Study of the rheological behavior of the calcium and sodium caseinate irradiated dispersions

Milk isolated proteins has gained a crescent commercial interest due to functional properties allied to excellent nutritional value. These properties could be improved when some treatments are applied, such as gamma-irradiation, combined or not with plasticizers. In the current work, protein solutions (calcium and sodium caseinates) were mixed with glycerol. The mixtures (8% protein base), at the ratios 1:1 and 2:1 (protein: glycerol) were submitted to gamma-irradiation (60 Co), in the doses 0 kGy, 5 kGy, 15 kGy and 25 kGy, and the rheological behavior was studied. The irradiation was in a 60 Co source, model Gammacell 220 (AECL), with dose ratio 8.2 kGy/h. The viscosity measurements were made in a Brookfield, model LV-DVIII, spindle SC4-18 and SC4-31, according methodology described previously, at temperature 10.0 deg C ± 0,1 deg C, using a Neslab water bath. As irradiation dose increases, the viscosity measurements decrease significantly (p<0.05) for calcium/glycerol solution. The measurements for sodium/glycerol mixtures remained constant as dose irradiation increases, with a slight augmentation at 5 kGy. (author)