I have been trying to reverse engineer a packaged glaze mix for fruit pies. It weighs 1oz/28g, and contains "modified tapioca starch, citric acid, salt, artificial flavors and coloring." The mix can't be purchased in our area, we would have to purchase an entire case online, hence the drive to replicate it. The instructions are to sift the contents with 3/4 cup sugar, then add 1 cup of very hot water (I used water that had just stopped boiling). Upon mixing with the water, it instantly thickens into gel which is thicker than honey, you fold in fruit, and pour over into a crust and put it in the refrigerator.
Tasting the mix, I approximated just shy of 1oz tapioca starch, 1/8 tsp citric acid, and a small pinch pickling salt. The end result was 1oz, and tasted nearly identical to the packaged mix when raw.
Upon adding hot water, with a tiny amount of water it begins to set up similar to the store bought mix. However once you get beyond 1/4 cup of water, the gel breaks and basically becomes slightly viscous water.
I have tried several times with arrowroot, tapioca starch, potato starch, and I simply cannot achieve the same behavior as the store bought mix. All I can think of is that the "modified" tapioca starch is the secret. But I can't figure out what "modified" means. In the US, in nutritional labling, what can "modified" mean when describing an ingredient?