[Emulsified intermediate moisture foods].

Abstract

A water-in-oil emulsion with IMF behavior has been studied within DGRST Grant Nr. 75-7-0406. The dispersion of a sirupy aqueous phase of known aw into a more or less hardened fatty continuous phase was looked into through its effects, particularly how the fatty phase would modify the water behaviour of the dispersed aqueous phase. The emulsion was conventionally prepared by a preemulsion of the syrup into the lecithinated fat, an homogeneisation till enough dispersion and a centrifugation to get rid of free fat. Lecithin has to promote sufficient fat incorporation, correct dispersion and a final viscosity allowing pumpability. To get a cold centrifugate of enough consistency implies an efficient dispersion but before all a judicious choice of the continuous fatty phase, making allowance of organoleptic properties and shelf-life stability. The water behaviour has been worked at on two model systems, of initial phase volume phi = 0,36, with an internal phase made of partially inverted sucrose syrup (aw = 0,79) and an external fatty phase of either refined soybean oil or hydrogenated palm oil (m.p. 42 degrees C). These models respectively retained after centrifugation 12,5 p. 100 oil and 19,5 p. 100 fat; sorption-desorption isotherms were determined by the saturated salt solution method both at 37 degrees C and room temperature, exhibiting that the solid fat content of the continuous fatty phase positively reduces the water transfer velocity from-and-into the syrup. Such a W/O emulsified structure with a prevalent internal aqueous behaves like a pasty IMF, inherently protected against outside relative humidity variations; it also leads the system to a better consistency.