Panagiotis Tataridis

Yeasts are among the intrinsic factors affecting the quality of beer due to their impact on flavor. Apart from a long and rich brewing tradition of natural fermentations, involving different yeast and bacterial species in regions such as Belgium, non-Saccharomyces yeasts have not been the preferred industrial inoculation strains in both winemaking and brewing sectors. This is mainly due to their slower fermentation rates, lower alcohol tolerance, and limited ability to complete fermentation. This review explores the brewing characteristics of Torulaspora delbrueckii strains, focusing on the aromatic profile of the produced beers, in comparison with the well-known Saccharomyces cerevisiae brewing strains. The effect of fermentation parameters, as well as the use of mono- and mixed cultures with S. cerevisiae, is discussed. Specific T. delbrueckii strains have demonstrated the ability to ferment wort sugars and produce alcohol levels of up to 4–6% (v/v). The main volatile compounds produced include higher alcohols, such as isoamyl and phenyl ethyl alcohol, as well as esters and their acid precursors. Among these, ethyl hexanoate and ethyl octanoate are particularly important due to their contribution to fruity aromas. Mixed fermentations involving T. delbrueckii and S. cerevisiae have been shown to enhance ester production, resulting in improved aromatic complexity in the final product.

There is an increasing trend to develop beers supplemented with local plant ingredients in order to increase their bioactivity. Carob (Ceratonia siliqua L.) is a xerophytic endemic tree typically found in Mediterranean ecosystems. The aim of this study was to develop a strong dark ale hybrid beer enriched with carob syrup prepared by using carob fruits from the University Campus (Athens, Greece). Three batches of beer were fermented, a dark ale (6% alcohol by volume or ABV) without carob and two strong dark ale beers (8% and 10% ABV) with carob syrup. After the second fermentation (bottle conditioning, 60 days), both carob beers had significantly increased bioactivity. The total phenolic content (176.4 mg GAE/100 mL), the antiradical activity (206.6 mg Trolox Equivalent (TE)/100 mL), and the antioxidant activity (838.2 mg Fe²⁺/100 mL) of the carob strong dark ale 10% ABV beer was increased by more than three times, six times, and eight times, respectively, compared to the standard dark ale (6% ABV) without carob. Moreover, LC-QToF-MS analysis ascertained the enhancement of the phenolic profile of carob beers by ten phenolic compounds compared to the control dark ale beer without carob, indicating their significant antioxidant activity.

Wine quality and typicity are complex concepts that can be hard to define. Wine is a product destined to not only be consumed and appreciated but also marketed, and its distinctiveness, quality and typicity are important characteristics that describe a wine’s sensory profile and, ultimately, add value to the finished product. Even though both quality and typicity are mostly assessed using a sensory evaluation, many studies have examined the feasibility of using chemical analysis methods in order to increase the objectivity of assessments. Today, the use of chemometrics facilitates the handling of big data, and outcomes from various analytical techniques can be integrated to produce more accurate results. This study discusses the existing sensory and analytical approaches, implications and future prospects for an objective measurement of quality and typicity as well as methods for the selection of appropriate data for predictive model development.

This study evaluated the antioxidant capacity, total phenol content, and sensory profile of selected Greek wines made from Vitis vinifera L. c.v. Moschofilero in two consecutive vintages, treated with powdered Hippophae rhamnoides L. leaves (HRL). Radical Scavenging activity, reducing power, total phenol content (TPC), and color intensity increased in a linear manner in relation to HRL treatments. Indicatively the addition of 0.8 g/L of HRL increased the radical scavenging activity as determined via the inhibition of the 2,2-diphenyl-1- picrylhydrazyl (DPPH) radical from 28.4 to 55.8% in comparison to the initial values. Equally the reducing power as determined by the ferric reducing antioxidant power (FRAP) assay increased from 35.3 to 62.1%, and total phenol content values increased from 11% to 23.7% and the color intensity increased from 39.9 to 50.7%. The main oenological attributes examined, remained unchanged after the HRL addition. The addition of up to 0.4 g/L of HRL did not have a major impact on the organoleptic characteristics of the wines tasted whereas concentrations higher than 0.8 g/L were not considered beneficial. Results denote that the addition of H. rhamnoides leaves to white wines contributes positively to the overall antioxidant capacity and could be used if authorized as an antioxidant agent in wines vinified in the absence of or in synergy with sulphur dioxide.

This study aimed at investigating the benefits of immersing oak sticks in the Greek pomace brandy named tsipouro, regarding its total phenolic content, antiradical-antioxidant activity, colour parameters and sensory profile. In order to induce rapid aging of tsipouro, alternative experimental conditions were applied. Results revealed that the phenolic migration from the wood to the tsipouro significantly increased both with temperature increase during aging as well as with the oak sticks /tsipouro ratio (w/v). The impact of oak wood diversity was also tested, by selecting different types of French oak (Quercus robur) and French and American oak mix (Quercus robur- Quercus alba) sticks. Results exhibited a significant effect of wood stick type on total phenolic content, antioxidant and antiradical activity, colour values and sensory attributes, especially on overall acceptance. High positive correlation among total phenolic content, antiradical and antioxidant activity and overall acceptance was found for all the extracts studied. Wood aging promoted the migration of phenolic compounds from the wood into the tsipouro, which, apart from the organoleptic characteristics, could possess health beneficial effects.

This study evaluated the influence of the addition of increasing quantities of Hippophae rhamnoides L. leaves (HRL) on the radical scavenging activity, main oenological parameters and organoleptic characteristics of three white wines made from moschofilero and one white wine made from riesling grapes respectively. Radical Scavenging activity, reducing power, total phenol content (TPC) and color intensity increased in a linear manner in relation to HRL treatments. Indicatively the addition of 0.8 g/L of HRL increased the radical scavenging activity as determined via the inhibition of the DPPH radical from 23.2 to 58.4% in comparison to the initial values. Equally the reducing power as determined by the FRAP assay increased from 34.5 to 82.3%, TPC increased from 12.3 to 26.8% and the color intensity increased from 39-50% . The main oenological attributes examined, remained unchanged after the HRL addition. The addition of up to 0.4 g/L of HRL did not have a major impact on the organoleptic characteristics of the wines tasted whereas concentrations higher than 0.8 g/L were not considered beneficial. Results denote that the addition of Hippophae rhamnoides L. leaves to white wines contributes positively to the overall antioxidant capacity and could be used as an antioxidant agent in wines vinified in the absence of sulphur dioxide.