I beliee it is a flavor neutral amd tasteless additive. This, however does not mean tasteless.But, chances are you tasted MSG, salt, and preservatives. Natural or not, I cannot tell.
I agree with devilsknew, xanthan gum is a viscosity modifier with no discernable tast in the amounts normally used in cooking. I checked the ingredients for Newman’s marinades and the fat free ones are lemon pepper and teriyaki. Neither one has any listed ingredients that would give an objectionable taste, although both were full of chemicals. Which one was it that gave you the problem?
When you use a thickener, it generally takes more of a spice to achieve the same intensity of taste. I’ve no cite, but I’m pretty sure that different flavors are affected to varying degrees by changing viscosity. So while a thickener may not add a flavor, it can effectively change the flavors that are already there.
The structure of the thickening agent used matters too. Slimyness is an issue with xanthan gum too. That can wreck anything.
Xanthan gum - it’s in everything. Food, face soap, toothpaste… shudder
Once I started noticing it, I pointed it out to friends and now we have a tin-foil hat theory that xanthan gum works as a mind control agent.
I’ve been experimenting lately with xanthan gum as a stabilizer in savory sauces, as opposed to the more traditional flour, cornstarch, etc. It’s definitely got a different texture profile, but I don’t detect any flavor. And, if I do say so myself, I’ve got a pretty senstitive palate for such things.
I’m with you regarding the non-fat dressings universally tasting off, but I don’t think it’s due to any specific ingredient. More likely it’s because most flavors and spices are either water soluble of fat soluble. In a specific fat-free recipe there are going to be flavors that simply disappear without the fat to carry and distribute them, the lack of those flavors will in effect amp-up the water soluble flavors. I think that what you are finding objectionable is the water soluble flavors coming on too strong and unbalanced.
I think I have some Xanthan powder in a cupboard somewhere - left over from my experiments with gluten-free bread making - if I still have it, I’ll try tasting some alone and report back.
If I don’t report back, assume that when consumed alone, it tastes deadly.
I’ve got a package of powdered xanathan gum, and it’s tasteless, although it has a definite mouth “feel” to it. Comes in handy as a sauce thickener when eating a low carb diet.