Emanuele Boselli

Fresh refrigerated Tuber melanosporum truffle: effect of the storage conditions on the antioxidant profile, antioxidant activity and volatile profile

The antioxidant properties of fresh black truffles (Tuber melanosporum) (T.) refrigerated at 4xa0°C under different packaging conditions: air atmosphere (A), reduced pressure (V), mix 1% O2/99% N2 (ON) and mix 40% CO2/60% N2 (CN) were evaluated during 28xa0days of storage. The results were compared with the volatile fingerprint determined by SPME-GC/MS and with the phenolic antioxidants characterized by HPLC–MS/MS. The total antioxidant content and the antioxidant activity decreased during the storage, regardless of the packaging method. The principal component analysis (PCA) showed that the total antioxidant content was well correlated with low storage times, high antioxidant activity and three volatile aldehydes. In contrast, 2-propyl-butanoate and 2-nonen-1-ol inversely correlated with the antioxidant activity, as well as gentisic acid, which was the only phenolic antioxidant which increased during the storage. V, CN and ON were always better strategies than A to preserve the freshness of T. However, V is a valid and cheap alternative to normal atmosphere to prolong the shelf life for up to 2xa0weeks.

Isotopic Exchange HPLC-HRMS/MS Applied to Cyclic Proanthocyanidins in Wine and Cranberries

AbstractCyclic B-type proanthocyanidins in red wines and grapes have been discovered recently. However, proanthocyanidins of a different chemical structure (non-cyclic A-type proanthocyanidins) already known to be present in cranberries and wine possess an identical theoretical mass. As a matter of fact, the retention times and the MS/MS fragmentations found for the proposed novel cyclic B-type tetrameric proanthocyanidin in red wine and the known tetrameric proanthocyanidin in a cranberry extract are herein shown to be identical. Thus, hydrogen/deuterium (H/D) exchange was applied to HPLC-HRMS/MS to confirm the actual chemical structure of the new oligomeric proanthocyanidins. The comparison of the results in water and deuterium oxide and between wine and cranberry extract indicates that the cyclic B-type tetrameric proanthocyanidin is the actual constituent of the recently proposed novel tetrameric species ([C60H49O24]+, m/z 1153.2608). Surprisingly, the same compound was also identified as the main tetrameric proanthocyanidin in cranberries. Finally, a totally new cyclic B-type hexameric proanthocyanidin ([C90H73O36]+, m/z 1729.3876) belonging to this novel class was identified for the first time in red wine.n Graphical Abstractᅟ

Selective binding of potassium and calcium ions to novel cyclic proanthocyanidins in wine by high-performance liquid chromatography/high-resolution mass spectrometry

RATIONALEnCyclic B-type (referred also as crown) proanthocyanidins were recently identified in wines. An HPLC-HRMS/MS method was applied to study the binding of cyclic and non-cyclic PAC to potassium and calcium ions, which affect the chemico-physical stability of wines. Different binding affinities suggest that cyclic and non-cyclic analogues, despite the equal number of monomer units, influence the colloidal stability of wine and are related to the grape variety or winemaking conditions.nnnMETHODSnNineteen red and white wines were analysed by HPLC high resolution tandem mass spectrometry with positive electrospray ionization to investigate the distribution of novel cyclic proanthocyanidins and their calcium, potassium and sodium adducts. Principal Component Analysis was used to study the distribution of the wines and the relationships among proanthocyanidins with and without cation complexes.nnnRESULTSnA dependence on specific isomers (and conformations) was found for the non-cyclic procyanidin (PC) trimer whereas the cyclic tetrameric PAC were shown to bind better to potassium than their non-cyclic analogues. The binding to these metals appeared to be influenced not only be the number of monomer units but also by the conformation assumed by the molecules. Statistical analysis evidenced that the adducts distribution in different wines is less influenced by the grape variety used for winemaking than their associated [M+H]+ species studied earlier.nnnCONCLUSIONSnWines from 19 grape varieties were investigated in order to identify potassium and calcium complexes of non- and cyclic B-type proanthocyanidins that were recently discovered. The results showed a dependence of the distribution of metal complexes according to the cyclic or non cyclic geometry of proanthocyanidins. The multivariate analysis of the mass spectrometric results showed a relationship with the grape variety, however not so straightforward as evidenced for the non-complexed species.

High resolution mass approach to characterize refrigerated black truffles stored under different storage atmospheres

Freshly harvested Tuber melanosporum samples were packed and stored at 4°C under reduced atmospheric pressure or modified atmosphere for four weeks. Multivariate analysis was employed to correlate the antioxidant power of the ethanolic extracts of the samples with the chemical composition determined by high resolution mass spectrometry. High performance liquid chromatography coupled with a coularray detector was applied to select the chemical species associated with the antioxidant power. Four classes of chemical compounds were investigated in more detail by a targeted approach: derivatives of glutathione, adenine (such as S-adenosyl-homocysteine), oxidized linoleic acid and ergosterol. Adducts containing glutathione and adenine with oxidized linoleic acid were observed in TM for the first time and can be considered markers of freshness of the product. S-adenosyl-homocysteine, the acetyl-carnitine adduct with cysteinyl-glycine and several oxidized linoleic acid derivatives were among the markers of degradation.

Disambiguation of Isomeric Procyanidins with Cyclic B-Type and Non-cyclic A-Type Structures from Wine and Peanut Skin with HPLC-HDX-HRMS/MS

AbstractHydrogen/deuterium exchange coupled with high-resolution mass spectrometry was successfully applied for the identification of A-type tetrameric, pentameric, and hexameric procyanidins in peanut skin. This extended a previous study on isomeric cyclic B-type unconventional tetramer, pentamer, and hexamer procyanidins found in wine and cranberries. Not only had the method successfully identified the procyanidins with a single A-linkage (e.g., tetrameric m/z 1153.2608) by means of distinguishing them from their isomeric cyclic B-type analogues, but this method also worked for procyanidins with two or more A-linkages (such as the tetrameric m/z 1151.2452). As a further consequence, B-type cyclic pentamers and hexamers in wine have been elucidated with hydrogen/deuterium exchange (HDX) for the first time.n Graphical Abstractᅟ

Volatile, phenolic, and sensory profiles of in-amphorae Chardonnay wine by mass spectrometry and chemometric analysis

The sensory properties, the phenolic composition, and the volatile profile of Chardonnay wine made in amphorae were compared with the wine obtained in large wooden barrels (2000xa0L) and small toasted barrels (225xa0L). Hierarchical cluster analysis and principal component analysis built on the phenolics and volatiles variables allowed to group effectively the samples according to the winemaking material used. In-amphorae wines showed more abundant catechin and caffeic acid and less abundant caftaric acid and trans-coutaric acid. Condensation reactions proceeded in the wood containers leading to esterification of organic acids with ethanol and alcohols, whereas in-amphorae wines were characterized by a higher content of free phenolic acids and higher volatile alcohols. Among the volatile compounds, ramified ethyl esters contributed mostly in samples made in small toasted barrels, whereas nonbranched ethyl esters contributed more for the samples made in large wooden tanks; higher alcohols contributed more for the in-amphorae wine. The sensory analysis showed negligible differences induced by the in-amphorae vinification with respect to the wooden one. Four variables could distinguish wines made in-amphorae compared with the other containers: solvent and acetone (SA), astringent/pungency (AP), fruity (FR), and color intensity (CI). The overall approach proposed here is promising for future developments of innovative types of Chardonnay wine blends.

Relative abundances of novel cyclic prodelphinidins in wine depending on the grape variety

The identification of cyclic B-type procyanidins in grape and wine was recently disclosed. Some of these were also found in berries of totally different vegetal species (eg, Vaccinium sp.). However, presence of a wider class of these cyclic condensed tannin compounds with variably substituted monomers has never been addressed so far. Here, an extended list of oligomeric cyclic proanthocyanidins (PAC) bearing variable substitution patterns on the main flavan-3-ol unit has been searched in wines. Nearly 7600 theoretical structures were calculated and searched in red and white wine samples made from different grape varieties. Moreover, a hydrogen/deuterium exchange approach (already applied to a cyclic tetrameric procyanidin) coupled to high-resolution mass spectrometry was applied to confirm their cyclic B-type structure rather than a non cyclic A-type structure, otherwise isomeric and undistinguishable by LC-MS alone. The main group of novel cyclic PAC observed is shown to contain (epi)gallocatechin beside (epi)catechin as the constituent monomers.