Exploring the presence of oligopeptides in wines into identify possible compounds with umami or kokumi properties

Abstract

Umami is defined as a pleasant and savory taste derived from glutamate, inosinate and guanylate, which are naturally present in meat, fish, vegetables and dairy products. The term “kokumi” refers to a complex flavour sensation, characterized by thickness, fullness and continuity. In the food sector, it has been associated with small oligopeptides. This sensation is important in determining the taste, aroma, flavour and aftertaste quality of a wide variety of foods. The presence of monosodium glutamate induces kokumi sensations and palatability in foods containing kokumi and basic taste substances. Surprisingly, the presence of kokumi compounds in wines has so far been almost completely ignored and has concerned only glutathione. Also, the combined role of glutamate and kokumi substances in wine has not been explored to date.

A targeted metabolomic method based on ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) capable of quantifying both amino acids and oligopeptides in wines has been developed and validated, confirming the presence of 50 oligopeptides in Trentodoc sparkling wines, most of which were previously unexplored [1]. The in silico analysis of peptides, investigated for their capacity to interact with the so-called Calcium Sensing Receptor (CaSR), the protein required to trigger kokumi sensations [2], highlighted the presence of 8 dipeptides and 3 tripeptides as potential kokumi compounds. This novel in silico approach has indeed the potential to identify new potential kokumi tasting sequences.

These putative kokumi compounds were ubiquitous in a representative sample of Trentodoc classic method sparkling wines, with a mean concentration of kokumi oligopeptides of 19.8 mg/L, ranging from 9.1 to 33.3 mg/L. Half of the sparkling wine samples analysed also contained glutamic acid at concentrations equal to or above the suggested threshold for umami taste in wine, i.e. 48 mg/L [3].

Sensory testing of wine oligopeptides is still ongoing, with encouraging results for the first dipeptide tested, Gly-Val [1]. Preliminary laboratory-scale fermentation tests have shown that the oligopeptide profile in wines is matrix-specific, i.e. linked to the starting matrix, which seems to determine the pattern and quantity of peptides produced under the action of yeasts.

References

[1] Daniele Perenzoni, Luca Dellafiora, Florinda Perugino, et. al. Exploring putative kokumi oligopeptides in classic sparkling wines with a UHPLC-ESI-MS/MS targeted protocol. J. Agric. Food Chem. (2024) 72, 47, 26189-26208.

[2] L. Dellafiora, F. Magnaghi, G. Galaverna, C. Dall’Asta. A mechanistic investigation on kokumi-active gamma-Glutamyl tripeptides – a computational study to understand molecular basis of their activity and to identify novel potential kokumi-tasting sequences. Food Res. Int., 162 (2022), Article 111932

[3] Franceschi, D.; Lomolino, G.; Sato, R.; Vincenzi, S.; De Iseppi, A. Umami in wine: impact of glutamate concentration and contact with lees on the sensory profile of Italian white wines. Beverages (2023), 9, No. 52.