Free and Bound Volatile Aroma Compounds of ´Maraština´ Grapes as Influenced by Dehydration Techniques

Abstract

Dehydration or drying of grapes is one of the most important steps in the production of Croatian traditional dessert wine Prošek. The natural sun drying of grapes is the traditionally used method in Prošek production. Alternative methods, such as dehydration under controlled conditions, have been studied as safer and faster methods than the traditional sun drying but without precise knowledge of the effect on volatile compounds. The objective of this work was to study how dehydration of grapes carried out in a greenhouse and an environmentally controlled chamber impacts on the free and glycosidically bound volatile compounds of native grape cv. ‘Maraština’. The 36 volatile compounds were identified and quantified using headspace solid-phase micro extraction coupled with gas chromatography-mass spectrophotometry (HS-SPME-GC/MS). The results showed that the aroma profile of dehydrated grapes was significantly different from that of fresh grapes. Regarding free forms, significant increases in the concentration of 2-methyl-1-propanol, 1-butanol, 2-hexen-1-ol, 1-hexanol, ethyl hexanoate, hexyl acetate, o-cymene, linalool oxide, and terpinen-4-ol and geraniol were found in greenhouse-dried grapes, whereas increases in cis-limonene-epoxide, trans-limonene epoxide, and γ-hexalactone were higher in chamber-dried grapes compared to greenhouse-dried grapes. Glycosidically bound forms of o-cymene, linalool oxide, linalool, and terpinen-4-ol were increased in both types of drying, whereas β-damascenone was increased only in greenhouse-dried grapes.

Aromatic Characterisation of Moscato Giallo by GC-MS/MS and Validation of Stable Isotopic Ratio Analysis of the Major Volatile Compounds

“…trans-8-hydroxy linalool n.d. Floral [43] cis-8-hydroxy linalool n.d. Floral [43] Norisoprenoids β-damascone 0.09 [44] Fruity-flowery, exotic-spicy [52] β-damascenone 0.05 [44] Apple, rose, honey [44] α-pinene n.d. Woody, resinous [53] α-ionone 2.6 [54] Violets, berry [55] α-ionol n.d. Floral and woody [55] Aliphatic alcohols 1-hexanol 8000 [44] Resin, green (cut grass) [44] trans-3-hexen-1-ol 1000 [54] Grassy green, earthy [56] cis-3-hexen-1-ol 400 [44] Lettuce-like, green, grass [44] Benzenoid benzaldehyde 2000 [57] Bitter almond [57] methyl salicylate 50 [58] Mint-like [43] Vanillins zingerone n.d. Toasty, dry fruit Phenols guaiacol 10 [44] Smoke, sweet, medicine [44] According to the quali-quantitative results of the volatile fraction, the main monoterpenes (geraniol, linalool, diendiol I, diendiol II, geranic acid, trans-8-hydroxy linalool, and cis-8-hydroxy linalool) characteristic of Moscato Giallo grapes and wine were further investigated by means of isotopic analysis. For the stable isotope ratio analysis, free and bound VOCs were merged, as reported above.…”

Analysis of the Volatile Organic Compound Fingerprint of Greek Grape Marc Spirits of Various Origins and Traditional Production Styles

“…Anise is a plant native to the Middle East that has been used since ancient Egypt, and its major volatile compound is anethol, which is responsible for aniseed's fragrant characteristics [29,48,49]. Anethol was found in very high concentration in Limnos samples, followed by aniseed Muscat samples from Macedonia, while estragole, menthol, 4-anisaldehyde, p-anisaldehyde diethyl acetal, alpha-himachalene, gamma- o-Cymene [34,40,41], alpha-pinene [42][43][44], beta-myrcene [21], D-limonene [21,45], ylangene [18,29], alpha-cedrene [46] and alpha-terpinene [14,29] were detected mostly in Muscat, Muscat of Alexandria and Merlot wines, grape musts, and spirits, as they are characteristic metabolites of these cultivar grapes; however, in this study, their concentration was found to be over 50-fold higher in some Muscat grape marc spirit samples originated from Macedonia. Caryophyllene has been previously found in Cabernet Sauvignon berries [47], while Garcia-Martin et al [35] found terpenols in orujo samples and Giannetti et al [14] and Lukic et al [19] detected terpenes, such as alpha-terpinene, p-cymene, alpha-cubebene, and alpha-calacorene in several European spirit samples.…”

Design of Two-Mode Spectroscopic Sensor for Biomedical Applications: Analysis and Measurement of Relative Intensity Noise through Control Mechanism

“…After the characterization and calibration of the system, said system is used to analyze the substances. The sample holder is cleaned using Propanol [67,68], followed by a spray of nitrogen gas, in order to ensure non-presence of any contamination. This is essential for reliable and accurate measurements, and must be done before the commencement of each experimentation with a different substance.…”