Utilisation of Whey

Utilization of whey has been of great concern in the dairy industries engaged in manufacturing of cheese and coagulated milk products. The techno-economic problems associated with the utilisation of whey have been receiving considerable attention and remarkable advancements have been made. Today, modern industrial processing techniques such as ultrafiltration (UF), reverse osmosis (RO), new drying methods, hydrolysis, electrodialysis, ion-exchange, fermentation and protein fractionation, among others, have converted whey into a major source of ingredients with differing functional and nutritional properties, that could be used in food and dairy industry. The predominant driving force behind the development of whey utilisation has been stringent regulations imposed by the environmental pollution agencies all over the world. Other aspect relates to economic return from whey,which contains almost half the solids of original milk. Presence of lactose, protein,minerals and water- soluble vitamins make the whey a highly nutritious product.

Being a rich source of lactose, whey is a good fermentation media for a number of fermented products. In many applications, lactose in whole or deproteinised whey is hydrolysed to glucose and galactose, thereby increasing its sweetness. Such lactosehydrolysed syrups, generally after condensing, are mostly utilised in sweet confectionery products and in ice cream.

The production of whey beverages, whey protein concentrates, lactose, and many others product from whey have prominence in advanced dairy countries, but Indian dairy industry is still a novice in this field. It is only during the about last 12 years that with the economic liberalisation and delicensing of the dairy industry, rapid changes are being witnessed in Indian dairy industry. A number of by-products based dairies with large automatic and continuous manufacturing plants have been set up.

Whey cheeses like Gjetost, Mysost and Gudbrandsdulsost are produced in Norway,while Manouri, Anthotryos, Cryzittroa and Giza in Greece. The names of whey cheeses in Greece indicate their quality. Ricotta cheese is another cheese, which is popular in Italy and in many other countries.

A major problem with many whey based products is their salty flavour owing to their high mineral content. A small percentage of utilised whey (less than 5%) is demineralised to produce dry demineralised whey for specialised uses. These include whey protein based infant formulas and other medical and nutritional products that require lactose, special nutritional quality of whey proteins and low mineral content.

Demineralized sweet whey (25-65% demineralization) can be used in foods such as coffee whitener, soft serve ice cream, milk shakes, whey drinks and caramel, citrus drinks, salad dressing, animal feeds, bakery goods, confectionery coatings and dry mixes.

Despite significant gains in the amount of whey being processed, a large amount of whey produced still is disposed off as raw whey. Much of this represents production from small plants, where the cost of purchasing, processing as well as the subsequent transportation and handling clearly exceeds the value of any whey product that might be produced. In small plants, the choice remains some form of disposal, be it municipal treatment, spreading raw whey on local farm lands for its nutrient value or feeding to local livestock. Further, acid whey, because of high mineral content and low pH pose considerable difficulties in utilisation and, therefore, mostly remain unutilised.