Heuristic algorithms for a storage location assignment problem in a chaotic warehouse

The extensive application of emerging technologies is revolutionizing warehouse management. These technologies facilitate working with complex and powerful warehouse management models in which products do not have assigned fixed locations (random storage). Random storage allows the utilization of the available space to be optimized. In this context, and motivated by a real problem, this article presents a model that looks for the optimal allocation of goods in order to maximize the storage space availability within the restrictions of the warehouse. For the proposed model a construction method, a local search algorithm and different metaheuristics have been developed. The introduced algorithms can also be used for other purposes such as to assess when and how it is convenient to perform relocation of stored items to improve the current level of storage space availability. Computational tests performed on a set of randomly generated and real warehouse instances show the effectiveness of the proposed methods.     

A method for disentangling β-Si3N4 seeds obtained by SHS

The manufacture of β-Si₃N₄ seeds by self-propagating high temperature synthesis (SHS) presents some advantages, such as the low production costs, compared to other preparation methods based on sintering of α-Si₃N₄ powders and subsequent leaching out of the glassy phase. However, SHS process produces seed clusters that must be disentangled before use as reinforcing particles. Different mechanical and chemical treatments were tried to achieve good seed dispersion, proving that a combined treatment based on a hot basic etching and a short time attrition milling gave almost agglomerate-free particles with adequate features for seeding use.     

Cr(VI) removal from synthetic and real wastewaters: The use of the invasive biomass Sargassum muticum in batch and column experiments

The macroalgae Sargassum muticum was selected for the treatment of solutions containing Cr(VI). Very acidic pH values were established as optimal for Cr(VI) reduction. Algae chemical modification reduced equilibrium time to 4 h. First order kinetic model was used to describe the reduction kinetic of Cr(VI). A column experiment allowed to distinguish the processes occurring during Cr(VI) elimination: its reduction to Cr(III) and the subsequent adsorption of this species formed. Under the selected conditions the biomass was capable of reducing all the incoming Cr(VI) during 77 h. Industrial wastewaters from chrome plating industry were also tested for chromium removal.     

Beta-glucans improve growth, viability and colonization of probiotic microorganisms

Probiotics, prebiotics and synbiotics are frequently-used components for the elaboration of functional food. Currently, most of the commercialized probiotics are limited to a few strains of the genera Bifidobacteria, Lactobacillus and Streptococcus, most of which produce exopolysaccharides (EPS). This suggests that the beneficial properties of these microorganisms may be related to the biological activities of these biopolymers. In this work we report that a 2-substituted-(1,3)-β-d-glucan of non-dairy bacterial origin has a prebiotic effect on three probiotic strains. Moreover, the presence of this β-d-glucan potentiates in vitro adhesion of the probiotic Lactobacillus plantarum WCFS1 to human intestinal epithelial cells.     

Evolution of phenols and pigments in extra virgin olive oil from irrigated super‐intensive orchard

Phenolic compounds have a high importance in olive oil because of their effect on shelf life and sensory properties. This study reports on the HPLC profiles of the phenolic compounds of virgin olive oils obtained from Arbequina olives from the harvesting in a super‐intensive orchard under a linear irrigation system. In addition, phenolic content, carotenoid and chlorophyllic pigments, and oxidative stability were analyzed. Total phenol content and 3,4‐DHPEA‐EDA increased up to a maximum throughout the ripening process. The simple phenols tyrosol and hydroxytyrosol acetate increased throughout the ripening process, however, there was not found a clear trend in hydroxytyrosol content. Minor constituents such as vanillic acid and p‐coumaric acid increased up to a maximum and then decreased, since vanillin decreased progressively throughout the time of harvest. 3,4‐DHPEA‐EDA and lignans were present in considerable amounts in the studied samples, while oleuropein aglycone was present in a low amount. Total phenol content and oil stability followed the same trend throughout the study, so a very good correlation was established between them. Total secoiridoids and, specifically, 3,4‐DHPEA‐EDA seemed to be responsible for oil stability. The pigment content decreased during ripening, and not a positive correlation was found between pigments and oil stability. Practical applications : The results can be used to determine the best time for harvesting in order to obtain olive oils with different phenols and pigment contents. This is important for sensory characteristics of the olive oils and also for olive oil stability.     

Antimicrobial food packaging film based on the release of LAE from EVOH

The aim of this work was to develop antimicrobial films for active packaging applications containing the natural antimicrobial compound LAE (lauramide arginine ethyl ester) in EVOH copolymers with different mol % ethylene contents (i.e. EVOH-29 and EVOH-44). EVOH-29 and EVOH-44 films were made by casting and incorporating 0.25%, 1%, 5%, and 10% LAE in the film forming solution (w/w with respect to polymer weight). Previously, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of LAE against Listeria monocytogenes, Escherichia coli, and Salmonella enterica were determined by a microdilution assay. The antimicrobial activity of the resulting films was tested in vitro against these microorganisms in liquid culture media. The activity of the films was also evaluated over time. The results showed that films containing 5% and 10% LAE produced total growth inhibition and viable counts decreased with 0.25% and 1% LAE. Finally, the effectiveness of the films was tested by applying them to an infant formula milk inoculated with L. monocytogenes and S. enterica and stored for 6 days at 4°C. The application of films with LAE to infant formula milk inoculated with L. monocytogenes reduced at the end of storage period about 4 log in case of 10% LAE and with S. enterica reduced 3.74 log and 3.95 log with EVOH 29 5% and 10%, respectively, and EVOH-44 5% and 10% LAE reduced 1 log and 3.27 log, respectively, at the end of storage. The antimicrobial capacity of EVOH-29 films was greater than that of EVOH-44 films in all the cases tested. In general, the films were more effective in inhibiting the growth of L. monocytogenes than S. enterica, this inhibition being more acute at the end of the storage time.     

Lipid and protein structure analysis of frankfurters formulated with olive oil-in-water emulsion as animal fat replacer

Lipid and protein structural characteristics of frankfurter formulated with olive oil-in-water emulsion stabilized with soy protein isolate (SPI) as pork backfat replacer were investigated using Fourier transform infrared spectroscopy (FT-IR). Proximate composition and textural properties were also evaluated. Different frankfurters were reformulated: F/PF with pork backfat, F/SPI with oil-in-water emulsion stabilized with SPI and F/SPI + SC + MTG with emulsion stabilized with a combination of SPI, sodium caseinate (SC) and microbial transglutaminase (MTG). Replacement of pork backfat with these emulsions produced an increase (P < 0.05) of hardness, springiness, cohesiveness and chewiness but a reduction (P < 0.05) of adhesiveness. F/SPI and F/SPI + SC + MTG frankfurters showed the lowest (P < 0.05) half-bandwidth in the 2922 cm⁻¹ band, which could be related to lipid chains were more ordered than in F/PF. Modifications in the amide I band profile revealed a higher concentration of aggregated intermolecular β-sheets in F/SPI + SC + MTG samples. Lipid and protein structural characteristics could be associated with specific textural properties of healthier frankfurters.