Fatty Acids Composition of Vegetable Oils and Its Contribution to Dietary Energy Intake and Dependence of Cardiovascular Mortality on Dietary Intake of Fatty Acids

Characterizations of fatty acids composition in % of total methylester of fatty acids (FAMEs) of fourteen vegetable oils—safflower, grape, silybum marianum, hemp, sunflower, wheat germ, pumpkin seed, sesame, rice bran, almond, rapeseed, peanut, olive, and coconut oil—were obtained by using gas chromatography (GC). Saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), palmitic acid (C16:0; 4.6%–20.0%), oleic acid (C18:1; 6.2%–71.1%) and linoleic acid (C18:2; 1.6%–79%), respectively, were found predominant. The nutritional aspect of analyzed oils was evaluated by determination of the energy contribution of SFAs (19.4%–695.7% E_RDI), PUFAs (10.6%–786.8% E_RDI), n-3 FAs (4.4%–117.1% E_RDI) and n-6 FAs (1.8%–959.2% E_RDI), expressed in % E_RDI of 1 g oil to energy recommended dietary intakes (E_RDI) for total fat (E_RDI—37.7 kJ/g). The significant relationship between the reported data of total fat, SFAs, MUFAs and PUFAs intakes (% E_RDI) for adults and mortality caused by coronary heart diseases (CHD) and cardiovascular diseases (CVD) in twelve countries has not been confirmed by Spearman’s correlations.     

Quantification of a 3D structural evolution of food composites under large deformations using microrheology

Microrheology involves simultaneous determination of microstructure and deformation properties, which is essential for understanding structure–deformation relationships. The unit used combines a confocal laser scanning microscope with a compression unit. The main advantage of this approach is that the changes in the microstructure during deformation can be visualised and quantified in three dimensions. It was used to measure microstructural changes and breakdown mechanisms in whey protein isolate/polysaccharide gels. Microstructural changes in protein continuous and bicontinuous gels were quantified. The changes relate to the amount of serum released from the gels during compression. Additionally, the gels showed similar breakdown mechanisms, i.e. they fractured through the protein beams into the serum phase.     

Microstructural features of composite whey protein/polysaccharide gels characterized at different length scales

Mixed biopolymer gels are often used to model semi-solid food products. Understanding of their functional properties requires knowledge about structural elements composing these systems at various length scales. This study has been focused on investigating the structural features of mixed cold-set gels consisting of whey protein isolate and different polysaccharides at different length scales by using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Whey protein cold-set gels were prepared at different concentrations to emulate stiffness of various semi-solid foods. Mixed gels contained different concentrations of gellan gum, high methyl pectin or locust bean gum. Results obtained with CLSM, at the micrometer length scale, indicated the homogeneous nature of the investigated gels. Results obtained with SEM, at the sub-micron length scale, indicated the presence of spherical protein aggregates. During the gel preparation (acidification), the presence of polysaccharides in the whey protein gels led to on initially segragative phase separation into a gelled protein phase and a polysaccharide/serum phase at a micrometer length scale. At the final pH of the gels (pH 4.8, i.e. below the pI of whey proteins), the negatively charged polysaccharides interacted with the protein phase and their spatial distribution was effected by charge density. Polysaccharides with a higher charge density were more homogeneously distributed within the protein phase. Neutral polysaccharide, locust bean gum, did not interact with the protein aggregates but was present in the serum phase. Using SEM, a new type of microstructure formed in the whey protein/polysaccharide gels was characterized. It composed of a protein continuous, porous network at the length scale of 100 μm, coexisting next to the pools of serum which contained spherical protein-rich domains. Heterogeneity of the structure strongly related to the macroscopic behavior of the gels under large deformation. Upon uniaxial compression these heterogeneous gels releases a large amount of serum. Combination of the results of two microscopic techniques, CLSM and SEM, appeared to offer unique possibilities to characterize the structural elements of whey protein/polysaccharide cold-set gels over a wide range of length scales.     

Czech Ethanol‐Free Propolis Extract Displays Inhibitory Activity against a Broad Spectrum of Bacterial and Fungal Pathogens

Propolis acts primarily as a biocide against invasive bacteria and fungi in the hive, suggesting its potential for industrial applications. In food application, propolis is considered as a chemical preservative in meat products, extending shelf life of frozen meat and other food. The mechanism of action is still unclear due to the synergy of multiple compounds contained in propolis and due to parallel targeting of multiple pathways within each affected organism. Here, we examined the antimicrobial properties of dimethylsulfoxide (DMSO) Czech propolis extract. Until recently, DMSO was only rarely used in the propolis studies, although the other solvents tested (mostly ethanol) may significantly affect the observed inhibitory effects, notwithstanding the antimicrobial effects of ethanol itself. Here, we provide results of zone inhibition tests against Aspergillus fumigatus, Microsporum gypseum, Microsporum canis, Candida albicans, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis. Although we determined inhibitory effects against all the microorganisms tested, the dose‐dependent response curves were not similar to each other. While inhibitory effects against C. albicans or S. aureus were strictly dose‐dependent, responses of M. gypseum and E. faecalis displayed plateau across the broad range of concentrations tested. Interestingly, response of E. coli revealed the double‐peak dose‐dependent curve, and responses of M. canis and L. monocytogenes decreased at the highest concentrations tested. Suggested is evaluation of DMSO propolis extracts in experimental treatment of human and veterinary infections, preferably in multitherapy with antibiotics.