Colegio Universitario 16

Vigo, Spain

Colegio Universitario 16

Vigo, Spain
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Fucinos C.,University of Vigo | Fucinos C.,University of Minho | Amado I.R.,University of Vigo | Fucinos P.,International Iberian Nanotechnology Laboratory | And 3 more authors.
Food Control | Year: 2017

Pimaricin is a fungicide commonly used on the cheese surface. In this work poly(N-isopropylacrylamide) nanohydrogels copolymerized with acrylic acid (PNIPA-20AA(5)) were proposed to encapsulate pimaricin and release it in a controlled manner to prevent a real food product, Arzúa-Ulloa DOP cheese, from food spoilage. The results reflect that the nanohydrogel coating neither impart any adverse effects (compared to the control) nor influence the natural ripening process of Arzúa-Ulloa DOP cheese. In the bioassay with artificial contamination, the total fungal counts in cheeses with the pimaricin-loaded nanohydrogel coating (NP) were lower than those of all the other treatments, during all the assay (30 days). Despite significant (p < 0.05) differences were not maintained for a long time, probably due to the very high initial microbial load, the antimicrobial effect of the NP-coating evidenced its protective effect in cheeses. A new qPCR method that allows the total fungal counts to be quantified directly from the cheese samples was also developed to avoid the inconveniences associated with the traditional methods based on Standard Plate Count (SPC). The efficiency of the reaction in the cheese matrix was good, and the qPCR assay was highly linear. A good correlation between both analysis (SPC and qPCR) was observed (around 100% of accuracy). The results obtained in this work reveal the usefulness of thermosensitive nanohydrogels for encapsulating and releasing pimaricin to reduce the amount of free pimaricin in the foods bulk but getting sufficient inhibition of fungal growth. © 2016 Elsevier Ltd

Fucinos C.,University of Vigo | Fucinos C.,University of Minho | Fucinos P.,University of Vigo | Fucinos P.,International Iberian Nanotechnology Laboratory | And 4 more authors.
Food and Bioprocess Technology | Year: 2015

Pimaricin-loaded poly(N-isopropylacrylamide) nanohydrogels with and without acrylic acid, were evaluated as food-spoilage inhibitors in a model system and a real food product: grape juice. Pimaricin was proposed as a non-allergenic alternative to sulphites for protecting juices against recontamination. However, pimaricin may degrade under conditions and treatments (heating, acidification, lighting) commonly applied in producing fresh juices. Nanohydrogel encapsulation may be a feasible procedure to avoid pimaricin degradation, improving its antimicrobial activity. Pimaricin-free nanohydrogels did not affect the growth of the indicator yeast either in the food model system or in grape juice. Conversely, pimaricin-loaded nanohydrogels effectively inhibited the growth of the indicator yeast. In some cases, the inhibition was extended even further than using free pimaricin. For instance, in the food model system, pimaricin-loaded nanohydrogels with acrylic acid (NPPNIPA-20AA(5)) prevented the yeast growth for more than 81 h while free pimaricin was only effective for 12 h. Despite pimaricin-loaded nanohydrogels without acrylic acid (NPPNIPA(5)) were able to reduce maximum yeast growth, as in all treatments with pimaricin, the extent of the inhibitory effect was not significantly (p > 0.05) different to that achieved with free pimaricin. In grape juice, both free pimaricin and NPPNIPA-20AA(5) treatment completely inhibited the growth of the indicator yeast until the end of the bioassay. However, the latter provided similar inhibition levels using a smaller amount of pimaricin due to PNIPA-20AA(5) protection and its controlled release from the nanohydrogel. Therefore, nanohydrogel encapsulation may help to optimise antifungal treatments and decrease the incidence of food allergies. © 2015, Springer Science+Business Media New York.

Amado I.R.,University of Vigo | Fucinos C.,University of Vigo | Fucinos C.,University of Minho | Fajardo P.,Colegio Universitario 16 | Pastrana L.,International Iberian Nanotechnology Laboratory
Journal of Dairy Science | Year: 2016

In this study, we assessed the potential as silage additive of a bacteriocin produced by Pediococcus acidilactici Northern Regional Research Laboratory (NRRL) B-5627 (pediocin SA-1). Maize was inoculated either with a bacterial starter alone (I) or in combination with the bacteriocin (IP), and untreated silage served as control. We monitored the products of fermentation (ethanol, and lactic and acetic acids), the microbial population, and the presence of the indicator strain Listeria monocytogenes Colección Española de Cultivos Tipo (CECT) 4032 (1 × 105 cfu/g) after 1, 2, 5, 8, 16, and 30 d of ensiling. Our results indicated antilisterial activity of the bacteriocin, anticipating the disappearance of L. monocytogenes in IP compared with I and control silages. The PCR-denaturing gradient gel electrophoresis analysis revealed the addition of the bacteriocin did not affect the bacterial communities of the spontaneous fermentation, and the inoculant-containing bacteria (Lactobacillus plantarum, Lactobacillus buchneri, and Enterococcus faecium) were found in addition to the bacterial communities of untreated maize silages in I and IP silages. Both treatments increased the concentration of antimicrobial compounds (acetic acid, ethanol, and 1,2-propanodiol) and led to lower residual sugar contents compared with the control, which would provide enhanced aerobic stability. The fact that the identified species L. plantarum, L. buchneri, and E. faecium produce some of these inhibitory compounds, together with their persistence throughout the 30 d of fermentation, suggest these bacteria could actively participate in the ensiling process. According to these results, pediocin SA-1 could be used as an additive to control the presence of L. monocytogenes in maize silages selectively, while improving their fermentative quality and eventually their aerobic stability. © 2016 American Dairy Science Association.

Fajardo P.,Colegio Universitario 16 | Martins J.T.,IBB Institute for Biotechnology And Bioengineering | Fucinos C.,University of Vigo | Pastrana L.,University of Vigo | And 2 more authors.
Journal of Food Engineering | Year: 2010

The purpose of this study was to evaluate the effects of the application of chitosan coating containing natamycin on the physicochemical and microbial properties of semi-hard cheese. Three cheese groups were prepared: samples without coating, samples coated with chitosan and with chitosan containing 0.50 mg mL-1 of natamycin, whose minimum inhibitory concentration was previously determinated on cheese surface. Microbiological analyses showed that natamycin coated samples presented a decrease on moulds/yeasts of 1.1 log (CFU g-1) compared to control after 27 days of storage. Addition of natamycin also affected O2 and CO2 permeability, increasing from 7.12 to 7.68 × 10-15 g·(Pa s m) -1, and from 10.69 to 64.58 × 10-14 g·(Pa s m)-1, respectively. The diffusion coefficient values of natamycin from the film to phosphate buffered saline solution and to the cheese were 3.60 × 10-10 and 1.29 × 10-12 cm2 s -1, respectively. This study demonstrated that chitosan-based coating/films can be used as release system containing natamycin to create an additional hurdle for moulds/yeasts in cheese thus contributing to extend its shelf-life. © 2010 Elsevier Ltd. All rights reserved.

Rodriguez-Turienzo L.,University of Santiago de Compostela | Cobos A.,University of Santiago de Compostela | Moreno V.,Colegio Universitario 16 | Caride A.,Colegio Universitario 16 | And 2 more authors.
Food Chemistry | Year: 2011

The effects of different whey protein concentrate coating formulations (with or without glycerol or sorbitol in two proportions) on frozen Atlantic salmon quality parameters were evaluated. The influence of the moment of coating application (before or after freezing) was also studied. The coating application after freezing increased the thaw yield, decreased the drip loss, and modified colour parameters of frozen and thawed fillets, in comparison with application before freezing. The moment of coating also influenced the colour of cooked fish fillets. The type of plasticiser affects the colour of thawed and cooked samples, but not the colour of frozen samples. The protein coatings delayed lipid oxidation of salmon fillets, providing better protection against it than water glazing, and this effect was more pronounced when glycerol instead of sorbitol was used in the coating formulation. WPC + glycerol (1:1) coating was the best for frozen Atlantic salmon protection. The sensory properties of salmon fillets were not modified by the use of this coating. © 2011 Elsevier Ltd. All rights reserved.

Chapela M.-J.,Colegio Universitario 16 | Fajardo P.,Colegio Universitario 16 | Garrido A.,Colegio Universitario 16 | Cabado A.G.,Colegio Universitario 16 | And 3 more authors.
Journal of Agricultural and Food Chemistry | Year: 2010

The main objective of the present work was to evaluate a real-time polymerase chain reaction (PCR) method to detect toxigenic Vibrio cholerae in Pangasius hypophthalmus, a freshwater fish cultured mainly in South East Asia. A FDA traditional culture method and a real-time PCR method of the ctx gene were used for detection of V. cholerae in spiked samples of pangasius fish. After an overnight enrichment of samples at 37 °C in alkaline peptone water, 2 cfu/25 g of fish was detected with both methods. Although both methods were very sensitive, obtaining results with culture methods may take several days, while real-time PCR takes only a few hours. Furthermore, with traditional methods, complementary techniques such as serotyping, although not available for all serogroups, are needed to identify toxigenic V. cholerae. However, with real-time PCR, toxigenic serogroups are detected in only one step after overnight enrichment. © 2010 American Chemical Society.

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