Aroma profile evaluation in whole grape juices

Abstract

Table grapes (Vitis labrusca and hybrids) are widely cultivated in Brazil [1] due to the climate, their resistance to disease and the way they are consumed and commercialized, either in-natura or for processing, producing whole juices, jams and table wines. Focusing on juices, which are widely studied for their antioxidant characteristics and for being alcohol-free products, the diversity of cultivars is interesting due to their specific organoleptic characteristics [2] to increase consumption. The aim of this study was to evaluate the volatile composition profile of 9 grape juices produced in the summer harvest 22/23 using the enzymatic method [3] in the microprocessing laboratory of the Agronomical Research Centre of Minas Gerais (EPAMIG) in Caldas – Minas Gerais/Brazil. The juices of Bordô Clone Bocaína, BRS Carmem, BRS Concord Clone 30, BRS Cora, Isabel, Isabel Precoce, BRS Magna, BRS Rúbea and BRS Violeta cultivars were analyzed by HS-SPME/GC-MS and a total of 118 free compounds were identified among the varieties, with qualitative as well as quantitative differences between them. Among the classes of compounds that stand out most for their pleasant sensory characteristics are benzenoids, terpenoids, furanoids and esters, and it is possible to see differences in these classes between the cultivars. For Isabel Precoce, Bordô, Isabel and Concord Cl 30 cultivars, the classes that stand out are the benzenoids, mainly the phenethyl alcohol compound with a rose aroma, and the terpenoids, the α-terpineol and linalool compounds, with a lilac and pleasant flower smell, respectively, as well as the combination of other compounds in smaller quantities. In the Cora and Violeta cultivars, the esters were more prominent, with ethyl 2-butenoate having a caramelized, fruity smell. Furanoids such as mesifuran (sweet, baked caramel, strawberry) and to a lesser extent furfural (sweet, almond, baked bread), and terpenoids linalool and β-damascenone (fruity, sweet, honey) in the juice of Rúbea cultivar. For Carmem juice, furanoids stand out, especially the compound furfural; and for Magna juice, esters and terpenoids, ethyl 2-butenoate, ethyl phenylacetate (odor suggestive of honey), β-damascenone and linalool. Studies have shown that the main compounds in Vitis labrusca and hybrid grapes are methyl anthranilate and furaneol, which have a foxy, earthy and sweet aroma; nevertheless, methyl anthranilate and ethyl anthranilate were evaluated in greater quantities in the Bordô cl Bocaína and Concord cl 30 juices and furaneol in the juice of Concord Cl 30 cultivar. Thus, the volatile compounds evaluated on this first harvest showed the peculiarities on the aromatic profile of grape juices from 9 different cultivars, demonstrating the potential to diversify grape juices production.

References

[1] Maia, J.D.G., Ritschel, P., Lazzarotto, J.J. (2018). Territoires du vin, online since 09/10/2018, URL: http://preo.u-bourgogne.fr/territoiresduvin/index.php?id=1546

[2] Wang, WN., Qian, YH., Liu, RH., Liang, T., Ding, YT., Xu, XL., Huang, S., Fang, YL., Ju, YL. (2023). Foods, 12, 3371.

[3] Bender, A., Souza, A.L.K., Malgarim, M.B., Caliari, V., Kaltbach, P., Costa, V.B. (2021). Semina: Ciênc. Agrár, 42(3), 1615-1634.