Effects of gelatin origin, bovine-hide and tuna-skin, on the properties of compound gelatin-chitosan films

With the purpose to improve the physico-chemical performance of plain gelatin and chitosan films, compound gelatin-chitosan films were prepared. The effect of the gelatin origin (commercial bovine-hide gelatin and laboratory-made tuna-skin gelatin) on the physico-chemical properties of films was studied. The dynamic viscoelastic properties (elastic modulus G', viscous modulus, G″ and phase angle) of the film-forming solutions upon cooling and subsequent heating revealed that the interactions between gelatin and chitosan were stronger in the blends made with tuna-skin gelatin than in the blends made with bovine-hide gelatin. As a result, the fish gelatin-chitosan films were more water resistant (∼18% water solubility for tuna vs 30% for bovine) and more deformable (∼68% breaking deformation for tuna vs 11% for bovine) than the bovine gelatin-chitosan films. The breaking strength of gelatin-chitosan films, whatever the gelatin origin, was higher than that of plain gelatin films. Bovine gelatin-chitosan films showed a significant lower water vapour permeability (WVP) than the corresponding plain films, whereas tuna gelatin-chitosan ones were only significantly less permeable than plain chitosan film. Complex gelatin-chitosan films behaved at room temperature as rubbery semicrystalline materials. In spite of gelatin-chitosan interactions, all the chitosan-containing films exhibited antimicrobial activity against Staphylococcus aureus, a relevant food poisoning. Mixing gelatin and chitosan may be a means to improve the physico-chemical performance of gelatin and chitosan plain films, especially when using fish gelatin, without altering the antimicrobial properties. © 2011 Elsevier Ltd.Peer Reviewe

Role of sulfites and 4-hexylresorcinol in microbial growth and melanosis prevention of deepwater pink shrimp (Parapenaeus longirostris) using a controlled atmosphere

A controlled atmosphere containing 48% CO2 and 7% O2 was used in association with refrigeration for storage of deepwater pink shrimp (Parapenaeus longirostris). Shrimp were treated with two different concentrations of sodium metabisulfite or 4-hexylresorcinol and subjected to the controlled atmosphere immediately after capture onboard ship or on arrival in port. Total volatile basic nitrogen, total viable counts, enterobacteria, lactic acid bacteria, and luminescent bacteria were determined, and black spot progression was evaluated. The combined effect of controlled atmosphere and melanosis inhibitors was used to delay black spot development as compared to the shrimp stored in ice alone. Storage under the controlled atmosphere without ice limited microbiological quality, namely, total viable counts, but enterobacterial growth was lower.Peer Reviewe

Melanosis inhibition and SO2 residual levels in shrimps (Parapenaeus longirostris) after different sulfite-based treatments

The effectiveness of different sulfite-based treatments to prevent melanosis in fresh deepwater pink shrimp (Parapenaeus longirostris) was evaluated. Increasing the concentration of sulfites, different methods of application (immersion and dust) and synergy with other compounds, such as citric acid and chelants, were investigated. The level of SO2 residues in the muscle was determined in a selection of the most effective treatments. One-hour dip treatment with 50 g kg-1 sulfite, together with citric acid and chelants, was effective for melanosis prevention for at least one week. With this treatment, the statutory limit of 0.3 g kg -1 SO2 in edible part was not exceeded by the majority of samples analysed. © 2005 Society of Chemical Industry.Peer Reviewe

Evolución de la relación entre atención primaria y especializada 1992-2001: estudio Delphi

ObjetivoValorar la tendencia en la relación de atención primaria (AP) y especializada (hospital) en 2 momentos diferentes de la reforma sanitaria, al inicio (1992) y tras una fase de consolidación (2001).DiseñoEstudio cualitativo basado en la técnica Delphi modificada.EmplazamientoComunidad Valenciana.ParticipantesSe seleccionó a un total de 196 profesionales de la Comunidad Valenciana (103 coordinadores de AP, 43 directores médicos hospitalarios y de AP, y 50 jefes de servicio de medicina interna/urgencias).ResultadosSe enviaron 196 cuestionarios, con una tasa de respuesta del 38%. Desde AP los problemas se mantienen, con un empeoramiento en la desmotivación del personal sanitario (+1,34), la falta de visión integral del paciente (+1,10) y la masificación asistencial (+1,06), y un mejoría en la presencia de especialistas de ambulatorio no integrados (–1,32). Desde el ámbito hospitalario empeora la falta de visión integral del paciente (+0,51), pero destaca la mejoría generalizada de los problemas, sobre todo la falta de comunicación y diálogo (–1,14). Las soluciones que aumentan su demanda desde AP son una historia clínica única informatizada (+1,50), la elaboración de protocolos comunes (+0,86) y las rotaciones periódicas de los médicos de AP (MAP) por servicios hospitalarios (+0,85), con una disminución de las derivaciones burocráticas a AP (–0,60) y la necesidad de especialistas en AP como consultores (–0,36). Desde el ámbito hospitalario, todas las soluciones disminuyen su valoración y entre ellas destaca facilitar el acceso de MAP para el seguimiento de los pacientes ingresados (–2,44) y la realización de guardias hospitalarias por MAP (–2,30).ConclusionesLos problemas y las soluciones siguen siendo los mismos que en 1992, pero en AP se observa una tendencia a empeorar y en el ámbito hospitalario se detecta una visión más positiva.AimTo evaluate the trends in the inter-professional relationship between primary health care (PHC) and secondary care (hospital) at 2 different moments of the health reform, at its start in 1992 and after a phase of consolidation (2001).DesignObservational study based on modified Delphi technique.SettingValencia Community, Spain.ParticipantsOne hundred and ninety six professionals from Valencia Community were selected (103 PH centre administrators, 43 hospital and PC medical directors, and 50 heads of internal medicine or emergency services).ResultsOne hundred and ninety six questionnaires were sent out, with a response rate of 38%. In PHC problems remained the same, but the following got worse: “lack of motivation” (+1.34), “lack of overall vision of patients” (+1.10), and “overuse of medical services” (+1.06). The existence of non-integrated out-patient specialists got better (–1.32). In hospitals, “lack of overall vision of patients” got worse (+0.51), but in general problems got better, especially in “lack of communication and dialogue” (–1.14). PC increased its demand for “a single computerized clinical record” (+1.50), drawing up of common protocols (+0.86), and periodic rotations of PC doctors through hospitals (+0.85), but bureaucratic referrals to PC (–0.60) and the need for specialists in PC as consultants (-0.36) diminished. In hospitals all solutions showed lower scores, particularly access of PC doctors to monitoring of admitted patients (–2.44) and PC doctors doing hospital cover (–2.30).ConclusionsProblems and solutions from PHC and hospitals remain the same, but there is a trend to the worse in PHC, whereas in hospitals the trend is more positive

Functional and bioactive properties of collagen and gelatin from alternative sources: A review

The rising interest in the valorisation of industrial by-products is one of the main reasons why exploring different species and optimizing the extracting conditions of collagen and gelatin has attracted the attention of researchers in the last decade. The most abundant sources of gelatin are pig skin, bovine hide and, pork and cattle bones, however, the industrial use of collagen or gelatin obtained from non-mammalian species is growing in importance. The classical food, photographic, cosmetic and pharmaceutical application of gelatin is based mainly on its gel-forming properties. Recently, and especially in the food industry, an increasing number of new applications have been found for gelatin in products such as emulsifiers, foaming agents, colloid stabilizers, biodegradable film-forming materials and micro-encapsulating agents, in line with the growing trend to replace synthetic agents with more natural ones. In the last decade, a large number of studies have dealt with the enzymatic hydrolysis of collagen or gelatin for the production of bioactive peptides. Besides exploring diverse types of bioactivities, of an antimicrobial, antioxidant or antihypertensive nature, studies have also focused on the effect of oral intake in both animal and human models, revealing the excellent absorption and metabolism of Hyp-containing peptides. The present work is a compilation of recent information on collagen and gelatin extraction from new sources, as well as new processing conditions and potential novel or improved applications, many of which are largely based on induced cross-linking, blending with other biopolymers or enzymatic hydrolysis. © 2011 Elsevier Ltd.Peer Reviewe

Functional and bioactive properties of collagen and gelatin from alternative sources: A review

The rising interest in the valorisation of industrial by-products is one of the main reasons why exploring different species and optimizing the extracting conditions of collagen and gelatin has attracted the attention of researchers in the last decade. The most abundant sources of gelatin are pig skin, bovine hide and, pork and cattle bones, however, the industrial use of collagen or gelatin obtained from non-mammalian species is growing in importance. The classical food, photographic, cosmetic and pharmaceutical application of gelatin is based mainly on its gel-forming properties. Recently, and especially in the food industry, an increasing number of new applications have been found for gelatin in products such as emulsifiers, foaming agents, colloid stabilizers, biodegradable film-forming materials and micro-encapsulating agents, in line with the growing trend to replace synthetic agents with more natural ones. In the last decade, a large number of studies have dealt with the enzymatic hydrolysis of collagen or gelatin for the production of bioactive peptides. Besides exploring diverse types of bioactivities, of an antimicrobial, antioxidant or antihypertensive nature, studies have also focused on the effect of oral intake in both animal and human models, revealing the excellent absorption and metabolism of Hyp-containing peptides. The present work is a compilation of recent information on collagen and gelatin extraction from new sources, as well as new processing conditions and potential novel or improved applications, many of which are largely based on induced cross-linking, blending with other biopolymers or enzymatic hydrolysis. © 2011 Elsevier Ltd.Peer Reviewe

Quality of thawed deepwater pink shrimp (Parapenaeus longirostris) treated with melanosis-inhibiting formulations during chilled storage

This work investigates how the treatment of thawed deepwater pink shrimp (Parapenaeus longirostris) with several melanosis-inhibiting formulations, affects the quality of the shrimp during chilled storage. Formulations were as follows: a formulation containing 4-hexylresorcinol (0.1 and 0.05%), in combination with organic acids and chelating agents, a commercial formula based on sulphites, and a mixture of gluconic acid and commercial sulphites. No noticeable differences were observed for both trimethylamine and total volatile bases during chilled storage. pH evolution was irrespective of the treatment condition. Microbial load enlarged after the sixth day of chilled storage. Higher total bacteria counts were associated with the control and sulphite treatment conditions, while lactic acid bacteria growth seemed to be favoured under formulations based on 4-hexylresorcinol. The appearance of melanosis occurred more rapidly in control shrimp or in shrimp treated with commercial sulphites. 4-hexylresorcinol formulations preserved the quality of thawed shrimp and could replace traditional sulphites. © 2007 The Authors. Journal compilation 2007 Institute of Food Science and Technology Trust Fund.Peer Reviewe

Tween 80 Improves the Acid-Fast Bacilli Quantification in the Magnetic Nanoparticle-Based Colorimetric Biosensing Assay (NCBA)

Despite its reduced sensitivity, sputum smear microscopy (SSM) remains the main diagnostic test for detecting tuberculosis in many parts of the world. A new diagnostic technique, the magnetic nanoparticle-based colorimetric biosensing assay (NCBA) was optimized by evaluating different concentrations of glycan-functionalized magnetic nanoparticles (GMNP) and Tween 80 to improve the acid-fast bacilli (AFB) count. Comparative analysis was performed on 225 sputum smears: 30 with SSM, 107 with NCBA at different GMNP concentrations, and 88 with NCBA-Tween 80 at various concentrations and incubation times. AFB quantification was performed by adding the total number of AFB in all fields per smear and classified according to standard guidelines (scanty, 1+, 2+ and 3+). Smears by NCBA with low GMNP concentrations (≤1.5 mg/mL) showed higher AFB quantification compared to SSM. Cell enrichment of sputum samples by combining NCBA-GMNP, incubated with Tween 80 (5%) for three minutes, improved capture efficiency and increased AFB detection up to 445% over SSM. NCBA with Tween 80 offers the opportunity to improve TB diagnostics, mainly in paucibacillary cases. As this method provides biosafety with a simple and inexpensive methodology that obtains results in a short time, it might be considered as a point-of-care TB diagnostic method in regions where resources are limited

Antioxidant and antimicrobial peptide fractions from squid and tuna skin gelatin

27 páginas, 4 figuras, 4 tablas.Gelatin extracted from tuna skins and giant squid tunics were hydrolysed with Alcalase at 50ºC for 3h. Two peptide fractions (1-10K and ≤1K) were obtained from each gelatin hydrolysate by subjecting them to centrifugal ultrafiltration using successively a 10 kDa and a 1 kDa membrane. The peptide fractions were characterized in terms of amino acid composition and Fourier transform infrared (FTIR) spectroscopy. Antioxidant properties were tested according to the Ferric Reducing Antioxidant Power (FRAP) assay and the radical scavenging capacity (ABTS) assay. A disk diffusion test was performed to test antimicrobial action against a panel of Gram-positive and Gramnegative pathogenic and fish spoilage-associated microorganisms. Although antioxidant and antimicrobial properties could be detected in all tested peptide fractions, the lowermost molecular weight fraction from squid hydrolysate presented the highest reducing and radical scavenging capacities, whereas microbial growth inhibition was found to be specifically related to the type of microorganism.This study was supported by the Spanish “Ministerio de Educación y Ciencia” (project AGL2005-02380/ALI and AGL2008-02135/ALI).Peer reviewe