Hybrid technologies: examples of applications

Food and beverage processing

Membrane filtration is a good example of a simple and efficient technology used to enhance food quality with excellent future prospects. The use of membrane filtration offers a wide range of advantages for the consumer as well as for the producer. On the one hand, filtration technology offers an efficient way to gain superior quality and safety without destroying the fundamental sensory qualities of the product.

It removes unwanted ingredients like microorganisms, dregs or sediments that have a negative impact on product quality, making the final product more attractive in texture and increasing its shelf life. On the other hand, it may reduce some production steps and increase yield, has a high degree of selectivity, improves control over the production process and has low energy costs.

In the food and beverage industries, membrane filtration is state-of-the-art technology for clarification, concentration, fractionation (separation of components), desalting and purification of a variety of beverages. It is also applied to improving the food safety of products while avoiding heat treatment. Some examples of final products using this technique are fruit and vegetable juices, like apple or carrot; cheeses, like ricotta, ice cream, butter or some fermented milks; skimmed or low-lactose dairy products; microfi ltered milk; non-alcoholic beers, wines and ciders, etc. Membrane equipment for the dairy industry has become integral to manufacturing milk, cheese and whey proteins.

• Cheese making: Ultrafi ltration of milk represents the fi rst real innovation in the history of cheese making. During the cheese making process UF is an effective means of recovering the by-products that are otherwise lost in the whey. At the same time cheese products of higher nutritional value are obtained at a better price.

• Microfiltered milk: Classical techniques used to improve milk’s shelf-life and safety are based on heat treatments, like pasteurisation and sterilisation. Microfi ltration constitutes an alternative by improving the microbiological safety of dairy products whilst preserving the taste.

Despite the market’s age, there are still emerging, and potentially large growth applications in protein isolation and other uses of separation. Manufacturers are placing increased emphasis on using membrane methods to replace functions formerly performed by chemical processing. One area of focus is removing or minimizing problems associated with diatomaceous earth (DE) in beverage processing. Substituting membranes for DE in these applications is more environment-friendly, it protects the health and safety of the workforce, and more efficiently and economically resolves maintenance and disposal issues.

In numerous industry processes, competitive technologies (such as centrifugation, adsorption, evaporation, distillation, pasteurization, and ion exchange) are used as a complement to methods based on membrane technology. In many instances, this hybrid approach helps manufacturers ensure the quality and safety of products as required by consumers and government agencies. The development of filtration techniques and their distribution is not yet complete. There is continuing development of new applications based on the technique. New methods, in particular development of better and longer lasting membranes, offer new perspectives. Nanofiltration (for selective recovery of high value compounds), membrane reactors (with enzymes for biotransformation or viscosity reduction) and membrane contactors (e.g. membrane evaporation for the concentration of fruit juices) have emerged as technologies with a strong growth potential.