Sistema para la detección de antibióticos en alimentos

Sistema para la detección de antibióticos en alimentos. La presente invención hace referencia a un sistema para la detección de antibióticos en alimentos que comprende una carcasa (1) que a su vez comprende al menos 1 hendidura para la adición de la muestra a analizar (3) y al menos 1 ventana de visualización de resultados (4) y una tira reactiva (2). Además la invención se refiere a un procedimiento para la detección de antibióticos en alimentos mediante el sistema anterior, que comprende las etapas de preparación del sistema de detección de antibióticos en alimentos, preparación de la muestra a analizar y detección de antibióticos.Ciencias de la Alimentació

Effects of Cyclodextrin Type on Vitamin C, Antioxidant Activity, and Sensory Attributes of a Mandarin Juice Enriched with Pomegranate and Goji Berries

The effects of the addition of cyclodextrins (CDs), β-CD, or HP-β-CD (1%), on the protection of antioxidant compounds of mandarin juices enriched with pomegranate extract and goji berries juice, was studied. Juices were prepared and after their thermal treatment (98 ◦C, 30 s) they were stored at 4 ◦C during 75 d. Vitamin C content, CIE L∗a∗b∗ color, antioxidant capacity, retinol equivalents, and sensory properties were studied. Losses on vitamin C were higher (6%) for juices with β-CD than juices with HP-β-CD. Retinol equivalents degradation was lower (3.4%) in juices with HP-β-cyclodextrins than in those treated with β-CD. Lower losses were observed for the instrumental and sensory color intensity in juices with HP-β-CD addition. Finally, the antioxidant capacity was also higher in juices treated with HP-β-CD. Finally, the overall sensory quality of juices with HP-β-CD was the best one after 30 d of cold storage. Even though β-CD addition did not cause any improvement compared with control juice (without CD addition), the benefits of adding HP-β-CD to this particular juice were shown in almost all parameters under study.Ciencias de la Alimentació

Removal of an Azo Textile Dye from Wastewater by Cyclodextrin-Epichlorohydrin Polymers

Native cyclodextrins (CDs), α-, β- and γ-CDs, were employed to synthetise three different cyclodextrin-based polymers using epichlorohydrin (EPI) as a cross-linker. These polymers were applied as adsorbent material to remove an azo textile dye, Direct Blue 78 (DB78), from water. The formation of inclusion complexes between the alone CDs and DB78 molecules were first studied in aqueous solutions. Then, adsorption experiments of the dye were performed by means of cyclodextrin/epichlorohydrin (CD/EPI) polymers. The effects of various parameters, such as contact time, adsorbent dosage, initial dye concentration, pH and temperature, were examined to determine the better adsorption conditions. The equilibrium isotherms and the adsorption kinetics were also analysed using opportune mathematic models. The chemical-physical characteristics and the morphology of the adsorbent polymers were, respectively, observed by differential scanning calorimetry and field emission scanning electron microscope. The CD/EPI polymers showed a very good ability in the removal of DB78 from aqueous solution; indeed, the maximum efficiencies in the dye removal were found to be about 99% for β-CD/EPI polymer and about 97% for γ-CD/EPI polymer, at pH 6 and 25°C conditions. It is possible to assume that the good adsorbent aptitude of CD/EPI polymers is due to their double peculiarity to include the dye in the inner cavity of CDs and to adsorb the dye on their porous surfaces by physical interaction

Degradation of an azo dye by a fast and innovative pulsed light/H2O2 advanced oxidation process

Pulsed light (PL) is a food processing technology initially intended for microbial inactivation that can potentially be applied in other UV-light based processes. PL lamps emit high intensity broad spectrum light from UV to infrared. This research tested the use of PL as part of an advanced oxidation process (AOP) for degrading polluting dyes. Experiments were performed in a batch reactor, and the efficiency of the AOP under different parametric values: dye concentration, pH and H2O2 doses on Direct yellow 106 decolourization was followed by spectrophotometry. Effects on chemical oxygen demand and electrical efficiency were also determined. Decolourization process follows a pseudo-first order kinetic. It was improved by increasing H2O2 concentrations and low pH; while there was little influence of dye concentration, perhaps due to the reactor configuration. The highest constant rate observed was 0.0410 cm2 / J. The decolourization by PL/H2O2 fits to a typical mechanism of a conventional UV/H2O2 process; since no direct photolysis or thermal effects were observed. Mineralization was incomplete likely due to the highly resonant structure of the dye. An electrical energy per order of 1009 kWh/m3 /order was calculated. Ninety % of colour removal was reached at 40 J/cm2 , which is achievable in less than 30 s by most of PL systems existing in the market. The PL/H2O2 process seems to be useful for decolourization of wastewater and could offer the advantage of a very fast degradation.Ciencias de la Alimentació

Antioxidant Activity, Color, Carotenoids Composition, Minerals, Vitamin C and Sensory Quality of Organic and Conventional Mandarin Juice, cv. Orogrande

The effects of organic farming on antioxidant activity, CIE L*a*b* color, carotenoids composition, minerals contents, vitamin C and sensory quality of Orogrande mandarin juices were studied. Independent of the farming type, mandarin juices can be considered as good source of some important nutrients, such as potassium and antioxidant chemicals, for example, b-cryptoxanthin. Organic farming of mandarins resulted in juices with higher antioxidant activity, total carotenoids concentrations, minerals (Ca, K and Fe) contents, vitamin C content, more appealing and intense orange color and better sensory quality. For instance, organic Orogrande juice contained significantly (p<0.001) higher total carotenoids content (22.7±0.3 mg/L) than conventional juice (15.7±0.4 mg/L); a similar pattern was observed for the antioxidant activity, with values being 0.076±0.004 and 0.053±0.003mM Trolox m/L in organic and convectional juices, respectively. A trained panel stated that organic Orogrande juices had higher intensities of orange color, fresh mandarin and floral aromas than conventional juices.Ciencias de la Alimentació

Adsorption of Direct Blue 78 using chitosan and cyclodextrins as adsorbents

The dyeing industry is one of the most polluting in the world. The adsorption of dyes by polymeric matrixes can be used to minimize the discharge of dyes into the environment. In the present study, chitosan-NaOH and β-cyclodextrin-epichlorohydrin polymers were used to remove the dye Direct Blue 78 from a wastewater model. To understand the adsorption behavior of Direct Blue 78 onto the polymers, adsorption rate and maximum adsorption capacity were calculated using kinetic tests and isotherm curves respectively. The kinetic data and mechanism of the adsorption process were analyzed by three models and the equilibrium data by three adsorption isotherms; also the different thermodynamic parameters were calculated. Results showed that the adsorption process follows pseudo-second-order kinetics in both polymers and the Langmuir isotherm best-fitted data for chitosan-NaOH polymer and the Freundlich isotherm for the β-CDs-EPI polymer. The adsorption process is exothermic in both cases and spontaneous for the β-CDs-EPI polymer to a certain temperature and not spontaneous for the chitosan-NaOH polymer and β-CDs-EPI polymer at higher temperatures. The complementary action of an advanced oxidation process eliminated >99% of the dye from water. The coupled process seems to be suitable for reducing the environmental impact of the dyeing industry.Ciencias de la Alimentació

Evaluation of Pulsed Light to Inactivate Brettanomyces bruxellensis in White Wine and Assessment of Its Effects on Color and Aromatic Profile

Brettanomyces bruxellensis is a wine spoilage yeast that could be inactivated by pulsed light (PL); however, this technology may induce changes in the quality of this alcoholic drink. The present research aimed to determine the potential of PL to inactivate B. bruxellensis inoculated in white wine and to assess the effect of this technology on the color and aromatic profile of the wine. For this, a cocktail of B. bruxellensis strains was inoculated into the wine and its inactivation by PL was determined and fitted to a microbial inactivation model. Along with this, the effect of PL on instrument-measured color, and the volatile compounds of the wine were evaluated by GC/MS and descriptive sensory analysis, respectively. B. bruxellensis was inactivated according to the Geeraerd model including the tail effect, with a maximum inactivation of 2.10 log reduction at 10.7 J/cm2; this fluence was selected for further studies. PL affected wine color but the total color difference was below the just noticeable difference at 10.7 J/cm2. The concentration of 13 out of 15 volatile compounds decreased due to the PL, which was noticeable by the panel. It is not clear if these compounds were photolyzed or volatilized in the open reactor during treatment. In conclusion, PL is able to inactivate B. bruxellensis in white wine but the treatment impairs the volatile profile. The use of a closed reactor under turbulent flow is recommended for disaggregating yeast clumps that may cause the tailing of the inactivation curve, and to avoid the possible escape of volatile compounds during treatment.Ciencias de la Alimentació

Stability of microencapsulated strawberry flavour by spray drying, freeze drying and fluid bed

The main goal of this paper was to study the stability of a microencapsulated strawberry flavour using different encapsulating agents and drying techniques: spray drying, freeze drying and fluid bed. According to the quantification of volatile compounds, the blend MDs/Hi-Cap (9/1) at a fixed concentration of CDs (1.7%) was the most appropriate for microencapsulating the strawberry flavour. The best drying yield was observed in the case of freeze drying. In the case of the moisture content, spray drying samples presented the lowest values, followed by freeze drying and fluid bed. The study of stability at different temperatures and times revealed that the presence of CDs in the blend enabled a higher presence of volatile compounds in the powder than in its absence. Microphotographs showed smooth spherical particles in the case of spray drying, whereas the structure of the powder was amorphous, like glass, with freeze drying and irregular in the case of fluid bed.Ciencias de la Alimentació

Egg By-Products as a Tool to Remove Direct Blue 78 Dye from Wastewater: Kinetic, Equilibrium Modeling, Thermodynamics and Desorption Properties

Eggshell, a waste material from food manufacturing, can be used as a potential ecofriendly adsorbent for the elimination of textile dyes from water solutions. The adsorption process was evaluated varying factors such as initial dye load, contact time, pH, quantity of adsorbent, and temperature. The initial dye load (Direct Blue 78) was in the range of 25–300 mg/L. The kinetics of adsorption were analyzed using di erent models, such as pseudo-first-order, pseudo-second-order, and intraparticle di usion model. Also, the experimental data at equilibrium were studied using Freundlich, Langmuir, and Temkin isotherms. The kinetics followed pseudo-second-order, then pseudo-first-order, and finally the model of intraparticle di usion. The results obtained for data at equilibrium follow the order: Freundlich > Langmuir > Temkin. The adsorption equilibrium showed a maximum capacity of adsorption (qmax) of 13 mg/g at pH 5, and using 0.5 g of eggshell. Dye adsorption was enhanced with increasing temperatures. The thermodynamic study revealed the spontaneity and endothermic nature of the adsorption process. The desorption study shows that the eggshell could be reused in di erent adsorption/desorption cycles. A novel advanced oxidation process could degrade more than 95% of the dye. The results show that eggshell is a waste material useful to remove hazardous dyes from wastewater, which may alleviate the environmental impact of dyeing industries.Ciencias de la Alimentació

Complexation of resveratrol by native and modified cyclodextrins: Determination of complexation constant by enzymatic, solubility and fluorimetric assays

The complexation of resveratrol with native a-, b- and c-cyclodextrins (CDs) and modified CDs (hydroxypropyl-b-(HP-b-CDs), maltosyl-b-(G2-b-CDs), methyl-b-, carboxymethyl-b- and acetyl-b-cyclodextrins) was studied, and the complexation constants (Kc) were compared. The complexation constant between resveratrol and each type of CD was calculated using three different methods: enzymatic, solubility and fluorimetric. The Kc values obtained showed that HP-b-CDs with their very high Kc of 18,048 ± 625 M 1, were the most effective for complexing resveratrol. Moreover, comparison of the results obtained by the three methods revealed that the fluorimetric method undervalued the Kc between resveratrol and all cyclodextrins, while the enzymatic and solubility methods were more precise for calculating the Kc between resveratrol and CDs, as demonstrated by the cyclodextrin-assay.This work was partially supported by Fundación Séneca (03025/PPC/05) and Ministerio de Educación y Ciencia (AGL2006-08702/ALI). C.L.A. is a holder of a research grant from the Programa Nacional de Formación de Personal Investigador (FPI), Ministerio de Educación y Ciencia (Spain) (BES-2007-16082).Ciencias de la Alimentació