Recently, phytoliths of garlic mustard seed (Alliaria petiolata) were found in carbonized food deposits on prehistoric pottery from the western Baltic dating from 6,1 k.a to 5,7 k.a cal BP (Ertebölle Complex). This archaeological evidence suggests a much greater antiquity to the spicing of foods than previously thought within a hunter-gatherer context (http://www.aggsbach.de/2011/07/papaver-somniferum-during-the-european-neolithic/).
Garlic mustard or Hedge garlic (Alliaria petiolata) is a inconspicuous plant, found in large tuffs in light deciduous forest, which belongs to the Brassicaceae family. It is native to Europe, western and central Asia, and northwestern Africa. The leaves, flowers and fruit are edible as food for humans. They have a mild flavor of both garlic and mustard. The green seed-pods of A. petiolata are fried, the crushed seed is a condiment, and the garlic-scented leaves are added to savory dishes. Garlic mustard produces a variety of secondary compounds including flavonoids, defense proteins, glycosides, glucosinolates, particularly Sinigrin, a breakdown product allyl isothiocyanate (AITC) that reduce its palatability to herbivores. The total glucosinolate content may differ signiﬁcantly among populations and over continents. Sinigrin is not only the main compound for the characteristic aroma of Garlic mustard, but also of black mustard and Japanese horseradish, which are better known in the modern kitchen.
Electrophysiological records in both peripheral and central nervous system show that primate sensory taste system is basically organized around two major clusters of fibers and their cortical projections. Co-variation between the neural responses to various compounds was observed for sugars, on the one hand, and for tannins and alkaloids on the other hand. The human taste perception system is not basically different from that of the other primates, with this dichotomy allowing discrimination of noxious vs beneficent substances as a result of evolution. A growing body of evidence shows that animals such as insects, birds and primates use plant parts with secondary compounds to improve their comfort or their health. The concept of self-medication now generally accepted in primates but also in other vertebrates was first proposed by D.H Janzen (1978), an ecologist at the University of Pennsylvania. Taste perception may be a major clue for such a specific choice. Bitterness is suggested to represent a reliable signal of toxicity for animals and humans. A number of secondary compounds are bitter tasting (Saponins, Alkaloids and some Sesquiterpenoids, Terpenoids and Steroid Glycosides) and many of these substances possess important pharmacological activity(http://www.aggsbach.de/2012/08/molecular-archaeology/).
A number of flavors involve a burning or tingling which is picked up by mechanoreceptors in the mouth rather than by the chemoreceptors of physiological taste. Evolution has taught us, that this sensations come with the intake of pharmacological substances, significant for our health. Sinigrin, for example, has strong antimicrobial effects, prevents postprandial hypertriglyceridemia and is an inhibitor of several cyclooxygenases (anti-inflammatory) and of tumor cell proliferation. If such effects are really of significance in the long term in human health remains to be proven.
Anyhow, from an evolutionary point of view, “Acceptance of food depends not only on taste, but also on olfactory, tactile and visual signals, as well as memories of previous, similar experiences and social expectations. Food palatability and hedonic value therefore play central roles in nutrient intake. As a result, ancestral humans who liked spicy food—and therefore gained from its health benefits—might well have had longer, healthier lives and more offspring” (Nilius & Giovanni 2011)