Can I substitute agar-agar for gelatin in pudding?
Agar is not a good choice for pudding because it makes a brittle gel and it won't melt in your mouth at body temperature. What you want for pudding is a starch based thickener. What we call pudding in the US at least is typically thickened with cornstarch. Modified starches like Ultra-Tex 3 can also work well. Are you thinking of something more along the lines of panna cotta, which does normally have gelatin in it? If so, you might try carageenan instead of agar. Here's a recipe that looks promising: http://irishherault.wordpress.com/2009/12/24/vegetarian-panna-cotta/