In vitro gastrointestinal digestion of meat and fish with alcoholic beverages : oxidation and fatty acid ethyl ester formation

Oxidative reactions during cooking and gastrointestinal digestion of meat and fish lead to the formation of various lipid-and protein oxidation products, some of which are toxic. The intake of alcoholic beverages with meat and fish, may have an antioxidant effect due to polyphenols present but, may also stimulate the formation of possibly toxic fatty acid ethyl esters (FAEE’s). Therefore, the effect of different alcoholic beverages on the formation of oxidation products and FAEE’s during in vitro digestion of meat/fish was investigated. Cooked chicken, pork, beef or salmon was combined with ethanol, or alcoholic beverages (lager, dark beer, triple, white wine, red wine) in two volumes. These combinations were exposed to in vitro digestion, simulating conditions from mouth to small intestine. 4-hydroxy2-hexenal, 4-hydroxy-2-nonenal, hexanal and propanal were determined via HPLC fluorescence; malondialdehyde, protein carbonyl components, polyphenol content and total antioxidant capacity (TAC) via spectrophotometer, and FAEE’s via GC-MS. Depending on their polyphenol content and TAC, most alcoholic beverages significantly reduced oxidation by approx. 25 to 90% during digestion of meat/fish, with red wine being the most antioxidative. FAEE’s were formed during digestion of meat/fish with alcohol, corresponding to the fatty acid profile of the digested muscle

Model-Driven Controlled Alteration of Nanopillar Cap Architecture Reveals its Effects on Bactericidal Activity

Nanostructured surfaces can be engineered to kill bacteria in a contact-dependent manner. The study of bacterial interactions with a nanoscale topology is thus crucial to developing antibacterial surfaces. Here, a systematic study of the effects of nanoscale topology on bactericidal activity is presented. We describe the antibacterial properties of highly ordered and uniformly arrayed cotton swab-shaped (or mushroom-shaped) nanopillars. These nanostructured surfaces show bactericidal activity against Staphylococcus aureus and Pseudomonas aeruginosa. A biophysical model of the cell envelope in contact with the surface, developed ab initio from the infinitesimal strain theory, suggests that bacterial adhesion and subsequent lysis are highly influenced by the bending rigidity of the cell envelope and the surface topography formed by the nanopillars. We used the biophysical model to analyse the influence of the nanopillar cap geometry on the bactericidal activity and made several geometrical alterations of the nanostructured surface. Measurement of the bactericidal activities of these surfaces confirms model predictions, highlights the non-trivial role of cell envelope bending rigidity, and sheds light on the effects of nanopillar cap architecture on the interactions with the bacterial envelope. More importantly, our results show that the surface nanotopology can be rationally designed to enhance the bactericidal efficiency