Recent and emerging applications of membrane processes in the food and dairy industry

Membrane processes have been major tools in food processing for more than 25 years. The food industry represents a significant part of the turnover of the membrane manufacturing industry world-wide. The main applications of membrane operations are in the dairy industry (whey protein concentration, milk protein standardization, etc.), followed by beverages (wine, beer, fruit juices, etc.) and egg products. Among the very numero ts applications on an industrial scale, a few of the main separations which represent the latest advances in food processing, are reported. Clarification of fruit, vegetable and sugar juices bl, microfiltration or ultrafiltration allows the flow sheets to be simplified or the processes made cleaner and the final product quality improved. Enzymatic hydrolysis combined with selective ultrafiltration can produce beverages from vegetable proteins. In the beer industry, recovery of maturation and fermentation tank bottoms is already applied at industrial scale. During the last decade significant progress has been made with microfiltration membranes in rough beer clarification which is the most important challenge of this technology. In the wine industry the cascade cross-flow microfiltration (0.2 mum pore diameter) - electrodialysis allows limpidity, microbiological and tartaric stability to be ensured. In the milk and dairy industry, bacteria removal and milk globular fat fractionation using cross-flow microfiltration for the production of drinking milk and cheese milk are reported. Cross-flow microfiltration (0.1 mum) makes it possible to achieve the separation of skim milk micellar casein and soluble proteins. Both streams are given high added value in cheese making (retentate) through fractionation and isolation of soluble proteins (beta -lactoglobulin; alpha -lactalbumin) (permeate). At last, a large field of applications is emerging for the treatment of individual process streams at source for water and technical fluids re-use, and end-of-pipe treatment of wastewaters, while reducing sludge production and improving the final purified water quality.