Calcium-induced skim milk gels using different calcium salts

•Changes to calcium activity in milk varied depending on type of calcium salt added.•Changes to pH in milk varied depending on type of calcium salt added.•Calcium salts with higher calcium activity induced higher final G′. This study investigated the effects of heating skim milk with soluble calcium salts, calcium chloride, calcium lactate, calcium gluconate and calcium lactobionate, on the physico-chemical and rheological properties of milk. Regardless of the type of salt added, the amount of casein in milk serum decreased and the amount of calcium in centrifuge sediment increased along with the serum calcium. The amount of calcium salt required for gelation and the gel firmness (G′) varied depending on the salt. The aCa2+ order in milk was calcium chloride>calcium lactate>calcium gluconate>calcium lactobionate. With the same amount of added calcium salt, the final G′ of milk gel followed the same order. The findings from this study suggest that the different association constants and formation of an intermediate calcium complex with hydroxycarboylate groups affected the calcium ion activity, which may influence the gelation properties in milk.