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.

Assessment of colour and tannin extraction in Tempranillo and Cabernet-Sauvignon using small-scale fermentation vessels

Researchers typically perform winemaking experiments using small volumes of grapes. This study examined which small-vessel volume (10, 25, 50 and 100 L) gives better repeatability during red winemaking extraction of colour and tannin in research studies. Few studies have actually evaluated the repeatability of small-scale fermentations using two varieties of different phenolic potential: Tempranillo and Cabernet-Sauvignon. We investigated how volume size may affect the composition of colour and tannins for these two varieties and result in potentially different phenolic contents. Furthermore, for each variety, we compared the small scale vessel with a commercial fermentation using a 2.500 L capacity. 50 L tanks resulted in optimum extraction of phenols and colour. High repeatability was observed for alcohol content, pH and total acidity, anthocyanins, and procyanidins for both varieties amongst vessel sizes. Kinetics of fermentation performed faster in big berry driven grapes (Tempranillo) regardless of the volume. Instead, for small berry grapes (Cabernet-Sauvignon), vessel size affected the kinetics or fermentation and therefore the extraction can be altered. Very high repeatability for the alcohol by volume, pH and total acidity (CV ≤ 7 %) as well as anthocyanins and procyanidins by HPLC (15 % ≤ CV ≤ 20 %) for both varieties in all volume sizes. This research provides a solid basis for validating the reproducibility of small-scale fermentations of two red grapevines with different phenolic potential and sheds new light on the potential and limitations of small-scale winemaking.

Biosorption of Chromium from Textile Wastewater Using Mimosa pudica Tannin Gel

<p>The heavy metal content is very dangerous because it can pollute the environment. One of the heavy metals waste commonly found in the textile industry is chromium (Cr). <em>Mimosa pudica</em> is a weed plant and its availability is very abundant. However, it also contains tannin which can be developed into tannin gel biosorbent to adsorption heavy metal content in the wastewater. The purpose of this research is to study <em>Mimosa pudica</em> tannin as a Cr biosorbent from textile wastewater. There are two steps to synthesis tannin gel biosorbent. They are the tannin extraction and the condensation polymerization process. Tannin is easily soluble in water so the condensation polymerization process is needed to make it insoluble in water. The extraction of <em>Mimosa pudica </em>tannin was done using water solvent. The condensation polymerization process was done by the reaction of tannin extract and formaldehyde. The Cr content of textile industry wastewater in the Pasar Kliwon, Surakarta was 4 ppm. The results of the biosorption of Cr heavy metal using <em>Mimosa pudica</em> tannin gel showed that the remaining Cr heavy metal was 0.7098 ppm. It was already below the threshold which was 1 ppm.</p><p> </p><p><strong>Keywords:</strong> biosorption, condensation polymerization, extraction, <em>Mimosa pudica</em>, tannin gel</p>

Commercial Mannoproteins Improve the Mouthfeel and Colour of Wines Obtained by Excessive Tannin Extraction

In the production of red wines, the pressing of marcs and extended maceration techniques can increase the extraction of phenolic compounds, often imparting high bitterness and astringency to finished wines. Among various oenological products, mannoproteins have been shown to improve the mouthfeel of red wines. In this work, extendedmaceration (E), marc-pressed (P), and free-run (F) Sangiovese wines were aged for six months in contact with three different commercial mannoprotein-rich yeast extracts (MP, MS, and MF) at a concentration of 20 g/hL. Phenolic compounds were measured in treated and control wines, and sensory characteristics related to the astringency, aroma, and colour of the wines were studied. A multivariate analysis revealed that mannoproteins had a different effect depending on the anthocyanin/tannin (A/T) ratio of the wine. When tannins are strongly present (extended maceration wines with A/T = 0.2), the MP conferred mouthcoating and soft and velvety sensations, as well as colour stability to the wine. At A/T = 0.3, as in marc-pressed wines, both MF and MP improved the mouthfeel and colour of Sangiovese. However, in free-run wine, where the A/T ratio is 0.5, the formation of polymeric pigments was allowed by all treatments and correlated with silk, velvet, and mouthcoat subqualities. A decrease in bitterness was also obtained. Commercial mannoproteins may represent a way to improve the mouthfeel and colour of very tannic wines.

Continuous tannin extraction by use of screw reactor

A pilot-size screw reactor (extraction unit) was used for tannin extraction of spruce. Yield of the same magnitude or better was obtained when comparing a screw reactor with batch reactors. A longer presoaking time in water seemed to be better than a short one for obtaining higher yield. A higher yield is obtained with lower dry-water ratio, which suggests that the internal diffusion in bark does not determine mass transfer as much as is the case without presoaking of bark. The higher dry-water ratio decreased the yield. The prior soaking of the bark also minimized the mechanical reactor feeding problems (clogging). The benefits of a screw reactor likely are that run time changes for different process conditions are flexible; it simplifies design and construction of an industrial unit for tannin production; and it saves space because of the need for fewer and smaller intermediate storage tanks.

Optimization of protein and tannin extraction in Moringa oleifera leaf as antioxidant source

Moringa oleifera contains high nutritional and bioactive compounds that have the potential as a source of antioxidants. The main objective of this study was to obtain optimal conditions in the extraction process of Moringa leaf, maintain protein and antioxidant activity, and reduce tannin. It is carried out through the response surface method which consists of two factors. The first factor (X1) was the extraction temperature (°C) which contains three levels, namely 70, 80, and 90°C. The second factor (X2) was time (mins) consisting of three levels, namely 5, 10, and 15 mins. The parameters in this study were total protein, antioxidant activity, and total tannin. The results revealed that the optimum condition for Moringa leaf extraction is found to be temperature 80.54°C and a time of 12.19 mins. In that treatment, the total protein is 17.4594%, antioxidant activity is up to 10.2629 µg/mL, and tannin is 7.853% with the desirability of 0.792 or 79.2%.