Processed Cheeses Made With and Without Peptization. Submicroscopic structure and thermodynamic characteristics

The osteoporosis is regarded as a widespread disease all over the world. In the prevention therapy of this disease there is a primary role of the daily calcium intake with the proper Ca:P ratio (1:1–1:2). The primary source of Ca for people the dairy products are implied, from which only the processed cheeses have inadequate ratio of Ca:P. In cheeses processed without peptization developed in the Hungarian Dairy Research Institute (HDRI) the Ca:P ratio meets the requirements (1.5:1), moreover these products can be enriched with Ca. In this study we used both processing technologies. The electronmicroscopic photographs demonstrate the differences clearly. The traditionally processed cheese (with peptization) has a 'spongy’ structure well known from literature, while a space-net can be seen resulting from the casein-filamentous hydrocolloid interaction in the structure of heat-treated cheese without peptization. DSC curves are the same in the temperature range 0–40°C, showing endotherm melting process in two well-distinguished temperature interval (0–20 and 22–40°C). They are different in the temperature interval 40–100°C: in the case of processed cheese with peptization the gel-sol transformation gives a higher endotherm peak in a narrow temperature range, while for heat-treated cheese without peptization this temperature range is wider with a lower endotherm peak. Both electronmicroscopic and DSC investigations have proved that contrary to the traditionally processed cheese where the structure is formed by the linked peptized protein, in the heat- processed cheese without peptization the frame-forming element is the huge hydrocolloid molecule interacted with the protein. The enthalpy change is substantially lower at the disintegration of the latter structure. This revised version was published online in July 2006 with corrections to the Cover Date.