A Metabolomic Approach to the Study of Wine Micro-Oxygenation

Wine micro-oxygenation is a globally used treatment and its effects were studied here by analysing by untargeted LC-MS the wine metabolomic fingerprint. Eight different procedural variations, marked by the addition of oxygen (four levels) and iron (two levels) were applied to Sangiovese wine, before and after malolactic fermentation

Vinegar production from fruit concentrates: effect on volatile composition and antioxidant activity

Vinegar stands as a highly appreciated fermented food product due to several functional properties and multiple applications. This work focuses on vinegar production from fruit wines derived from fruit concentrates, to attain a food product with nutritional added value. Four fruit vinegars (orange, mango, cherry and banana), were produced and characterized, with total acidities of 5.3 ± 0.3% for orange, 5.6 ± 0.2% for mango, 4.9 ± 0.4% for cherry and 5.4 ± 0.4% for banana. Acetification showed impact on aroma volatiles, mainly related to oxidative reactions. Minor volatiles associated with varietal aroma were identified, monoterpenic alcohols in orange vinegar, esters in banana vinegar, C13-norisoprenoids in cherry vinegar and lactones in mango vinegar, indicating fruit vinegars differentiated sensory quality. Total antioxidant activity analysis by FRAP, revealed fruit vinegars potential to preserve and deliver fruit functional properties. Antioxidant activity of fruit vinegars, expressed as equivalents of Fe2SO4, was of 11.0 ± 1.67 mmol L1 for orange, 4.8 ± 0.5 mmol L1 for mango, 18.6 ± 2.33 mmol L1 for cherry and 3.7 ± 0.3 mmol L1 for banana. Therefore, fruit vinegars presented antioxidant activity close to the reported for the corresponding fruit, and between 8 and 40 folds higher than the one found in commercial cider vinegar, demonstrating the high functional potential of these novel vinegar products.Authors would like to acknowledge the financial funding of: FruitVinegarDRINK QREN Project (Ref. 23209), Project "BioInd-Biotechnology and Bioengineering for improved Industrial and Agro-Food processes, REF. NORTE-07-0124-FEDER-000028" Co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER and the FCT Strategic Project Pest OE/EQB/LA0023/2013. Authors would also like to acknowledge the participation of Mendes Goncalves S.A. and Frulact S.A. staff, for the active input, which led to the work basis and rationale.info:eu-repo/semantics/publishedVersio

Phenolic composition of monovarietal red wines regarding volatile phenols and its precursors

The aim of this study was to characterise and compare wines from different grape varieties focusing on the volatile phenols and on the respective precursor compounds, both on the free form (p-coumaric, ferulic and caffeic acids) and as tartaric esters of hydroxycinnamic acids (caftaric, coutaric and fertaric acids). Fifty-eight commercial monovarietal red wines from eight selected grape varieties were used: Cabernet Sauvignon, Syrah, Aragonez, Castelão, Touriga Franca, Touriga Nacional, Trincadeira and Vinhão (Sousão). It was found that volatile phenol precursors exist mostly as esters of tartaric acid, with caftaric acid as the most abundant cinnamate (17–111 mg/L), followed by coutaric and fertaric acids. The predominant hydroxycinnamic acid was p-coumaric acid, the highest concentrations being found in Syrah and Touriga Franca (6–7 mg/L) and the lowest in Touriga Nacional and Trincadeira (2–3 mg/L). Touriga Nacional exhibits the highest difference between bound and free forms. Malvidin-3-O-(6-p-coumaroyl)-glucoside, a potential source of p-coumaric acid, was found in most of the wines with average values varying between 1 and 5 mg/L. Twenty-two percent of the wines analysed presented levels of volatile phenols above the perception threshold. Ethylphenols were the highest in Vinhão and Trincadeira, showing an average value well above the perception threshold. The concentrations found in Cabernet Sauvignon and Syrah wines were around ten times lower than those reported in previous works. The results show relevant differences among grape varieties but the availability of the precursors in meaningful amounts may not be the only factor explaining the formation of volatile phenols in wines.info:eu-repo/semantics/publishedVersio