Sensory characteristics of membrane treated-milk (Studies on the sensory characteristics and physicochemical properties of UHT processed milk, 6)

For the purpose of investigating the influences of monovalent minerals on the sensory characteristics of milk, the physicochemical properties of milks composed of a mixture of two UHT nonfat milks, namely reverse osmosis membrane-treated milk and nanofiltration membrane-treated milk, were studied and a sensory evaluation of these milks was conducted by a panel of 31 experts. The nanofiltration membrane-treated milk had a lower monovalent mineral content and had a lower electrical conductivity than the reverse osmosis membrane-treated milk, but no differences were found between them in regards to their divalent minerals, lactose, and protein contents. An evaluation of their sensory attributes and a principal component analysis of these attributes revealed the following results : the higher the proportion of the reverse osmosis membrane-treated milk, the higher the thickness of the nonfat milk, and the higher the proportion of the nanofiltration membrane-treated milk, the higher the thinness and the sweetness of the nonfat milk. Comprehensive evaluation of the palatability of the nonfat milks showed that nonfat milk composed of reverse osmosis membrane-treated milk and nanofiltration membrane-treated milk in a proportion of 2 : 1 was most preferred, and that moderate levels of saltiness and moderate thickness derived from the minerals in the milks were important factors for palatability.