EXTRACTION AND COMPOSITION OF THE AQUEOUS -PHASE OF EMMENTALER DURINGRIPENING

A new pressing unit was designed to improve the extraction methodology of the cheese aqueous phase, originally proposed by Barthel at al (19 28a). Emmental aqueous phases extracted from cheeses at different ripe ning ages: after brining - before and after the warm room and at comme rcialization were characterized bacteriologically, physico-chemically and biochemically. Total solids content which is originally 90 g/kg of the aqueous phase increases up to 170 g/kg in the fully ripened chees e phase. Most of this increase in caused by the proteolysis, mainly du ring the warm room period, which leads to a 5 times higher nitrogen co ntent. A large part (56%) of the nitrogen water soluble components is free amino acids, some being at oversaturation (Tyr and Glu). No resid ual sugar was determined in aqueous phase and 25% of the lactate prese nt in the brined cheese phase is consumed by propionibacteria during t he warm room period, mainly as L form. Deep modifications of phosphoca lcic salts are detected: Ca/P ratio varies between 8.2 and 5.4 in the aqueous phase instead of 1.3 in milk. Na/Cl ratio also does not agree with the theoretical value in NaCl molecule, leading to the conclusion that part of Cl ion is mobilized in other saline forms, maybe chlorhy drate. Characterization of the cheese aqueous phase appears to be a pr ivileged methodology to follow precisely the effects of technological cheesemaking parameters and ripening conditions.