Alumina porous nanomaterials obtained by colloidal processing using d-fructose as dispersant and porosity promoter

Recently, great effort has been devoted to obtain porous materials with customized pore size distribution, high surface area and submicrometer sized microstructures or nanostructures. In this work, the viability of colloidal processing routes to obtain porous bulk ceramics using alumina nanopowders and d-fructose as a dispersant and a porosity former has been explored.The rheological behaviour of nanosuspensions was studied in order to assure their stability and to analyse the influence of different parameters (solids loading, fructose content, pH, sonication time). Mesoporous green bodies were obtained by slip casting with d-fructose in concentrations ranging from 5 to 50 wt%. The drying and burning-out conditions were determined by DTA-TG measurements and the sintering cycles were selected from the dynamic sintering curve. Sintered alumina materials with high porosity (>60%), open microstructures, submicrometer sized porosity (d_p = 140–210 nm) and grain size lower than 500 nm, were obtained for pieces sintered at temperatures of 1300 and 1400 °C. The influence of different processing parameters on the porosity and the microstructure of the sintered materials is discussed.     

Jumbo squid (Dosidicus gigas) myofibrillar protein concentrate for edible packaging films and storage stability

Properties and storage stability of two different jumbo squid myofibrillar protein-based films were investigated. Myofibrillar proteins were extracted by isoelectric precipitation after acidic and alkaline solubilization, obtaining the same extraction yield. During extraction the edible fraction, which was discarded during mantle skinning, was recovered, and the fishy flavour produced by nitrogen and other undesirable compounds was removed, although some sarcoplasmic proteins were lost simultaneously. In alkaline-Concentrate (C), myosin unfolding led to water resistant films, less water vapour permeable and more mechanically resistant than acidic–Films (F); whereas acidic-C protein hydrolysis resulted in more transparent and soluble films, with higher protein release (∼80 g/L). During 4 months of storage some structure reorganization occurred, and both films incremented their yellowish tendency, especially the acidic-F, being this attributed to a Maillard reaction with plasticizers. After storage time, water solubility increased in C-films. While acidic-F aggregation led to a protein release reduction and tensile strength improvement, alkali-F became weak and brittle, loosing transparency. C-films offered different filmogenic properties, proving to be promising biodegradable packaging materials.     

Behaviour of egg white and starch in gelation of sardine muscle (Sardina pilchardus)

Response surface methodology was used to determine the role played by egg white and starch in gelation of minced and washed sardine muscle. There was no detectable interaction, either positive or negative, between the effects of the two ingredients. Both egg white and starch significantly affected gel strength. Egg white had a direct, positive influence on hardness and adhesiveness. Starch had a direct, positive influence on cohesiveness and the ability to retain water.     

A Novel Functional Wrapping Design by Complexation of ε-Polylysine with Liposomes Entrapping Bioactive Peptides

An innovative edible wrapping with potential use for designing functional foods with antimicrobial capacity was developed by complexation of ε-polylysine with peptide-loaded liposomes. Unmarketable long-term frozen cooked shrimp (Litopenaeus vannamei) muscle was used as a source of both bioactive peptides and complex liposomal suspension carrier, producing a sustainable value-added protein wrapping material with desirable sensory properties. A <10-kDa peptide fraction (SH) with antioxidant and angiotensin-converting enzyme inhibitory capacity was encapsulated in partially purified phosphatidylcholine (PC) liposomes (LSH) with an entrapment efficiency of 85 %. The average size and zeta potential of LSH were 164?±?2 nm and –37.0?±?1.7 mV, respectively. The LSH surface changed from electronegative to electropositive upon adsorption of ε-polylysine (PL) with an optimal concentration of 0.5 %. The average diameter and zeta potential of the resulting complex ε-polylysine-adsorbed liposomes containing the peptide hydrolysate (PL-LSH) were 216?±?5 nm and +51.1?±?1.1 mV, respectively. The ε-PL proved to be effective as liposome stabilizing and antimicrobial agent. The PL-LSH suspension was incorporated in the formulation of the protein wrapping to provide it with both bioactive and antimicrobial properties. The wrapping showed low water solubility (≈30 %) and low mechanical resistance (tensile strength?=?0.23?±?0.06 MPa; elongation at break?=?0.91?±?0.19 %) properties that allowed it to be very versatile for varied food design and was effective against Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Yersinia enterocolitica.     

Analysis of Cheese Small Molecules by UPLC–QToF-MS and Multivariate Statistical Methods Using Several Extraction Procedures

Lyophylized (L) and nonlyophylized (NL) samples of two cheeses from different batches were extracted with either methanol:water (8:2, v/v) or isopropanol:water (7:3, v/v), and the extracts were analyzed by ultraperformance liquid chromatography coupled with electrospray ionization/quadruple-time-of-flight mass spectrometry (UPLC–ESI–QToF-MS) in both positive and negative modes. Chromatographic and mass spectrometric data were further compared for different samples by paired t test and principal component analysis (PCA). Mass spectra at different elution times were manually checked and major peaks tentatively identified according to their m/z values by search in available databases. A number of gangliosides and polyglycosilated ceramides were found to be the most abundant components. PCA showed samples could be clustered according to extraction procedure and cheese, and paired t test comparison also showed significant (p?<?0.05) differences between L and NL samples extracted with methanol:water. L and NL samples could only be distinguished in PCA when data from the whole chromatographic range were used. Results are discussed based on extraction solvent polarity and feasibility of PCA for comparison of cheese chemical composition after untargeted UPLC–MS analysis.     

Scalable and flexible wireless distributed architecture for intelligent video surveillance systems

Multimedia Tools and Applications - This paper presents a novel distributed intelligent video surveillance architecture based on Wireless Multimedia Sensor Networks (WMSNs). This architecture is...