Prevention of quercetin precipitation in red wines: a promising enzymatic solution

Flavonols are known for causing undesirable deposits in both red and white wines. Among flavonols, quercetin is widely considered the principal factor determining this phenomenon. One of the most accredited hypotheses claims that glycosylated derivatives of quercetin undergo hydrolysis of the glycosylic bond during the fermentation and the wine ageing, releasing quercetin aglycone, which is much less soluble in water solution and causes the precipitation. Our work describes the dynamics of quercetin-derived deposition in Chianti wines and purposes a new method, based on the enzymatic quercetin glycoside hydrolysis of the glycosidic bond, to prevent the unpleasant deposit formation during the wine ageing. In our study, forty-four monovarietal wines obtained from 7 different Italian grape varieties were compared in the content of total quercetin-3-glycosides (rutin, quercetin-3-glucuronide, quercetin-3-glucoside) and quercetin aglycone. The data confirmed the literature revealing Sangiovese as the richest in quercetin. We tested then, in a Sangiovese wine, four fining agents (PVPP, PVPP/PVI, bentonite and a vegetal protein) for quercetin removal, showing that only the PVPP had a modest aglycone removal activity. Then, the kinetics of deposit formation was studied in three Chianti wines which differed in the initial content of quercetin aglycone. This investigation highlighted that the chemical equilibrium of quercetin changes over time as the turbidity slowly increases, as previously documented. The comparison of the three dynamics also permitted us to conclude that different wines show a different ability to keep in solution quercetin. Finally, a new approach for deposit prevention was studied by a precocious Chianti wine treatment with a pectolytic enzyme having secondary glycosidase activity. This enzyme significantly accelerated the hydrolysis of glycosylated quercetins into their aglycone, which could enhance the deposition before bottling, without serious wine colour depletion. Our study represents the first evidence of the promising potential of using the pectolytic enzyme with secondary glycosidase activity to prevent quercetin deposit during Chianti ageing, in a way that is compatible with organic wine production.

The Application of Ultrasound and Enzymes Could Be Promising Tools for Recovering Polyphenols during the Aging on Lees Process in Red Winemaking

The final concentration of phenolic compounds in wines is usually lower than what might be expected, given their concentration in grapes. This is in part due to the interactions between cell walls from grapes and yeast with phenolics during red winemaking. Most of these aggregates are insoluble and end up precipitating, forming part of the lees. The objective of this study is to determine the capacity of ultrasounds and/or enzymes treatments (β-glucanase and a pectolytic enzyme) to release the anthocyanins and tannins adsorbed in the lees. The ultrasound (US) applied for 120 min slightly favored the extraction of anthocyanins and doubled tannin extraction. Shorter sonication times did not show any positive effect. The combination of β-glucanase and pectolytic enzyme was always more effective in the liberation of anthocyanins (both no-acylated and acylated anthocyanins) and tannins than the enzymes acting separately. The combination of US (120 min), β-glucanase and pectolytic enzyme showed an additive effect, increasing the extraction of phenolic compounds with respect to the individual treatments and also releasing a large quantity of low molecular weight polysaccharides, compounds of enological importance. These results of this study could be of enological interest, facilitating and accelerating the aging on lees process, through the liberation of polysaccharides and the recovery of the phenolic compounds lost during vinification.

EFFECT OF NUTRIENTS ON CELLULOLYTIC AND PECTOLYTIC ENZYME PRODUCTION OF ALTERNARIA ALTERNATA A LEAF SPOT PATHOGEN OF TEAK (TECTONA GRANDIS L.F.)

Alternaria alternata is a potential pathogen of Tectona grandis L.f., was isolated from diseased Tectona grandis L.f. leaves from Nashik and used for the present study. Pathogen was grown on the Czapek-Dox liquid medium substituting or adding different carbon, nitrogen to study cellulolytic and pectolytic enzyme production and total phenol production. The activity of enzyme was observed on the 8th day of incubation period. A great extent of growth variation was observed on different carbon, nitrogen. Among the carbon source) the maximum loss in percentage viscosity maximum in lactose and fructose. While minimum in glucose and dextrose as compared to other nitrogen source. From nitrogen source the cellulolytic enzyme activity was maximum in control and cobalt nitrate followed by similar activity in potassium nitrate and nickel nitrate. While minimum cellulolytic enzyme activity was seen in barium nitrate.. Variation was also observe in pectolytic enzyme activity. the cellulolytic enzyme activity was maximum in glucose while minimum in dextrose as compared to lactose, control and fructose.. From nitrogen source the cellulose activity was maximum in potasium nitrate and minimum in cobalt nitrate as compared to nickel nitrate, barium nitrate and control.

COMPLEX OF ENZYMES FOR EFFICIENT CONVERSION OF DRIED APRICOT BIOCOMPONENTS IN THE PRODUCTION OF FOOD INGREDIENTS FOR ALCOHOLIC BEVERAGES

The effectiveness of the use of pectolytic enzyme preparations - Fructocim P6L and fungal cellulase - Bruzaym BGX for biocatalysis of high-molecular substances of dried apricot pulp in the preparation of food ingredients (alcoholic juices and fruit drinks) for alcoholic beverages is shown.

Volatile Aroma Compounds of Brandy ‘Lozovača′ Produced from Muscat Table Grapevine Cultivars (Vitis vinifera L.)

Grape brandy, known as ‘Lozovača’, is one of the most produced alcoholic beverages in the Republic of Serbia. Muscat cultivars are highly priced in grape brandy manufacturing. Among the numerous factors, cultivar-specific characteristics have a significant influence on its quality and aroma profile. Pectolytic enzymes play a part in increasing intensity of the prefermentative aroma by hydrolysis of terpenic glycosides, from which the compounds that contribute to the aroma of brandy are released. In this study, grape brandy samples were produced from five Muscat table grapevine cultivars (Vitis vinifera L.) namely, Early Muscat, Radmilovac Muscat, Banat Muscat, Italia Muscat, and Muscat Hamburg, with the addition of pectolytic enzyme in two different concentrations or without it (control). A total of 58 volatile aroma compounds were detected by means of combined gas chromatographic-mass spectrometric (GC/MS) method. Ethyl esters of C8–C18 fatty acids (21) and terpene (16) compounds were considerably more abundant in all grape brandy samples compared to the other volatile compounds identified. Pectolytic enzyme, positively affected terpenes content in the brandy of all studied cultivars. The similarities between brandy samples produced from Muscat Hamburg (MH) and other Muscat cultivars may be attributed to the parentage of MH to those cultivars.

Роль технологических факторов в формировании аромата красных столовых вин

В настоящей публикации представлены результаты аналитических и органолептических исследований ароматобразующего комплекса и профиля аромата красных столовых сухих вин, полученных из винограда разных сортов, произрастающего в Крыму, 2013-2017 годов урожая, в условиях микровиноделия при варьировании технологических приемов переработки и параметров сульфитации мезги. На основании статистической обработки (критерий Mann-Whitney) и обобщения экспериментальных данных установлены значимые (р 0,05) различия количественного содержания аро-матобразующих компонентов в винах, полученных по различным схемам, и определены технологические приемы, позволяющие получать вина с ароматом заданного направления. Показано, что брожение сульфитированной до 60-80 мг общего диоксида серы на 1 кг мезги до 1/3 остаточных сахаров от их исходного количества приводит к наименьшему накоплению терпеновых спиртов в винах: вина (при 80 мг общего SO2 на 1 кг мезги) характеризуются выраженным ягодно-фруктовым ароматом. Внесение в мезгу до брожения препарата конденсированного танина или увеличение дозы сульфитации мезги до 100 5 мг общего SO2 на 1 кг мезги, а также брожение сусла после настаивания мезги способствуют усилению цветочных оттенков в аромате вин, в том числе за счет увеличения концентрации терпеновых спиртов в винах в 1,6-1,9 раза. Внесение в мезгу до брожения ферментного препарата пектолитического действия и снижение дозы сульфитации мезги до 605 мг/кг приводит к усилению пряных оттенков. Совместное использование препаратов пектолитического действия и конденсированного танина приводит к формированию сложного аромата с яркими пряными и цветочными оттенками.The paper summarizes analytical and organoleptic data on the aroma-building complex and aroma profile of red table dry wines produced from different cultivars of Crimean grapevines of the 2013-2017 vintages under conditions of micro-vinification using various technological processing methods and must sulfitation param-eters. Based on statistically processed (Mann-Whitney test) and consolidated experimental data, the study established significant variations (p 0.05) in the quantitative content of the aroma-building components of wines produced by different processing schemes. Processing methods were determined that make it possible to obtain wines with pre-determined aroma. The study demonstrates that fermentation of must sulfited to 60-80 mg of total SO2 per 1 kg of must to 1/3 of residual sugars from the original amount decreases terpene alcohols accumulation in wines: wines (sulfited to 80 mg/kg) demonstrate pronounced berry-fruit aroma. Introduction of condensed tannin preparation into the must before fermentation or increasing must sulfitation dose to 1005 mg of total SO2 per 1 kg of after must maceration enhances flowery overtones in the wine aroma, which includes a 1.6-1.9 increase in the concentration of terpene alcohols in wines. Introduction of pectolytic enzyme preparation into the must before fermentation and decreasing must sulfitation to 605 mg/kg strengthens spicy overtones. The combined use of pectolytic enzyme preparation and condensed tannin produces complex aroma with pronounced spicy and flowery notes.

Influence of Pectolytic Enzymes on the Quality of Wine Maceration

Obtaining high-quality wines with a registered designation of origin means making the most of the specific features of the variety and those imprinted with technology and the place of harvesting. The aroma is due to the chemical compounds of terpenic nature that accumulate in the grapes (variety flavors) and the secondary aromas that are formed during the alcoholic fermentation and the aging period of the wines (Amrani, and Glories, 1995). The wine-making of the varieties is followed by the appreciation of the primary grapes. This is achieved by preferential maceration of the must by means of enzymes (Marin et al., 1998). The technology of aromatic wines has two fundamental objectives: extracting the primary aromas of grapes (terpenols) and favoring the formation of secondary fermentation aromas. In order to obtain aromatic wines with variety typology, the preferential stage is decisive. Pectolytic enzyme preparations are used in oenology to accelerate and complete the extraction and clarification processes of the must, extracting and stabilizing the color, highlighting the varietal aromatic potential of the varieties and improving the filterability and maturation of the wines.

Effects of pectolytic enzyme treatment and microfiltration on antioxidant components of elderberry juice

In this study, pectolytic enzymes (Pectinex BE XXL,Trenolin Rot, andFructozym P) were investigated for their influence on phenolic, anthocyanin content, and antioxidant activities of elderberry (Sambucus nigraL.) pulps during juice processing. Prior to pressing the berries, three different enzymes were added to pulps in order to evaluate the effect of different pectolytic enzyme treatments on the valuable components of elderberry juice. Control sample was prepared without enzyme. After treatment, squeezing, and clarification steps, microfiltration was carried out with ceramic membrane. The effect of this technology on the antioxidant capacity, total polyphenol content, and total anthocyanin content of the clarified elderberry juices has been evaluated in permeate and retentate samples, and membrane retention was calculated. Significantly lower antioxidant capacity was detected in the case of control sample than that obtained using enzyme-treated juices. Retention of antioxidant content on the microfiltration membrane was greatly reduced by using the enzymes. Higher valuable component yield was obtained usingFructozym Penzyme compared withPectinex BE XXLused in industry.