Just a few quick notes on the different types of sour cream. Sour cream gets the tangy/sour flavor from lactic acid created by bacteria in the cream (good bacteria)
Regular sour cream – made from cream and contains about 12-16% butterfat
Light sour cream – made from a mixture of milk and cream so the butterfat is reduced around 40% from regular sour cream
Non-fat sour cream – contains to butterfat and uses stabilizers to keep it firm
Creme fraiche (French sour cream) – made from cream and has about 28% butterfat. Made with bacteria cultures but it is thicker and not quite as sour. Doesn’t curdle when cooking.
All commercial sour cream uses stabilizers like corn starch or rennin or gelatin. Obviously there are more in the lower fat/no fat varieties.