Replacing acetaldehyde for regulatory reasons is an interesting challenge. The character of this aldehyde is quite distinctive, sharp and pungent, adding unique freshness to a wide range of profiles but especially important for juicy orange flavors. Propionaldehyde is one possibility, but it has a noticeably harsher character than acetaldehyde. Additionally, the distinct disadvantage of readily forming acetals with propylene glycol is having peculiarly unattractive profiles. The next best alternatives are the acetals of acetaldehyde itself. A wide range are now available and most have attractive profiles. Of these, the best option is probably the most obvious, acetal (FEMA# 2002, CAS# 105-57-7), which is the simple acetal formed from acetaldehyde and ethanol.