Response Surface Modeling of the Multiphase Juice Composition from the Compaction of Sardine Discards

In this work, sardine fish was processed in a hydraulic press in order to obtain a solid cake and a press juice presenting solid, aqueous, and oil phases. The influence of pressing conditions, such as total pressure (50–350 bar), compression speed (0.935–3.135 cm/min), number of pressing stages (1–5), and time of relaxation between two consecutive pressing stages (100–300 s), was studied following a rotatable central composite design. Response surface methodology was used to relate the yields of each phase with the operation parameters. According to the regression equations, the content of solids in the press liquor was markedly affected by the target pressure, attaining a maximal yield at 350 bar (0.028 g solids/g sardine). The yield of both liquid phases was maximum after an intensive compacting treatment comprising five pressing steps at the highest compression speed. Under these conditions, the maximum yield of oil was achieved after 100 s of time of relaxation (0.021 g oil/g sardine), while longer times of relaxation increased the amount of blood water and solids in the press liquor to the detriment of the oily phase.     

PARAFFIN DEPOSITION IN OIL PRODUCTION. OIL COMPOSITION AND PARAFFIN INHIBITORS ACTIVITY

ABSTRACT

Several commercial paraffin inhibitors were evaluated with highly paraffinic crudes. Pour point depression was observed in some of the studied crudes in the presence of any product, while others showed insignificant changes in this parameter. Crudes characterization was achieved with physico-chemical analysis (pour point, cloud point and API gravity) and hydrocarbon analysis (thin layer chromatography with flame ionization detection, wax content, gel permeation chromatography and high temperature simulated distillation). A correlation between crude oil composition and paraffin inhibitors activity was found. The normal / cyclo+iso-paraffins ratio of the crudes that were not affected by the paraffin inhibitors was found higher compared to the others. The molecular weight distribution of the crudes which responded to modifiers, showed a bimodal character and a concentration of components with more than 24 carbon atoms lower than 39 % wt. On the other hand, the crudes insensitive to the action of the inhibitors displayed monomodal molecular weight distributions with larger contributions of heavy components (more than 52 % wt). Doping experiments supporting the former findings, permitted to asses the inefficiency of commercial paraffin inhibitors for crudes rich in C24+ alkanes.     

Analysis of used frying oils

The analysis of used frying oils to ensure quality of fried foods has become a subject of great concern for health administrations, food processors and consumers, especially since some compounds formed at high temperatures impair the nutritional value of fats and have adverse health effects. At present, three lines of research on the analysis of frying oils stand out: first, development of techniques for the quantitative analysis of the new compounds formed; second, the evaluation of useful rapid methods to be applied in situ for monitoring oil quality in fried food outlets; and third, the application of the most advanced analytical techniques to delve into the structure of individual oxidized compounds present in fried foods.     

Structure and mechanical properties of sodium and calcium caseinate edible active films with carvacrol

Edible active films based on sodium caseinate (SC) and calcium caseinate (CC) plasticized with glycerol (G) at three different concentrations and carvacrol (CRV) as active agent were prepared by solvent casting. Transparent films were obtained and their surfaces were analysed by optical microscopy and scanning electron microscopy (SEM). The influence of the addition of three different plasticizer concentrations was studied by determining tensile properties, while Fourier transformed infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to evaluate the structural and thermal behavior of such films. The addition of glycerol resulted in a reduction in the elastic modulus and tensile strength, while some increase in the elongation at break was observed. In general terms, SC films showed flexibility higher than the corresponding CC counterparts. In addition, the presence of carvacrol caused further improvements in ductile properties suggesting the presence of stronger interactions between the protein matrix and glycerol, as it was also observed in thermal degradation studies. FTIR spectra of all films showed the characteristic bands and peaks corresponding to proteins as well as to primary and secondary alcohols. In summary, the best results regarding mechanical and structural properties for caseinates-based films containing carvacrol were found for the formulations with high glycerol concentrations.     

Species distribution,antibiotic resistance and virulence traits in enterococci from meat in Tunisia

Antimicrobial resistance and the mechanisms implicated were studied in 119 enterococci from 105 meat samples from Tunisian markets. Almost 24.5% of recovered enterococci showed resistance against four or more antimicrobial agents and these isolates were identified to the species level. Enterococcus faecalis was the most prevalent species (41%). High percentages of erythromycin and tetracycline resistances were found among our isolates, and lower percentages were identified to aminoglycosides, ciprofloxacin and chloramphenicol. All tetracycline-resistant isolates carried the tet(M) and/or tet(L) genes. The erm(B) gene was detected in 78.5% of erythromycin-resistant isolates, ant(6)-Ia gene in 58.8% of streptomycin-resistant isolates, and cat(A) gene in one chloramphenicol-resistant isolate. Forty-eight isolates carried the gelE gene and exhibited gelatinase activity. The hyl and esp genes were detected in one and three Enterococcus faecium isolates, respectively. Streptomycin-resistant isolates showed a high genetic diversity by PFGE and MLST. Meat might play a role in the spread through the food chain of enterococci with these virulence and resistance characteristics to humans.     

Poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)/clay nanocomposites for replacement of mineral oil based materials

Due to the short‐running of mineral oil and the increasing waste problem, biopolymers become more and more important. However, they still suffer from disadvantages, and in many cases, their properties are still insufficient to replace mineral oil based plastics. In this study, the biobased and biodegradable polymer poly (3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) is reinforced by different clay types and their effect on the properties profile is investigated. Natural as well as organomodified montmorillonite and bentonite are dispersed by melt mixing within the PHBV matrix. Thermal stability, crystallization behavior, and dynamic mechanical properties as well as the materials morphology is analyzed. Dispersion state of the nanoclay is found to be crucial for the improvement of the material performance and well dispersed organomodified clays reveal to simultaneously improve different properties of PHBV matrix. POLYM. COMPOS., 34:1033–1040, 2013. © 2013 Society of Plastics Engineers     

Polyphenolic Extract of Barbary-Fig (Opuntia ficus-indica) Syrup: RP–HPLC–ESI–MS Analysis and Determination of Antioxidant, Antimicrobial and Cancer-Cells Cytotoxic Potentials

The traditionally derived syrup of Opuntia ficus-indica fruit is commonly used in homemade confectionery. Herein, the aqueous-acetone extract prepared from the Tunisian O. ficus-indica syrup was investigated. The qualitatively and quantitatively polyphenolic content was analysed using reversed-phase high-performance liquid chromatography–diode array detection (RP-HPLC–DAD) coupled to electrospray ionisation–mass spectrometry (ESI–MS). The extract contained 19.95?±?2.01 mg phenolics per gram of fresh starting material with isorhamnetin 3-O-robinobioside as the major compound (22.76%). The syrup extract showed strong antioxidant potentials as assessed by both ABTS and DPPH functional methods. It exhibited effective antimicrobial activity, particularly against Staphylococcus aureus and Staphylococcus epidermidis with a minimal bactericide concentration (MBC) of 1.3 mg phenolics/ml. Furthermore, at final concentrations in the range of 41.38–186.25 μg polyphenols/ml, the extract decreased human SH-SY5Y neuroblastoma and 3T3 fibroblast in vitro cell viability in a dose- and time-dependent manner compared to non-treated control cells. The observed effects were significantly (P?<?0.05) high against cancer lines. Extract concentrations higher than 106.43 μg/ml reduced cancer cells viability to 50–60% 1–3 h post-treatment. Further in vivo insight studies should emphasise and validate the herein obtained results.     

Study of the content in volatile compounds during the aging of sweet Sherry wines obtained from grapes cv. Muscat and fermented under different conditions

Several experiments of aging in oak wood and stainless steel of sweet Sherry wines obtained from grapes cv. Muscat fermented under different enological conditions have been carried out. These wines were periodically sampled and their volatile content was analyzed using SBSE–GC–MS. A sensory study was also carried out. Data were submitted to different statistical techniques. An important influence of the three factors considered, fermentation type, aging type, and aging time, have been observed. In cluster analysis, the grouping obtained demonstrated that the volatile compounds considered possess sufficient explanatory power to detect the type of aging process and differentiate the two yeast strains studied. In the case of the linear discriminant analysis, high percentages of correct classification were obtained for the three factors considered. Taking into account the global volatile profile, the factor “aging type” (oak cask or stainless steel) has demonstrated the highest influence on the volatile content of the wines, with those wines from Experiments D4 and D5 (fermented with S. bayanus) and aged in oak wood clearly differentiated from those ones fermented with S. cerevisiae and aged in wood or stainless steel. From a sensorial point of view, the wines fermented with S. Cerevisiae and aged in wood (D1C and D2C) were the most valued ones.     

Potential of olive oil phenols as chemopreventive and therapeutic agents against cancer: A review of in vitro studies

Olive oil is a common component of Mediterranean dietary habits. Epidemiological studies have shown how the incidence of various diseases, including certain cancers, is relatively low in the Mediterranean basin compared to that of other European or North America countries. Current knowledge indicates that the phenolic fraction of olive oil has antitumor effects. In addition to the ability to be chemopreventive, with its high antioxidant activity, the antitumor effects of olive oil phenols (OO‐phenols) has been studied because of their capacity to inhibit proliferation and promote apoptosis in several tumor cell lines, by diverse mechanisms. This review will summarize and discuss the most recent relevant results on the antitumor effect of OO‐phenols on leukemia tumor cells, colorectal carcinoma cells, and breast cancer (BC) cells. In particular, very recent data will be reported and discussed showing the molecular signaling pathways activated by OO‐phenols in different histopathological BC cell types, suggesting the potential use of OO‐phenols as adjuvant treatment against several subsets of BC. Data summarized here represent a good starting point for more extensive studies for better insight into the molecular mechanisms induced by OO‐phenols and to increase the availability of chemopreventive or therapeutic drugs to fight cancer.