Peel and seeds are the main byproducts from tomato ( P. Mill) processing with high concentrations of polyphenols that have been underexploited. Herein, polyphenolic profiles in tomato peel and seeds were elucidated by untargeted liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) with an LTQ Orbitrap analyzer.
View Article and Find Full Text PDFOne of the most used methods to measure antioxidant capacity in food is the ferric reducing antioxidant power (FRAP) test, which is simple, sensitive, and economical, nevertheless has long analysis times, causing measurement errors due to the instability of the FRAP reagent due to its precipitation sequential injection analysis (SIA) is a flow technique that can correct these disadvantages because it is more quickly. So, a novel FRAP-SIA method was developed to evaluate the antioxidant capacity. The system was optimized using a central composite design for hydrodynamic and chemical factors, resulting in a flow rate of 35 μL s, and aspirate volumes of 33 μL-38 μL-33 μL for the sequence (FRAP-Antioxidant-FRAP).
View Article and Find Full Text PDFThe curing process (CP) of pods, which is a long and tedious process, is necessary to obtain the natural vanilla extract. This research evaluated the application of microwave (M) and ultrasound (U) during the "killing" stage of the CP and its effect on vanillin content and β-glucosidase activity. The pods were immersed in a container with water or with moistened samples for the M treatments.
View Article and Find Full Text PDFA µPAD to determine the total polyphenol content (TPC) by Folin-Ciocalteau (FC) method, and antioxidant capacity by ABTS method, coupling an in-situ pretreatment zone with Carrez reagents is proposed. Conditions of FC, KSO, ABTS reagents concentrations, pH, and incubation were established using 2 factorial designs. The proposed µPAD showed linearities upper than 0.
View Article and Find Full Text PDFUnlabelled: Tea ( (L.) Kuntze-surname of German origin) is a popular beverage consumed worldwide due to its health benefits. Its quality depends on measuring features that may discriminate teas from distinct provenances.
View Article and Find Full Text PDFA novel fluorescent ORAC-SIA method to determine antioxidant capacity in several food samples using fluorescein as the probe was developed. The optimization of the method was through a multivariable design, decreasing the analysis time to 5 min and the AAPH concentration to 67% compared with 90 min in the standard 96-well microplate method. The aspiration order was AAPH-sample/standard-fluorescein injected into a stream of a water-based carrier.
View Article and Find Full Text PDFIn recent decades, scientific interest in the development of devices capable of performing routine clinical analyses through the application of standardized traditional laboratory protocols in a miniaturized lab-on-a-chip device has increased. In the present work, an innovative microdevice for the on-line whole blood dilution with a phosphate buffer solution (PBS) and separation of plasma was designed, manufactured, and characterized. The microdevice was constructed with a rectangular cross-section and spiral-shaped microchannels by photolithography and soft litography.
View Article and Find Full Text PDFAnti-cyclic citrullinated peptide IgG antibodies (anti-CCP) are produced as an immune response in the presence of post-translational modified peptides known as cyclic citrullinated peptides (CCP). Anti-CCP have been considered as specific biomarkers for the diagnosis of rheumatoid arthritis (RA), and due to their high specificity, it is possible to make a differential diagnosis of other rheumatic diseases. These autoantibodies can be detected in the early stages of RA and even up to 10 years before presenting the first symptoms of the disease opening a window of opportunity for timely treatment.
View Article and Find Full Text PDFWe developed a portable device made of poly(dimethylsiloxane) (PDMS)/polymethylmethacrylate (PMMA) for long-term 3D cell culture of vascular endothelial cells for the development of a vascular network and evaluated the device under different transitions between normoxia and hypoxia with good optical accessibility. The combination of a nested reservoir device and a bicarbonate/ascorbate buffer system accomplished on-chip incubation with 4.91 ± 0.
View Article and Find Full Text PDFThe use of membranes for on-line separations in flow-through dialyser as a part of a flow system is extremely useful for automated samples preparation. In this paper a method to couple the dialysis and the UV detection on-line of Vitamin B(12) from milk is proposed. Firstly, the milk samples were pre-treated with trichloroacetic and centrifuged (to eliminate proteins and fats) and later, using a dialyser coupled a flow-continuous manifold was possible dialyse the Vitamin B(12), which was monitored spectrophotometrically at 361nm.
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