Aliphatic aldehyde production in butter-peppermint flavored candy (Buttermints)

 From a reputable, well-established company.

Tonic water deterioration

 Dimerization of active ingredient; discoloration

Pleasant aroma from Magnolia

Pleasant aroma from Texas Mountain Laurel

 Pleasant aroma from Texas Mountain Laurel 

One of the earliest trees to produce prominent & fragrant blooms in spring

A case of "crazing" (numerous fine cracks) at the bottom of a 2 liter bottle of Coke

Some breakdown products in Olive Oil of various grades

Aliphatic aldehyde production from peanuts and peanut butter