Microbiological,immunological, and histological changes in the gut of Salmonella Enteritidis-challenged rats fed goat cheese containing Lactobacillus rhamnosus EM1107

Cheeses are able to serve as suitable matrices for supplying probiotics to consumers, enabling appropriate conditions for bacteria to survive gastric transit and reach the gut, where they are assumed to promote beneficial processes. The present study aimed to evaluate the microbiological, immunological, and histological changes in the gut of Salmonella Enteritidis-challenged rats fed goat cheese supplemented with the probiotic strain Lactobacillus rhamnosus EM1107. Thirty male albino Wistar rats were randomly distributed into 5 experimental groups with 6 animals each: negative (NC) and positive (PtC) control groups, control goat cheese (CCh), goat cheese added with L. rhamnosus EM1107 (LrCh), and L. rhamnosus EM1107 only (EM1107). All animals, except NC group were challenged with Salmonella Enteritidis (10⁹ cfu in 1 mL of saline through oral gavage). Microbial composition was assessed with high-throughput 16S rRNA sequencing by means of Illumina MiSeq (Illumina, San Diego, CA). Nuclear factor kappa B (NF-κB) from the animal cecum tissue was determined by real-time PCR and interleukins (TNF-α, IL-1β, IL-10, and IFN-γ) by means of ELISA. Myeloperoxidase and malondialdehyde levels were determined biochemically. The administration of the L. rhamnosus EM1107 probiotic strain, either as a pure culture or added to a cheese matrix, was able to reduce Salmonella colonization in the intestinal lumen and lessen tissue damage compared with rats from PtC group. In addition, the use of cheese for the probiotic strain delivery (LrCh) was associated with a marked shift in the gut microbiota composition toward the increase of beneficial organisms such as Blautia and Lactobacillus and a reduction in NF-κB expression. These findings support our hypothesis that cheeses might be explored as functional matrices for the efficacious delivery of probiotic strains to consumers.     

Aromatic-imide-based TADF material as emitter for efficient yellow and white organic light-emitting diodes

An aromatic-imide based TADF emitter (AI-4Cz) was designed and synthesized. The TADF emitter showed high thermal stability, good electrochemical properties, obvious AIE activity, small ΔE_ST value of 0.02 eV, and intense yellow emissions with PLQY of 76%. AI-4Cz also exhibited obvious microsecond-scale delayed fluorescence lifetime. Yellow OLED based on AI-4Cz was further fabricated, which achieved EQE_max of 16.7%. Moreover, a white OLED was fabricated through the dual emission layer strategy by using AI-4Cz and DMAC-DPS as emitting dopants, and the device obtained CIE coordinates of (0.30, 0.40), CRI value of 66, and an EQE_max of 13.6%.     

A century of gray: A genomic locus found in 2 distinct Pseudomonas spp. is associated with historical and contemporary color defects in dairy products worldwide

Some gram-negative bacteria, including Pseudomonas spp., can grow at refrigeration temperatures and cause flavor, odor, and texture defects in fluid milk. Historical and modern cases exist of gray and blue color defects in fluid milk due to Pseudomonas, and several recent reports have detailed fresh cheese spoilage associated with blue-pigment-forming Pseudomonas. Our goal was to investigate the genomes of pigmented Pseudomonas isolates responsible for historical and modern pigmented spoilage of dairy products in the United States to determine the genetic basis of pigment-forming phenotypes. We performed whole genome sequencing of 9 Pseudomonas isolates: 3 from recent incidents of gray-pigmented fluid milk (Pseudomonas fluorescens group), 1 from blue-pigmented cheese (P. fluorescens group), 2 from a historical blue milk spoilage incident (Pseudomonas putida group), and 3 with no evidence for blue or gray pigment formation (2 from P. fluorescens group and 1 from Pseudomonas chlororaphis group). All 6 isolates collected from products with a gray or blue pigment defect were confirmed to produce pigment using potato dextrose agar or pasteurized milk. A subset of 2 isolates was selected for inoculation into milk and onto the surface of a model cheese for subsequent color measurement. These isolates produced different colors on potato dextrose agar, but produced nearly identical color defects in milk and on model cheese. For the same subset of 2 isolates, the gray color defect in milk was produced only in containers with ample headspace and not in full containers, suggesting that oxygen is vital for pigment formation. This work also demonstrated that a Pseudomonas isolate from cheese can produce a pigment defect in milk, and vice versa. Comparative genomics identified an accessory locus encoding tryptophan biosynthesis genes that was present in all isolates that produced gray or blue pigment under laboratory conditions and was only previously reported in 2 P. fluorescens isolates responsible for blue mozzarella in Italy. Because this locus was found in genetically distant isolates belonging to different Pseudomonas species groups, it may have been acquired via horizontal gene transfer. These data suggest that several past and present gray- or blue-pigmented dairy spoilage events share a common genetic etiology that transcends species-level identification and merits further investigation to determine mechanistic details and modes of prevention.     

The role played by dopant ions for the production of broadband white light emission from metal oxide nano-powders under laser diode excitation

We report on the role played by dopant ions to create broadband white light emission from metal oxide nano-powders. Y₂O₃ was doped with different rare earth ions (Nd³⁺, Er³⁺, Yb³⁺) and Cr³⁺ ion to investigate their role on the production of white light emission. We have determined that the dopant ions have a facilitator but not a decisive role on the production of the white light emission by doing measurements such as reflectance, white light emission, excitation power dependency and color quality parameters. All measurements showed that the production of white light does not depend on the amount and the type of the dopant ions.     

Viscoelasticity and texture of spreadable cheeses with different fat contents at refrigeration and room temperatures

The effect of the 2 common consumption temperatures, refrigeration temperature (10°C) and room temperature (22°C), on the viscoelasticity, mechanical properties, and perceived texture of commercial cream cheeses was studied. Two samples with different fat contents, regular and low fat, from each of 4 selected commercial brands were analyzed. The selection criteria were based on identification of brands with different percentages of fat content reduction between the regular- and low-fat samples (35, 50, 84, and 98.5%). The fat content of regular-fat samples ranged from 19.8 to 26.0% (wt/wt), and that of low-fat samples ranged from 0.3 to 13.0% (wt/wt). Viscoelasticity was measured in a controlled-stress rheometer using parallel-plate geometry, and the mechanical characteristics of samples were measured using the spreadability test. Differences in the intensity of thickness, creaminess, and roughness between the regular- and low-fat samples of each commercial brand were evaluated at each of the selected temperatures by using the paired comparisons test. At 10°C, all samples showed higher viscoelastic modulus values, firmness, and stickiness, and lower spreadability than when they were measured at 22°C. Differences in viscoelasticity and mechanical properties between each pair of samples of the same brand were greater at 10°C than at 22°C because of the influence not only of fat content but also of fat state. Ingestion temperature did not modify the sensory differences detected between each pair of samples in terms of creaminess and roughness, but it did modify the differences detected in thickness. The joint consideration of sample composition, fat state, and product behavior during oral processing could explain the differences detected in thickness perceived because of measurement temperatures.     

Going from green to white color electroluminescence through a nanoscale complex of Zinc (II)

In this paper, we report application of four novel Nano Zinc (II) complexes as the emitter dyes in organic light emitting diodes (OLEDs). The Nano Zinc (II) complexes emission, particularly its absorption, fluorescence spectra and quantum yield, tuned by varying sizes which affects environments of the Zinc (II) ion. OLED Devices with Nano Zinc (II) complexes were fabricated, giving rise to devices with peak emission ranging from 498 to 541 nm. Here, we have successfully employed sonoelectrochemical method for fabricating white OLEDs. The white emission ascribed to the exciton emission in Nano Zinc (II) complex emitter and from exciplex formation at the interface of PVK/Nano Zinc (II) complex. The experimental results demonstrate that this approach is ideal for color tuning of single and multilayer conducting semiconducting thin films used in the fabrication of organic electronic devices such as OLEDs.     

The kinetic and thermodynamic analysis of ultrasound-extraction of minerals from aerial parts of white lady's bedstraw (Galium mollugo L.)

The present paper deals with the extraction of some minerals (potassium, calcium and magnesium) from ground, dried aerial parts of white lady's bedstraw (Galium mollugo L.) using an aqueous ethanol solution (50% by volume) at different temperatures (from 23 to 40 °C) in the presence and absence of ultrasound. The main goal was to establish the kinetics and the thermodynamics of the two extraction processes. A phenomenological model involving simultaneous washing and diffusion was proved for both ultrasound-assisted and silent extraction of the minerals. The minerals extraction both in the presence and the absence of ultrasound is endothermic and irreversible since the enthalpy change and the entropy change are positive in the ranges of extraction temperature applied. The Gibbs free energy change for the extraction of minerals is negative, indicating that the process is feasible and spontaneous. The minerals yield increased by a factor of 1.02–1.06 and 1.14–1.27 in the absence and the presence of ultrasound, respectively for every 10 °C rise in temperature.     

The effect of probiotics (Lactobacillus rhamnosus HN001, Lactobacillus paracasei LPC-37, and Lactobacillus acidophilus NCFM) on the availability of minerals from Dutch-type cheese

The use of probiotic cultures in the production of Dutch-type cheeses did not lead to significant changes in their chemical composition but it lowered their acidity. The availability of calcium and magnesium analyzed by in vitro enzymatic hydrolysis was 19 and 35%, respectively; the availability of phosphorus was significantly higher, at >90%. The use of probiotic cultures significantly increased the availability of calcium (~2.5%), phosphorus (~6%), and magnesium (~18%). The in vitro method supports accurate determination of the effect of the Lactobacillus spp. cultures on the availability of mineral compounds ingested with Dutch-type cheese.     

Near-infrared spectroscopy to assist authentication and labeling of Asiago d’allevo cheese

This study investigated the possibility of using near-infrared spectroscopy (NIRS) for the authentication of Asiago d’allevo, a protected designation of origin cheese from northern Italy. Latent variable models applied on spectral data were developed and used to estimate several chemical properties and to classify the available dataset according to the location and management of the cheesemaking factory (lowland and alpine), the ripening age (6, 12, 18 and 36 months), the altitude of milk production (low, medium, medium–high and high), and the period of the year of the cheese production (May, July and September). The variable importance in projection index was used to identify the most informative spectral regions for discrimination. Results showed that NIR spectra can be used both to accurately estimate several chemical properties and to classify the samples according to the different experimental conditions under investigation with the same discrimination capacity provided by traditional chemical analysis.