Leveraging the use of ionic liquid capillary columns and GC×GC-MS for fatty acid profiling in human colostrum samples.

Lipids in human colostrum provide the majority of energy intake and essential fatty acids for developing infants. The fatty acid composition of human colostrum is highly variable and influenced by multiple factors. Human colostrum is a complex sample bringing challenges to fatty acid profiling. This work aimed to optimize the use of ionic liquid (IL) columns and flow-modulated comprehensive two-dimensional gas chromatography coupled to mass spectrometry (FM-GC×GC-MS) for fatty acid profiling in human colostrum. Derivatization strategies were optimized and the elution behavior of fatty acid methyl esters (FAME) on various 1D column phases (Solgel-WAX, SLB-IL60i, SLB-IL76i, and SLB-IL111i). Derivatization with sodium methoxide yielded a satisfactory recovery rate (90%) at milder conditions and reduced time. The use of IL60 as the 1D column provided superior separation, good peak shape, and better utilization of elution space. As a proof of concept, the developed method was applied to access the effects of the mode of neonatal delivery (vaginal vs. C-section) on the fatty acid profile of human colostrum samples. The integrated multidimensional gas chromatography strategy improved FAME detection and separation and can be a useful tool for accessing the effects of different factors on the fatty acid profiling of complex samples.

Development of low-cost planar electrodes and microfluidic channels for applications in capacitively coupled contactless conductivity detection (C4 D).

Electrochemical techniques are commonly applied to micro total analysis system (µTAS) devices mainly due to its high sensitivity and miniaturization capacity. Among many electrochemical techniques, capacitively coupled contactless conductivity detection (C4 D) stands out for not requiring direct electrode-solution contact, avoiding several problems such as electrolysis, bubble formation, and metal degradation. Furthermore, the instrumentation required for C4 D measurements is compact, low cost, and easy to use, allowing in situ measurements to be performed even by nonspecialized personal. Contrarily, the production of metallic electrodes and microchannels adequate for C4 D measurements commonly requires specialized facilities and workers, increasing the costs of applying these methods. We propose alternatives to batch manufacture metallic electrodes and polymeric microchannels for C4 D analysis using more straightforward equipment and lower-cost materials. Three devices with different dielectric layer compositions and electrode sizes were tested and compared regarding their analytical performance. The constructed platforms have shown a reduction of more than 64% in cost when compared to traditional techniques and displayed good linearity (R2 ≥ 0.994), reproducibility (RSD ≤ 4.07%, n = 3), and limits of detection (≤0.26 mmol/L) when measuring standard NaCl samples. Therefore, the proposed methods were successfully validated and are available for further C4 D applications such as diagnosis of dry-eye syndrome.

Brazilian Capsicum peppers: capsaicinoid content and antioxidant activity.

BACKGROUND: Capsicum peppers are known as a source of capsaicinoids, phenolic compounds and antioxidants. Brazilian Capsicum peppers are important spices used in foods worldwide. However, little information is available on the chemical composition and antioxidant activity of these peppers. RESULTS: Capsaicin, dihydrocapsaicin, total phenolic compounds and antioxidant activity were investigated in extracts of three Brazilian peppers: Capsicum frutescens, C. chinense and C. baccatum var. pendulum, in two different harvest years and at two ripening stages. The bioactive compound content was dependent on harvest year, and changes in the concentration profiles were found for capsaicin. Mature fruits of C. chinense harvested in the first year had the highest capsaicin concentration (2.04 mg g-1 fresh pepper), and mature fruits of C. frutescens harvested in the same first year had the highest dihydrocapsaicin content (0.95 mg g-1 fresh pepper). Mature fruits of C. frutescens harvested in the first year showed the major total phenolic compound content (2.46 mg g-1 fresh pepper). The total phenolic compound content was directly related to antioxidant activity. CONCLUSION: Our results suggest that phenolic compounds significantly contribute to the antioxidant activity of the investigated peppers. Also, these data add valued novel information that enhances current knowledge of Brazilian pepper fruits. © 2017 Society of Chemical Industry.

Solid-phase microextraction combined with comprehensive two-dimensional gas chromatography for fatty acid profiling of cell wall phospholipids.

The combination of solid-phase microextraction (SPME) with comprehensive two-dimensional gas chromatography is evaluated here for fatty acid (FA) profiling of the glycerophospholipid fraction from human buccal mucosal cells. A base-catalyzed derivatization reaction selective for polar lipids such as glycerophospholipid was adopted. SPME is compared to a miniaturized liquid-liquid extraction procedure for the isolation of FA methyl esters produced in the derivatization step. The limits of detection and limits of quantitation were calculated for each sample preparation method. Because of its lower values of limits of detection and quantitation, SPME was adopted. The extracted analytes were separated, detected, and quantified by comprehensive two-dimensional gas chromatography with flame ionization detection (FID). The combination of SPME and comprehensive two-dimensional gas chromatography with FID, using a selective derivatization reaction in the preliminary steps, proved to be a simple and fast procedure for FA profiling, and was successfully applied to the analysis of adult human buccal mucosal cells.

Identification of volatiles from pineapple (Ananas comosus L.) pulp by comprehensive two-dimensional gas chromatography and gas chromatography/mass spectrometry.

Combining qualitative data from the chromatographic structure of 2-D gas chromatography with flame ionization detection (GC×GC-FID) and that from gas chromatography-mass spectrometry (GC/MS) should result in a more accurate assignment of the peak identities than the simple analysis by GC/MS, where coelution of analytes is unavoidable in highly complex samples (rendering spectra unsuitable for qualitative purposes) or for compounds in very low concentrations. Using data from GC×GC-FID combined with GC/MS can reveal coelutions that were not detected by mass spectra deconvolution software. In addition, some compounds can be identified according to the structure of the GC×GC-FID chromatogram. In this article, the volatile fractions of fresh and dehydrated pineapple pulp were evaluated. The extraction of the volatiles was performed by dynamic headspace extraction coupled to solid-phase microextraction (DHS-SPME), a technique appropriate for slurries or solid matrices. Extracted analytes were then analyzed by GC×GC-FID and GC/MS. The results obtained using both techniques were combined to improve compound identifications.

Umami Ingredient: Flavor enhancer from shiitake (Lentinula edodes) byproducts.

An alternative use of shiitake stipes, usually treated as waste, was proposed for the production of a powder ingredient, rich in umami compounds, aiming its application in food. The extraction of umami compounds was optimized through the Response Surface Methodology (RSM), in order to obtain an extract with high umami taste intensity. From the optimized condition, a comparative analysis of shiitake stipes dehydration method was performed. Stipes were dehydrated by hot air drying (HD) and freeze drying (FD), submitted to extraction and the umami compounds in the extracts were compared. The comparative analysis showed that the 5' - nucleotides are more sensitive to prolonged heating, while the release of free amino acids (FAA) was favored by hot air drying. The HD samples extract showed higher Equivalent Umami Concentration (EUC). The spray drying of the HD samples extract allowed the production of a newly powder ingredient rich in umami compounds (Umami Ingredient) that can be applied in diverse food matrices. Due to the presence of umami compounds, Umami Ingredient can be a potential alternative to help in the process of sodium reduction by enhancing food flavor.

Development and evaluation of a vegetable oil blend formulation for cutaneous wound healing.

This work aimed to evaluate the in vivo capacity of a vegetable oil blend formulation (VOB) developed to accelerate cutaneous wound closure. Total thickness wounds were punctured on the skin on the back side of each animal and topically treated with the VOB formulation, Dersani® ointment or the vehicle control. After 2, 7, 14, 21 days post-wounding, five animals from each group were euthanized, and the rates of wound closure and re-epithelialization were evaluated. The wounds were harvested for histological and biochemical analysis. VOB resulted in faster and greater re-epithelialization in the in vivo excisional wounds, exhibiting significant wound area reduction of 8.9, 8.0, 35.1, 45.2 and 47.0% after 2, 5, 10, 14 and 21 days post-wounding, respectively, when compared with the vehicle control. Histological and biochemical analyses showed that the VOB-treated wounds exhibited a significant increase of granular tissue and controlled inflammatory response by modulation of the release of pro-inflammatory cytokines TNF-α, IL-6 and IL-1. Moreover, VOB-treated wounds showed a significant and concrete increase in the deposition and organisation of collagen fibres in the wound site and improved the quality of the scar tissue. Altogether, these data revealed that VOB accelerates wound healing processes and might be beneficial for treating wound disorders.