The influence of pre-fermentative treatments on the volatile, chromatic features, organic acids and phenolic content of Fetească albă Romanian wine

Abstract

Abstract. The present study evaluates the influence of some pre-fermentative treatments on the volatile content, the chromatic parameters, the total polyphenol index and Folin-Ciocâlteu index of experimental wines obtained from Feteascȃ albȃ grape variety. Five experimental samples were produced: FA V0 (control sample), FA V1 (sodium bentonite treatment), FA V2 (glutathione treatment), FA V3 (tannin treatment), FA V4 (oenological coal treatment). The use of pre-fermentative treatments show lower values of Folin-Ciocâlteu index and total polyphenol index, excepting sample treated with tannin. Major color differences are found in the sample treated with tannin and oenological coal. Gas-chromatographic analysis reveals the presence of common wine esters, such as: hexanoic acid ethyl ester, ethyl caprylate, ethyl lactate, ethyl caprate, ethyl myristate, ethyl palmitate, that contributes at the accomplishment of the wines from the sensorial point of view. Diethyl malonate, a compound that occurs naturally in grapes has an apple-like odor and it was identified in the control sample and in the samples treated with tannin and oenological coal, being found n greater quantity in the control sample (0.02 mmol/L)and the sample treated with coal (0.03 mmol/L). Another ester, methyl oleate that offers a mild-fatty odor wasn't identified in the control sample, but it was detected in the samples treated with clay, tannin and oenological coal. Using the HPLC method it was also analysed the presence of some organic acids in wine samples.

Effect of Different Winemaking Conditions on Organic Acids Compounds of White Wines

“…Previous studies [26][27][28] showed similar results on sparkling wines and are in accordance with other literature data [29].…”

“…The lowest values of tartaric acid were identified in V4 and V5, in which the fermentation took place in tanks, which may be due to a considerable increase in ethanol during the fermentation stage, combined with low fermentation temperature. Comparable values of tartaric acid were obtained by Moros , anu et al [27]. Bayraktar [10] reported a positive correlation between tartaric acid concentration and citric acid in wine.…”

Volatile Composition of Some Red Wines from Romania Assessed by GC-MS

“…Also, Merlot wines from the south-east region aged for 12 months (Table 3) contained a higher quantity of ethyl decanoate compared with the samples aged for 6 months ( Table 2). The presence of esters in higher concentrations in wines from the south-east region compared to those from the north-west region might be explained by the different environmental conditions [38].…”

“…The volatile compounds are usually extracted by different methods, such as solid-phase extraction [32], solid-phase micro-extraction [33], stir bar sorptive extraction [34], or liquid-liquid extraction methods using organic solvents [35] before the gas chromatographic analysis. There are few data available for the volatile compounds of the international grape varieties grown in Romania and wines, but also for Romanian grape varieties and wines [36][37][38]. Fetească Neagră is one of the most widespread and economically important cultivars grown in Romania [39].…”