Corn starch vs arrowroot...even exchange?
The answer is yes and no.The following is PUBLIC DOMAIN TEXT,hope it helps.I use it often to avoid allergies and stay KOSHER for PASSOVER.
to substitute a pure starch for a roux (wheat flour and fat)10oz roux is by weight 60% flour. (thickening power .60)
Thickening power rice flower:0.6 arrowroot:0.5 potato starch:0.2 cornstarch:0.5
arrowroot more translucent than cornstarch,does not gel or weep when cooled
cornstarch,translucent,thickens when heated,gels and weeps upon cooling,power diminishes with excessive heating
tapioca/cassava flour,translucent,thickening power a tad more than cornstarch
potato starch,translucent,MORE thickening power than cornstarch(x2) stable and cheap
rice flour,translucent,relatively weak thickening power,FREEZES well,expensive
Health options are about the same.I have a problem with corn so use the alternatives.
Found on the shelf of all the Asian markets I frequent.
Temperature sensativities vary some,a little practice is all you need.
hope this helps
Though I don't know about the health effects (one isn't normally using a whole lot of either, I suppose!), I believe the two have approximately the same thickening power in water (so it would be one to one for water or stock), but don't behave the same in other liquids. In particular, arrowroot doesn't seem to do well in thickening dairy, and cornstarch doesn't do much in acid (so doesn't work well in pie, for example). If you're looking for alternatives, potato starch and rice flour also work well in many contexts!