A recent study led by Hayley Saul of the University of York found that at least some of our prehistoric ancestors liked to spice up their food for a more palatable cuisine. By examining isolated carbonized (burned) food deposits from pottery shards dated from ca. 6,100 to 3,750 BP from three sites in Denmark and Germany, Saul and colleagues identified phytoliths from plant remains that are likely mustard garlic seeds.
     Phytoliths are created when plants absorb silica from the soil. The silica is deposited within different intracellular and extracellular structures of the plant and, after the plants decay, it is redeposited in the soil in the form of phytoliths, which are rigid, microscopic structures of varying sizes and shapes. These phytoliths are naturally decay-resistant and are thus preserved in soil and other contexts, ready to be discovered and examined by archaeologists thousands of years later.  
     In addition to the phytoliths, most of the samples studied contained evidence for marine and terrestrial animals, and starchy plant foods, all carbonized together with the phytoliths, suggesting that the garlic mustard seed substance was carbonized concurrent with the other animal and plant foods in the pots as food for consumption. While all of the food types identified in the analysis indicated substances with nutritional and calorie-rich value, the garlic mustard seed is known to have very little of such value. Moreover, garlic mustard seed spice, made from plants ranging from Europe to Central Asia, northern India and west China, is also known to have a strong peppery, mustard flavor, and is used today to flavor salads and sauces such as pesto.
     Concludes Saul and colleagues in their report, "despite the modest number of samples, it is demonstrated beyond doubt that the use of spice was practised regularly during the decades when domesticates were introduced in the western Baltic region... It is now established that the habit of enhancing and altering the flavour of calorie rich staples was part of European cuisine as far back as the 7th millennia cal BP." The study authors add that "it is still uncertain if the practise was the result of Neolithic influence ultimately derived from the Near East, from where Old World farming originates, or if such advanced culinary practice was developed locally prior to the arrival of Neolithic elements in northern Europe".

Edited from PLOS One (August 2013), Popular Archaeology (21 August 2013)