What are two functions of citric acid in the feta cheese? what are the two functions of agar in the feta cheese?

The following are the two functions of citric acid in the feta cheese:  

1. Coagulation, that is, the chemical reaction of citric acid with proteins in milk leads to separation of curd and whey.  

2. The citric acid functions as a chelating agent, which is required for syneresis, that is, for controlling the moisture content.  

The following are the two functions of agar in the feta cheese:

1. Feta means to slice, and agar offers sliceable texture to the feta cheese as it produces a solid gel-like composition.  

2. It is a vegetarian alternative for gelatin and exhibits higher gelling properties.