RESUMEN
In the face of the environmental problems caused by using food packaging composed of non-renewable sources, the aim of this study was producing a new antimicrobial film, biodegradable and with UV barrier based on commercial κ-carrageenan/starch polysaccharides loaded zinc oxide nanoparticles (ZnONPs) for the first time by casting method. Different formulations of κ-carrageenan/starch/ZnONPs were extensively characterized. The X-ray patterns displayed diffraction peaks characteristics of the crystallographic plane of ZnONPs. The formation of the material composite was confirmed by specific signals in the FTIR spectrums and endothermic peak shift after ZnONPs addition. The ZnONPs (1.5 and 2 %) produce a more resistant material. The analysis of SEM (cracks remotion of film surface), mechanical properties (higher elongation at rupture and tensile strength), and opacity (low transparency) confirm this. Still, ZnONPs at 2 % produce a hydrophobic surface, justified by lower moisture content, water solubility, and higher WCA. The ZnONPs promoted UV barrier and antimicrobial activity against Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus microorganisms. Thus, the new active material was applied as a coating on fresh strawberries and delayed the ripening of the fruit, extending its shelf life. Therefore, we produced, characterized, and applied an active material with potential application in fresh food packaging.
Asunto(s)
Antiinfecciosos , Nanopartículas , Óxido de Zinc , Carragenina/química , Óxido de Zinc/química , Antiinfecciosos/química , Nanopartículas/química , Embalaje de Alimentos , Escherichia coli , Almidón/químicaRESUMEN
Trans-resveratrol (t-RESV) is an important and natural polyphenolic antioxidant generally found in grapes and in its derivatives such as red wine and grape juices. The t-RESV has been explored in the pharmaceutical industry for its anti-inflammatory, anti-cancer, and neuroprotective properties. The t-RESV electrochemical determination has basically been carried out using modified electrodes-based sensors. Although these devices show good analytical performance, the electrode preparation can be laborious, and the devices may lack reproducibility. In this sense, it was proposed here a new methodology for the t-RESV electrochemical detection using unmodified screen-printed electrodes and differential pulse voltammetry (DPV). The response of the anodic signal has optimized varying the most important parameters of DPV (pulse time, pulse potential, and pulse step) using the response surface methodology. We showed based on analysis of variance that the new mathematical model developed can predict responses for the t-RESV using DPV. Furthermore, the new analytical method was validated from the limits of detection and quantification. We have still shown that t-RESV can be quantified in commercial drug using DPV with the optimized parameters. The selectivity test also showed that the sensor can be used to determine the antioxidant in other more complex matrices. Additionally, the proposed electrochemical system is completely portable and can work with its own energy, which facilitates point-of-care analysis.
Asunto(s)
Resveratrol , Electrodos , Límite de Detección , Reproducibilidad de los ResultadosRESUMEN
This work has proposed the application of optimized dispersive liquid-liquid microextraction (DLLME) in order to extract acrylamide from brewed coffee samples for its subsequent determination by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). DLLME achieved superior results employing 300⯵L of brewed coffee, 100⯵L of dichloromethane, 400⯵L of acetonitrile and without sodium chloride addition. Quantitative analyses were carried out by the standard addition method, and the limits of detection and quantification were 0.9 and 3.0⯵gâ¯L-1, respectively. Recoveries ranged from 97 to 106%, and the intra- and inter-assay precisions ranged from 6 to 9%. The proposed analytical method was applied to seventeen brewed coffee samples prepared in a filter coffee maker, and acrylamide amounts varied from 10.5 to 28.5⯵gâ¯L-1. Therefore, the suggested DLLME-UPLC-MS/MS method is promising for routine analysis in order to guarantee the quality control of acrylamide in brewed coffee.
Asunto(s)
Acrilamida/análisis , Café/química , Espectrometría de Masas en Tándem , Acrilamida/aislamiento & purificación , Cromatografía Líquida de Alta Presión , Café/metabolismo , Límite de Detección , Microextracción en Fase Líquida/métodosRESUMEN
The aims of this study were the optimization and validation of a new ultrasound assisted phytosterol method through analysis of response surface generated from Box-Behnken design. Variables quantity of sample (g), volume of KOH/MeOH (mL) and ultrasound time (s) were investigated in three levels. The evaluation process of the methodology was executed through determination of analytical parameters, such as selectivity, linearity, accuracy, dynamic linear range, "intra-day" accuracy and limits of detection and quantification. Optimized conditions for stigmasterol determination were 0.25g; 2.5mL; 300s; and ß-sitosterol were 0.25g; 5.4mL; 300s. The evaluated conditions and all investigated analytical parameters showed that the method is effective for determination of analytes ß-sitosterol and stigmasterol. This new analytical method has the same efficiency of the traditional method, while significantly reducing the total time of extraction for 300s regarding saponification step when compared to 3600s from the traditional method.
Asunto(s)
Fitosteroles/análisis , Aceites de Plantas/química , Sitoesteroles , Estigmasterol , Ondas UltrasónicasRESUMEN
The ComDim chemometrics method for multi-block analysis was employed to evaluate thirty-two vegetable oil samples analyzed by near infrared (NIR) and ultraviolet-visible (UV-Vis) spectroscopy, and by Gas Chromatography with flame ionization detection (GC-FID) for their fatty acids composition. This unsupervised pattern recognition method was able to extract information from the tables of results that could be presented in informative graphs showing the relationship between the samples through the scores, the predominance of information in particular tables through the saliences and the contribution of the variables in each table which were responsible for the similarities observed in the samples, through the loadings plots. It was possible to infer similarities and differences among the samples studied according to the specific absorption in the UV-Vis and NIR region, as well as their fatty acids composition. The proposed methodology demonstrates the applicability of ComDim for the characterization of samples when different variables (different techniques) describe the same samples. In this particular study, the ComDim chemometrics method was able to discriminate samples by their characteristics and compositions.
Asunto(s)
Cromatografía de Gases , Ácidos Grasos/análisis , Ionización de Llama , Aceites de Plantas/análisisRESUMEN
BACKGROUND: The homeopathic complex HomeoAqua Mega 3(®) was designed to stimulate fish liver function resulting in enhanced lipid metabolism and improved overall performance. The effect of the complex in fatty acid compounds in the muscle tissues and the performance of Nile tilapia (O. niloticus) were evaluated. METHODS: A control diet with 40 mL of alcohol solution (30° Gay Lussac (GL) alcohol) per kg of feed and another diet with 40 mL/kg of the homeopathic complex were analysed in sex-reversed juvenile male Nile tilapia with mean initial weights of 89.54 g (±7.97) and 89.74 g (±8.83) and initial total mean lengths of 16.93 cm (±0.56) and 16.85 cm (±0.56) for the control and homeopathy-treated fish, respectively. Overall, 200 fish were distributed into 10 water tanks, with 20 specimens in each 600 L tank, they were kept for 63 days. Monitoring of the water's physical and chemical parameters was performed. Additionally, the percentage chemical composition and the composition of the muscle tissue fatty acids were determined, and fish performance was evaluated. RESULTS: No significant differences (p > 0.05) were found between treatments with regard to the water's physical and chemical parameters, moisture, ashes, proteins of the Nile tilapia muscular tissue and mean rates of total weight and length of the animals in the final period of the assay. The total lipid (TL) rates of the tilapia muscle tissue were 1.133 ± 0.2% at the start (control and homeopathy) and 0.908 ± 0.14% (control) and 0.688 ± 0.14% (homeopathy) at the end of the experiment (p < 0.06). The sum total of the SFAs (saturated fatty acids) was 338.50 ± 0.15 at the start (control and homeopathy) and 271.49 ± 0.34 mg/g of the TLs for the control and 226.12 ± 0.77 mg/g of TL for the homeopathy at the end of the experiment (p < 0.05). The n-6/n-3 ratio was also lower for the homeopathy-treated fish (8.45 ± 0.40) compared with the control fish (9.60 ± 0.14), (p < 0.05) at the end of the 63-day period. CONCLUSION: Nile tilapia juveniles that received the HomeoAqua Mega-3(®) in their diets had a decrease in the TL rates, mainly for the SFAs, and the n-6/n-3 ratio, compared with the control group, without any changes in the animal performance during the experimental period.
Asunto(s)
Cíclidos/metabolismo , Ácidos Grasos/metabolismo , Enfermedades de los Peces/metabolismo , Homeopatía/métodos , Hígado/metabolismo , Materia Medica/farmacología , Músculo Esquelético/metabolismo , Alimentación Animal , Animales , Enfermedades de los Peces/tratamiento farmacológico , Hígado/efectos de los fármacos , Masculino , Materia Medica/administración & dosificación , Músculo Esquelético/efectos de los fármacos , Preparaciones de Plantas/farmacologíaRESUMEN
This study evaluated the effect of the dietary replacement of sunflower oil with perilla oil in Nile tilapia (GIFT strain) at 0, 10, 20 and 30 days. There was an increase in total omega 3 fatty acids (n-3) in muscle tissue (from 63.6 to 181.5 mg g(-1)) and a decrease in total concentration of omega 6 fatty acids (n-6) ranging between 255.6 and 196.1 mgg(-1). Amongst the n-3 fatty acids, the concentrations of alpha-linolenic acid (18:3n-3) and docosahexaenoic acid (20:6n-3) increased by 9.4 and 1.9 times, respectively, after 30 days for the perilla oil-enriched diet. The n-6/n-3, polyunsaturated and saturated fatty acids (PUFA/SFA), and polyunsaturated and monounsaturated fatty acids (PUFA/MUFA) ratios tended to stabilize after 20 days under the perilla oil-enriched diet. Incorporation of perilla oil as a lipid source in the diet of tilapia for 20 or 30 days resulted in significant changes in the fatty acid composition of the fish muscle tissue, contributing to increase its nutritional value.
Asunto(s)
Alimentación Animal/análisis , Cíclidos/metabolismo , Suplementos Dietéticos/análisis , Ácidos Grasos/química , Músculo Esquelético/química , Aceites de Plantas/metabolismo , Ácido alfa-Linolénico/metabolismo , Animales , Ácidos Grasos/metabolismo , Aceites de Pescado/química , Aceites de Pescado/metabolismo , Carne/análisis , Músculo Esquelético/metabolismo , Valor Nutritivo , Alimentos Marinos/análisis , Aceite de GirasolRESUMEN
The effects of corn replacement by different glycerine levels on carcass characteristics and meat quality of 40 young Purunã bulls, weighing 209 ± 33.3 kg and 8 ± 0.9 months old, finished in feedlot, were evaluated. The treatments were G00: without glycerine; G06: 6% glycerine; G12: 12% glycerine; and G18: 18% glycerine in the diets, on a DM basis. Hot weight, dressing, conformation and length carcass, leg length and cushion thickness were not (P>0.05) modified by different glycerine levels in the diets. Glycerine in the diets did not (P>0.05) affect fat thickness, Longissimus muscle area, marbling and texture. Muscle, fat and bone percentages were not (P>0.05) influenced by glycerine levels in the diets. No changes (P>0.05) in lightness (L*), redness (a*) and yellowness (b*) on LM occurred when glycerine was included at 0, 6, 12 or 18% in the diet. There was no (P>0.05) difference in LM moisture, ash, crude protein and total lipids when feeding different glycerine levels. The inclusion of glycerine decreased (P<0.01) total saturated (10.8%), and increased monounsaturated (7.4%) and poly-unsaturated (44.0%) fatty acids, which resulted in a higher PUFA:SFA ratio (0.57).