Review of the effects of food processing and formulation on flavonol and anthocyanin behaviour

In spite of the growing interest over the last few years in flavonoids and their antioxidant capacity, little work has been devoted to investigate the effect of the processes on the structure and the activities of these molecules during processing and storage steps. Most of the studies concern the characterization and analyses of these compounds in raw materials before their processing. Flavonoids are sensitive to heat and to the physico-chemical environment; thus the steps of processing (heating, mechanical and domestic processes), of formulation (food matrix) and the storage period and conditions may lead to a degradation of the flavonoids and an alteration of their antioxidant properties. In this paper, we review the main studies describing the effects of processing, formulation and storage on flavonol and anthocyan content and we also report the models describing the degradation kinetics under a wide range of temperature and operating conditions.     

Semibatch anionic ring‐opening polymerization of octamethylcyclotetrasiloxane in emulsions: effect of the amount of seed polymer particles

Semibatch anionic ring‐opening polymerization of octamethylcyclotetrasiloxane with the use of seed polymer particles in emulsions was studied. The concentration of the emulsifier was set above the critical micelle concentration. We investigated the effect of the amount of seed polymer particles on the chemical kinetics and the average particle size and distribution. During monomer starving conditions the polymerization rate strongly depended on the monomer feed rate and not on the amount of seed particles. Throughout the entire monomer feed period the average particle size increased. This increase depended on the number and the size of seed particles. In emulsions with higher particle sizes higher equilibrium conversions were obtained. In our opinion, a greater extent of backbiting reactions is responsible for lower equilibrium conversions during and at the end of the process. The seeded semibatch process seems a reasonable choice for designing emulsion products with high monomer conversion and desired particle size. © 2012 Society of Chemical Industry     

Characterization and oxidation behavior of MTCVD Ti–B–N coatings

In this work, Ti–B–N coatings have been prepared by moderate temperature chemical vapor deposition (MTCVD). The effect of a varying boron concentrations (9.6 and 55.4 at.%) on the chemical composition and the oxidation behavior was investigated by XRD, SEM, WDS, XPS and Raman spectroscopy. The results clearly demonstrate a good correlation between the different techniques. The same transition trends were observed in the examined Ti–B–N system in the progression from TiN to TiB₂ by the addition of boron. At boron concentrations ≥ 18 at.%, the coatings reveal a two phase structure comprising a nanocrystalline TiN phase embedded in an amorphous TiB₂ matrix. In Ti–B–N coatings with boron concentrations ≤ 18 at.%, the high sensitivity of Raman spectroscopy enabled the identification of an amorphous TiB phase.The oxidation behavior of Ti–B–N coatings was found to be affected by the boron concentration as well. Boron concentrations ≤ 18 at.% improve the thermal stability compared to TiN, most likely due to the TiB phase present in these coatings. Ti–B–N coatings with a high boron concentration show a higher degree of oxidation compared to TiN manifested in a higher oxide layer thickness. In addition, these coatings tend to form boron oxides on their surface, which lead to the formation of metastable anatase rather than the thermodynamically stable rutile.     

White tea intake interferes with the expression of angiogenic factors in the corpora lutea of superovulated rats

White tea derived from the Camellia sinensis (L.) plant has anticancer effects. Its main catechin decreases the gene expression of Vegf in tumours. However, VEGF is also the angiogenic factor of the reproductive organs. In this study, Wistar rats were divided into the following groups (n = 30): the control group (CT), which received water, and the white tea intake group (WT), for 3 months. At the end of every month, the corpora lutea (CL) of ten rats were removed to evaluate the gene expression of Vegf and its receptors (Flt‐1 and Kdr). White tea increased the relative mRNA abundance of Vegf (CT = 0.95 ± 0.06 and WT = 2.13 ± 0.19), Kdr (CT = 0.88 ± 0.06 and WT = 1.94 ± 0.32) and Flt‐1 (CT = 0.94 ± 0.06 and WT = 2.11 ± 0.22) in CL (P < 0.05). White tea increased angiogenic‐related genes in rat CL but did not alter the number of rat CL.     

An in silico re-design of the metabolism in Thermotoga maritima for increased biohydrogen production

Microbial hydrogen production is currently hampered by lack of efficiency. We examine how hydrogen production in the hyperthermophilic bacterium Thermotoga maritima can be increased in silico. An updated genome-scale metabolic model of T. maritima was used to i) describe in detail the H₂ metabolism in this bacterium, ii) identify suitable carbon sources for enhancing H₂ production, and iii) to design knockout strains, which increased the in silico hydrogen production up to 20%. A novel synthetic oxidative module was further designed, which connects the cellular NADPH and ferredoxin pools by inserting into the model a NADPH-ferredoxin reductase. We then combined this in silico knock-in strain with a knockout strain design, resulting in an in silico production strain with a predicted 125% increase in hydrogen yield. The in silico strains designs presented here may serve as blueprints for future metabolic engineering efforts of T. maritima.     

Identification of organically farmed Atlantic salmon by analysis of stable isotopes and fatty acids

Using isotope ratio mass spectrometry (IRMS), the ratios of carbon (δ ¹³C) and nitrogen (δ ¹⁵N) stable isotopes were investigated in raw fillets of differently grown Atlantic salmon (Salmo salar) in order to develop a method for the identification of organically farmed salmon. IRMS allowed to distinguish organically farmed salmon (OS) from wild salmon (WS), with δ ¹⁵N-values being higher in OS, but not from conventionally farmed salmon (CS). The gas chromatographic analysis of fatty acids differentiated WS from CS by stearic acid as well as WS from CS and OS by either linoleic acid or α-linolenic acid, but not OS from CS. The combined data were subjected to analysis using an artificial neural network (ANN). The ANN yielded several combinations of input data that allowed to assign all 100 samples from Ireland and Norway correctly to the three different classes. Although the complete assignment could already be achieved using fatty acid data only, it appeared to be more robust with a combination of fatty acid and IRMS data, i.e. with two independent analytical methods. This is also favourable with respect to a possible manipulation using suitable feed components. A good differentiation was established even without an ANN by the δ ¹⁵N-value and the content of linoleic acid. The general applicability in the context of consumer protection should be checked with further samples, particularly regarding the variability of feed composition and possible changes in smoked salmon.     

Effect of previous gutting on rancidity development in horse mackerel (Trachurus trachurus) during frozen storage at −20 °C

Gutting was applied to fresh horse mackerel (Trachurus trachurus) to study its effect on rancidity development during a prolonged frozen storage (up to 12 months at −20°C). To do so, chemical (free fatty acids, FFA; peroxide value, PV; thiobarbituric acid index, TBA-i; fluorescence ratio, FR) and sensory (odour and taste) analyses were carried out. The results showed that the gutting of horse mackerel led to a higher degree of oxidation in the frozen product, according to the chemical (PV, TBA-i and FR) and sensory (odour and taste) analyses. However, a lower extent of lipid hydrolysis (FFA formation) was detected at the end of the storage (twelfth month) as a result of gutting. It is concluded that the gutting of a medium-fat fish species such as horse mackerel is not recommended as previous treatment to frozen storage.     

Utilization of Hemicelluloses as Example for Holistic Recovery of Agricultural Residues

The objective of this work was to separate and characterize the hemicellulose from agricultural residues of annual plants and to achieve a suitable application for it. Therefore, different treatments for producing pulp were tested and compared. Wheat straw and oat husks were digested by alkaline pulping and delignification. Pectin from sugar beet pulp was obtained by acid extraction. Beside the production of pulp, the separation and utilization of hemicellulose as resource was a key aspect of this work. The hemicelluloses were tested as paper additives, flame retardants and flotation agents.     

Hollow mesoporous silica capsules loaded with copper,silver, and zinc oxide nanoclusters for sustained antibacterial efficacy

Intensive and overuse of antibiotics during the last years has triggered a distinct rise in antibiotic resistance worldwide. In addition to the newly developed antimicrobials, there is a high demand for alternative treatment options against persistent bacterial infections. The biocidal impact of metal ions like copper (Cu²⁺), silver (Ag⁺), and zinc (Zn²⁺), also known as the oligodynamic effect has been used for ages to kill or inhibit the growth of microorganisms and to employ long-term prevention strategies against their biological antagonists. Herein, we report on the synthesis of Cu, Ag, and Zn metal and corresponding oxide nanoparticles immobilized on hollow mesoporous silica capsules (HMSCs) obtained by a hard-template assisted sol-gel synthesis followed by reduction of appropriate metal salts in the presence of HMSCs. Compartmentalization of nanosized metal and oxide clusters in Ag@HMSCs, Cu@HMSCs, and ZnO@HMSCs particles prevented their agglomeration and offered high release kinetics of metal ions between 2.0 and 3.7 mM during 24 h, as monitored by UV-vis analyses. The distribution and morphology of pristine and metal functionalized HMSCs were evaluated by transmission electron microscopy analysis revealing the successful synthesis of Ag, Cu, and ZnO nanoparticles supported on HMSCs. X-ray photoelectron spectroscopy revealed that mainly Cu(II), Ag(0), and Zn(II) species were present in the modified HMSCs. In addition to the surface attachment of preformed metal (Ag and Cu) and metal oxide (ZnO) cluster, nucleation of metal nanoparticles inside the void of HMSCs provided an internal reservoir which allowed for a time-dependent release of metal ions through slower dissolution rates leading to a long-term and sustained bacterial inhibition over several hours. The high antimicrobial efficiency of Ag@HMSCs, Cu@HMSCs, and ZnO@HMSCs particles was investigated toward both Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria by INT assays showing a complete growth inhibition for both bacteria types after 24 h. While Ag@HMSCs and Cu@HMSCs showed a higher susceptibility against Gram-negative bacteria, ZnO@HMSCs showed a higher susceptibility against Gram-positive bacteria. This demonstrates the promise of metal-loaded capsules as antibacterial delivery vehicles with dual-mode time-release profiles being potential alternatives for antibiotic drugs.