Nutritional composition and bioactive properties of commonly consumed wild greens: Potential sources for new trends in modern diets

Beyond the composition of the usual macronutrients and micronutrients, it is important to provide information on the composition of bioactive compounds and antioxidant capacity of foods, particularly of wild species to regain them for nowadays' dietary habits. Many greens are known as excellent sources of natural antioxidants, and consumption of fresh plants in the diet may contribute to the daily antioxidant intake. In the present study five leafy wild greens traditionally consumed (Borago officinalis, Montia fontana, Rorippa nasturtium-aquaticum, Rumex acetosella, Rumex induratus) were studied in order to document macronutrient, micronutrient and non-nutrient composition. R. induratus revealed the highest levels of sugars, ascorbic acid, tocopherols, lycopene, chlorophylls, flavonoids, and one of the highest antioxidant activity expressed as DPPH scavenging activity, β-carotene bleaching inhibition, and TBARS formation inhibition. R. nasturtium-aquaticum showed the healthier PUFA/SFA and n-6/n-3 ratios, and B. officinalis proved to be a source of γ-linolenic acid and other fatty acids from n-6 series that are precursors of mediators of the inflammatory response. The nutritional characteristics and antioxidant potential of these wild greens require reconsideration of their role in traditional as well as in contemporary diets. Furthermore, their extracts might find applications in the prevention of free radical-related diseases, as functional food formulations.     

Legumes reduced intestinal fat deposition in the Caenorhabditis elegans model system

Wild type Caenorhabditis elegans (C. elegans) were fed with powdered legumes (1%, w/v): light red kidney, black, navy, white kidney, cranberry, great northern, lentil, lima, or dark red kidney (20%, 33% and 50% of a 1% suspension). Lipophilic fluorescent Nile red dye-stained intestinal fat deposition (IFD) indicated an IFD reduction by legumes in a descending order: light red kidney, black, navy, white kidney, cranberry, great northern, lentil, lima, or dark red kidney. Increased pharyngeal pumping rate (PPR), a surrogate marker of aging, was observed in all legumes at 50% dosage. Both inverse and direct relationships between IFD and PPR were detected in the wild type C. elegans in this study. These results suggested that whole legumes may promote health through regulation of lipid metabolism and lifespan in the model system C. elegans, which enhances our understanding of the effect of legumes and suggests further legumes study in human health.     

Effect of natural and synthetic antioxidants incorporation on the gas permeation properties of poly(lactic acid) films

Gas permeation properties (permeability, diffusivity and solubility coefficients) were determined for carbon dioxide and oxygen in poly(lactic acid) (PLA) films enriched with 0, 2, 4 and 10 wt.% of different antioxidants, at three temperatures, 284, 293 and 303 K, using a time-lag apparatus. Three antioxidants, a natural, α-tocopherol (AT), and two synthetic, butylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ), were tested. DSC results show that the polymer glass transition temperature slightly decreases with the increase of the antioxidant content. The crystallinity degree of PLA films decreases with the addition of BHT and TBHQ, whereas the incorporation of AT increases the crystallinity of PLA films. The permeability towards water vapour, at 299 K and 45% of relative humidity, and surface energy show a decreased in the wettability of the prepared materials with the increase of the antioxidants content. The incapacity to measure gas permeation in PLA films with 10 wt.% of AT and BHT incorporated was due to phase separation, proved by SEM images. The CO₂ and O₂ permeation results show that PLA barrier properties can be improved by the incorporation of antioxidants but are strongly dependent on the amount and structure of the antioxidant added.     

A bacteriocin-like substance produced from Lactobacillus pentosus 39 is a natural antagonist for the control of Aeromonas hydrophila and Listeria monocytogenes in fresh salmon fillets

We studied the ability of Lactobacillus pentosus 39, a BLS (Bacteriocin-like substance)-producing strain, to control the growth of Aeromonas hydrophila ATCC 14715 and Listeria monocytogenes ATCC 19117 artificially added to fresh salmon fillets at refrigeration temperatures and under simulated cold-chain break conditions.At refrigeration temperatures, Lb. pentosus 39 protective culture and its putative bacteriocin significantly reduced A. hydrophila counts compared with the control (2.1 and 1.4 log CFU/g reductions, respectively). Similar behaviour was observed for L. monocytogenes (3.6 and 1.3 log CFU/g reductions, respectively).Under simulated cold-chain break conditions, an increase in temperature (30°C for 12h) produced an evident increase in the development of A. hydrophila, L. monocytogenes, but also of Lb. pentosus 39, with a consequent increase in BLS production. This condition resulted in a greater reduction of both pathogens compared with samples stored at 4°C throughout the experiment (2.8 log CFU/g reduction for A. hydrophila, 5.8 log CFU/g reduction for L. monocytogenes). In samples treated with the putative bacteriocin alone, a less marked decrease was observed.Our study demonstrates the capability of Lb. pentosus 39 to control the growth of psychrotrophic bacteria in an experimental seafood model system. A similar biopreservation technology could provide more prolonged shelf-life during storage of ready-to-eat seafood, ensuring safety, even under extreme conditions.     

Analytical Tools Used to Distinguish Chemical Profiles of Plants Widely Consumed as Infusions and Dietary Supplements: Artichoke,Milk Thistle,and Borututu

Artichoke, borututu, and milk thistle are three medicinal plants widely consumed as infusions or included in dietary supplements (e.g., pills and syrups). Despite the high consumption of these plants, studies on their nutritional value and primary metabolites are scarce, with their composition in secondary metabolites such as phenolic compounds being only reported. Therefore, their nutritional value was assessed, and analytical tools (liquid and gas chromatography coupled to different detectors) were used to distinguish their chemical profiles according to their hydrophilic (sugars and organic acids) and lipophilic (fatty acids and tocopherols) components. Chromatographic techniques are important analytical tools used in the identification and quantification of several molecules, also being a standard requirement to distinguish different profiles. Borututu gave the highest energetic value with the highest content of carbohydrates and fat, sucrose and total sugars, shikimic and citric acids, and α-, β-, δ-, and total tocopherols. Artichoke had the highest ash and protein contents, oxalic acid, SFA (mainly palmitic acid), and γ-tocopherol, and also the best n-6/n-3 ratio. Milk thistle showed the highest levels of fructose and glucose, quinic acid and total organic acids, and PUFA, mainly linoleic acid, and the best PUFA/SFA ratio. The hydrophilic compounds identified in the studied plants, mostly sugars, are responsible for the energy contribution of their widely consumed infusions. Otherwise, the bioactivity of lipophilic compounds, namely, unsaturated fatty acids and tocopherols, is lost in those preparations but can be recovered in dietary supplements based on the plants. As far as we know, this is the first report on the detailed composition of the three plants regarding their nutritional features.     

Isolation and molecular characterization of antibiotic-resistant lactic acid bacteria from poultry and swine meat products

The transfer via the food chain from animals to humans of microbes that are resistant to antimicrobial agents is of increasing concern. To determine the contributions of nonpathogenic microflora to the occurrence and spread of antibiotic resistance (AR) genes in the food chain, 123 lactic acid bacteria were isolated from 29 samples of raw and processed pork and chicken meat products that had previously tested positive for one or more AR genes that encode clinically relevant ARs: tet(M), tet(O), tet(K), erm(A), erm(B), erm(C), aac (6')-Ie aph (2")-Ia, mecA, and blaZ. All of the isolates were initially tested for their AR gene profiles by PCR. The 59 isolates carrying a tet, erm, or blaZ gene were taken through molecular identification, analyzed by determination of the MIC, and subjected to genetic fingerprinting. Lactococcus garvieae was the predominant species (28 isolates), followed by Lactobacillus plantarum (11 isolates) and L. salivarius (6 isolates), whereas Lactococcus lactis subsp. lactis, Lactobacillus johnsonii, L. reuteri, L. crispatus, and L. brevis were identified at lower frequencies. The tet(M) and erm(B) genes were the most frequently detected. Assessment of multiple resistances in 18 tet positive (tet+) isolates revealed that tet(M) plus erm(B) and tet(K) plus erm(B) were the most frequent AR gene patterns. Partial sequencing of the tet(M) open reading frame of three selected strains showed high sequence similarities (> 99%) with tet(M) genes previously found in human pathogens (Listeria monocytogenes and Neisseria meningitidis). Southern hybridization with plasmid profiles revealed these strains contained tet(M)-carrying plasmids.