Hi Andy I bought the traganth gum from a cake decorating supplier, but you can also get it from a natural handmade cosmetics supplier (google for company names) - it's added to creams etc to add with the smooth feel, and is usually food grade. Guar gum, pectin and gelatine can be used. I believe that these ingredients are the basis (in some combination) of the commercially available sorbet stabilisers. Trish