Of these four titular ingredients, can someone please help elucidate for me when one would want to use each one? So far the only one I've used personally is glucomannan(konjac root flour), and I have used it in a pudding and in cakes, both of which completely lacked any sort of grain or flour. I'm wondering primarily for making things like syrups, sauces and jellies. I've stumbled across some Walden Farms products and saw that different combinations of these gums seem to appear in nearly all of their products and was wondering what I would want to use to imitate those recipes. I've seen recipes like this online: http://gwens-nest.com/stevia-syrup-recipe/ And also like this: http://jamesonwolfffitnesssystems.com/2014/homemade-walden-farms-pancake-syrup/ And am not sure what to expect the difference(s) between them to be. Would I be able to get away with only using glucomannan, or would that only be able to give me a "solid" gel and not a syrup? If it wouldn't work, what would? Any help appreciated.
Methyl Cellulose is the same stuff used in wallpaper paste. Food grade, with no fungsides added (etc) obvious.
A notable property is that it thickenes as you heat it. And it thins as it cool. The oposite of most gels. This let's you create things like 'hot ice cream'
Guar and Xanthan gums are ment to be pretty interchangeable in baking (I think). I find that Guar gum when used in sauses/gravey can be a bit slimy to my taste. (I haven't tried Xanthan gum for that yet)
I haven't used glucomannan before.
There are a few other gelling agents you can look at:
Sodium alginate. Made from seaweed. This is the thicker used in MacDonald's apple pies. It is temperature stable. (Same thickness hot or cold) Adding calcium causes it to thickened more. This let's you make 'fruit caviar' by dropping slightly thickened juice into a bath of water with calcium added.
There are kappa and iota carrageen. Also made from seaweed. I forget which but one is a very brittle gel (think like jello or egg white) the other is a not brittle (think soft boiled egg yoke)
There is gelan. It is very clear. Good for making fancy cocktail jelly's. Haut couture jello shots!
There is pectin. Made from citrus. This is what makes jam thick. Nuf said.
This site has some good info, recipes, and a shop for these gelling agents etc: http://molecularrecipes.com/
I don't know about the other two, but both xanthan and guar gum are hydrocolloids (hydrocolloids are essentially substances that gel up in the presence of water). Guar gum comes from the guar bean while xanthan gum is essentially bacteria poop. Both gums are usually used in commercial ice creams; guar gum helps prevent the formation of ice crystals while xanthan gum helps retain the air. If you want to read up more about these, try ChefStep's Ingredient Wiki. They might have information on the other two.
Glucomanan (konjac root) is suitable for making syrups, but it will have a different consistency than xanthan (some people use them completely interchangeably in puddings and sauces), though it is completely interchangeable with xanthan gum/guar gum in gluten free baking. Cellulose gum is also very similar to guar gum.