Physicochemical and microbiological characterization of the sensory deviation responsible for the origin of the special sherry wines "palo cortado" type

Determination of volatile compounds for the differentiation of PDO fortified wines with different ageing methods as a tool for controlling their authenticity

The aim of this work was to study the differentiating volatile profiles of the Spanish protected designation of origin (PDO) fortified wines obtained by headspace solid phase microextraction in conjunction with gas chromatography-mass spectrometry and powerful chemometric tools, to finally identify the marker volatile compounds most related to fortified wine types. Results revealed a satisfactory discrimination, for the first time, of the different types of PDO fortified wines, involving only a reduced number of volatile compounds selected by chemometrics. Thus, 28 volatile compounds were responsible for the differentiation according to ageing type (biological, oxidative, or mixed) resulting useful markers for the identification of each specific type of fortified wine. Among them, some esters were strongly related to biological ageing, aldehydes and acids to oxidative ageing, and lactones to mixed ageing. These volatile molecules involved in their differentiation could explain the unique organoleptic characteristics or attributes of these PDO fortified wines.

Analytical, Chemometric and Sensorial Characterization of Oloroso and Palo Cortado Sherries during Their Ageing in the Criaderas y Solera System

Oloroso and Palo Cortado are two types of sherry wines, produced in the Sherry Wine Region in Southern Spain, known as Marco de Jerez, where it is aged following the traditional Criaderas y Solera system. All of them are aged through oxidative ageing, even though the peculiar Palo Cortado Sherry wine is also aged biologically under a veil of flor yeasts in the first stage. Total dry extract, organic acids, aldehydes, esters, higher alcohols and phenolic compounds in these sherry wines evolve during their ageing as a consequence of evaporation and/or perspiration processes, chemical reactions, extraction of compounds from oakwood and microbiological activity. Sherry wines develop their characteristic organoleptic profile during their ageing, as could be proven through their tasting sessions. According to the sherry type, some natural groupings of the wines could be observed after their principal component analysis. Furthermore, by multiple linear regression methods, an important correlation between the parameters that were analyzed and the ageing of each specific wine has been confirmed, which allowed us to establish two different models, each corresponding to the sherry type in question. Only five of the variables that were investigated were required to successfully estimate each wine's age at over 99% confidence. This represents a rather convenient tool for wineries to monitor the ageing of these sherry wines.

Effect of Grape Over-Ripening and Its Skin Presence on White Wine Alcoholic Fermentation in a Warm Climate Zone

The current trend of rising temperatures and sun irradiation associated to climate change is pushing traditional grape-producing areas with a warm climate towards a very accelerated ripening, leading to earlier harvesting dates and grape must with an unbalanced composition. However, this climatic trend could be exploited to produce other types of wine. In this sense, the increase in temperature could be used to produce wines with overripe grapes. In this regard, the aim of this research work is to evaluate the influence of different degrees and techniques of grape over-ripening to produce wines with the presence or absence of its skins during alcoholic fermentation. To this end, a physicochemical characterization of grape musts and wines obtained from overripe grapes and the monitoring of their fermentation has been performed. Over-ripening grapes by sun-drying has been established as a viable technique viability, producing musts and wines with unique physicochemical and sensory characteristics. In view of the above, it is considered that the production of wines from overripe grapes and in the presence or absence of grape skins is a viable approach to make new white wines taking advantage of the conditions imposed by climate change in a warm climate zone and meet the trends and expectations of current wine consumers.

Bee Pollen Role in Red Winemaking: Volatile Compounds and Sensory Characteristics of Tintilla de Rota Warm Climate Red Wines

One of the main aspects that define wine quality is its aromatic profile. Nutritional deficiencies in musts can lead to olfactory defects and a decline in quality. Commercial activators and nutrients are usually added to the must in these cases. The natural composition of bee pollen can provide all the necessary nutrients for yeasts. This investigation aims to analyze the impact of pollen addition on the profile of volatile and sensory compounds in Tintilla de Rota warm climate red wines. Volatile compounds were measured by Gas Chromatography–Mass Spectrometry, Odorant Activity Values analysis to find out each compound’s fragrant participation, and sensorial analysis was conducted for a qualified panel of wine-tasters. As a result of the chromatographic analysis, 80 volatile compounds of different chemical families were identified and quantified. Bee pollen increased mainly isoamyl alcohol, esters, and terpenes compounds families in wines. Odorant Activity Values analysis showed an increase in fruity odorant series mainly, followed by floral, for all wines with pollen addition. The sensory analysis showed that low pollen doses (0.1 g/L and 0.25 g/L) increased tasting notes of fruit and floral attributes and fruit and floral odorant series as well, highlighting an increase in red and black fruit notes mainly. On the other hand, high doses deviated the sensory profile towards fleshy stone fruit, and raisin fruit, mostly. In addition, high bee pollen doses produce an increase in the odorant category responsible for the chemical, fatty, and grassy aromas mainly, and high and intermediate dose (1 g/L) an increase in the earthy notes in the aromas. Therefore, low bee pollen doses (0.1 and 0.25 g/L) can improve both the aromatic compound profile, as well as the Odorant Activity Values levels and the sensory profile in Tintilla de Rota red wines.

The impacts of Schizosaccharomyces on winemaking

In the past century, yeasts from the genus Saccharomyces represented the only option in fermentation industries, such as winemaking, to produce wine, beer, and other fermented products. However, other genera are currently emerging to solve challenges in modern enology. Schizosaccharomyces pombe is showing promising results in solving specific challenges in northern, cool viticulture regions with highly acidic wines by deacidifying these wines through its malic acid metabolism. In addition, this microorganism is considered beneficial in warm growing regions with challenges such as the control of wine food safety problems such as the presence of biogenic amines, ochratoxin A, or ethyl carbamate. Indeed, the genus Schizosaccharomyces positively influences other important wine quality parameters, such as color and polysaccharide content. However, the main challenge of using this genus remains the selection of proper strains that alleviate problems such as the production of high acetate concentrations. Industries other than wine production such as ginger fermentation, apple wine, Kei-apple fermentation, plum wine, sparkling wine, and bilberry fermentation industries have also started to study Schizosaccharomyces species as an alternative tool for solving specific related problems. The review discusses the influence of Schizosaccharomyces on different fermentation quality parameters and its main applications in different industries.