The use of Gum Arabic is critical in so many different products from baked goods and candy to medicines and cosmetics. Why haven’t these industries come up with a substitute that could replace it in case something happened to the supply?
For example, the area around Darfur in the Sudan is in turmoil and is one of the prime growing areas of the two kinds of acacia trees that produce Gum Arabic.
If science can’t come up with a substitute, couldn’t these trees be planted in a more stable area with a cheap labor force like Mexico?
Because it’s a highly complex mixture of lots of different high-molecular-weight polysaccharides and polypeptides. There are a few artificial starch products that have some of its qualities - sorta, kinda, if you squint a little - but it’s very hard to chemically synthesize something like this. There would be a great many necessary synthesis steps; furthermore, reliably and efficiently synthesizing specific highly-branched high-molecular-weight polysaccharides is a very non-trivial thing. Not to mention that we don’t fully know the molecular structure of every component of gum arabic - of which, by the way, there are a great many varieties with very different compositions.
The cost of developing a highly complex, most likely low-efficiency process to synthesize what would likely be a poor replacement for the current product would be very high. Nobody would undertake this project unless the current supply entirely dried up - and even then, it’d probably be cheaper to pay for a military expedition to Sudan to stabilize the acacia-growing region than to pay for R&D on this. In all likelihood, the what would happen if the entire supply suddenly vanished is that the poor substitutes developed to date would be pressed into service. It’s the cheapest and most likely the most optimal alternative.
There’s nothing magic about Gum Arabic, but it’s cheap, and it’s used in a lot of different products. Each one of those would have to be reformulated with a substitute. That would not be cheap.
I’ve no idea why they don’t grow the trees in Mexico.