I'm trying to make strawberry jam with agar-agar as replacement of pectin, where for it I'm using 0,4% of agar (of final product). I have read in many places that by replacing 0.1-0.2% of agar with locust beam gum is possible to prevent syneresis effect. My problem is that I tried but it does not work very well. After a single day water starts to show up. On the contrary, the same recipe but with pectin is syneresis free. So, is it possible to totally prevent syneresis using agar-agar?
Unfortunately, syneresis is a byproduct of an agar gel. It is the nature of the molecular structure formed in the gel. This can be desirable, especially when using agar as a clarifying agent, however, not good for your jam. According to www.molecularrecipes.com, you can prevent this by replacing 0.1 - 0.2 percent agar with locust bean gum. I see you've tried this, but it is the common wisdom/suggestion. Maybe up the lbg a little? Alternate thickeners are gelatin, arrowroot or chia seeds.