Biogenic amine content in Chilean Gauda cheese: physico‐chemical and microbiological factors that may influence this content

The presence of four biogenic amines in Chilean Gauda cheese was studied, and the effect of certain factors may influence the production of those amines. Histamine, tyramine, putrescine and cadaverine were quantified with high‐performance liquid chromatography (HPLC), in cheeses from the three major Chilean cheese manufacturers. Multiple regression analysis revealed that water activity, free amino acid content and the Enterobacteriaceae count all favoured production of biogenic amines. The total amount of biogenic amines in the samples studied was between 47.9 and 150.5 mg/kg of cheese, much lower than that associated with a possible consumer health risk (1000 mg/kg).     

Modified Triglyceride Oil Through Reactions with Phenyltriazolinedione

Most of the current lubricants originate from petroleum stock, which may make them difficult to dispose of and be environmentally unfriendly. Triglyceride oils are good platforms for new products that can substitute for conventional mineral oil-based lubricating oils and synthetic esters. As part of the effort to develop new uses of triglyceride oils, a modified triglyceride oil was synthesized through the reactions with 4-phenyl-1,2-4-triazoline-3,5-dione (PTAD). The process required no solvent or catalyst and entailed only the mixing of triglyceride and PTAD. ¹H NMR was used for structure determination and to monitor the reactions. Several reaction products were produced, and their relative yields depended on the stoichiometry and temperature of the reaction. The reaction product mixture exhibited a self-curing behavior as a function of time. Thus, the viscosity of a mixture containing PTAD and triglyceride in a 3:10 weight ratio increased 40-fold in about 2 h at room temperature, suggesting its possible use as an additive in lubricants, caulking, cement and thickener applications.     

Viscosity and rheological behavior of carbon dioxide-expanded fish oil fatty acid ethyl esters: Measurement using a rotational viscometer and modeling

The viscosity of fish oil fatty acid ethyl esters (FAEE) in equilibrium with CO₂ was determined at 40, 55, and 70 °C and pressures ranging from 0.1 to about 12 MPa using a rotational rheometer equipped with a high pressure cell. Viscosity of CO₂-expanded (CX) FAEE decreased due to the dissolution of CO₂ with pressure, which was temperature dependent. The viscosity of CX FAEE was correlated using a new empirical model utilizing saturation pressure and temperature with temperature-dependent parameters, which allows interpolation of viscosity data for any pressure and temperature within the envelope of this study. As well, viscosity was modeled using available data for CO₂ solubility in FAEE at specific temperatures of this study utilizing simpler models with only one parameter, such as the Grunberg and Nissan model. The rheological data suggest shear thickening behavior of CX FAEE at elevated pressures. The limitations of the rotational rheometer for measuring CX liquids at viscosities below 1 mPa s are discussed. Understanding of viscosity and rheological behavior of CX FAEE is essential for equipment and process design involving such lipids.     

Acetate Treatment Increases Fatty Acid Content in LPS-Stimulated BV2 Microglia

Acetate supplementation increases plasma acetate, brain acetyl-CoA, histone acetylation, phosphocreatine levels, and is anti-inflammatory in models of neuroinflammation and neuroborreliosis. Although radiolabeled acetate is incorporated into the cellular lipid pools, the effect that acetate supplementation has on lipid deposition has not been quantified. To determine the impact acetate-treatment has on cellular lipid content, we investigated the effect of acetate in the presence of bacterial lipopolysaccharide (LPS) on fatty acid, phospholipid, and cholesterol content in BV2 microglia. We found that 1, 5, and 10 mM of acetate in the presence of LPS increased the total fatty acid content in BV2 cells by 23, 34, and 14 % at 2 h, respectively. Significant increases in individual fatty acids were also observed with all acetate concentrations tested with the greatest increases occurring with 5 mM acetate in the presence of LPS. Treatment with 5 mM acetate in the absence of LPS increased total cholesterol levels by 11 %. However, neither treatment in the absence of LPS significantly altered the content of individual phospholipids or total phospholipid content. To determine the minimum effective concentration of acetate we measured the time- and concentration-dependent changes in histone acetylation using western blot analysis. These studies showed that 5 mM acetate was necessary to induce histone acetylation and at 10 mM acetate, the histone acetylation-state increased as early as 0.5 h following the start of treatment. These data suggest that acetate increases fatty acid content in LPS-stimulated BV2 microglia that is reflected by an increase in fatty acids esterified into membrane phospholipids.     

Effects of E‐beam irradiation and vacuum packaging on biogenic amines formation in common carp (Cyprinus carpio) fillets

The effects of vacuum packaging followed by E‐beam irradiation treatment on the shelf life of common carp (Cyprinus carpio) fillets were studied by measuring biogenic amines and sensory analysis. Samples were irradiated at doses of 0.10, 0.50, 1.0 and 2.0 kGy. Putrescine, cadaverine, histamine and tyramine showed very good correspondence with the irradiation dose and the time of storage. Spermine, spermidine, tryptamine and phenylethylamine did not show statistically significant changes with the time of storage. According to the sensory assessment and biogenic amines index (BAI), the shelf life of unirradiated common carp fillets was found to be approximately seven days. The 1 and 2 kGy irradiation doses extended the shelf life of samples up to 66 and 77 days, respectively. High values of correlation coefficients (r < ?0.86) between BAI and sensory evaluation indicated that BAI could be considered as a quality indicator of common carp fillets.     

Ultrasound‐assisted extraction kinetics,fatty acid profile,total phenolic content and antioxidant activity of green solvents' extracted passion fruit oil

The main objective of this current work was to evaluate the feasibility of green solvent's application on passion fruit oil extraction. In this study, the effects of green solvent on oil yield, fatty acid profile, oil physicochemical properties, total phenolic content and antioxidant activity associated with extracted oil were compared to those of conventional solvent, hexane application. Therefore, this study may provide supplementary information on previous studies that focused on oil recovery. Oilseeds' proximate composition and the influence of oilseeds‐to‐solvent (w/v) ratio on oil yield were investigated. The oilseeds contained high fibre, fat and protein. Oilseeds‐to‐solvent (w/v) ratio (1:8) provided the highest oil yield. Overall, acetone was suggested as a suitable hexane replacer due to its higher oil recovery, similar fatty acid profile and oil physicochemical properties with higher antioxidant activity. Ethanol‐extracted oil contained higher amounts of omega‐9 MUFA, which may indicate the influence of extraction solvent on final fatty acid composition and thus final oil application.     

Effect of rose polyphenols on oxidation,biogenic amines and microbial diversity in naturally dry fermented sausages

Rose polyphenols (RPs) have antioxidant and antibacterial activities. In order to evaluated the application of RPs in meat products, the effect of RPs on the safety of fermented sausages was investigated. In the present study, RPs inhibited the increase of pH. Phenylethylamine, putrescine, cadaverine, tyramine and spermidine can be detected in sausages, while spermine and tryptamine were not observed. Sausages containing RPs had lower thiobarbituric acid reactive substance values and biogenic amines than the control. Moreover, RPs decreased the total bacterial count but increased growth rate of lactic acid bacteria. The effect of RPs on oxidation, biogenic amines and bacterial growth is dependent on the concentration. High-throughput DNA sequence analysis revealed that operational taxonomical units (OTUs) of samples without PRs were higher than those containing 3 mg/g RPs, and 323 OTUs shared between two batches. Especially, a higher level of Lactobacillales OTUs was observed in the 3 mg/g batches. These results indicated that RPs could be used to improve the safety of fermented sausage by inhibiting lipid oxidation, biogenic amines formation and spoilage bacterial growth, and increasing growth rate and richness of lactic acid bacteria.