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Hausmann A.,Institute for Sustainability and Innovation | Sanciolo P.,Institute for Sustainability and Innovation | Vasiljevic T.,Victoria University of Melbourne | Kulozik U.,TU Munich | Duke M.,Institute for Sustainability and Innovation
Journal of Dairy Science

Membrane distillation is an emerging membrane process based on evaporation of a volatile solvent. One of its often stated advantages is the low flux sensitivity toward concentration of the processed fluid, in contrast to reverse osmosis. In the present paper, we looked at 2 high-solids applications of the dairy industry: skim milk and whey. Performance was assessed under various hydrodynamic conditions to investigate the feasibility of fouling mitigation by changing the operating parameters and to compare performance to widespread membrane filtration processes. Whereas filtration processes are hydraulic pressure driven, membrane distillation uses vapor pressure from heat to drive separation and, therefore, operating parameters have a different bearing on the process. Experimental and calculated results identified factors influencing heat and mass transfer under various operating conditions using polytetrafluoroethylene flat-sheet membranes. Linear velocity was found to influence performance during skim milk processing but not during whey processing. Lower feed and higher permeate temperature was found to reduce fouling in the processing of both dairy solutions. Concentration of skim milk and whey by membrane distillation has potential, as it showed high rejection (>99%) of all dairy components and can operate using low electrical energy and pressures (<10kPa). At higher cross-flow velocities (around 0.141m/s), fluxes were comparable to those found with reverse osmosis, achieving a sustainable flux of approximately 12kg/h·m2 for skim milk of 20% dry matter concentration and approximately 20kg/h·m2 after 18h of operation with whey at 20% dry matter concentration. © 2014 American Dairy Science Association. Source

Cran M.J.,Institute for Sustainability and Innovation | Rupika L.A.S.,Victoria University of Melbourne | Sonneveld K.,Victoria University of Melbourne | Miltz J.,Technion - Israel Institute of Technology | Bigger S.W.,Institute for Sustainability and Innovation
Journal of Food Science

The migration of the naturally derived antimicrobial (AM) agents, linalool, carvacrol, and thymol, from low-density polyethylene (LDPE) films containing ethylene vinyl acetate (EVA) copolymer into the food simulants, isooctane and various ethanol/water mixtures, was studied with a view towards examining the applicability of a first-order kinetic approach as well as a diffusion model approach for describing these systems. The results suggest that the proposed models adequately describe the release of AM agents. The combination of kinetic and diffusion analyses can provide additional information about the release process using the same data set. The analyses suggest that the release of linalool from LDPE/EVA depends on the EVA content in the formulation and that an optimum level of EVA is required to minimize the rate of release. A modification of the existing " idealized diffusion" model is proposed that enables the model to be applied to systems that demonstrate a departure from linearity when subjected to conventional analysis. The applicability of the idealized diffusion model was compared with the " simulant-limited" model and the results suggest that the former model is appropriate for describing most real systems when the simulant (or foodstuff) is favored in the partitioning of the AM agent between the film and the simulant. © 2010 Institute of Food Technologists®. Source

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