Abstract: In this experiment, we investigated the impacts of calcium chloride addition at different levels (0.1%, 0.2%, 0.3% and 0.4%) on rheological, gel and texture properties of apple pectin-apple polyphenol compound so as to determine the optimal concentration of added calcium ions in calcium-fortified foods produced from apple pectin and apple polyphenols. The results showed that addition of calcium chloride had a notable influence on both rheological, gel and textural properties. Gel strength increased with calcium chloride addition up to 0.3% and then decreased. In addition, the gel formation rate gradually accelerated, the gel structure became more stable, leading to good gel properties, with increasing calcium chloride addition to 0.3%. But when further increasing the amount of added calcium chloride, the gel stability continued to decrease, and the gel formation rate became slower, prolonging the gel formation process. Moreover, texture properties of apple pectin-apple polyphenol compound were also greatly influenced by addition of calcium ion. Compound hardness, elasticity, viscosity, cohesiveness and chewiness increased to the maximum values with increasing addition of calcium ion to 0.3%, and then decreased with further increase in calcium ion addition. Therefore, in order to ensure the optimal rheological, gel and textural properties of calcium-fortified foods containing apple pectin-apple polyphenol compound system, the calcium ion concentration should be set as 0.3%.

Key words: apple pectin, apple polyphenols, calcium ion, rheology, gel properties, textural properties