RESUMEN
Biomimetic cooperativity of hydration effect and effect of ethanol favorable for binding of bad organic sorbates were observed for their vapor sorption by cross-linked poly(N-6-aminohexylacrylamide) (PNAHAA) in the absence of liquid phase. The vapor sorption isotherms were determined for these systems by the static method of gas chromatographic headspace analysis at 298 K. The hydration above 0.09-0.13 g of H(2)O/(g of polymer) gives a cooperative increase in the PNAHAA binding affinity for benzene, cyclohexane, dioxane, and propanols up to a level which does not change by further hydration, indicating the polymer antiplasticization. Bad sorbates (dioxane, benzene) were observed to have a biomimetic cooperative influence on the binding of ethanol by the dried PNAHAA. This cooperativity does not occur in ternary systems with good nonhydroxylic sorbate acetonitrile.
Asunto(s)
Acrilamidas/síntesis química , Biomimética , Reactivos de Enlaces Cruzados/química , Polímeros/síntesis química , Solventes/química , Acetonitrilos/química , Acrilamidas/química , Adsorción , Benceno/química , Fenómenos Químicos , Química Física , Desecación , Dioxanos/química , Etanol/química , Polímeros/química , Temperatura , Volatilización , Agua/químicaRESUMEN
The binding properties of dry proteins are relatively poorly known. Many proteins are present in emulsions and suspensions and also in dry forms. This is particularly true of dairy proteins, which are often stored and sold in powdered form. In the present work, the binding of three terpenes (alpha-terpinene, gamma-terpinene, and terpinolene), which belong to the basic aroma components, and of decane by powdered beta-lactoglobulin (BLG) was studied at different hydration levels (0.05-0.40 g of H(2)O/g of protein) and temperatures (298 and 309.5 K), in the presence or absence of lipids and small concentrations of ethanol. Vapor sorption isotherms were determined for these systems by a static method of headspace gas chromatographic analysis. A cooperative effect of hydrophobic hydration was observed for the binding of aroma terpenes and decane by the solid BLG. The temperature increase from 298 to 309.5 K reduced the observed hydration threshold of BLG by 0.05-0.08 g of H(2)O/g of protein. Lipids (1.2% w/w) in hydrated BLG gave at least a 2-fold increase in its binding affinity for the hydrocarbons studied, and synergic effects of the hydration and lipid on this affinity were observed.