We vacuum pack COPIOUS amounts of supplies. You can vaccum pack stuff like flour, pulses, grains and anything we collect and dry, e.g. mushrooms, powdered mushrooms, that kind of thing; these keep really well, for many years.
Forget mylar bags, they are pointless -AND they do not actually vacuum as that's not what the bags are designed for; you need the textured inside wall in the specific vacuum pack bags to allow sucking out the air. Mylar bags simply seal, otherwise they are too smooth at the mouth and don't allow the vac machine to suck the air out of them, and it struggles. You can add oxy and humidity absorbers, and these will take up all the oxygen and vapours, but they will not do the same 'vacuum' in the same sense as you will achieve with vacuum bags.
Get actual vacuum pack bags, or rolls -better, as you can make them to the length you require. They are dirt cheap, way cheaper than mylar bags.
Mylar bags have their place of course; we use those for sealing stuff like batteries and other stuff that should stay dry or isolated from air. You can add oxy and humidity absorbers, or things like VP90 pads for metal stuff to stop corrosion, but it's pointless for foodstuff as it's too expensive and you are better off with vac bags.
Do not ever try to use vacuum packing in lieu of canning. Unless you are talking about very dried stuff, it does not preserve food. We can a lot of food every year, both water-bath canning and pressure canning. There are very specific guidelines for what can be done and under what conditions, and it will kill you if you get it wrong. Vacuum packing will not stop bacterial growth.
If you make your own pancake mix, or oats and dried fruits, or risotto mix / similar and want to preserve it during hikes, I would recommend vacuum packing. Mylar bags do have the advantage of being resealable though, so you might want to get for those if you won't be using the whole thing in one go. Or, make your own small vacuum bags from rolls cut to the length you want, and portion it.
