Effect of Sonication Treatment and Maceration Time in the Extraction of Polysaccharide Compounds during Red Wine Vinification

The application of high-power ultrasounds (US) at 28 kHz to the crushed grapes and the use of different pomace contact times caused changes in the content and composition of monosaccharides and polysaccharides in the musts and wines. These differences were maintained from the moment of pressing (end of maceration) until the end of the alcoholic fermentation. The US increased the content of monosaccharides and polysaccharides in the musts by facilitating their extraction from the solid parts during maceration. The application of medium maceration time (3 days) to sonicated grapes led to an extraction of polysaccharides rich in arabinose and galactose, rhamnogalacturonan type II (RG-II) and mannoproteins (MP), similar to that observed in the control wines made with an extended maceration of 7 days (968.21 vs. 1029.45; 895.04 vs. 1700.50; 356.81 vs. 343.95, respectively). This fact was attributed to a higher extraction in the must during the sonication process and to an important release of pectic polysaccharides during the pressing of the sonicated pomace, which is reported here for the first time. Therefore, the US technology could be useful for increasing the polysaccharide content in the wines or for reducing the maceration time needed to achieve certain levels of wine polysaccharides.     

Solid-phase extraction versus matrix solid-phase dispersion: Application to white grapes

The use of matrix solid-phase dispersion (MSPD) was tested to, separately, extract phenolic compounds and organic acids from white grapes. This method was compared with a more conventional analytical method previously developed that combines solid liquid extraction (SL) to simultaneously extract phenolic compounds and organic acids followed by a solid-phase extraction (SPE) to separate the two types of compounds. Although the results were qualitatively similar for both techniques, the levels of extracted compounds were in general quite lower on using MSPD, especially for organic acids. Therefore, SL-SPE method was preferred to analyse white “Vinho Verde” grapes. Twenty samples of 10 different varieties (Alvarinho, Avesso, Asal-Branco, Batoca, Douradinha, Esganoso de Castelo Paiva, Loureiro, Pedernã, Rabigato and Trajadura) from four different locations in Minho (Portugal) were analysed in order to study the effects of variety and origin on the profile of the above mentioned compounds. Principal component analysis (PCA) was applied separately to establish the main sources of variability present in the data sets for phenolic compounds, organic acids and for the global data. PCA of phenolic compounds accounted for the highest variability (77.9%) with two PCs, enabling characterization of the varieties of samples according to their higher content in flavonol derivatives or epicatechin. Additionally, a strong effect of sample origin was observed. Stepwise linear discriminant analysis (SLDA) was used for differentiation of grapes according to the origin and variety, resulting in a correct classification of 100 and 70%, respectively.     

Comparison of extraction methods for volatile compounds of Muscat grape juice

Typical flavour of Muscat d’Alexandrie wines is mainly due to volatile compounds coming from grapes of this variety. Therefore, the choice of grapes is crucial to obtain musts with a great aromatic potential, which will contribute to the final aroma of wines derived from those musts. In this study, three sampling techniques, liquid-liquid extraction (LLE), solid phase extraction (SPE) and simultaneous distillation-extraction (SDE), were compared for the analysis of volatile compounds in Muscat grape juice. Results showed that although the three techniques can be recommended for the quantitative analysis of volatile compounds from musts, LLE and SPE are better sample preparation techniques than SDE, mainly for determination of polar compounds such as acids or alcohols.     

Effects of Saignée and Bentonite Treatment on Phenolic Compounds of Marquette Red Wines

To improve the phenolic extraction and color stability of red wine made from cold-hardy grapes, two winemaking practices, saignée and bentonite, were applied separately and in combination on Marquette grapes at crushing. The effects of these winemaking strategies on Marquette wine’s basic chemical properties, monomeric and polymeric phenolic compounds were studied, as well as the development of color characteristics from crushing to 5 months of aging. The saignée (9% juice run-off) treatment showed little impact on the phenolic content of the finished wine, but showed an increase in color intensity. A hue shift towards an orange-yellow tone was observed in the bentonite-treated wines, which was associated with a loss of monomeric anthocyanins. The combination of saignée and bentonite showed less impact on removing anthocyanins and wine color, and increased phenolics content, therefore improving the extraction of non-anthocyanins monomeric phenolics. Although this combination treatment led to the highest concentration of tannin content after pressing, this difference between the control and other treatments disappeared over time. These results suggested that the interactions between tannins and other wine compounds still occur after removing proteins in Marquette wines.     

微波能用于酵母中海藻糖高效液相色谱分析样品制备的研究

利用微波能提取酵线中的海藻糖，建立了一种海藻糖分析样品的快速制备方法。高效液相色分析结果表明，无论是提取选择性、还是提取时间消耗，用微波法提取均具有常规提取法所无法比拟的优越性。经２０ｓ微波处理后，海藻糖酶已失活，故有效防止了提取过程中海藻糖的降解。微波提取不失为一种良好的样品的制备方法，尤其适用于对酵母低谢的研究。     

Determination of spiroxamine residues in grapes, must, and wine by gas chromatography/ion trap-mass spectrometry

Analytical methodology was developed and validated for the determination of spiroxamine residues in grapes, must, and wine by gas chromatography/ion trap-mass spectrometry (GC/IT-MS). Two extraction procedures were used: the first involved grapes, must, and wine extraction with alkaline cyclohexane-dichloromethane (9 + 1, v/v) solution, and the second grape extraction with acetone, dichloromethane, and petroleum ether. In both procedures, the extract was centrifuged, evaporated to dryness, and reconstituted in cyclohexane or 2,2,4-trimethylpentane-toluene (9 + 1, v/v), respectively. Spiroxamine diastereomers A and B were determined by GC/IT-MS, and a matrix effect was observed in the case of grapes but not in must and wine. Recovery of spiroxamine from fortified samples at 0.02 to 5.0 mg/kg ranged from 78-102% for grapes and must, with relative standard deviation (RSD) <13%; for red and white wines, recoveries ranged from 90 to 101% with RSD <9%. The limit of quantification was 0.02 mg/kg for grapes, must, and wine or 0.10 mg/kg for grapes, depending on the extraction procedure used.     

Determination of amino acids in selenium-enriched yeast by gas chromatography–mass spectrometry after microwave assisted hydrolysis

A simple, rapid microwave digestion procedure for protein hydrolysis preceding the determination of amino acids in yeast using gas chromatography–mass spectrometry (GC–MS) is described. Protein hydrolysis was performed in a focused microwave using 4 M methanesulfonic acid (MAS). Amino acids were derivatized with methyl chlorofomate (MCF) and extracted into chloroform prior to GC–MS analysis. The microwave parameters, including power, temperature and heating time, were optimized. It was found that temperature and heating time were the most influential factors. A total of 17 amino acids were determined in selenium-enriched yeast with use of standard addition calibration. Limits of detection and quantitation (LODs/LOQs) of the amino acids measured were in the sub-nmol range, suitable for monitoring of amino acids in yeast and other food products.     

Dry Red Wine Making Using Yeast Immobilized on Cork Pieces

The commercial Saccharomyces cerevisiae Uvaferme 299 wine yeast was immobilized on cork pieces to produce a biocatalyst for use in dry red wine making. The immobilized biocatalyst was suitable for clarified and non-clarified grape must fermentation at ambient and low temperatures (0–25 °C). Fermentation times were low and very low amounts of residual sugar were detected, showing suitability for dry wine production. The presence of suspended solids in the non-clarified must did not affect the activity of the immobilized cells. Complete fermentation of sugars at 0 °C was possible with immobilized Uvaferme 299, although not a cryotolerant strain, indicating a cryoprotective effect of cork. The presence of cork did not affect the composition of major volatiles with methanol and acetaldehyde kept at low levels. Reduction of amyl alcohols on total volatiles was also observed in wines fermented at low temperatures. Differences in the headspace aroma profile in wines produced by immobilized and free cells were found by GC–MS analysis, but no cork taint compounds were detected.     

Towards the Optimization of Microwave-Assisted Extraction and the Assessment of Chemical Profile,Antioxidant and Antimicrobial Activity of Wine Lees Extracts

Wine lees, a sub-exploited byproduct of vinification, is considered a rich source of bioactive compounds, such as (poly)phenols, anthocyanins and tannins. Thus, the effective and rapid recovery of these biomolecules and the assessment of the bioactive properties of wine lees extracts is of utmost importance. Towards this direction, microwave-assisted extraction (MAE) factors (i.e., extraction time, microwave power and solvent/material ratio) were optimized using experimental design models in order to maximize the (poly)phenolic yield of the extracts. After optimizing the MAE process, the total phenolic content (TPC) as well as the antiradical, antioxidant and antimicrobial activity of the extracts were evaluated. Furthermore, Fourier transform infrared spectroscopy (FTIR) was employed to investigate the chemical profile of wine lees extracts. Red varieties exhibited higher biological activity than white varieties. The geographical origin and fermentation stage were also considered as critical factors. The white variety Moschofilero presented the highest antioxidant, antiradical and antimicrobial activity, while Merlot and Agiorgitiko samples showed noteworthy activities among red varieties. Moreover, IR spectra confirmed the presence of sugars, amino acids, organic acids and aromatic compounds. Thus, an efficient, rapid and eco-friendly process was proposed for further valorization of wine lees extracts.     

Volatiles Formation from Grape Must Fermentation Using a Cryophilic and Thermotolerant Yeast

Grape must fermentation performance and volatiles formation by simultaneously cryophilic and thermotolerant yeast (strain AXAZ-1), isolated from grapes in Greece, was evaluated in a wide temperature range (5?C40°C). Yeast strain was immobilized on brewer??s spent grains (BSG) and the formed biocatalyst was introduced into a Multi-Stage Fixed Bed Tower (MFBT) bioreactor. Almost complete sugar utilization from the aforementioned biocatalyst was observed in a wide temperature spectrum, ranging from 5?°C to 37?°C, while at 40?°C residual sugar was up to 29?g/l. Time to complete fermentation with the immobilized yeast ranged from 290?h at 5?°C and 120?h at 40?°C to 25?h at 33?°C. The daily ethanol productivity reached maximum (88.6?g/l) and minimum (5.6?g/l) levels at 33?°C and 5?°C, respectively. The aroma-related compounds?? profiles of immobilized cells at different fermentation temperatures were evaluated by using solid phase microextraction (SPME) gas chromatography/mass spectrometry (GC/MS). Must fermentation resulted in a high-quality fermentation product due to the low concentrations of higher and amyl alcohols at all temperatures tested. AXAZ-1 is a very promising strain for quality wine production, as it is capable of performing fermentations of high ethanol concentration and productivities in both low and high temperatures.     

A New Process for Wine Production by Penetration of Yeast in Uncrushed Frozen Grapes

Different types of red and white wines were prepared by fermentation of the juice which was naturally separated from uncrushed frozen grapes during thawing (A) and from the residual juice by fermentation inside the berries (B). Yeast penetrated the skin of uncrushed grapes and fermented the content completely. The new types of wines were compared with wines prepared conventionally from the whole material of frozen grapes. Chemical and chromatographic analysis (gas chromatography (GC) and solid-phase microextraction–GC/mass spectrometry) showed similar profiles of the aroma volatiles but with significant quantitative differences among the new types of wines, which reflected to the differences observed during the sensory evaluations. The majority of identified compounds were esters, with higher amounts found in (A) wines due to the higher concentration of the must which was separated during thawing. The proposed process is new and of industrial interest for the production of different types of wines from the same raw material in one fermentation batch.     

Identification of S-methylmethionine in Petit Manseng grapes as dimethyl sulphide precursor in wine

A procedure for the extraction of free amino acids was applied to isolate S-methylmethionine (SMM) from late harvest Petit Manseng grapes. Grapes were destemmed and crushed, and the obtained clarified must was percolated through cation-exchange resins (Dowex 50 WX4-100). The retained compounds were eluted with ammonia solution and the extract was finally concentrated. Taking into account the potential DMS (PDMS using heat-alkaline treatment assay) of the initial grape juice used (51.5 nmol mL⁻¹) and the concentration factor of the extract (17.9-fold), the PDMS of the final extract (678 nmol mL⁻¹) gave an overall recovery of 73.5% for juice SMM. This compound was identified and quantified (484.5 nmol mL⁻¹ relatively to [²H₃]-SMM used as internal standard) by its selective detection in this extract without derivatization by MALDI-TOF-MS using instrumentation and procedures previously reported to analyze SMM in complex natural extracts. SMM and 22 other amino acids in the initial must and in the final SMM extract were also determined using a Biochrom 30 amino acid analyser with post-column ninhydrin derivatization. SMM peak identification and quantification (401.2 nmol mL⁻¹ relatively to norleucine used as internal standard) were carried out by comparison with commercial SMM.     

Recovery of Chlorogenic Acids from Agri-Food Wastes: Updates on Green Extraction Techniques

The agri-food sector produces a huge amount of agri-food wastes and by-products, with a consequent great impact on environmental, economic, social, and health aspects. The reuse and recycling of by-products represents a very important issue: for this reason, the development of innovative recovery and extraction methodologies must be mandatory. In this context of a circular economy, the study of green extraction techniques also becomes a priority in substitution of traditional extraction approaches. This review is focused on the recovery of chlorogenic acids from agri-food wastes, as these compounds have an important impact on human health, exhibiting several different and important healthy properties. Novel extraction methodologies, namely microwave and ultrasound-assisted extractions, supercritical fluid extraction, and pressurized-liquid extraction, are discussed here, in comparison with conventional techniques. The great potentialities of these new innovative green and sustainable approaches are pointed out. Further investigations and optimization are mandatory before their application in industrial processes.     

Antioxidant Properties of Bio-active Substances from Shrimp Head Fermented by Bacillus licheniformis OPL-007

Antioxidative activities were found in the culture supernatant of Bacillus licheniformis OPL-007 using shrimp head waste (SHW) as the sole carbon and nitrogen source. After optimizing fermentation conditions, some bio-active substances were determined from the broth. The contents of total phenols, polysaccharides, reducing sugars, free amino acids, and organic acids were 888.80, 402.74, 85.88, 2,061.79, and 5,426.74 mg/l, respectively. Moreover, the fermentation liquid was found rich in eight essential amino acids and non-protein amino acids. The antioxidant activity of the culture supernatant, in terms of the scavenging activity of DPPH radicals, reducing power, and metal chelating ability, was monitored, and the fermentation liquid showed a strong antioxidant capacity. The results indicate that bio-deproteinization of SHW by B. licheniformis OPL-007 can increase its antioxidant activity, and SHW has the potential application in the production of functional foods.     

微波萃取在中药提取中的应用

微波萃取是一种新型高效的萃取技术,对中药的现代化发展尤为重要。微波萃取技术具有选择性好、萃取速度快、提取效率高等特点,可应用于黄酮类、多糖类、苷类、挥发油、蒽醌类、有机酸类、生物碱类等中药有效成分的提取中。     

微波提取龙须藤多糖的最佳条件研究

选取微波功率、提取温度、提取时间和料液比作为因素,以毛细管电泳-紫外检测测定龙须藤多糖水解产物中的单糖峰面积总和为指标,通过单因素和正交试验,对提取条件进行了优化.结果表明,最大影响因素为微波功率,其次为提取温度,再次为提取时间,最后为料液比.最优提取条件为微波功率600 W,提取温度70 ℃,提取时间25 min,料液比1:35.     

Microwave-assisted solid-phase synthesis of hydantoin derivatives

A microwave-assisted synthesis of 3,5- and 1,3,5-substituted hydantoins starting from various resins for solid-phase combinatorial chemistry has been developed. The hydantoins were synthesized from pre-loaded resins with amino acids via treatment with isocyanate or phenylisocyanate and subsequent intramolecular cyclization. Both reactions were performed under microwave irradiation. We studied the cyclative cleavage leading to hydantoin compounds dependent on the nature of the amino acid and the nucleofuge properties of the resin.     

Screening of Oleaginous Yeast Strains Tolerant to Lignocellulose Degradation Compounds

High cost of triacylglycerol lipid feedstock is the major barrier for commercial production of biodiesel. The fermentation of oleaginous yeasts for lipid production using lignocellulose biomass provides a practical option with high economic competitiveness. In this paper, the typical oleaginous yeast strains were screened under the pressure of lignocellulose degradation compounds for selection of the optimal strains tolerant to lignocellulose. The inhibitory effect of lignocellulose degradation products on the oleaginous yeast fermentation was carefully investigated. Preliminary screening was carried out in the minimum nutritious medium without adding any expensive complex ingredients then was carried out in the lignocellulosic hydrolysate pretreated by dilute sulfuric acid. Seven typical lignocellulose degradation products formed in various pretreatment and hydrolysis processing were selected as the model inhibitors, including three organic acids, two furan compounds, and two phenol derivatives. The inhibition of the degradation compounds on the cell growth and lipid productivity of the selected oleaginous yeasts were examined. Acetic acid, formic acid, furfural, and vanillin were found to be the strong inhibitors for the fermentation of oleaginous yeasts, while levulinic acid, 5-hydroxymethylfurfural, and hydroxybenzaldehyde were relatively weak inhibitors. Trichosporon cutaneum 2.1374 was found to be the most adopted strain to the lignocellulose degradation compounds.