Raffinose family of oligosaccharides from lupin seeds as prebiotics: application in dairy products

The raffinose family of oligosaccharides (RFOs) isolated from lupin seeds (Lupinus albus var. Multolupa) was evaluated for bifidogenic effects during the manufacture of probiotic fermented milk. A mixed starter inoculum was composed of Bifidobacterium lactis Bb-12 and Lactobacillus acidophilus (1:1). Lupins are a rich source of RFOs that can be used as functional food ingredients. The addition of RFOs to milk increased B. lactis Bb-12 and L. acidophilus populations at the final fermentation time compared with controls. Final fermentation products are positively affected by addition of RFOs, and time of fermentation was reduced from 12 to 10 h. When RFOs were added to milk, they were preferentially used as a carbon source (57.7%) compared with lactose (23.7%) at the end of fermentation. These results suggest that the eventual choice of B. lactis Bb-12 and L. acidophilus in a mixed culture at a 1:1 ratio and addition of RFOs to produce a fermented milk product would have the advantages of rapid growth and acidificationrate and would likely increase the probiotic effect of the final functional product.     

Experimental analysis of natural convection in open joint ventilated façades with 2D PIV

The main particularity of Open Joint Ventilated Facades (OJVF) is that they have an exterior opaque coating separated from the mass wall by a ventilated air cavity. The exterior coating material is arranged in slabs separated by open joints that enable exterior air to enter and leave the cavity all along the wall. Under radiation conditions (and negligible wind velocity) the natural thermal convection produces a chimney effect that forces external air to circulate along the air cavity at an unknown rate. As a consequence of this mass exchange through the openings, the heat transfer problem turns more complex: air motion and thermal field are strongly coupled and therefore highly dependent on geometric characteristics of the wall. This article reports the application of Particle Image Velocimetry technique (PIV) to measure the velocity field inside the air cavity of an OJVF model in laboratory conditions. Measurements were performed for the vertical central plane of the cavity, for three different heating conditions corresponding to Ra = 5.92 × 10⁸, Ra = 9.19 × 10⁸ and Ra = 1.35 × 10⁹, based in the channel height, and with a Re about 10⁴. Detailed information of the flow behaviour inside the air cavity are presented and discussed. Special attention is paid to the ventilation effect through the joints.     

High-added-value antioxidants obtained from the degradation of wine phenolics by Lactobacillus plantarum

Disposal of the waste from wine production has long been a problem for wineries, mainly because of the presence of phenolic compounds. In this study, we analyzed the antimicrobial activities of 10 wine phenolic compounds against Lactobacillus plantarum strains. Inhibition increased in this order: catechin = gallic acid < epicatechin = salicylic acid < methyl gallate = caffeic acid < ferulic acid = tryptophol < p-coumaric acid. The obtained results indicated that L. plantarum is able to grow in the presence of high concentrations of some wine phenolic compounds. Of the 10 compounds analyzed, only the hydroxycinnamic acids, gallic acid, and methyl gallate were metabolized by the four L. plantarum strains studied. Results also revealed that 4-vinylphenol and 4-vinylguaiacol are originated from p-coumaric and ferulic acids. These phenolic compounds are valuable intermediates in the biotechnological production of new fragrances. In addition, gallic acid and its ester, methyl gallate, are metabolized to produce the powerful antioxidant pyrogallol. Therefore, it might be possible to use L. plantarum strains to obtain high-added-value antioxidants from the degradation of phenolic compounds found in wine wastes.     

Inhibition of Listeria monocytogenes by enterocin EJ97 produced by Enterococcus faecalis EJ97

Enterocin EJ97 from Enterococcus faecalis EJ97 showed a concentration-dependent antimicrobial activity against Listeria monocytogenes CECT 4032. Activity of enterocin EJ97 against L. monocytogenes CECT 4032 increased slightly at 4 degrees C, and cold-adapted cells did not show any increased resistance. Sensitivity of L. monocytogenes CECT 4032 to enterocin EJ97 was not modified by the addition of sodium benzoate, sodium acetate, NaCl or sodium tripolyphosphate. Anti-listeria activity was enhanced by potassium nitrate, and especially by sodium nitrite at concentrations of 50 microg/ml or above. E. faecalis EJ97 produced bacteriocin activity during cocultivation with L. monocytogenes CECT 4032 at 37 degrees C and also at 15 degrees C, but not at 4 degrees C. Growth of L. monocytogenes CECT 4032 was inhibited by bacteriocin produced during cocultivation at 37 and 15 degrees C, and the degree of inhibition was influenced by the incubation temperature and the initial concentrations of enterococci and listeria. E. faecalis EJ97 also produced bacteriocin during cocultivation in half-skimmed milk, although its capacity to control L. monocytogenes was limited to populations of 10(3) CFU/ml or lower.     

Effect of enterocin EJ97 against Geobacillus stearothermophilus vegetative cells and endospores in canned foods and beverages

Geobacillus stearothermophilus is a thermophilic bacterium typically responsible for the flat-sour spoilage of low-acid canned food with high water activity. Control of vegetative cells and spores of G. stearothermophilus strains CECT 48 and CECT 49 by enterocin EJ97 produced by Enterococcus faecalis EJ97 is described. Both strains were highly sensitive to EJ97 in a culture medium. In samples from canned foods inoculated with a cocktail of vegetative cells or endospores of the two strains and stored at 45 °C for 30 days, viable cell counts were reduced below detection levels. The time course of microbial inactivation depended on the food sample and bacteriocin concentration. Dormant endospores were resistant to EJ97 short-time treatments (5 min), but endospores activated to germinate by heat became bacteriocin sensitive. The simultaneous application of enterocin EJ97 and heat treatments (90 and 95 °C) on dormant endospores had an increased antimicrobial effect that depended both on the bacteriocin concentration and the heat temperature. Results from this study strengthen the potential of enterocin EJ97 for biopreservation against G. stearothermophilus in canned vegetable foods and drinks.     

Short communication: Technological and seasonal variations of vitamin D and other nutritional components in donkey milk

Vitamin D is an essential nutrient that plays a crucial role in calcium homeostasis and bone metabolism and also acts as a hormone. Although several studies on the content of vitamin D in bovine milk have been conducted, little information is available regarding donkey milk. In the context of the nutritional assessment of donkey milk, the aim of this study was to assess the vitamin D content in donkey milk and its chemical profile, with particular reference to seasonal and technological modifications after pasteurization. The study was conducted on a dairy farm that produces donkey milk for human consumption located in central Italy. At sampling time, an aliquot of total bulk milk production was sampled before and after pasteurization (63°C for 30 min without homogenization) with a total of 20 raw and 20 pasteurized milk samples. The samples were collected for 10 mo, every 15 d, from May to February 2017. All the samples were analyzed for the chemical composition and vitamin D₂ and D₃ content by HPLC after saponification. The donkey milk analyzed showed a higher average vitamin D content (raw milk: vitamin D₂ = 1.68, vitamin D₃ = 0.60 μg/100 mL; pasteurized milk: vitamin D₂ = 1.38, vitamin D₃ = 0.30 μg/100 mL) than reported for bovine and human milk. The results of the effect of pasteurization on milk did not highlight significant differences in the total content of vitamin D. However, vitamin D₃ has a poor thermal stability, which led to a significant reduction in content in pasteurized milk compared with raw milk. The total vitamin D content of donkey milk did not show significant variations between seasons; however, a higher concentration of vitamin D₃ was found in spring and summer. In conclusion, raw and pasteurized donkey milk showed a high content of vitamin D, which could be useful in meeting the deficiencies of this vitamin in humans. Further investigations are needed to improve the vitamin D content in donkey milk by increasing its endogenous synthesis or its transfer in milk and to clarify other variability factors.     

VIP/VPAC Axis Expression in Immune-Mediated Inflammatory Disorders: Associated miRNA Signatures

Few studies have considered immune-mediated inflammatory disorders (IMID) together, which is necessary to adequately understand them given they share common mechanisms. Our goal was to investigate the expression of vasoactive intestinal peptide (VIP) and its receptors VPAC1 and VPAC2 in selected IMID, analyze the effect of biological therapies on them, and identify miRNA signatures associated with their expression. Serum VIP levels and mRNA of VPAC and miRNA expression in peripheral blood mononuclear cells were analyzed from 52 patients with psoriasis, rheumatoid arthritis, Graves’ disease, or spondyloarthritis and from 38 healthy subjects. IMID patients showed higher levels of VIP and increased expression of VPAC2 compared to controls (p < 0.0001 and p < 0.0192, respectively). Receiver operating characteristic curve analysis showed that the levels of VIP or VPAC2 expression were adequate discriminators capable of identifying IMID. Treatment of IMID patients with anti-TNFα and anti-IL12/23 significantly affected serum VIP levels. We identified miRNA signatures associated with levels of serum VIP and VPAC2 expression, which correlated with IMID diagnosis of the patients. The results indicate that the expression of VIP/VPAC2 is able of identify IMIDs and open up a line of research based on the association between the VIP/VPAC axis and miRNA signatures in immune-mediated diseases.