, Gonçalo; Silva, Cristina L. M.; Morais, Alcina M. M. B.; Silva, Joana; Teixeira, Paula
- Effect of different levels of CO2 on the antioxidant content and the polyphenol oxidase activity of ‘Rocha’ pears during cold storagePublication . Galvis-Sánchez, Andrea C.; Fonseca, Susana C.; Gil-Izquierdo, Ángel; Gil, María I.; Malcata, F. XavierAbstract: Pears (Pyrus communis L. cv. ‘Rocha’) were exposed to air or controlled atmosphere (CA) containing various concentrations of CO2: 0, 0.5 and 5 kPa, all with 2 kPa O2. After 4months of storage at 2 ◦C, the fruits were transferred to air at room temperature, and assessed in terms of soluble solids, titratable acidity, pH, incidence of brown heart and flesh browning, phenolic content, vitamin C content and polyphenol oxidase activity. By 4months of storage, soluble solids and pH increased, and acidity decreased relative to harvest, but no differences were detected between pears stored under air or any of the CA tested. Higher contents of hydroxycinnamic derivatives and flavan-3-ols in the peel than in the flesh were recorded. However, the content of arbutin was higher in the flesh than in the peel, whereas flavonols were only detected in the peel. In general, hydroxycinnamic derivatives and flavonols were stable throughout storage, but flavan-3-ols decreased in concentration under air or CA. Arbutin was the only phenolic compound that increased in concentration as time elapsed. No clear relation was found between the storage conditions tested and the phenolic concentration in pears. Regarding ascorbic acid (AA) and dehydroascorbic acid (DHA), their concentrations were higher in the peel than in the flesh. Furthermore, AA and DHA were strongly affected by storage: the former decreased, whereas the latter increased in content. A decrease in PPO activity was apparent after harvest and during storage, particularly under higher levels of CO2. The combination 2 kPa O2 + 5kPa CO2 increased the incidence of internal disorders (viz. brown heart and flesh browning) after storage.
- Microstructural analysis of fresh-cut red bell pepper (Capsicum annuum L.) for postharvest quality optimizationPublication . Fonseca, Susana C.; Silva, Cristina L. M.; Malcata, F. XavierThe main objective of this work was to evaluate the microstructure of fresh-cut red bell pepper (Capsicum annuum L.) after cutting, when maintained (for 0,4 and 7 d) under refrigerated storage (2°C). In order to assess the microstructure of the product, scanning electron microscopy (SEM) was applied; however, to improve this technique, preparation procedures and quantitative image analysis were specifically developed. Since sample preparation affects deeply image quality, three sample preparation procedures (viz. freezing by immersion in liquid nitrogen and subsequent storage at -80°C, freezing by storage at -80 °C and subsequent freeze-drying, and freezing by immersion in liquid nitrogen and subsequent freezedrying) were tested. One could also test (with success) a methodology of quantitative image analysis via a panel – a large number of people (N=25) rated the degree of cellular destruction, using a continuous scale (from 1- no cellular destruction to 9-extreme cellular destruction). Statistical analysis of the experimental data revealed that frozen samples exhibited higher cellular destruction than via the other two procedures; no statistically significant differences were observed between these two other procedures. Red bell pepper samples stored for 4 and 7 d presented (as expected) higher degree of cellular destruction than initial day samples. This work allowed one to develop appropriate preparation procedures of sample and quantitative image analysis – that will permit the application of this microscopy technique in future work in this area.
- Relationship between instrumental and sensory quality parameters of various pear varietiesPublication . Galvis-Sánchez, Andrea C.; Teixeira, Claudia; Fonseca, Susana C.; Malcata, F. Xavier
- Comparison of antilisterial effects of two strains of lactic acid bacteria during processing and storage of a Portuguese Salami-like Product “Alheira”Publication . Vaz-Velho, Manuela; Jácome, Samuel; Noronha, Lúcia; Todorov, Svetoslav; Fonseca, Susana; Pinheiro, Rita; Morais, Alcina M. M. B.; Silva, Joana; Teixeira, PaulaTraditional smoked and/or cured salami-like products are much appreciated by Southwest European consumers. However modern consumers require products that not only have high appealing sensory attributes but are also safe. In this work the effect of the application of two bacteriocinogenic lactic acid bacteria (LAB) Lb. plantarum ST202 and Lb. sakei ST153 for controlling Listeria monocytogenes growth in "Alheira", a traditional salami-like product, was investigated. The paste of "Alheira',' produced by an industrial meat company, was sterilized by autoclaving before inoculation and L. monocytogenes growth was evaluated during 15 days of storage. Both LAB strains showed antilisterial activity in the inoculated paste, but as in preliminary experiments with sterilized minced pork meat only strain ST153 presented activity against L. monocytogenes. it was decided, for further industrial tests, to use only this strain. Therefore, the effect of Lb. sakei ST153 against L. monocytogenes in industrially processed "Alheira", packed under vacuum or under modified atmosphere (MA) (20 % CO2 and 80 % N-2), was evaluated during 7 days storage at 4 degrees C. The effect of the inoculation of the bacteriocinogenic culture in the organoleptic properties of "Alheira" was also investigated. A quantitative descriptive sensory test was performed by a semi-trained panel after 5 days storage. No significant differences were observed in the microbiological and sensory quality of "Alheira" packed under vacuum or MA. A significant reduction in the level of L. monocytogenes was observed in the presence of Lb. sakei ST153 (2 log cycles reduction during the first 7 days). Results showed that panellists did not find significant differences between "Alheira" with Lb. sakei ST153 addition and commercial control, except for mass connection, acid taste and atypical taste. Despite that, both samples were scored above conformity limit. Thus, the application of LAB is a very promising mean of preventing L. monocytogenes growth in "Alheira".
- Microstructural analysis of fresh-cut red bell pepper (Capsicum annuumL.) aiming at postharvest quality optimizationPublication . Fonseca, Susana C.; Silva, Cristina L. M.; Malcata, F. Xavier
- Application of controlled and modified atmospheres for the preservation of postharvest quality in fresh fruits and vegetablesPublication . Fonseca, Susana C.; Malcata, F. XavierUses of preservation technologies for fruits and vegetables based on alteration of the overhead atmosphere have been increasing in the latest decades, as consumers demand fewer and less extensive treatments (of chemical nature or otherwise) of food items. This paper provides a specific review of available technologies which share as common core the deliberate formulation of the overhead atmosphere, with the goal of extending the useful life of fresh fruits and vegetables. Classical and novel technologies pertaining to controlled and modified atmospheres are duly presented and discussed, in terms of principles, advantages, limitations and applications. Finally, updated recommendations encompassing controlled and modified atmospheres are listed.
- Effects of lactobacillus plantarum bacteriocinogenic culture on physicochemical, microbiological, and sensorial characteristics of "Chouriço Vinha d'Alhos", a traditional Portuguese sausagePublication . Macieira, A.; Barros, D.; Vaz Velho, Manuela; Pinheiro, R.; Fonseca, S.; Albano, H.; Teixeira, P.Background: “Chouriço Vinha d’Alhos” is a traditional fermented dry meat sausage from North of Portugal. The aim of this work was to evaluate the effects of a fresh and a lyophilized bioprotective Lactobacillus plantarum ST153Ch culture, on an industrial scale, on the physicochemical, microbiological, and sensorial characteristics of “Chouriço Vinha d’Alhos”. Methods: “Chouriço Vinha d’Alhos” added with Lb. plantarum ST153Ch (fresh or lyophilized) were analyzed for the physicochemical, microbiological, and sensorial characteristics, over 90 days of storage at 4 ºC. All data were statistically analyzed using an ANOVA procedure by IBM SPSS Statistics v. 25. Results: The results showed that there was no difference in the reduction of L. monocytogenes, without or with the addition of Lb. plantarum either fresh or lyophilized. There were no significant differences (p>0.05) in some analyzed physicochemical parameters of products added with fresh or lyophilized Lb. plantarum cultures over the 90 days of storage; but both, fresh and lyophilized cultures, influenced some of the tested physicochemical parameters. Conclusion: Considering no significant differences between application methodologies (fresh or lyophilized Lb. plantarum), industry might be able to choose the most suitable method according to their manufacturing process.
- Development of perforation-mediated modified atmosphere packaging to preserve fresh fruit and vegetable quality after harvestPublication . Oliveira, F.A.R.; Fonseca, S.C.; Oliveira, J.C.; Brecht, J.K.; Chau, K.V.The use of perforations as a means of obtaining large size containers suitable for modified atmosphere packaging (MAP) would greatly enhance the applicability of this technology for storage and distribution of fresh and minimally processed products. General concepts of MAP, and advantages and drawbacks of using perforations to achieve it are discussed. Products for which perforated packages can be used are listed. The variables that affect this type of package are presented and the methodology for designing an adequate package is described and illustrated with the case study of shredded cabbage.