Calcium-induced skim milk gels: Impact of holding temperature and ionic strength

The effects of holding temperature and ionic strength on the physicochemical and rheological properties of calcium-added skim milk were investigated. In skim milk with 10-20 mmol L-1 of added calcium chloride, increasing the temperature from 20 to 53 degrees C decreased the calcium ion activity and pH, but increased the particle size. Increasing the holding temperature from 70 to 90 degrees C increased the final G' of skim milk gels with 10-40 mmol L-1 of added calcium chloride. No gelation was observed when calcium chloride was replaced with sodium chloride to the equivalent ionic strength (60-120 mmol L-1). Furthermore, adding sodium chloride in addition to calcium chloride resulted in lower final G'. The results showed that the gel strength of calcium-induced skim milk gels was influenced by holding temperature, and the effect of ionic strength was dependent on the type of salt added (Ca(2+ )or Na+). (C) 2020 Elsevier Ltd. All rights reserved.