CBQF Escola Superior de Biotecnologia

Vila Real de Santo António, Portugal

CBQF Escola Superior de Biotecnologia

Vila Real de Santo António, Portugal
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Borges S.,CBQF Escola Superior de Biotecnologia | Barbosa J.,CBQF Escola Superior de Biotecnologia | Camilo R.,CBQF Escola Superior de Biotecnologia | Carvalheira A.,CBQF Escola Superior de Biotecnologia | And 10 more authors.
International Journal of Food Science and Technology | Year: 2012

The effect of microencapsulation on the viability of Lactobacillus casei, L. paracasei, L. acidophilus Ki and Bifidobacterium animalis BB-12 during exposure to lethal conditions (25% NaCl, pH 3.0 and 55-60°C) was evaluated. Results demonstrated that survival of probiotic strains to the imposed lethal stress conditions was strain dependent. With the exception of exposure to 25% (w/v) NaCl, L. acidophilus Ki (free and encapsulated cells) demonstrated the highest survival rates through exposure to lethal conditions of temperature and pH. For this probiotic strain exposed to heat, microencapsulated cells expressed a higher heat tolerance at 55°C than free cells. For the other tested bacteria, in general, encapsulation had no positive effect on survival through the tested lethal conditions. © 2011 Institute of Food Science and Technology.


Reis P.J.M.,CBQF Escola Superior de Biotecnologia | Malcata F.X.,Superior Institute of Maia
Small Ruminant Research | Year: 2011

Most Portuguese cheeses possessing a Protected Designation of Origin (PDO) status are still manufactured following traditional methods - the majority of which use raw milk from small ruminants (mainly sheep), coagulated with a rennet from plant origin (wild thistle flowers) and without deliberate addition of any starter/nonstarter culture; the most famous and representative of these cheeses is Serra da Estrela. Most steps required for its manufacture are performed manually (or otherwise empirically), and are controlled by the cheesemaker herself based on own intuition and past experience - thus leading to a wide variability among dairy farms, and even from day to day cheese batches. This paper reviews and updates fundamental and applied knowledge encompassing technological, microbiological, chemical, organoleptic and textural features of traditional PDO cheeses, manufactured in Portugal from ovine and caprine (or both) milks. © 2011 Elsevier B.V.


Reis P.J.M.,CBQF Escola Superior de Biotecnologia | Malcata F.X.,Superior Institute of Maia | Malcata F.X.,New University of Lisbon
Journal of Dairy Science | Year: 2011

Despite its relevance to sensory features and to fundamental explanation of the changes observed throughout cheese ripening, microstructural studies of specialty cheeses have lagged far behind those of industrialized cheeses. Hence, the purpose of this study was to pinpoint microstructural differences in the gel network of traditional Serra da Estrela cheese throughout ripening, using 2-dimensional image analysis, and to unfold correlations of such microstructural indicators with classical bulk chemical and textural parameters. Hence, samples were taken throughout the ripening period, following a nested design; uniform thin sections were systematically observed via light microscopy (LM, 200 ×) and transmission electron microscopy (TEM, 4,400 ×), and computer-assisted quantitative analysis of digital images was comprehensively performed following standard stereological methodology. Fresh cheeses exhibited the highest porosity and ratio of surface area to volume. Significant negative correlations were found between microstructural parameters and proteolysis indicators. Light microscopy images suggested that rearrangements exist, up to 21 d, of the cheese matrix that leave porosity and pores unchanged, whereas TEM images indicated a significant decrease in number of pores within the same time frame, especially those above 1 × 10 -2 μm 2 in area. The larger pores, chiefly with cross-sectional areas above 40 μm 2, were less represented by the end of ripening-and likely explain the observed significant decrease of cheese porosity without a change in number of pores. Field viewing significantly affected the microstructural parameter values, whereas section viewing affected significantly only LM-based ones. Categorical principal component analysis between the 2 types of microstructural data sets was performed, and permitted discrimination of each stage of ripening. Multiple linear regression analysis indicated that the variables associated with the nitrogen fraction were well predicted by stereological-based parameters (R 2 ≥ 0.96). Therefore, our findings demonstrate the potential of image analysis to monitor microstructure throughout ripening, and that the microstructure revealed by LM reflects more clearly cheese aging than that revealed by TEM. © 2011 American Dairy Science Association.


Mayor L.,Universidad Politécnica de Ingeniería | Flynn K.,The European Association for Food Safety | Dermesonluoglu E.,National Technical University of Athens | Pittia P.,University of Teramo | And 6 more authors.
European Food Research and Technology | Year: 2015

The food sector is the largest employer in the European Union, yet it ranks low in innovation and few educated young people pursue food careers. Updating both the skills and the image of food science and technology professionals (FSTs) first requires understanding the current situation. This work compares the view of currently employed FSTs (3,007) with that of food science and technology (FST) employers (602) regarding skills and when and where they should be developed. European FSTs responded to a web-based survey in 2011 and 2012, and FST employers responded to an e-mail-based survey and/or attended brainstorming workshops from 2009 to 2012. Soft skills, especially those related with communication, were the best evaluated by both groups, whereas technical non-food skills were in the lowest positions. FSTs were judged qualified by their employers in some food skills (food safety and quality, product development, production), while others (engineering maintenance, consumer and nutritional sciences, environmental issues) were more poorly evaluated. In general, FSTs believe themselves to be well qualified by higher education programs, and most of them do not continue training once they are working, with the notable exception of those that achieve positions of high responsibility. However, employers appeared to disagree, recommending that education and training in soft, food and technical skills continue throughout working life. Additionally, they recommended more frequent reinforcement of soft than of food or technical skills. A competitive food sector requires FSTs of the highest quality, and understanding the view of FSTs and their employees can contribute to improved training and thus benefit the European food sector. © 2014, Springer-Verlag Berlin Heidelberg.


Tavares T.G.,CBQF Escola Superior de Biotecnologia | Tavares T.G.,New University of Lisbon | Monteiro K.M.,University of Campinas | Possenti A.,University of Campinas | And 4 more authors.
International Dairy Journal | Year: 2011

Peptide concentrates generated by hydrolysis of whey with aqueous extracts of flowers of Cynara cardunculus were studied for possible protection of the stomach mucosa against ulcerative lesions caused by oral administration of absolute ethanol. Both the whole peptide fraction obtained via hydrolysis of whey protein concentrate (peptide concentrate, PepC) and its fraction below 3kDa (PepCF) were able to reduce gastric injuries to significant levels (p<0.05). Single-dose experiments, using 100mgkg-1 body weight (bw) of either PepCF or PepC, led to 68.5% and 37.4% protection, respectively - which compare well with 93.4% protection by 200mgkg-1bw carbenoxolone (a positive control). No dose-response correlation could be demonstrated. Gastric cytoprotection by PepCF appears to depend on sulphydryl-containing moieties, whereas PepC likely protects the gastric mucosa via the prostaglandin cycle and production of nitric oxide. © 2011.


Ramos T.L.,CBQF Escola Superior de Biotecnologia | Ramos T.L.,New University of Lisbon | Silva S.I.,CBQF Escola Superior de Biotecnologia | Soares J.C.,CBQF Escola Superior de Biotecnologia | And 5 more authors.
Food Research International | Year: 2012

The goal of this research effort was to assess the efficacy of edible films produced from whey protein isolate (WPI) and glycerol, including incorporation of lactic acid (LA) and propionic acid (PRO), chitooligosaccharides with nominal MW of 3kDa (COS) and natamycin (NA) as antimicrobial agents. Their features were evaluated in vitro via agar diffusion and viable cell counting, against spoilage microflora often found contaminating cheese surfaces. The effect of incorporating the aforementioned compounds upon thickness, moisture content (MC), solubility (S), density (ρ s), water activity (a w) and water vapor permeability (WVP), as well as upon tensile and optical properties of those films were also evaluated. Films formulated with LA, PRO or COS exhibited antimicrobial activity against all microorganisms tested, yet the viable cell count assay was more sensitive and reproducible. COS was the most active against Gram-negative bacteria, whereas LA was the most active against Gram-positive ones. NA was not active against bacteria, but displayed the strongest effect against yeasts. Incorporation of said antimicrobial compounds did not significantly (p>0.05) affect film thickness, yet it significantly (p<0.05) reduced tensile strength (TS). Incorporation of LA and NA in particular did not significantly (p<0.05) affect MC, S, ρ s, WVP, elongation at break (EB) and Young's modulus (YM) values; however, a statistically significant increase (p<0.05) of MC, S and WVP, together with a statistically significant decrease (p<0.05) of ρ s were attained upon incorporation of PRO or COS. Moreover, PRO produced the highest variation (p<0.05) in EB, TS and YM, whereas COS produced the highest change (p<0.05) in optical properties. © 2011 Elsevier Ltd.


Tavares T.G.,CBQF Escola Superior de Biotecnologia | Tavares T.G.,New University of Lisbon | Xavier Malcata F.,New University of Lisbon | Xavier Malcata F.,Superior Institute of Maia
Food Chemistry | Year: 2012

The remarkable longevity of people in specific regions of Portugal, whose diets are based on whey cheese, has puzzled researchers for quite some time. Our data indicate that several oligopeptides are released from glycomacropeptide (originated in κ-casein) and α-lactalbumin - and one surprisingly from β-lactoglobulin, by plant proteases previously used in cheesemaking. A few of such peptides (e.g. DKVGINYW, KGYGGVSLPEW and DAQSAPLRVY) exhibit unusually strong antihypertensive roles in vitro, following generation in situ or synthesis de novo. The activities of the latter two are not significantly affected by simulated gastrointestinal digestion, despite undergoing partial hydrolysis. This piece of information is rather promising toward more comprehensive attempts to scientifically rationalise this Portuguese Paradox. © 2011 Elsevier Ltd. All rights reserved.


Ramos O.L.,CBQF Escola Superior de Biotecnologia | Ramos O.L.,New University of Lisbon | Reinas I.,CBQF Escola Superior de Biotecnologia | Silva S.I.,CBQF Escola Superior de Biotecnologia | And 8 more authors.
Food Hydrocolloids | Year: 2013

This manuscript describes the detailed characterization of edible films made from two different protein products - whey protein isolate (WPI) and whey protein concentrate (WPC), added with three levels of glycerol (Gly) - i.e. 40, 50 and 60%(w/w). The molecular structure, as well as barrier, tensile, thermal, surface and optical properties of said films were determined, in attempts to provide a better understanding of the effects of proteinaceous purity and Gly content of the feedstock. WPI films exhibited statistically lower (p < 0.05) moisture content (MC), film solubility (S), water activity, water vapor permeability (WVP), oxygen and carbon dioxide permeabilities (O 2P and CO 2P, respectively) and color change values, as well as statistically higher (p < 0.05) density, surface hydrophobicity, mechanical resistance, elasticity, extensibility and transparency values than their WPC counterparts, for the same content of Gly. These results are consistent with data from thermal and FTIR analyses. Furthermore, a significant increase (p < 0.05) was observed in MC, S, WVP, O 2P, CO 2P, weight loss and extensibility of both protein films when the Gly content increased; whereas a significant decrease (p < 0.05) was observed in thermal features, as well as in mechanical resistance and elasticity - thus leading to weaker films. Therefore, fundamental elucidation was provided on the features of WPI and WPC germane to food packaging - along with suggestions to improve the most critical ones, i.e. extensibility and WVP. © 2012 Elsevier Ltd.


PubMed | CBQF Escola Superior de Biotecnologia
Type: Journal Article | Journal: Journal of dairy science | Year: 2011

Despite its relevance to sensory features and to fundamental explanation of the changes observed throughout cheese ripening, microstructural studies of specialty cheeses have lagged far behind those of industrialized cheeses. Hence, the purpose of this study was to pinpoint microstructural differences in the gel network of traditional Serra da Estrela cheese throughout ripening, using 2-dimensional image analysis, and to unfold correlations of such microstructural indicators with classical bulk chemical and textural parameters. Hence, samples were taken throughout the ripening period, following a nested design; uniform thin sections were systematically observed via light microscopy (LM, 200 ) and transmission electron microscopy (TEM, 4,400 ), and computer-assisted quantitative analysis of digital images was comprehensively performed following standard stereological methodology. Fresh cheeses exhibited the highest porosity and ratio of surface area to volume. Significant negative correlations were found between microstructural parameters and proteolysis indicators. Light microscopy images suggested that rearrangements exist, up to 21 d, of the cheese matrix that leave porosity and pores unchanged, whereas TEM images indicated a significant decrease in number of pores within the same time frame, especially those above 1 10(-2) m(2) in area. The larger pores, chiefly with cross-sectional areas above 40 m(2), were less represented by the end of ripening-and likely explain the observed significant decrease of cheese porosity without a change in number of pores. Field viewing significantly affected the microstructural parameter values, whereas section viewing affected significantly only LM-based ones. Categorical principal component analysis between the 2 types of microstructural data sets was performed, and permitted discrimination of each stage of ripening. Multiple linear regression analysis indicated that the variables associated with the nitrogen fraction were well predicted by stereological-based parameters (R(2) 0.96). Therefore, our findings demonstrate the potential of image analysis to monitor microstructure throughout ripening, and that the microstructure revealed by LM reflects more clearly cheese aging than that revealed by TEM.

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