Effect of terroir on the phenolic compounds of Muscat of Bornova Wines from 3 different sub-regions of Aegean, Turkey

Abstract

Characterization of the phenolic compounds of wines from Muscat of Bornova, a native aromatic white grape variety (Vitis vinifera) grown in the Aegean region of Turkey and the influence of terroir (Menderes, Halilbeyli and Kemaliye sub-regions) on these compounds were investigated. From Muscat of Bornova growing sub regions, Menderes/I ˙ zmir has a typical Mediterranean climate at around 90 m altitude which is located Eagean cost area with a fertile sandy-loamy soil; Halilbeyli/I ˙ zmir sub-region is located in inner I ˙ zmir, close to Manisa with 115 m altitude with same soil structure of Menderes. Kemaliye/Manisa has a transition climate between Mediterranean and continental climate at about 245 m altitude. Its soil is pale with a distinct amount of lime (~30%) and sandy-loamy, as well. High performance liquid chromatography-diode array dedector (HPLC-DAD) and mass spectrometry (MS) were used for the phenolic compounds analysis. Four flavanols, eight phenolic acids and a flavonol were identified and quantified. It was observed that the total phenolic content in the Halilbeyli sub-region was the highest, followed by the Menderes and Kemaliye sub-regions. Procyanidin B4 was the most abundant flavanol and quercetin-3-O-glucoside was the only flavonol identified in all regions' wines. Sensory analysis was also used to investigate the influences of terroir. Statistically significant (0.05) regional differences were observed. Based upon sensory analysis, the wine obtained from Halilbeyli was darker in color, and had more astringency and bitterness than the others, and was the least popular wine. Kemaliye and Menderes were both preferred due to their better coloring, flavour, less astringency and bitterness attributes. compounds are also responsible for browning reactions in grapes and wines. Phenolic compounds (coumaric acid derivatives, flavans) play an important role in the oxidative reactions stimulated by iron, copper and enzymes, and they also involve aldehydes, amino acids and proteins which can occur in musts and wines causing flavour alterations [3]. Soil and climate are the two main factors taken into consideration with regard to the influence on wine quality [5]. The effects of altitude [6], water availability [7], slope [8], and exposure [9] on vine have been evaluated for some important cultivars. However, the influence of the environmental factors on the phenolic characteristics of Muscat of Bornova grown in Turkey has not been studied, yet. The present research analyses the general composition and phenolic profile of the Muscat of Bornova grape variety grown in the Menderes/I ˙ zmir and Kemaliye/Manisa sub-regions to determinate the influence of terroir. 2. Materials and methods Chemicals. All chemicals used in this work were of analytical grade. Milli-Q water (Millipore, Bedford, MA) was used in all the work. HPLC-grade acetonitrile and formic acid were purchased from (Merck, Darmstadt, Germany). Flavan-3-ols [i.e. (+)-catechin, and (−)-epicatechin], procyanidin dimers (B1 and B2), phenolic acids (gallic,