Effect of Saccharomyces and non-Saccharomyces native yeasts on beer aroma compounds.

Recently, the increase in microbreweries and the consequent production of craft beers have reached exponential growth. The interest in non-conventional yeasts for innovation and a unique selling feature in beer fermentation is increasing. This work studied the autochthonous Saccharomyces and non-Saccharomyces yeasts, isolated from various food sources, with the ability to modify and improve the fermentative and aromatic profiles during alcoholic fermentation. The ability to ferment maltose and produce desirable aroma compounds were considered as the key characters for the screening selection. A synthetic beer wort was developed for this purpose, to simulate beer wort composition. A total of forty-seven yeast strains belonging to different genera were analysed according to their fermentation profile, volatile compounds production and sensory analysis. Three native strains of Saccharomyces cerevisiae, Zygoascus meyerae and Pichia anomala were selected to evaluate their aromatic profile in single and mixed fermentations. The strains produced 4-vinylguaiacol, ß-phenylethyl alcohol, and isoamyl alcohol at levels significantly above the sensory threshold, making them interesting for wheat and blond craft beer styles. The native Hanseniaspora vineae was also included in a co-fermentation treatment, resulting in a promising yeast to produce fruity beers.

Glycosylated simple phenolic profiling of food tannins using high resolution mass spectrometry (Q-Orbitrap).

Tannins are polyphenolic compounds extensively present in plants and used by food industry as processing aids. Due to the heterogeneity of plant sources, actions involved in food processing and tannin commercial costs can be different. In the last years different approaches aimed at correctly identifying the tannin botanical origin have been developed, in order to satisfy the industry's request to verify product labels. This work aimed to define the glycosidic simple phenolic profile of a large selection of monovarietal commercial tannins of different origin, using a high-resolution untargeted approach. Using accurate mass, isotopic pattern and MS/MS fragmentation, 167 precursors, 89 as monoglycosylated and 78 as diglycosylated derivatives were tentatively identified in tannins, validating the untargeted approach with 3 custom-synthesized glycosidic precursors. Almost all tannin botanical varieties were shown to be characterised by a specific glycosylated phenolic profile, providing possible tools for tannin classification in the case of glycosylphenol standard availability.

Non-targeted glycosidic profiling of international wines using neutral loss-high resolution mass spectrometry.

Many metabolites naturally occur as glycosides, since sugar moieties can be crucial for their biological activity and increase their water solubility. In the plant kingdom they may occur as glycosides or sugar esters, depending on precursor chemical structure, and in wine they have traditionally attracted attention due to their organoleptic properties, such as astringency and bitterness, and because they affect the colour and aroma of wines. A new approach directed at detailed description of glycosides in a large selection of monovarietal wines (8 samples each of Pinot Blanc, Muller Thurgau, Riesling, Traminer, Merlot, Pinot Noir and Cabernet Sauvignon) was developed by combining high performance liquid chromatography with high resolution tandem mass spectrometry. Analytical separation was performed on an Accucore™ Polar Premium LC column, while mass analysis was performed in negative ion mode with an non-targeted screening approach, using a Full MS/AIF/NL dd-MS2 experiment at a resolving power of 140,000 FWHM. Over 280 glycoside-like compounds were detected, of which 133 (including low-molecular weight phenols, flavonoids and monoterpenols) were tentatively identified in the form of pentose (6), deoxyhexose (17), hexose (73), hexose-pentose (16), hexose-deoxyhexose (7), dihexose (5) and hexose ester (9) derivatives. It was not possible to univocally define the corresponding chemical structure for the remaining 149 glycosides. Non-parametric statistical analysis showed it was possible to well characterise the glycosylated profile of all red and Traminer wines, while the identified glycosides were almost entirely lacking in Pinot Blanc, Riesling and Muller Thurgau wines. Also Tukey's Honestly Significant Difference test (p < 0.05) and Principal Component Analysis confirmed that it was possible to almost entirely distinguish the selected red wines from each other according to their glycosylated profile.

Free and glycosylated simple phenol profiling in Apulian Italian wines.

Free simple phenols have a significant role in defining the sensory and nutritional characteristics of wines, affecting the organoleptic profile and having positive effects on health, but glycosidically bound phenols can also be hydrolysed during the winemaking process, releasing the corresponding volatile compounds and making a possible contribution to the final sensory profile. In this work, application of on-line SPE liquid chromatography-high resolution mass spectrometry, operating in negative polarity with heated electrospray, allowed to detect over eighty free and glycosylated simple phenols in Primitivo di Manduria and Negroamaro wines. Sixty-one phenols, four of which phenolic glucosidic precursors, were quantified as having quantification limits ranging from 0.001 to 0.1µgmL(-1), calibration R(2) of 0.99 for over 92% of compounds, and precision (R.S.D.%) always lower than 12%. Twenty-four simple phenolic precursors were tentatively identified as hexoside, pentoside and hexoside-hexoside derivatives, on the basis of accurate mass, isotopic pattern and MS/MS fragmentation.

Identification and quantification of 56 targeted phenols in wines, spirits, and vinegars by online solid-phase extraction - ultrahigh-performance liquid chromatography - quadrupole-orbitrap mass spectrometry.

Phenolic compounds seriously affect the sensory and nutritional qualities of food products, both through the positive contribution of wood transfer in barrel-aged products and as off-flavours. A new targeted analytical approach combining on-line solid-phase extraction (SPE) clean-up to reduce matrix interference and rapid chromatographic detection performed with ultrahigh-performance liquid chromatography coupled with quadrupole/high-resolution mass spectrometry (Q-Orbitrap), was developed for the quantification of 56 simple phenols. Considering the advantages of using on-line SPE and a resolving power of 140,000, the proposed method was applied to define phenolic content in red (N=8) and white (8) wines, spirits (8), common (8) and balsamic (8) vinegars. The final method was linear from the limits of quantification (0.0001-0.001µgmL(-1)) up to 10µgmL(-1) with R(2) of at least 0.99. Recovery, used to define method accuracy, ranged from 80 to 120% for 89% of compounds. The method was suitable for analytical requirements in the tested matrices being able to analyse 46 phenols in red wines, 41 phenols in white wines and in spirits, 42 phenols in common vinegars and 44 phenols in balsamic vinegars.

Increased flavour diversity of Chardonnay wines by spontaneous fermentation and co-fermentation with Hanseniaspora vineae.

Discovery, characterisation and use of novel yeast strains for winemaking is increasingly regarded as a way for improving quality and to provide variation, including subtle characteristic differences in fine wines. The objective of this work was to evaluate the use of a native apiculate strain, selected from grapes, Hanseniaspora vineae (H. vineae) 02/5A. Fermentations were done in triplicate, working with 225 L oak barrels, using a Chardonnay grape must. Three yeast fermentation strategies were compared: conventional inoculation with a commercial Saccharomyces cerevisiae strain, ALG 804, sequential inoculation with H. vineae and then strain ALG 804 and spontaneous fermentation. Yeast strain identification was performed during fermentation, in which the apiculate strain was found to be active, until 9% of alcohol in volume, for the co-fermentation and the spontaneous fermentation was completed by three native S. cerevisiae strains. Basic winemaking parameters and some key chemical analysis, such as concentration of glycerol, biogenic amines, organic acids, and aroma compounds were analysed. Sensory analysis was done using a trained panel and further evaluated with professional winemakers. Sequential inoculation with H. vineae followed by S. cerevisiae resulted in relatively dry wines, with increased aroma and flavour diversity compared with wines resulting from inoculation with S. cerevisiae alone. Wines produced from sequential inoculations were considered, by a winemaker's panel, to have an increased palate length and body. Characteristics of wines derived from sequential inoculation could be explained due to significant increases in glycerol and acetyl and ethyl ester flavour compounds and relative decreases in alcohols and fatty acids. Aroma sensory analysis of wine character and flavour, attributed to winemaking using H. vineae, indicated a significant increase in fruit intensity described as banana, pear, apple, citric fruits and guava. GC analysis of the relative accumulation of 23 compounds to significantly different concentrations for the three fermentation strategies is discussed in relation to aroma compound composition.

Achyrocline satureioides essential oils from southern Brazil and Uruguay.

The essential oils of the aerial parts of Achyrocline satureioides (D.C.) Lam., a regional medicinal plant, from different collection locations in the South of Brazil and Uruguay were examined by GC and GC-MS. Monoterpene and sesquiterpene hydrocarbons were the main fractions of both the oils from Brazil and Uruguay. The oxygenated monoterpenes and sequiterpenes were at much lower percentage in both samples. The Uruguayan samples have 1,8-cineole which is not present in the Brazilian samples and has not been reported in other samples from Brazil. The results indicated a high biodiversity of the native populations of A. satureioides.

Uruguayan essential oil. 12. Composition of Nova and Satsuma mandarin oils.

The composition of the laboratory-prepared essential oils from Uruguayan Nova and Satsuma mandarins has been studied. The volatile fraction was analyzed by HRGC and HRGC/MS (quadrupole); 79 and 73 components were identified in Nova and Satsuma mandarin oils, respectively. The linear retention indices were calculated for almost all identified components on two different stationary phases. The enantiomeric distribution of beta-pinene, sabinene, limonene, linalool, and alpha-terpineol was studied by multidimensional gaschromatography (MDGC). Polymethoxylated flavones, present in the nonvolatile residue, were analyzed by normal-phase HPLC.

Composition of Aloysia gratissima Flower Essential Oil1.

Globulol, sabinene, caryophyllene, and caryophyllene epoxide have been isolated and identified in the essential oil of A. GRATISSIMA flowers from plants growing in Uruguay.