Ask A Scientist Chemistry Archive

Question:
I have a question about the so called fat free foods.  If you read the label
on some of them, there are di- and monoglycerides.  While fats are
triglycerides, aren't these substitutes very similar?  I also heard that
legally this is a kind of loophole, that these fat like materials can
be added to food without having to be listed as fats.
So I guess I would like to know, are these just as harmful as fats?
Can't they be saturated as well?
Any sources I can go to read more about this?
I am a chemistry teacher in High School, but a Zoology major, so please
take that into account when listing sources.

Thank You
 aram n langhans

Answer:
Gee, I'm no biochemist so I'm, really not qualified to answer
this one, but here goes...You asked several questions.
First of all, I don't know about whether di-and mono-glycerides
are as "harmful" as triglycerides...it depends on whether the
body handles them in a way similar to the way it handles
the tri-glycerides...evidence seems to be that saturated tri-glycerides
promote the deposition of plaque (solid deposits) in the arteries,
but I've never heard anyone say that this is also true of the
artificial mono- and di-glycerides. Maybe the jury is still
out on that.
 
As to your other question, yes, the mono-and di-glycerides can
be saturated. As you probably know, the term "saturated" means
that all of the C-C bonds on the long chains attached to the
glycerol are single bonds, i.e., there are no double bonds to
eliminate by adding hydrogen to both carbons (hydrogenation).
This is a general term which can be applied to any hydrocarbon
with no double or triple C-C bonds (but is usually reserved for
the alkane chains in triglycerides).
My source: "Chemistry" by Radel and Navidi (1994).
Hope this helps - anyone else who can comment on the metabolic
properties of this stuff?
-topper