Ultrafiltration dairy industry

In the dairy industry the high content of minerals in cow milk (Table IX) restricts the commercial utilization of its main by-products, that is, whey and ultrafiltration permeates. The discovery that desalted whey could be used in baby food production as an economic alternative to the more expensive skim... 

Ultrafiltration of whey is a major membrane-based process in the dairy industry however, the commercial availability of this application has been limited by membrane fouling, which has a concomitant influence on the permeation rate. Ultrasound cleaning of these fouled membranes has revealed that the effect of US energy is more significant in the absence of a surfactant, but is less markedly influenced by temperature and transmembrane pressure. The results suggest that US acts primarily by Increasing turbulence within the cleaning solution [91]. 

Beaton, N.C., Ultrafiltration and reverse osmosis in the dairy industry—an introduction to sanitary considerations, J. Food Prot., 42, 584, 1979. 

Maubois, J.L., Recent developments of ultrafiltration in the dairy industry, Polym. Sci. Technol., 13, 305,1980. 

Glover, F.A., The processes, in Ultrafiltration and Reverse Osmosis for the Dairy Industry, Technical Bulletin 5, The National Institute for Research in Dairying. Reading, England, 1985. 

Membrane processes are one of the most important separation technologies in food industry. The operate, at room temperature, require no addition of chemicals and are gentle and non-destruc ive. Their potentiality is confirmed by an annual growth rate of 37% (1). However the major area for ultrafiltration and reverse osmosis in food applications is mainly whey purification, and the dairy industry in general. This market has been estimated of 2 million US dollars in 1976 and 5 million US dollars in 1981. 

Industrial Application of Ultrafiltration and Hyperfiltration in the Food and Dairy Industries... 

The concept of coupling reaction with membrane separation has been applied to biological processes since the seventies. Membrane bioreactors (MBR) have been extensively studied, and today many are in industrial use worldwide. MBR development was a natural outcome of the extensive utilization membranes had found in the food and pharmaceutical industries. The dairy industry, in particular, has been a pioneer in the use of microfiltra-tion (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) membranes. Applications include the processing of various natural fluids (milk, blood, fruit juices, etc.), the concentration of proteins from milk, and the separation of whey fractions, including lactose, proteins, minerals, and fats. These processes are typically performed at low temperature and pressure conditions making use of commercial membranes. 

The ultrafiltration of milk using polysulphone or polyethersulphone type membranes has a number of applications. The ultrafiltration of milk on farms as a means of reducing refrigeration and transport costs, and the production of speciality milk-based beverages are attractive uses. Cheese manufacture using ultraliltration is another area where the use of membrane filtration is becoming more widespread in the dairy industry. 

Ultrafiltration is currently dominated by two large apphcations, the recovery of electropaint waste water and the recovery of proteins from dairy wastes. The former application results from the use of solvent-free paints, especially for automobiles. These paints are electrostatically apphed. Any wash water is then processed to recover suspended pigments and other colloidal material. In the dairy industry, cheese whey can be concentrated and purified. In some cases, ultrafiltration concentrates valuable albumins that are lost in conventional processes. 

The largest industrial use of ultrafiltration is the recovery of paint from water-soluble coat bases (primers) applied by the wet electrodeposition process (electrocoating) in auto and appliance factories. Many installations of this type are operating around the world. The recovery of proteins in cheese whey (a waste from cheese processing) for dairy applications is the second largest application, where a... 

Ultrafiltration is used in a wide range of applications, mainly in the food, dairy, textile, metallurgy and pharmaceutical industries. The feed is generally an aqueous solution containing macromolecular solutes, emulsions or suspended solids. Flux decline due to concentration polarisation and fouling presents a serious problem. To reduce this phenomenon, high cross-flow velocities are required. 

The Laboratory of Dairy Technology Research of the Institut National de la Recherche (INRA) in Rennes, France, is investigating the application of these techniques for improved propionic acid production (Boyaval and Corre 1995). Colomban et al. (1993) demonstrated the production of propionic acid from whey permeate by P. acidipropionici at high cell density combined with sequential cell recycling and ultrafiltration. O Figure 3.3 is a diagram of the process employing a 5-m industrial pilot plant bioreactor. 

Poly(vinylidene fluoride) (PVDF) is one of the promising polymeric materials that has prominently emerged in membrane research and development (R D) due to its excellent chemical and physical properties such as highly hydrophobic nature, robust mechanical strength, good thermal stability, and superior chemical resistance. To date, PVDF hollow-fiber membranes have dominated the production of modem microfiltration (MF) ultrafiltration (UF) membrane bioreactor (MBR) membranes for municipal water and wastewater treatment and separation in food, beverage, dairy, and wine industries. In the last two decades, increasing effort has been made in the development of PVDF hollow fibers in other separation applications such as membrane contractors [6,7], membrane distillation (MD) [8-11], and pervaporation [12,13]. 

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