Cloudy apple juice has been treated by high pressure carbon dioxide (HPCD) as non-thermal technology to inactive polyphenoloxidase and pectinmethylesterase in batch mode. Stirring speed (from 200 to 600 rpm) induced an increase in the enzyme inactivation rate while a triple cycle of pressurization/depressurization led to the same enzyme inactivation efficiency. Enzyme inactivation kinetics were determined at different temperatures (from 35 to 45 ºC) and pressures (from 10 to 20 MPa). Data were described by the first order kinetic model and the Weibull model. For the first order kinetic model, decimal reduction time for HPCD treatment was found to be smaller than for mild heating, in the same temperature range. The same tendency was observed for the first decimal reduction time in the Weibull model. HPCD treatment resulted in a homogenization effect reflected in the shifting of the particle size distribution towards smaller diameters after treatment. HPCD treatment did not result in a change of water and oxalate soluble pectin content, total phenolic compounds and hidroxymethylfurfural content.

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This study examines the effects of different formulation parameters on the physico-chemical properties of niosomes containing Span 80 (sorbitan monooleate), cholesterol and/or SDS (sodium dodecyl sulfate), and lactic acid for the future use of formulated niosomes as lactic acid extraction agents in aqueous solutions. Niosomes were prepared by direct ultrasonication of the aqueous samples containing all the aforementioned components. Results revealed that SDS acts as a niosome stabilizer that can be used as a substitute of cholesterol, because it increased the zeta potential absolute value while decreased the particle size. Additionally, SDS also increased the lactic acid entrapment efficiency, which indicates that Span 80 niosomes modified with SDS can be used as selective extraction agents for lactic acid present in aqueous solutions at low concentrations. The best formulation, based on niosome stability and maximum lactic acid entrapment efficiency, was obtained for 20 mol/m 3 of Span 80 + 2 mol/m 3 SDS + 10 mol/m 3 lactic acid, leading to niosomes with 36% of lactic acid entrapment efficiency, −47 mV of zeta potential, and 156 nm of hydrodynamic size.

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