Valeriu V. Cotea

Selection of aroma compounds for the differentiation of wines obtained by fermenting musts with starter cultures of commercial yeast strains

Nine wines obtained by fermenting Aligoté musts with individual starter cultures of eight Saccharomyces cerevisiae yeast strains and with the indigenous microbiota were compared in terms of their composition in minor volatile aroma compounds. An easy handle methodology Stir-Bar-Sorptive-Adsorption, Gas Chromatography-Mass Spectrometry based, permits the identification of 49 aroma compounds. The rearrangement of these aroma compounds in six chemical families permits the establishment of a finger printing for each wine. Eighteen aroma compounds that exhibit a high differentiation power (p⩽0.05) were selected for chemometric analysis. The Principal Component Analysis carried out with these aroma compounds reveal that the first two principal components explain 53.8% and 17.2% of the total variance, respectively, allowing the establishment of nine different groups, in accordance with the wine types obtained. These results reveal analytical differences among the wines that are not recognized by sensorial analysis.

Mesoporous silica SBA-15, a new adsorbent for bioactive polyphenols from red wine

The aim of this paper is to evaluate the ability of the mesoporous silica SBA-15 to adsorb polyphenols from red wine. The mesoporous molecular sieve silica SBA-15 was hydrothermally synthesized in acidic media and characterized by SAXRD, BET, EDX and SEM. The adsorption behavior of mesoporous silica SBA-15 was investigated at 5°C for 24h using an adsorbent dose of 8gSBA-15L(-1) red wine. The total polyphenols content expressed as mg of gallic acid equivalents (GAEL(-1)) was estimated from the standard curve of gallic acid (absorbance at 280 nm). HPLC chromatograms of methanolic extract from mesoporous SBA-15 at 256, 280, 324, and 365 nm exhibits the strong retention of quercetin and cis-resveratrol and a reasonable retention of trans-resveratrol, catechin, epicatechin, rutin, and phenolic acids (meta- and para-hydroxybenzoic, vanillic, caffeic, syringic, salicylic and para-coumaric acids). The obtained data showed that mesoporous silica SBA-15 was capable approximately to concentrate quercetin 4900 times and cis-resveratrol 1400 times. The verifiable diminution of polyphenolic compounds content in red and white wines avoid the oxidative browning process without modification of wine color. Due to their beneficial to human health thanks to antioxidative, antiinflamatory, antiviral, antihypersensitive, cardioprotective, anticarcinogenic and antimutagenic properties the polyphenolic extract might prove interesting as pharmaconutrients or as dietary sources.

Phenolic Compounds in Merlot Wines Obtained Through Different Technologies in Iaşi Vineyard, Romania

Abstract Obtaining red quality wines depends on the raw matter composition and also on the extraction technology, used in the processing of grape and must. Thus, two methods of maceration-fermentation on lees (classical and in rotating tanks), two thermal methods (thermomaceration and microwave maceration) and two methods rarely used industrially in wine-making (cryomaceration and ultrasound maceration) were experimented. Even in the years with less than favorable climatic conditions, from Merlot grape variety one obtained for the most part, legally speaking, quality wines (with the exception of microwave macerated and cryomacerated wines, which had only 21-22 g/L non-reducing extract. In regard to alcohol content, all obtained samples had more than 11% vol. The obtained Merlot wines were rich in glycerol (8-9 g/L), fact that favorably influenced their organoleptic traits. Total phenolic content had values between 1,97 and 2,86 g/L for the Merlot wines obtained through macerationfermentation and thermomaceration. Ultrasound maceration did not favor phenolic extraction from grape skins and the obtained wines were poor in anthocyans and tannins (0,94-1,1 g/L). In regard to the maceration technology used, free anthocyans were found in variable proportions in wines, between 77 and 91%. The sum of acylated anthocyans participation percentages was between 8,8 and 22,7%, and the ratio between the acetylated and cumarilated participation percentages registered small values, varietyspecific, between 1,1 and 2,8. Rezumat Compuşii fenolici din vinurile Merlot, obţinute prin diferite procedee în podgoria Iaşi. Obţinerea vinurilor roşii de calitate depinde atât de compoziţia materiei prime, cât şi de tehnologia de extracţie, aplicată la prelucrarea strugurilor şi a musturilor. În acest scop, s-au experimentat două metode de macerare-fermentare pe boştină (clasică şi în cisterne rotative), două metode termice (macerarea cu microunde şi termomacerarea) şi două metode neimplementate pe scară largă în producţie (criomacerarea şi macerarea cu ultrasunete). Chiar şi în anii cu condiţii climatice mai puţin favorabile, din soiul Merlot s-au obţinut vinuri de calitate, care întrunesc, în mare parte, condiţiile prevăzute în legislaţie, cu excepţia celor obţinute prin macerare cu microunde şi ultrasunete, care conţin numai 21-22 g/L extract sec nereducător. Sub aspectul conţinutului în alcool, la toate variantele analizate s-au realizat mai mult de 11% vol. Vinurile obţinute din soiul Merlot au fost bogate în glicerol (8-9 g/L), ceea ce a influenţat favorabil însuşirile organoleptice ale acestora. Conţinutul în polifenoli totali a avut valori cuprinse între 1,97 şi 2,86 g/L la vinurile Merlot, obţinute prin macerare-fermentare şi termomacerare. Macerarea cu ultrasunete nu a favorizat extragerea compuşilor fenolici din pieliţa boabelor, iar vinurile obţinute au fost sărace în antociani şi taninuri (0,94-1,1 g/L). În funcţie de modalitatea de macerare, antocianii liberi s-au regăsit în vinuri în proporţii diferite, variabile între 77 şi 91%. Suma dintre proporţiile de participare ale antocianilor acilaţi s-a situat între 8,8 şi 22,7%, iar raportul dintre procentele de participare ale antocianilor acetilaţi şi cumarilaţi a înregistrat valori mici, specifice soiului, situate în intervalul 1,1-2,8.

Study of the potential use of mesoporous nanomaterials as fining agent to prevent protein haze in white wines and its impact in major volatile aroma compounds and polyols

Mesoporous nanomaterials were used to prevent protein haze in Muscat Ottonel and Pedro Ximénez wines. Major volatile compounds, polyols and turbidity were analyzed in fined wines and the results were compared with untreated and fined with bentonite wines. Two commercial mesoporous nanomaterial labelled as SBA-15 and MCM-41 provided a notable turbidity reduction and prevent protein haze as was demonstrated by the heat stability tests. Only, the siliceous material labelled as KIT-6 was not suitable for wine fining. All the chemical families were affected by the fining agents, although the loss of aroma compounds was lower with nanomaterials than with bentonite. The impact on volatile compounds concentration depends on tested wine, independently on the fining agent used. Wines were distinguished by principal components analysis, which was carried out using the volatile compounds as classifying variables. Wines treated with SBA-15 were closest to the control wine in terms of volatile compounds concentration.