Preliminary study on microbeads production by co-extrusion technology

AbstractThe present paper describes preliminary results on the development of a batch lab-scale co-extrusion device for the production of alginate beads as carrier for hydrophilic compounds. A dual jet of liquid core (aqueous solution of glucose or vitamin B12 or olive oil) and liquid shell material (aqueous solution of alginates differing for guluronic to mannuronic ratio) was pumped through concentric extrusion nozzles and droplets were formed by means of a rotating fluid jet cutter. The shell of the bead was then hardened in the hardening bath containing a calcium chloride solution. Optimization of the co-extrusion plant accounts for the management of the operative conditions within the hardening unit (incubation time, molarity of the gelling agent), and for the control of the surface-tension-driven breakup of laminar jets which was managed by varying the jet cutter - hardening unit distance. Beads enriched in vitamin B12, that were formed according to the best plant set-up, were tested for the bioactive release when stressed under thermal conditions simulating typical dairy products processes. Cyanocobalamin was retained at all

AN ENGINEERING APPROACH TO DESIGN FOOD STRUCTURES FOR THE DELIVERY OF TARGETED FUNCTIONALITY: APPLICATION TO BIOACTIVES ENCAPSULATION

The food industry is constantly challenged to meet consumer demands for new food products that are safe, convenient, affordable, pleasurable and healthy. An understanding of fundamental structure and function relationships of food components is a key to stimulate and accelerate the development of innovative, complex and highly structured products and suitable production processes. The goal of the Thesis is the design of health supporting food functions with development of food structure/health benefits relationships based on fundamental soft material concepts. New capsules for bioactive controlled release to be used as ingredient for new formulated foods have been designed and developed. Food material science, engineering process and soft matter\u2019s basic principles are here linked to deliver new real products that could improve health and well-being. A first step of our research, described in chapter 1, was focused on the selection of the most appropriate shell material to be used in capsules manufacturing. A number of studies were performed regarding the gelation kinetics and the rheological properties of alginate, a natural biopolymer having unique properties that have enabled it to be used as a matrix for the entrapment and/or delivery of a variety of biological agents. The kinetics of alginate gelation has been investigated by means of photon correlation imaging (collaboration with POLIMI) and large deformation rheology. Our results showed that the alginate gelling kinetics displays a peculiar non-diffusive behavior, and the subsequent restructuring of the gel structure shares several features in common with the aging of colloidal gels, in particular for what concerns the occurrence of heterogeneous dynamics effects. A comparative analysis of the gel macroscopic mechanical properties at different aging stages further highlights distinctive effects arising from the non-permanent nature of the bonds. In addition to the selection of an appropriate shell material, the challenges in developing commercially viable microcapsules rely on the selection of the most appropriate process to provide the desired morphology and stability. Thus a second step of our work, described in chapter 2 of the thesis, was focused on the realization of a batch coaxial encapsulation unit on lab scale for the production of alginate microbeads. A dual jet of liquid core and liquid shell material was pumped through concentric extrusion nozzles and droplets were formed by jet cutting technology. The shell of the bead was then hardened in a cross-linking solution. After process optimization, microcapsules containing a liquid core of bioactive with a narrow size distribution and mean diameter of 0.73\ub10.03 mm were produced. As third step (see chapter 3), different types of microcapsules were produced and tested for engineered release of bioactive. Alginate microspheres containing a liquid core of cyanocobalamin, in presence or not of a double coating polymer, were tested for vitamin release under simulated intestinal peristaltic flow conditions of the lumen content. The small intestine model, designed and implemented at the University of Birmingham, mimics the peristaltic flow patterns by means of a pneumatic mechanism that reproduces the characteristic segmentation movements responsible for the flow and mixing. Diffusional experiment showed a good retention of the carried vitamin under simulated intestinal condition, and an overall mass transfer was calculated. Diffusivity seems to be directly related to the wall material solubility. Microbeads containing a modified luminescent Bifidobacterium longum were also efficiently used to protect bacteria\u2019s vitality under simulated gastric condition. While designing a functional ingredient, a prerequisite is that it could accomplish a specific function whilst being palatable enough to be eaten. The engineering of these properties is necessary and extremely challenging and clearly can be obtained at multiple length scales. Thus, the last research topic faced in this thesis and here reported in chapter 4 was aimed to increase knowledge on the influence of size-scale of the structures designed for bioactive release. In particular the investigation, developed in collaboration with the Food and Soft Material Group at ETH of Zurich, focused on exploring the potential of using a physical inspired (solvent shifting) production process of biopolymer-based nanoparticles. Specifically, we clearly demonstrated the possibility to produce nanospheres with a diameter as much as small as 20 nanometers without using any kind of mixing energy. Nanoparticles were studied by using advanced optical techniques, such as dynamic light scattering and depolarized dynamic light scattering, and finally used in preliminary experiments to increase the stability of a spontaneous food emulsion. A main deliverable of this thesis is a contribution in increasing knowledge on the influence of structure and physical properties of food materials on the nutritional and health inducing properties, an essential step which is needed in the studies of bio-physical and gastro intestinal engineering aspects of nutrient absorption. An innovative approach has been followed that explores the relationship: material properties-processing-destructurization behavior in the gut, aimed to food properties generation, preservation and delivery. It relies on the concepts of multiscale structure dynamics and on biophysics-driven strategies for structure design

Biopolymer gels with "physical" cross-links: gelation kinetics, aging, heterogeneous dynamics, and macroscopic mechanical properties

Alginate is a natural biopolymer that forms, in the presence of divalent cations, ionic-bound gels typifying a large class of biological gels stabilized by non-covalent cross-links, and displaying a consistent restructuring kinetics. We investigate the kinetics of formation and aging of alginate gels by slow permeation of a curing CaCl2 agent by means of photon correlation imaging, a novel optical technique that allows obtaining the microscopic dynamics of the sample, while retaining at the same time the spatial resolution of imaging techniques. Specifically, the gelling kinetics displays a peculiar non-diffusive behavior, and the subsequent restructuring of the gel structure shares several features in common with the aging of colloidal gels, in particular for what concerns the occurrence of heterogeneous dynamics effects. A comparative analysis of the gel macroscopic mechanical properties at different aging stages further highlights distinctive effects arising from the non-permanent nature of the bonds

Bipartite quantum channels using multipartite cluster-type entangled coherent states

We propose a particular encoding for bipartite entangled states derived from multipartite cluster-type entangled coherent states (CTECSs). We investigate the effects of amplitude damping on the entanglement content of this bipartite state, as well as its usefulness as a quantum channel for teleportation. We find interesting relationships among the amplitude of the coherent states constituting the CTECSs, the number of subsystems forming the logical qubits (redundancy), and the extent to which amplitude damping affects the entanglement of the channel. For instance, in the sense of sudden death of entanglement, given a fixed value of the initial coherent state amplitude, the entanglement life span is shortened if redundancy is increased.Comment: 6 pages, 3 figures, REVTeX 4.1, BibTe

Multianalytical approach to characterize composition and degradation processes of synthetic high-fashion textiles from the Nanni Strada Design Studio archives

Synthetic textiles are constituents of heritage objects and garments often displayed in museum collections or preserved in archives, presenting unprecedented and specific conservation challenges. These issues need to be addressed assessing degradation processes, and developing targeted restoration and preventive conservation practices. The present work aims at characterizing the composition of high fashion garments and design textiles by Nanni Strada conserved in the archives of Nanni Strada Design Studio (Milan). To identify the chemical composition of the fibers used for the manufacturing, and to investigate the degradation processes affecting the objects, the materials were investigated by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Evolved Gas Analysis coupled to Mass Spectrometry (EGA-MS), and multi-shot Pyrolysis coupled to Gas Chromatography and Mass Spectrometry (Py-GC/MS). The results will contribute to a better knowledge of the chemical properties of the textiles produced in the 1970s, and to plan conservation and exhibition strategies

Cross-generational trans fat intake exacerbates UV radiation-induced damage in rat skin

AbstractWe evaluated the influence of dietary fats on ultraviolet radiation (UVR)-induced oxidative damage in skin of rats. Animals from two consecutive generations born of dams supplemented with fats during pregnancy and breastfeeding were maintained in the same supplementation: soybean-oil (SO, rich in n-6 FA, control group), fish-oil (FO, rich in n-3 FA) or hydrogenated-vegetable-fat (HVF, rich in TFA). At 90days of age, half the animals from the 2nd generation were exposed to UVR (0.25J/cm2) 3×/week for 12weeks. The FO group presented higher incorporation of n-3 FA in dorsal skin, while the HVF group incorporated TFA. Biochemical changes per se were observed in skin of the HVF group: greater generation of reactive oxygen species (ROS), lower mitochondrial integrity and increased Na+K+-ATPase activity. UVR exposure increased skin wrinkles scores and ROS generation and decreased mitochondrial integrity and reduced-glutathione levels in the HVF group. In FO, UVR exposure was associated with smaller skin thickness and reduced levels of protein–carbonyl, together with increased catalase activity and preserved Na+K+-ATPase function. In conclusion, while FO may be protective, trans fat may be harmful to skin health by making it more vulnerable to UVR injury and thus more prone to develop photoaging and skin cancer

Control of entanglement dynamics in a system of three coupled quantum oscillators

Sem informaçãoDynamical control of entanglement and its connection with the classical concept of instability is an intriguing matter which deserves accurate investigation for its important role in information processing, cryptography and quantum computing. Here we consider a tripartite quantum system made of three coupled quantum parametric oscillators in equilibrium with a common heat bath. The introduced parametrization consists of a pulse train with adjustable amplitude and duty cycle representing a more general case for the perturbation. From the experimental observation of the instability in the classical system we are able to predict the parameter values for which the entangled states exist. A different amount of entanglement and different onset times emerge when comparing two and three quantum oscillators. The system and the parametrization considered here open new perspectives for manipulating quantum features at high temperatures.718Sem informaçãoSem informaçãoSem informaçã

Ricerche sulla crioconservazione di embrioni di Lepidotteri: sviluppo embrionale e sopravvivenza a seguito di trattamenti con agenti crioprotettivi

L’applicazione delle tecniche di crioconservazione, già sviluppate per gli embrioni di mammiferi, alla conservazione del germoplasma di artropodi presenta difficoltà legate all’elevata sensibilità al congelamento degli embrioni e alla riduzione della permeabilità ai crioprotettivi dovuta alla presenza dei rivestimenti esterni delle uova ( corion e membrana vitellina). Obiettivo del presente lavoro è la definizione di protocolli di conservazione di uova di Lepidotteri, condotte utilizzando stadi embrionali diversi di due specie modello di rilevante importanza nei settori degli studi di base e delle ricerche di tipo applicato, Galleria mellonella L. e Bombyx mori L. Studi preliminari sull’embriologia di queste due specie ci hanno permesso d’individuare gli con più elevata resistenza agli stress termici e quindi maggiormente idonei per le successive prove di crioconservazione. Vari protocolli per la decorionizzazione e permeabilizzazione degli embrioni sono stati messi a confronto

Tracing the dispersal route of the invasive Japanese beetle Popillia japonica

The Japanese beetle, Popillia japonica, is a highly polyphagous Scarabaeidae native to Japan that colonized North America and Azores in the last century and has recently invaded Italy and Switzerland. Considering its economic impact on the horticulture and turfgrass industries, this species was ranked within the EU priority pests list in 2019. According to the EU Convention on Biological Diversity, the identification of invasion routes is a pivotal aspect in an effective management program aimed at controlling invasive alien species. To reconstruct the source of introductions of this pest, we investigated the genetic variability of P. japonica in its native and invaded areas worldwide by analyzing 9 microsatellite loci and two mitochondrial genes, COX I and CytB. In its native area, P. japonica is structured into two populations: one in the southern and another in the northern-central region of Japan. A limited area within central Japan was identified as the putative source of the North American outbreak. Moreover, the ABC inference and phylogeographic reconstruction suggest that two European populations originated from two independent introductions. The Azores Islands outbreak occurred approximately 50 years ago and originated from the southeastern region of North America (For simplicity, in this paper North America refers to Canada and the USA), while the second introduction, more recently, occurred in Italy and Switzerland and originated from northeastern region of North America