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.
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.
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
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D 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
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D 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.
This study aimed at an unprecedented rheological investigation of starch (S)/gelatin (G)-based solutions (SG) as possible candidates for food packaging films. Phenolic extracts from acerola (M. ...emarginata) fruit (AFE) and açaí (E.oleracea) seed flour (ASFE) were incorporated as active compounds in two different concentrations (2 and 4 mg extract g-1 solution). All the solutions were more elastic than viscous (G’ > G”) and the extracts incorporation decreased their elastic character, leading to higher tanδ (G”/G’) values (from 0.157 ± 0.006 in SG to 0.338 ± 0.036 in SASFE4G). The extracts improved the viscoelastic stability of the solutions, with critical strain values about 100% greater than SG. Moreover, G’ and G” moduli were more susceptible to cross (flow point) both as a function of frequency and temperature in the ASFE-containing solutions. The viscosity of the solutions was more influenced by the type of the extracts than by their concentration, ranging from 73.85 ± 9.22 Pa s (SASFE2G) to 116.50 ± 7.63 Pa s (SAFE4G). SASFE4G was the least sensitive solution to temperature changes, with the lowest activation energy (20.63 kJ mol-1). All the solutions presented non-thixotropic behavior, and the ASFE-containing solutions supported higher % of strain but recovered the least after deformation. Therefore, the results of the complete rheological assessment of starch/gelatin-based solutions containing phenolics from acerola fruit and açaí seed flour are a previous and unprecedent characterization of these materials and can be related to the application of the films formed by them in subsequent food packaging studies.
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•Acerola fruit (AFE) and açaí seed flour (ASFE) extracts were obtained.•Starch/gelatin-based solutions containing AFE and ASFE were prepared.•AFE and ASFE decreased the elastic character and the viscosity of the solutions.•The TPC of the extracts had the greatest influence on the rheological properties.•ASFE solutions were the easiest to flow and the least recovered after strain.
The objectives of this study were twofold: (1) to identify potential differences in the ruminal and fecal metabolite profiles of Nelore bulls under different nutritional interventions; and (2) to ...identify metabolites associated with cattle sustainability related-traits. We used different nutritional interventions in the feedlot: conventional (Conv; n = 26), and by-product (ByPr, n = 26). Thirty-eight ruminal fluid and 27 fecal metabolites were significantly different (P < 0.05) between the ByPr and Conv groups. Individual dry matter intake (DMI), residual feed intake (RFI), observed water intake (OWI), predicted water intake (WI), and residual water intake (RWI) phenotypes were lower (P < 0.05) in the Conv group, while the ByPr group exhibited lower methane emission (ME) (P < 0.05). Ruminal fluid dimethylamine was significantly associated (P < 0.05) with DMI, RFI, FE (feed efficiency), OWI and WI. Aspartate was associated (P < 0.05) with DMI, RFI, FE and WI. Fecal C22:1n9 was significantly associated with OWI and RWI (P < 0.05). Fatty acid C14:0 and hypoxanthine were significantly associated with DMI and RFI (P < 0.05). The results demonstrated that different nutritional interventions alter ruminal and fecal metabolites and provided new insights into the relationship of these metabolites with feed efficiency and water intake traits in Nelore bulls.
This study aimed to investigate the application of biopolymeric materials (chitosan, gelatin, and pomegranate peel extract as photosensitizer) and antimicrobial photodynamic therapy (aPDT) on the ...physicochemical and microbial safety of strawberries. The photosensitizer potential of the materials was confirmed by a light-dose-dependent photobleaching profile. The application of light (525 nm; 50 J cm−2) decreased by >2 log CFU mL−1 the survival of Staphylococcus aureus on the surface of the photoactive-biopolymeric films. Moreover, the materials did not present in vivo cytotoxicity using Danio rerio (Zebrafish) as well as cytophytotoxic, genotoxic, or mutagenic potentials against Allium cepa plant model, which points out their safety to be used as films without posing a risk to the humans and the environment. The photoactive-polymeric coatings were able to maintain the strawberries weight, and the association with green light was 100 % effective in delaying fungal contamination. These coated-strawberries presented a significant reduction in S. aureus survival after light application (5.47–4.34 log CFU mL−1). The molecular level analysis of the photoactive compound cyanidin-3-glucoside indicates absorption on UV–Vis consistent with aPDT action. Therefore, this study showed that the antimicrobial effects of aPDT combined with photoactive-biopolymeric coatings were enhanced, while the quality of the strawberries was maintained.
The increased interest in greener sources of antioxidants has spurred the research on natural alternatives to enhance poultry production. This study aimed to investigate the effects of natural ...antioxidant extracts’ (hop β-acids extract) diet supplementation at different concentrations (0, 30, 60, and 120 mg kg−1) on the volatile compound profile of roasted chicken meat. A method based on headspace solid-phase micro-extraction coupled to gas chromatography-mass spectrometry (HS-SPME-GC-MS) was optimized by response surface design to extract the volatile compounds. The optimum extraction conditions were 80 °C and 45 min. A total of 95 volatile compounds were identified in roasted chicken meat, especially aldehydes, alkanes, alcohols, esters, and pyrazines. Principal component analysis (PCA) separated the samples as a function of β-acid supplementation, indicating that increased levels of supplementation lead to distinct volatile profiles in roasted chicken meat. Aldehydes such as octanal and hexanal (8.94% and 17.63%, respectively, for 30 mg kg−1 treatment) played an important role in distinguishing the samples. Those compounds are the main oxidation products of unsaturated fatty acids, which are possibly protected by the antioxidant properties of hop β-acid extracts. Some other compounds with odoriferous importance detected for this level of supplementation were: 2,6-dimethyl pyrazine (5.12%), 2-pentylfuran (2.94%), and 1-octen-3-ol (1.88%). This study significantly contributes to the elucidation of the impact of hops β-acids supplementation in the chicken meat aroma profile, opening new venues for its potential application.
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