Browsing by Author "Vaz-Velho, Manuela"
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- Anti-hypertensive activity of horse mackerel pulverized with three different extracts from marine originPublication . Nova, Paulo; Cunha, Sara A.; Barros, Diana; Ramos, Carlos; Castro, Inês; Vaz-Velho, Manuela; Pintado, Manuela; Gomes, AnaHypertension is a serious risk factor and the most prevalent trigger to fatal cardiovascular diseases such as stroke and myocardial infarction. The marine environment is a unique source of molecules with biological activity such as antioxidant, anti-coagulant and anti-hypertensive activities. In this study, the anti-hypertensive activity of horse mackerel fillets (HMF) pulverized with each of the following marine extracts (derived from enzymatic hydrolysis) were determined: microalgae (Tetraselmis sp. incubated with subtilisin and cellulase), Mussel_Sub (Mytilus galloprovincialis minced and incubated with subtilisin protease) and Mussel_ Pro+Alc (Mytilus galloprovincialis boiled and incubated with Protamex and Alcalase). Horse mackerel fillets were evenly sprayed with each extract and frozen until subsequent analyses. Non-sprayed HMF were used as control. Aqueous extracts were prepared from HMF by sonication. Anti-hypertensive activity was determined by the angiotensin I-converting enzyme (ACE) inhibitory activity method. Data are presented in Table.1 as average±standard deviation of two replicates. Table 1. Anti-hypertensive activity of Horse Mackerel fillets sprayed with Extracts from Marine Origin. Horse mackerel fillet showed by itself an interesting anti-hypertensive profile. Notwithstanding, the tested marine-derived extracts effectively increased its biological potential(up to four-fold), with the best anti-hypertensive profile being achieved with microalgae and Mussel_Pro+Alc extracts. These extracts have an enormous potential to be used in the development of innovative food products that emphasize functionality, convenience, nutrition and health – goal of the project VALORMAR (POCI-024517-FEDER)(PPS1).
- Anti-hypertensive activity of horse mackerel pulverized with three different extracts from marine originPublication . Nova, Paulo; Cunha, Sara A.; Barros, Diana; Ramos, Carlos; Castro, Inês; Vaz-Velho, Manuela; Pintado, Manuela; Gomes, Ana
- Bioconservação de alimentos tradicionais por adição de bactérias ácido-lácticas e das suas bacteriocinasPublication . Jácome, S. L.; Todorov, S. D.; Fonseca, S. C.; Pinheiro, R.; Guerreiro, J. S.; Monteiro, V.; Fernandes, P.; Noronha, L.; Almeida, Gonçalo; Gomes, Ana M. P.; Pintado, M. E.; Silva, Cristina L. M.; Morais, Alcina M. M. B.; Silva, Joana; Teixeira, Paula; Vaz-Velho, Manuela
- Can anti-listerial L AB strains, used as starter cultures, affect the sensory properties of a sausage-like smoked product?Publication . Jácome, Samuel L.; Fonseca, Susana; Pinheiro, Rita; Alvesa, Manuel Rui; Todorovb, Svetoslav; Noronha, Lúcia; Silva, Joana; Morais, Alcina M. M. B.; Teixeira, Paula; Vaz-Velho, Manuela
- 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".
- Comparison of milk from two different cow breeds Barrosã and FrísiaPublication . Pires, Preciosa; Fernandes, Élia; Vilarinho, Manuela; Barros, Mário; Ferreira, Rita; Carneiro, Luísa; Almeida, Gonçalo; Vaz-Velho, ManuelaMilk from two different cow breeds, Barrosã and Frísia, was studied. Within the same breed five and four milk samples were taken respectively for chemical and microbiological analysis. The following chemical parameters were analysed in triplicate: Total Fat, Fatty Acids Identification and Quantification, Protein, Casein, Albumin, Non-protein Nitrogen, Vitamin A, Vitamin D, Phosphorus, Potassium, Sodium, Iron, Magnesium, Calcium, Ash, Total solids, Lactic acid and Acidity. In general terms milk from Barrosã breed showed higher values for all analysed parameters except for Total Fat, Total Solids and Vitamin D. Statistical analysis, by testing the chemical parameters all together using the Hotelling T2 test showed that milk samples from the two cow breeds were significantly different (α=0,05). Microbiological analysis (Total Viable Counts (30ºC), Escherichia coli, Staphylococcus coagulase + and Listeria monocytogenes) was also performed. Staphylococcus coagulase + was found in one milk sample from Barrosã breed. Listeria monocytogenes was found in two milk samples from Frísia breed.
- Comparison of two pre-enrichments broths for recovering Listeria spp. from salmon (Salmo salar) and salmon-trout (Oncorhynchus mykiss)Publication . Vaz-Velho, Manuela; Duarte, Gabriela; Gibbs, PaulLow levels of occurrence of Listeria spp. in fresh salmon (Salmo_salar ) and salmon-trout (Oncorhynchus mykiss), may be related to the selectivity of the pre-enrichment broth recommended by ISO 11290-1. The purpose of this study was to compare the abilities of Fraser base (without supplements) and 0.1% (w/v) peptone water for recovering Listeria spp. from the fresh fish samples. Fifty-six fish were swabbed and the swabs placed in Fraser base and in 0.1% (w/v) peptone water. Samples were analysed 4–6 h later following the ISO 11290-1 protocol. A total of fifteen Listeria spp. positive samples were found. Three and twelve samples were found to contain respectively, L. monocytogenes and L. innocua. The Fraser base did not detect any of the three L. monocytogenes positive samples. Only two Listeria spp. positive samples were simultaneously recovered by the two broths.
- Development of a Southern European Atlantic Diet (SEAD) adherence index for elderly people in both northern Portugal and GaliciaPublication . Sobrosa, Cristina; Leitão, Raquel; Pinheiro, Rita; Pinto, Elisabete; Silveira, Joana; Vaz-Velho, Manuela; Vázquez-Odériz, M.ª Lourdes; Romero-Rodríguez, M.ª Angeles
- Effect of lactic acid bacteria on quality and safety of ready-to-eat sliced cured/smoked meat productPublication . Jácome, Samuel; Fonseca, Susana; Pinheiro, Rita; Toorov, Svetoslav Dimitrov; Noronha, Lucia; Silva, Joana; Gomes, Ana; Pintado, Manuela; Morais, Alcina M. M. B.; Teixeira, Paula; Vaz-Velho, ManuelaThe bioprotective properties of native lactic acid cultures and their bacteriocins may be used for increasing the microbiological safety and stability of traditional sliced smoked pork products. It is expected that this addition would not affect consumer’s perception and, consequently, the acceptability of these traditional smoked meat products. The effect of two different LAB cultures, two different application methods and two different modified atmosphere packaging conditions (MAP) on growth control of Listeria monocytogenes and on sensory properties of “Chouriço”, a sliced cured/smoked pork product, were studied. Lactobacillus sakei ST153 (autochthonous bacteria) and BLC35 (commercial mixed starter culture including strains of Lactobacillus curvatus, Staphylococcus xylosus and Pediococcus acidilactici; CHR Hansen) both with bacteriocinogenic activity against Listeria monocytogenes, were applied by immersion or spray on smoked pork slices that were produced at industrial scale and packed under MAP (8 % or 12 % v/v CO2) and stored at 5 ⁰C. Previously to the incorporation of LAB cultures, L. monocytogenes was gently spread with a sterile cotton swab into the slices. The enumeration of LAB and L. monocytogenes was performed during the storage at 5 ºC. A quantitative descriptive sensory test was performed by a sensory trained panel at 30, 90 and 120 days, involving previous sessions for main descriptors definition, their scale limits as well as verbal anchors by panel consensus. A final sheet with nine descriptors (meat colour, greasiness, characteristic odour, offodour, hardness, succulence, characteristic taste, acid taste, bitter taste), each one with a 13-point scale, was validated. Listeria monocytogenes decreased to values <100 CFU/g in smoked pork slices of both application techniques. Meat colour, succulence and characteristic taste were the common attributes for both LAB cultures that varied over the shelf life. The application method had no significant effect on any of the sensorial attributes analyzed. MAP influence was only noticed in terms of greasiness and hardness. The samples containing BLC35 addition were categorized as harder and as less succulent than the ones containing L. sakei ST153.
- Efficiency of four secondary enrichment protocols in differentiation and isolation of Listeria spp. and Listeria monocytogenes from smoked fish processing chainsPublication . Duarte, Gabriela; Vaz-Velho, Manuela; Capella, Christopher; Gibbs, PaulFour secondary enrichment protocols (conventional methods: UVM II, Fraser 24 h and Fraser 48 h: Impedimetric method: Listeria electrical detection medium) were studied for their ability to isolate Listeria spp. and Listeria monocytogenes from fish and environmental samples collected along the processing chain of cold-smoked fish. From all methods, Listeria spp. and L. monocytogenes were respectively present in 56 and 34 of 315 samples analysed. Fraser broth incubated for 48 h gave the fewest false negative Listeria spp. results [4/56; (7.1%)], but concurrently only 15/34 (44.1%) samples were correctly identified as containing L. monocytogenes. Listeria electrical detection (LED) medium detected only 36/56 (64.3%) Listeria spp. positive samples. Despite this lower isolation rate, LED identified 20/34 (58.8%) L. monocytogenes positive samples correctly and gave fewer false positive results. The overall conclusion was that more than one isolation method is needed to accurately estimate L. monocytogenes contamination rates.