Nature’s Chemical Signatures in Human Olfaction: A Foodborne Perspective for Future Biotechnology

Abstract

The biocatalytic production of flavor naturals that determine chemosensory percepts of foods and beverages is an ever challenging target for academic and industrial research. Advances in chemical trace analysis and post-genomic progress at the chemistry-biology interface revealed odor qualities of nature's chemosensory entities to be defined by odorant-induced olfactory receptor activity patterns. Beyond traditional views, this review and meta-analysis now shows characteristic ratios of only about 3 to 40 genuine key odorants for each food, from a group of about 230 out of circa 10 000 food volatiles. This suggests the foodborn stimulus space has co-evolved with, and roughly match our circa 400 olfactory receptors as best natural agonists. This perspective gives insight into nature's chemical signatures of smell, provides the chemical odor codes of more than 220 food samples, and beyond addresses industrial implications for producing recombinants that fully reconstruct the natural odor signatures for use in flavors and fragrances, fully immersive interactive virtual environments, or humanoid bioelectronic noses.

Spotlight on Varietal Thiols and Precursors in Grapes and Wines

“…[5] Especially important to this concept are odorants that impart a distinct effect as a result of being present at suprathreshold concentrations (defined in terms of odour activity value, OAV ¼ concentration/aroma detection threshold, with OAV . 1) and compounds having characteristic aroma qualities that may define a particular varietal wine.…”

Functional Metabolomics – a Useful Tool to Characterize Stress-Induced Metabolome Alterations Opening New Avenues Towards Tailoring Food Crop Quality

“…Therefore, it is no surprise that, although aided by visual inspection, the final recognition and quality evaluation of food crops made by consumers are mainly mediated by its flavor perception. Human flavor perception is induced by the interaction of volatile odor-active and non-volatile taste-active molecules with ~390 odorant receptor proteins located in the regio olfactoria in the nose and ~40 taste receptor proteins on the tongue [75]. To meet the consumers' demand on continuous available, fresh foods with a premium quality, the "flavor blueprint" of a golden standard, which is a combinatorial code of the entire set of odor-and taste-active metabolites in their natural concentrations, has to be known [76].…”

“…This so called molecular sensory science or sensomics approach has especially been shaped by Peter Schieberle´s and Thomas Hofmann´s working groups during the last three decades [75,76]. Today, it is well accepted that the presence of certain structural elements, so-called olfactophores and gustophores, as well as specific concentrations exceeding the sensory thresholds are important prerequisites of low molecular weight metabolites to become flavor-active [76].…”

“…Today, it is well accepted that the presence of certain structural elements, so-called olfactophores and gustophores, as well as specific concentrations exceeding the sensory thresholds are important prerequisites of low molecular weight metabolites to become flavor-active [76]. Although a total of more than 10,000 volatiles occur in crop plants, the use of the so-called sensomics approach gave evidence that the typical aroma impression of a crop based food stuff is caused by a limited number of aroma-active volatiles [75]. 1-(ethylsulfanyl)ethane-1-thiol, are necessary to explain the typical aroma impression of durian fruits [77], and to mimic the typical aroma impression of mangos only eight compounds are required [78].…”

Spider monkeys (Ateles geoffroyi) are less sensitive to the odor of aliphatic ketones than to the odor of other classes of aliphatic compounds

“…Likewise, short-chained carboxylic acids are typically described as smelling "sweaty" or reminiscent of "body odor" (Dravnieks, 1985). It is well-established that the odor quality of both bodily secretions and of food is often characterized by so-called "key compounds" (sometimes also referred to as "character impact compounds") (Dunkel et al, 2014). Animal studies have shown that certain "key compounds" of complex predator odors, for example, are sufficient to elicit adaptive behavioral responses in prey species (Apfelbach et al, 2005) and thus clearly demonstrate their behavioral relevance.…”