LAUSR

BACKGROUND In Southern European countries, whey cheeses are normally produced with ovine or caprine whey. Cow's cheese whey can also be used, but whey cheese yield is low (2-3%, w/v) which discourages its use. In the present study bovine cheese whey was concentrated by ultrafiltration for the production of four types of whey cheeses (Requeijão): conventional, without any addition (WC); with 10% (w/w) addition of cream (WCC); with cream fermented with Kefir culture (WCCK); with cream fermented with Bifidobacterium sp. culture (WCCBB12). RESULTS Whey cheeses with cream presented lower protein content (330-360 gkg-1 , db) and higher levels of total solids (220-250 gkg-1 ) and fat (300-330 gkg-1 , db) than WC. C16:0 and C18:1 were the most abundant fatty acids present, with 31% and 38%, respectively. The small differences found concerning instrumental determination of colour and texture, were not perceived by panelysts. However, the presence of Kefir and probiotics decreased the elastic modulus (G') of the samples, as well as their viscosity. Fermentation with Kefir presented the highest counts of LAB (7 logUFCg-1 ). However, after 14 days of refrigerated storage, the counts of yeasts and moulds reached 6 logUFCg-1 in all products, indicating the need for appropriate packaging solutions. CONCLUSION Ultrafiltration of bovine whey allows for the efficient production of bovine whey cheeses. The addition of cream fermented with Kefir or BB12 seems to be an efficient methodology to incorporate Kefir or probiotic bacteria in Requeijão, improving its nutritional and sensory characteristics, alongside with the potential for the extension of its shelf-life. This article is protected by copyright. All rights reserved.