Membrane Application for Food Industry

As a result, a new food service industry has emerged, supplied by food manufactures with high-quality, especially developed products, packaged in large container, refrigerated, thermally processed or frozen.

In developing countries food must be available and accessible to every person in nutritious, safe and appetising forms. This means that every consideration must be given to the entire food chain, from production to processing, distribution, consumption, and biological utilization.

The application of innovative techniques such as Membrane Technology (MT) in food transformation processes represents a real opportunity to increase and quality the productivity and reduce the environment pollution of farms. The commercial application of MT in food processing industry includes concentration of oil emulsions, blood treatment for proteins recovery, clarification of wine, concentration of fruit juices and treatment of a variety of food processing waste stream.

In general, MT’s are applied in different unit operations: concentration, purification, clarification, recovery and upgrading of products.

These operations allow to increase the product quality (taste, aroma, apperance,…), the recovery of process byproducts and a high reduction of the process energy consumption. In addition, MT permit a strong reduction of chemicals used for clarification or flocculation of raw natural compounds such as wine, vinegar, beer, fruit juices, coffee, tea, etc.

A substaintial difference between MT and the conventional filtration (dead-end filtration) regards the operation mode, as schematized in Figure 1. In the same figure the morphology of microfiltration membranes are reported.

In MT, the membrane module is operated in a continuously self-cleaning mode, with solutes and solids swept away by the concentrate stream which is running parallel to the membrane surface, hence the term “cross flow” or tangential filtration. In MT the concentrate stream, retained by membrane, can be recirculated through the module in order to obtain the desired concentration ration (VRC). This parameter is given by the ratio between feed volume and final concentrate volume.

Contrary to the distillation process, in MT the separation takes place in isothermal conditions without phase transition, with the opportunity for reusing both concentrate and permeate streams. This permits an energy saving and a low environmental impact, because no byproduct are generated during the seperation process.