I don't know any Semiotics! But, in an effort to drive the conversation, I can be more precise with what I'm trying to say.
I'm working with this informal idea that there is always a relationship between the audience and the speaker. That relationship define a shared knowledge space.
If I am speaking to a group of my friends and need to refer to my brother the set of identifiers that uniquely conveys his identify to my friends might be {brother, Joe, Joe Blow, brother-man, etc}. Any of those identifiers coming from to me specify exactly one person, my brother. The degeneracy is that they equally identify him to the audience.
If you were not that close to me, and I say "brother", you might wonder if I have more than one brother. If you did not know me at all I might say Dr. Joe Blow to identify him and why he might be relavent in some area of expertise. As the relationship between speaker and and audience grows more distant the set size decreases. Inversely, the context-free uniqueness of the identification provided by the remaining identifiers has to be greater, with proper names maintaining greater uniqueness (sorry to the John Smiths of the world!) than nicknames and so forth.
To return to my point, the scientist in question called it Nutella because he does not have a deep relationship with his audience and that is the most unique way of identifying it. I don't believe he was doing anything atypical or nefarious. If he knew the audience well, he could have just said "breakfast", and they would know exactly what he meant because he has the same thing for breakfast most mornings.
The problem is that brands, unlike most proper names(obviously famous people are an exception), have a greater ethos associated with them. If my brother was named Joe Blow or Jim Deal, my unique referencing of him doesn't do much to color the statement around it. This is contrast to how much extra you get when you call a car a Ferrari vs a grand tourer. My point is that advertisers recognize this linguistic norm and exploit it, this is what brand identity is. As such, just the natural mention of a good becomes advertising.