ABSTRACT The chemical stability of lycopene and the physical stability of lycopene emulsions diluted in 3 different food systems (skimmed milk, orange juice, and water as control) were studied. In these investigations, 3 different emulsifiers were used. It was found that lycopene stability strongly depends on the food system. In orange juice, lycopene is particularly stable. The emulsifiers used have only little influence on the stability of lycopene. Emulsions with α‐tocopherol as an additional antioxidant showed a good lycopene stability in all food systems. Coalescence of oil droplets was not observed in any of the food systems investigated. Keywords: lycopene, stability, food systems

Power ultrasound is one means among others of mechanically producing emulsions. In spite of numerous publications on the basic principles of this technique, there is insufficient knowledge of continuous ultrasound emulsification processes and the main parameters of practical relevance. A comparison of this system with other continuous mechanical emulsifying devices is made. The effect of continuous phase viscosity on droplet disruption due to ultrasound is the subject of a more detailed investigation. Continuous phase viscosity is varied by means of water soluble stabilizers (o/w systems) and different oils (w/o systems). At constant energy density, droplet size decreases when adding stabilizers, whereas the viscosity of the oil in w/o emulsions has no effect. Qualitative investigations of the local distribution of cavitation have shown very small penetration depths of cavitation into the liquid. This emphasizes the need for improvement of apparatus design to optimize the emulsification process.

Despite the apparent satisfaction of industry with the commercial design methods available to them, an outstanding question is the choice of the better cooling curve, differential or integral, for use with the equilibrium design approach. This is considered in the light of experimental data taken with a vapour mixture, condensing in a horizontal shell-side condenser of semi-industrial scale, (diameter 0.336m, and length 2.438 m). This configuration is frequently used in the petroleum industry but such condensers may perform poorly because of separation of the condensate from the vapour flow, leading to a fractionation effect. Thus the vapour may become richer in the more volatile components with a fall in saturation temperature and driving force. Therefore, the area required for a given degree of condensation might be larger compared with a condensation process following the integral cooling curve. Temperature profiles, which are predicted by the integral and differential cooling curves, are compared with experiment for condensation of methanol-water mixtures of varying composition.