Physicochemical,sensorial and rheological characterisation of whole-fat or low-fat milk jams as influenced by calcium chloride,sodium bicarbonate and sucrose content

Rheological properties of sixteen milk jam treatments produced from commercial full-fat (3 g/100 g) and skimmed (0.15 g/100 g) cow milk by the addition of sucrose, sodium bicarbonate and CaCl₂ were examined. pH, titratable acidity, total solids and ash contents in the milk jam samples ranged from 6.2 to 6.8, 1.3 to 3.3 g/100 g, 56.7 to 70.5 g/100 g and 1.7 to 3 g/100 g, respectively, with a significant variability (P < 0.05). The flow behaviour and consistency indices ranged from 0.7 to 0.9 and 2.7 to 208 Pa.sn, respectively. Rheological measurements showed that the maximal G' × 10² value showed considerable variation (5–932 Pa). As sucrose content increased, pH and total solid content increased, whereas ash content and the L value decreased. Also, a negative correlation between pH and L* (lightness) was found (P < 0.05). Dynamic rheology showed that the jam from skimmed milk with full sucrose and without sodium bicarbonate exhibited more solid-like behaviour than the ones prepared with full sucrose and with sodium bicarbonate. In conclusion, the increase in milk fat caused a decrease in resistance of the mixture subjected to the deformation, which is very important for production of quality milk jam.