See, each hydrocolloid or modified starch is selected based on their functionality or more specifically viscosity. Arabic gum is very thin and Newtonian in nature up to 30% concentration whereas pectin (depends upon the grade of the pectin). First you check the product where you would like to add hydrocolloid. You can check some of our paper if you are interested about rheology or viscosity. All the best.
Literature suggests that a modified starch, i.e. N-octenylsuccinylated starch (OSA-starch), is able to replace gum arabic in some applications. Commercial products are already available. See the attachments derived from Google Scholar. Functionality of OSA-starch depends on degree of modification (for tuning the emulsification properties) and degree of hydrolysis of the starch (for tuning the rheology).
As to pectin, the situation is more complicated because pectin displays its gelling functionality only at specific media conditions such as low pH and high sugar concentrations.