In vitro bioaccessibility of carotenoids and tocopherols from fruits and vegetables

Aim of the study

To assess the in vitro bioaccessibility of carotenoids, including xanthophyll esters, and tocopherols from fruits and vegetables.

Results

Stability for carotenoids and tocopherols was over 70%. Xanthophyll esters were cleaved by cholesterol esterase but not by human pancreatic lipase. Less than 40% of the β-cryptoxanthin initially present was hydrolyzed and the amount of free xanthophylls recovered was higher when liquid was used than when fresh homogenized matrix was employed. cis-Isomers of β-carotene and lutein did not significantly increase during the process. Xanthophylls were more efficiently transferred into supernatants than tocopherols and β-carotene. cis-Carotenoids, epoxy-xanthophylls and ester forms were also transferred.

Conclusion

The results are consistent with observations in other in vitro digestion models and human studies and support the usefulness of in vitro assessment to study food-related determinants of the bioavailability of carotenoids and tocopherols from fruits and vegetables.     

Preliminary evaluation of organosolv pre-treatment of sugar cane bagasse for glucose production: Application of 2 experimental design

Sugar cane bagasse was submitted to ethanol organosolv pre-treatment using a 50 L pilot scale reactor. The influence of catalyst type (H₂SO₄ or NaOH), catalyst concentration (1.25–1.50% w/w on dry fiber) and process time (60–90 min) on total solid recovery and solid composition (glucan, xylan and lignin contents) was evaluated by performing a 2³ full factorial experimental design. Pretreated sugar cane bagasse was further submitted to enzymatic hydrolysis using a commercial enzyme complex formed by cellulases and β-glucosidases. Glucose concentration in the hydrolysates and glucose yield referred to initial raw material (g glucose/100 g sugar cane bagasse) were used to select the best operational conditions. Concerning the enzymatic hydrolysis, the resulting glucose concentration was found to be dependent on xylan contents of the pretreated material. The modelling equations for glucose concentration and glucose yield as a function of the pre-treatment variables and the statistical analysis are also discussed in this work.     

Evaluation and Optimization of the Analysis of Fatty Acid Types in Edible Oils by 1H-NMR

In recent years, new different methods for the determination of fatty acid types (FAT) by nuclear magnetic resonance (NMR) have been developed. Although in general good results have been obtained, these methods employ long acquisition times and a wide variety of approaches and NMR parameters to resolve the FAT. For this reason, we have developed a NMR analysis optimization. This new method was used to evaluate the different ¹H-NMR methodologies against gas chromatography–flame ionization detection (GC-FID), considered as the reference method. We have applied our easy and quick methodology to the analysis of three different composition oils: sunflower, olive, and linseed oil. Using our optimized NMR methodology, it was possible to obtain in <1 min the FAT with the same accuracy and better reproducibility than by GC-FID. Furthermore, a complete ¹H-NMR spectrum assignation and evaluation of minor components allows obtaining extra information about the composition, quality, and conservation of the analyzed edible oils.     

Comparative performance of commercial polymeric membranes in the recovery of industrial hydrogen waste gas streams

The application of membrane separation processes to industrial hydrogen-rich waste gases promotes the efficient recovery of this clean fuel. The first step to address and overcome this waste of resources is to assess the real performance of commercially available polymeric membranes for hydrogen separation in terms of hydrogen purity that meets the quality standards to be used in hydrogen-based applications. Therefore, this work makes a comparison of the performance of commercial flat hydrogen-selective membranes based on non-porous polymeric materials through the experimental assessment in a lab-scale set up that contains a gas permeation cell with the aim of recovering hydrogen from the most suitable multicomponent waste gaseous streams. To assess the mixed-gas permeation performance, the influence of the feed gas composition, temperature and pressure was examined. The results of experimental tests indicated that there is a strong dependency of H₂ permeability on CO₂ concentration, that induces a decay of H₂/CO₂ selectivity in mixed-gas experiments for the membranes under study. Accordingly, the permeability-selectivity trade-off in the state-of-the-art membranes defines the balance between H₂ recovery and the product purity. Finally, it is worth noting that although H₂ purities obtained are higher than 98% vol. H₂ for APG and COG mixtures, which may indeed be used as a commodity chemical in many industrial processes, they are still far from fuel cell requirements.     

Wind farm grounding system design for transient currents

Wind turbines are often very high structures that are usually installed in high keraunic level areas. The keraunic level is the number of storm days per year. Therefore, wind farms are very vulnerable to lightning discharge. The damage due to a lightning strike can be reduced if the high current is quickly conducted to the ground.To date, wind turbine grounding system designs have been based on prior experience, without accurately studying transient grounding system behavior.In this work, typical wind farm grounding system geometries are analyzed in the context of lightning strikes.     

Lutein-enriched frankfurter-type products: Physicochemical characteristics and lutein in vitro bioaccessibility

This paper reports a study of the physicochemical characteristics of lutein-enriched frankfurter-type products with two fat levels, and the lutein in vitro bioaccessibility in these products. In general, the high-fat products possessed better emulsion stability and greater hardness and chewiness than low-fat samples. For each fat level, the addition of lutein extract in olive oil reduced emulsion stability in meat products. The presence of lutein reduced the lightness and increased the redness of samples. Lutein was highly stable upon in vitro digestion, with overall recovery of over 84% at the end of the duodenal phase and very low isomerisation. Micellarisation was high but depended on the fat content, ranging from 29–34% (for the low-fat sample) up to 73–81% of the amount initially present (for the high-fat sample). Storage (22 days at 4 °C) did not significantly affect lutein content or bioaccessibility. Our results support the suitability of meat products as lutein carriers and as a means to increase the systematic intake of lutein.     

Production of flavonoid and lignan aglycones from flaxseed and soy extracts by Bifidobacterium strains

Flaxseed and soybean are an important source of phytochemical compounds, mainly lignans and isoflavones, but also of flavones, flavanones and flavonols. These compounds appear mainly glycosylated in plant food and are converted into aglycones by the intestinal microbiota, increasing their bioavailability. In this work, we analyse the ability of Bifidobacterium strains (n = 25) to produce lignan and flavonoids aglycones from flaxseed and soybean extracts. Most of the Bifidobacterium strains increased the concentrations of secoisolariciresinol, daidzein, genistein, naringenin, eriodyctiol, luteolin and apigenin. Moreover, Bifidobacterium pseudocatenulatum and Bifidobacterium breve strains showed high production of herbacetin, increased the kaempferol concentration and produced quercetin and quercetagetin. B. pseudocatenulatum INIA P815 and B. breve INIA P367 produced 32.37 ± 2.81 and 28.64 ± 3.36 mg respectively of herbacetin g⁻¹ of lignan extract. Bifidobacterium strains transformed the glycosides of a wide range of flavonoids into their aglycones, increasing the antioxidant activity and improving their bioavailability.