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δ-Octalactone (FEMA# 3214, CAS# 698-76-0) is, puzzingly, one of the least widely used of the entire family of lactones. It has an attractive, predominantly coconut character with significant creamy and hay notes. However, most creative interest amongst δ-lactones is typically directed toward δ-decalactone (FEMA# 2361, CAS# 705-86-2) and δ-dodecalactone (FEMA# 2401, CAS# 713-95-1), both of which are predominantly creamy in character.
Coconut flavors derived from γ-nonalactone are quite powerful, but also relatively harsh and unrealistic. This is not at all surprising, because this chemical actually has no role in the character of coconuts in nature. δ-Octalactone is not normally the lactone present naturally in the highest quantities in coconuts, but organoleptically it is always the dominant note, usually with significant modification from the creamy notes of δ-decalactone and δ-dodecalactone.
Other lactones possessing notable coconut characters are δ-hexalactone (FEMA# 3167, CAS# 823-22-3), which has a dominant hay note; δ-heptalactone (CAS# 3301-90-4), which combines hay and coconut notes; δ-nonalactone (FEMA# 3356, CAS# 3301-94-8), which combines creamy and coconut notes; and γ-octalactone (FEMA# 2796, CAS# 104-50-7), which combines coconut and hay notes. All are interesting but none has the soft, realistic character and wide range of uses possessed by δ-octalactone.