Flavor and Volatile Metabolism in Produce 175
6.4.8.4 Microbial Sources
Produce inhabited by pathogenic microorganisms may exhibit pathogen-specific
volatile profiles or volatiles associated with characteristic change in the principal
substrates attacked [232]. When a disease organism is present, the volatile profile
will include those of the produce (normal metabolites and background) plus metab-
olites of active pathogens as a result of their metabolism and interaction with the
host material. Volatile monitoring has been demonstrated for the detection and
differentiation of pathogens in stored potatoes [232–234]. Infection-specific volatiles
associated with diseased potatoes (soft rot, Erwinia carotovara var. atroseptica)
included methanol, ethanol, acetone, 1-butanol, 2-butanol, 2-butanone, and
3-hydroxy-2-butanone (acetoin) [233,235]. Soft rot (Clostridium infection) in stored
potatoes was reported to cause pigsty-like off-odors due to formation of p-cresol,
indole, and skatole [236].
6.5 CONCLUSIONS
Development and application of advanced instrumental-sensory techniques in the
last two decades has led to tremendous progress toward our understanding of the
flavor chemistry of fruits and vegetables. This is exemplified by recent studies on
strawberry flavor that have led to identification of key aroma-impact components
and elucidatation of pathways involved in their formation. Such knowledge, coupled
with a greater understanding of important intrinsic and external factors that affect
the flavor quality of fruits and vegetables, will lead to development of improved
postharvest storage practices, with the ultimate goal of providing higher-quality
produce with long shelf lives.
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