Lipids, chemical reactions during

The significance of monolayers to biochemistry lies in their close relation to the molecular interactions that take place at the interface between aqueous and hydrophobic systems such as cell membranes and within enzymes. The molecular alignment in monolayers is closely related to the lipid bHayer structure proposed for membranes (46). Since stereospecific chemical reactions of living organisms often take place at the cell boundaries, it is small wonder that during the past 25 years much monolayer research has been reported by biochemists, physiologists, and pharmaceutical chemists (47-51). 

All ingredients in meat (proteins, lipids, carbohydrates) react during the normal meat preparation in a very complex chemical reaction to produce the final, highly appreciated flavour. It goes without saying, that each cook finds a new balance of this... 

Hydrocarbons are common components of many foods often occurring as constituents of essential oils and food hpids. They are either natural components of food raw materials and foods (primary substances) or form during food processing and storage by enzymatic and chemical reactions as secondary substances (e.g. as lipid oxidation products and degradation products of carotenoids). Some hydrocarbons may be present in food as endogenous or exogenous contaminants (e.g. polycychc aromatic hydrocarbons). 

The authors review the theoretical analysis of the hydrodynamic stability of fluid interfaces under nonequilibrium conditions performed by themselves and their coworkers during the last ten years. They give the basic equations they use as well as the associate boundary conditions and the constraints considered. For a single interface (planar or spherical) these constraints are a Fickean diffusion of a surface-active solute on either side of the interface with a linear or an erfian profile of concentration, sorption processes at the interface, surface chemical reactions and electrical or electrochemical constraints for charged interfaces. General stability criteria are given for each case considered and the predictions obtained are compared with experimental data. The last section is devoted to the stability of thin liquid films (aqueous or lipidic films). 

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