Evaluation of a Microwave-Assisted Extraction Method for Lignan Quantification in Flaxseed Cultivars and Selected Oil Seeds

An optimized microwave-assisted extraction (MAE) method was evaluated through repeatability, recovery and efficiency testing. The repeatability tests, performed by three users over time, were not significantly different. The recovery of lignan throughout the extraction, preparation and analysis steps is 97.5% with a coefficient of variation <1%. The MAE method is efficient for extracting lignans from the plant matrix, and it achieves significantly higher extraction yields than the two established reference methods. The applicability of the MAE method was demonstrated by extracting lignans from a variety of plant samples. The secoisolariciresinol diglucoside (SDG) content of seven flaxseed cultivars grown in Saint-Mathieu-de-Beloeil, QC, in 2009 ranged from 14.6 to 18.9 mg SDG per gram of seed. Flax hulls produced in Winchester, ON, in 2010 were very rich in lignan; their SDG content was 40.0 mg/g of flax hull. Sesame seeds contained 0.18–1.89 mg SECO (aglycone of SDG) per gram of seed, with significant differences among black, white and brown sesame seed. Chia seeds contained 0.99–1.29 mg SECO per gram of seed, with significant differences among batches of seeds. Sunflower seeds had 0.046 mg SECO per gram of sample and almonds had 0.029 mg SDG per gram of sample. The optimized and evaluated MAE method is recommended for the general analytical quantification of lignans in plant samples.     

Typing of Lactobacillus sanfranciscensis isolates from traditional sourdoughs by combining conventional and multiplex RAPD-PCR profiles

In the present work, a rapid and reproducible molecular method, based on the combination of conventional and multiplex RAPD-PCR reactions, was developed for typing Lactobacillus sanfranciscensis isolates from traditional sourdoughs. At first, four random primers, two used singly and two combined with the primer RD1, were chosen on the basis of their differentiating capability and reproducibility. The four resulting profiles for each isolate were integrated into a unique profile to be statistically treated by cluster analysis. The method was validated on 58 L. sanfranciscensis isolates coming from three traditional Italian sourdoughs. This new RAPD method was useful for determining the genomic diversity within the L. sanfranciscensis species. In particular, the intraspecific diversity of this species seemed to be related to the sourdough origin.     

Functional Properties of Lactic Acid Bacteria Isolated from Romanian Fermented Vegetables

A total of 139 lactic acid bacterium (LAB) strains isolated from Romanian traditionally fermented vegetables were screened for the ability to produce exopolysaccharides and for their antagonistic activity against a set of nine LAB strains, three Bacillus strains, and four Gram-negative bacteria. Eighty-five of the tested strains showed a variable antimicrobial activity against Listeria monocytogenes ATCC 1911, 35 of the strains showed a limited inhibition zone against Escherichia coli ATCC25922, and 26 strains against Salmonella enterica ATCC 14024, while 19 strains showed inhibition against one or all three Bacillus strains used as indicators. None of the tested strains showed an antimicrobial activity against Staphylococcus aureus ATCC 25923. Several strains showed antibacterial activity against more than one indicator strain. For instance, Lactobacillus plantarum 307, Lactobacillus brevis 308, and Lactobacillus plantarum/pentosus 358 were active against five of the indicator strains used, while other 23 LAB were active against three indicator strains. In the case of two strains, namely Leuconostoc citreum 344 and Lactobacillus brevis 183, the activity was maintained after neutralizing the pH of the cell-free supernatant likely due to the production of bacteriocins. The gel permeation chromatography-based screening revealed seven EPS-producing LAB strains. Two of the positive strains, namely Leuconostoc citreum 177 and Leuconostoc citreum 52, have been shown to produce large amounts of EPS, of about 20 g/L. All isolated EPS have a high molecular mass, of above 1400 KDa, and a monomer composition dominated by the presence of glucose.     

Novel Data on the Polyphenol Composition of Italian Ancient Apple Cultivars

The pulp polyphenol composition of some Italian ancient apple cultivars, Dominici, Giachetta, Grigia di Torriana, Pom d'Aram, Ronzè, and Ros Borsetta, was studied in comparison with a Golden Delicious commercial variety, over a three-year period. Polyphenols were analyzed by liquid chromatography coupled with diode array and mass spectrometer detectors. The results showed that ancient varieties, such as Grigia di Torriana, Ros Borsetta, and Giachetta, constitute good sources of polyphenols, even without the peel. It was demonstrated that some representative apple phenolics, such as chlorogenic acid and phloridzin, were clearly affected by the harvesting year, whereas others, such as catechins and procyanidins, did not.     

Characterization of melanoidins from a glucose-glycine model system

The properties of melanoidins prepared from glucose and glycine (GG) were investigated by a three step purification protocol consisting of dialysis, gel filtration at high ionic strength and ion metal affinity chromatography. The high molecular weight fraction obtained in the GG system is responsible for 80% of the total brown colour and its antioxidative ability was about 1/4 of that of Trolox measured by the inhibition of linoleic acid oxidation. GG melanoidins have good affinity towards Cu (II) (32% bound to the resin) while it is much lower towards Pb (II) (10%) and Fe (II) (5%). Capillary zone electrophoresis analysis suggests that GG melanoidins are positively charged, although no signal was observed analysing melanoidins by matrix-assisted laser desorption-ionisation time-of-flight mass spectrometry (MALDI-TOF/MS).     

Carotenoids from tomatoes inhibit heterocyclic amine formation

Tomatoes are a rich source of antioxidants and they are commonly used for meat cooking in Mediterranean countries. The effects of tomato antioxidants on the formation of carcinogenic/mutagenic heterocyclic amines were investigated. A liquid model system containing as precursors creatinine, glucose and glycine in molar concentrations comparable to those present in bovine meat (chemical model system) was employed. A freeze-dried bovine meat juice (meat juice model system) was also used for some experiments. In both model systems, an inhibiting effect of tomato carotenoid fraction on the formation of imidazoquinolines (IQx, MeIQx and DiMeIQx) was observed. Using carotenoid extract at a concentration of 1000 ppm, inhibitions of 36% and 11% of IQx and MeIQx formation respectively in the chemical system and of 13% of MeIQx and of 5% of 4,8-DiMeIQx in the meat juice system was observed. The effect of the main tomato flavonoid, quercetin, was investigated using the meat juice system. Quercetin gave an inhibition of MeIQx formation between 9% and 57% with a maximum effect of 67% at 10 ppm.     

Juice of New citrus hybrids (Citrus clementina Hort. ex Tan.×C. sinensis L. Osbeck) as a source of natural antioxidants

Fruit juices of pigmented and non-pigmented new citrus hybrids obtained by crossing clementine cv. Oroval with different cultivars of blood oranges were analysed to determine parameters related to fruit quality (total soluble solids titratable acidity, pH), and the content of ascorbic acid, total phenolics, flavanones, anthocyanins and phenolic acids. Antioxidant properties were evaluated by oxygen radical absorbance capacity (ORAC), and inhibition of induced linoleic acid peroxidation (InLAP) assays. The results of this study show that some hybrids with high antioxidant activity owing to considerable polyphenol content may be considered rich sources of phytochemicals. The OTA 9 hybrid was shown to be richest in polyphenols, suggesting that consumption of OTA 9 fruit or juice could be useful in health promotion and a disease-preventing diet. Moreover, the juice of this hybrid could be used as raw material to produce antioxidant ingredients for dietary, pharmaceutical, or cosmetic purposes.     

Study of the effect of noble metal promotion in Ni-based catalyst for the Sabatier reaction

This paper reports the preparation and the evaluation of the performance of Ni-based powder catalysts with low nickel loading on the CO2 methanation reaction, that is an integral part of the power-to-gas (PtG) technology. CeO₂, CeZrO₄ and CeO₂/SiO₂ were selected as possible supports, and the results of this first screening pointed out that 10%Ni/CeO₂ catalyst could offer the best reaction performances because of ceria's peculiar characteristics. Moreover, the promotion of this promising formulation with the addition of a small amount of noble metals (Pt, Ru, Rh) was investigated, showing that platinum in particular can enhance the catalyst performances. A further study related to the noble metal loading pointed out that platinum and ruthenium have a different optimum loading condition: this result, together with the activity tests performed on monometallic formulations with only the noble metal, suggested that the two metals are able to catalyse two different reactions, thus promoting two different reaction mechanisms.     

Multifunctional Bioinstructive 3D Architectures to Modulate Cellular Behavior

Biological structures control cell behavior via physical, chemical, electrical, and mechanical cues. Approaches that allow us to build devices that mimic these cues in a combinatorial way are lacking due to there being no suitable instructive materials and limited manufacturing procedures. This challenge is addressed by developing a new conductive composite material, allowing for the fabrication of 3D biomimetic structures in a single manufacturing method based on two‐photon polymerization. The approach induces a combinatorial biostimulative input that can be tailored to a specific application. Development of the 3D architecture is performed with a chemically actuating photocurable acrylate previously identified for cardiomyocyte attachment. The material is made conductive by impregnation with multiwalled carbon nanotubes. The bioinstructive effect of 3D nano‐ and microtopography is combined with electrical stimulation, incorporating biochemical, and electromechanical cues to stimulate cells in serum‐free media. The manufactured architecture is combined with cardiomyocytes derived from human pluripotent stem cells. It is demonstrated that by mimicking biological occurring cues, cardiomyocyte behavior can be modulated. This represents a step change in the ability to manufacture 3D multifunctional biomimetic modulatory architectures. This platform technology has implications in areas spanning regenerative medicine, tissue engineering to biosensing, and may lead to more accurate models for predicting toxicity.     

SN-38 loading capacity of hydrophobic polymer blend nanoparticles: formulation,optimization and efficacy evaluation

One of the most important problems in nanoencapsulation of extremely hydrophobic drugs is poor drug loading due to rapid drug crystallization outside the polymer core. The effort to use nanoprecipitation, as a simple one-step procedure with good reproducibility and FDA approved polymers like Poly(lactic-co-glycolic acid) (PLGA) and Polycaprolactone (PCL), will only potentiate this issue. Considering that drug loading is one of the key defining characteristics, in this study we attempted to examine whether the nanoparticle (NP) core composed of two hydrophobic polymers will provide increased drug loading for 7-Ethyl-10-hydroxy-camptothecin (SN-38), relative to NPs prepared using individual polymers. D-optimal design was applied to optimize PLGA/PCL ratio in the polymer blend and the mode of addition of the amphiphilic copolymer Lutrol^®F127 in order to maximize SN-38 loading and obtain NPs with acceptable size for passive tumor targeting. Drug/polymer and polymer/polymer interaction analysis pointed to high degree of compatibility and miscibility among both hydrophobic polymers, providing core configuration with higher drug loading capacity. Toxicity studies outlined the biocompatibility of the blank NPs. Increased in vitro efficacy of drug-loaded NPs compared to the free drug was confirmed by growth inhibition studies using SW-480 cell line. Additionally, the optimized NP formulation showed very promising blood circulation profile with elimination half-time of 7.4?h.