Propylene Glycol (E1520)

No. Propylene Glycol (E1520) is not one of the markers Open Food Facts uses to classify a food as processed or ultra-processed, so on its own it doesn't raise a product's NOVA group.

What it is

Emulsifiers are substances which make it possible to form or maintain a homogenous mixture of two or more immiscible phases such as oil and water in a foodstuff.

A product that contains it can still be ultra-processed for other reasons: 12 of the 14 products here that contain propylene Glycol (E1520) (86%) are in group 4 because of other ingredients or additives.

Function

Emulsifier: Emulsifiers are substances which make it possible to form or maintain a homogenous mixture of two or more immiscible phases such as oil and water in a foodstuff.
Humectant: Humectants are substances which prevent foods from drying out by counteracting the effect of an atmosphere having a low degree of humidity, or promote the dissolution of a powder in an aqueous medium.

Functional class definitions from the EU food additives regulation, via Open Food Facts.

More about propylene Glycol (E1520) on Wikidata