Microstructure and Corrosion Behavior of Hot-Deformed and Cold-Strained High-Mn Steels

The electrochemical corrosion properties of 26Mn-3Si-3Al and 27Mn-4Si-2Al austenitic steels in two different states were studied in 0.1 M H₂SO₄ and 3.5% NaCl using potentiodynamic polarization tests. The effect of cold deformation on the microstructure and corrosion behavior of steels was analyzed. In acid solution, both steels exhibited lower corrosion resistance than in chloride solution independently on the steel state (hot-rolled, cold-worked). Cold deformation decreases the corrosion resistance, though this effect is smaller than the effect of chemical composition related to the combined Al + Si addition. All steels showed the evidence of pitting corrosion. The intensive dissolution of Fe and Mn takes place in the acid medium.     

Characterization of the phenolic acid profile and in vitro bioactive properties of white beetroot products

The impact of boiling, baking and fermentation treatment on the phenolic acid profile, antioxidant capacity (AC) and angiotensin-1 converting enzyme (ACE) activity of white beetroot was investigated. The phenolic acids were analysed by liquid chromatography–mass spectrometry (micro-HPLC-MS/MS), while AC and ACE were determined by in vitro assays. Phenolic acids concentration was between 87.55 and 100.98 ng g⁻¹ d.m. Ferulic and p-coumaric acids were the main compounds among the nine phenolic acids identified. Boiling increased the phenolic acid content by 3%; however, baking and fermentation reduced the level of these acids by approximately 6% and 11%, respectively. A significant positive correlation was observed between the results of all AC assays and sinapic and caffeic acid content. The ACE inhibitory activity of white beetroot products may be attributable to the combined effect of the syringic, 4-hydroxybenzoic, ferulic and p-coumaric acids. Our study indicates that white beetroot as a novel product may be a valuable source of phenolic acids and functional properties.     

Changes of amino acid and fatty acid profile in freshwater fish after smoking

Three freshwater fishes: common carp, rainbow trout and northern pike were chosen for the evaluation of amino acid and fatty acid composition—fresh and after smoking. Smoking led to the increase in almost all amino acids, with the highest amount of EAA in common carp. This process led also to the enhancement in the level of SFA and the decrease in PUFA/SFA ratio in fishes. PI values were lower after this process for all fishes. HH ratio was also decreased (except for northern pike), while AI and TI were enhanced in all smoked samples.

Practical applications

Fish and fish products consumption (especially freshwater) is still insufficient despite their proven health‐promoting properties. Because of the susceptibility of fish to perish, their preservation becomes a necessity. Smoking is one of the oldest food processing methods in the world. It imparts a characteristic color and flavor of the product. This process influences also on chemical composition of muscle protein and fat. Thus, the aim of this study was to investigate changes in amino acids composition and fatty acids profile in common carp, rainbow trout and northern pike, as a result of smoking. It is very important to increase consumer knowledge concerned on the species being the most suitable for traditional preservation method, taking into consideration the retaining of beneficial fish compounds.     

Impact of processing on polysaccharides obtained from button mushroom (Agaricus bisporus)

Agaricus bisporus fruiting bodies were subjected to processing: blanching, boiling in water and blanching followed by lactic acid fermentation. Water soluble polysaccharides were obtained from fruiting bodies, quantified and analysed in terms of chemical composition, antioxidant capacity and antiproliferative activity towards cancer cell lines (MCF-7 and T-47D). The content of water soluble polysaccharides ranged from 7.35 ± 0.12 to 6.90 ± 0.17 mg g⁻¹ fresh weight of sample. Boiling in water and blanching followed by fermenting caused minor decrease in the content. Fourier Transform Infrared spectroscopy of the extracted polysaccharides showed that both α- and β-linkages are present in the samples. Size exclusion chromatography confirmed the presence of 163.3 and 1.9 kDa molecules. The processing caused changes in chemical composition (protein and phenolics content decreased). The isolated polysaccharides exerted antioxidant and antiproliferative activities. Both the activities were slightly lowered as the result of the processing.