Identification of objectionable flavors in purported spontaneous oxidized flavor bovine milk

Abstract

Spontaneous oxidized flavor (SOF) has been reported over the past 5 decades as a sporadic objectionable flavor problem in bovine milk. Parameters previously reported to influence SOF development in milk have been contradictory, limiting the ability to monitor and develop mitigation strategies. The current paper investigates the causative compounds associated with milk identified as SOF milk in the Midwest dairy region of the United States. Based on GC/MS-olfactometry analysis, endo-borneol, 2-methylisoborneol, and α-terpineol were identified as the off-flavor compounds. Sensory recombination studies further confirmed the sensory contribution of these compounds to the noted off-flavor attributes in the original milk, which were described as "green," "musty," and "unclean." These compounds are known microbial-derived flavor taints, indicating oxidation was not the origin of the objectionable flavor in the milk. This noted misclassification of the milk as SOF indicates the challenge of defining flavor defects without the identification of the active compounds.

Oxidative Quality of Dairy Powders: Influencing Factors and Analysis

“…In addition to LO, Maillard, and Strecker reaction products, other documented sources of off-flavours in dairy products include the presence of microbial-derived terpenoid compounds, such as endo-borneol, 2-methylisoborneol and α-terpineol [100], sulfur compounds present as a result of heat treatment [101,102], or direct transfer from feed and possibly isoflavone metabolism in the rumen leading to the formation of aromatic phenolic compounds [71,103]. Thus, incorporating GC-O analysis when attempting to identify the source of off-flavours in milk can be extremely beneficial.…”