Concentrated kefir production by ultrafiltration
Milk-based powders (skim milk powder, sodium caseinate, whey concentrate/isolate) or several filtration techniques (traditional cloth bag, centrifugation, reverse osmosis) can be used in manufacture of concentrated dairy products due to improve the texture, chemical and nutritional properties of products. Besides, membrane technology is one of the methods used to concentrate milk components. In ultrafiltration technique, a membrane with pores of certain sizes that allows the passage of water and small molecules is used. When skim milk is ultrafiltrated, concentration of casein and whey proteins that are larger than membrane pores collected in the retentate. Lactose and minerals in soluble phase of milk are removed with permeate. In previous studies, the ultrafiltration technique was used for Greek-style yoghurt, dahi and labne productions. In recent years, consumption of kefir has increased due to their nutritive value and positive health properties. Kefir is acidic, slightly alcoholic and a viscous fermented dairy beverage that has a health benefits including anti-obesity, anti-oxidative, cholesterol-lowering, anti-allergenic, anti-inflammatory, anti-tumour, and anti-microbial properties. The aim of this work was to manufacture of concentrated kefir by using ultrafiltration technique.