Statistical optimization of ethanol fermentation parameters for processing local grape cultivars to wines

Grape juice from two local grape cultivars viz. Punjab MACS purple and H‐144 was subjected to prefermentation skin treatment. Ethanol fermentation w.r.t agitation rate, temperature, inoculum size, and nutrient supplementation were optimized using Triple M medium following response surface methodology (RSM). RSM results were numerically optimized keeping temperature “in range” for red wine and “low” for white wine which showed agitation rate of 80 ± 1 rpm for 24 hr, diammonium hydrogen orthophosphate supplementation @ 150 mg/100 ml, inoculum size of 6.1 and 6.5% (vol/vol), and fermentation temperature of 24.6 and 21 °C as optimum for ethanol fermentation of red and white wines, respectively. Optimized results were validated on grape juice of Punjab MACS purple and H‐144 cultivars that lead to 12.0 and 11.2 (%vol/vol) ethanol production, respectively. Gas chromatography mass spectrometry analysis revealed the presence of 41 volatile compounds in the form of phenols, alcohols, terpenes, esters, ketones, and amines that add to the nutraceutical and antioxidant value of the wines.

Practical applications

Present study provides the statistical optimized fermentation parameters for red and white wine production separately. Optimization of an efficient processing technology to produce local grape wines will help to reduce the price of wines so that they are available to common masses at affordable costs besides improving the economic status of grape growers in the state and providing valuable information to wine makers to establish winery under North Indian conditions. Use of synthetic grape juice (Triple M media; during off season of grapes) lead to optimization of ethanol fermentation parameters in two separate fashions considering fermentation temperature as key parameter. Gas chromatography mass spectrometry analysis showed the presence of flavonoids, terpenes, and esters increasing nutritive value of product, providing antioxidants to the consuming person.     

自酿葡萄酒中甲醇和杂油醇检测分析

随着南方农户自酿葡萄酒的增加,由于采用传统酿制方法,存在质量安全的主要危害因子是甲醇和杂油醇。本实验收集6种自酿葡萄酒,采用气相色谱法进行检测分析,检测结果甲醇含量在430~640mg/L。国家限定标准要求甲醇含量每升果酒不超过400 mg,表明6个自酿葡萄酒中甲醇含量都超标。国家限定标准中,每10 m L果酒中杂油醇(以异丁醇和异戊醇计)不超过0.20 g,而实验检测结果杂油醇含量范围为0.04~0.10 g/100 m L。虽然检测的自酿葡萄酒中的杂油醇含量不超标,但是在人体内积累会导致慢性中毒。本实验对自酿酒中甲醇杂油醇含量进行测定与分析,对自酿葡萄酒质量安全与风险评估进一步研究提供科学依据。     

D-最优混料设计优化方便粥粉配方

为开发动植物复合健康营养早餐,对方便粥粉的配方进行了研究。应用D-最优混料设计,以溶解度、膨胀度、崩解值和碘蓝值理化指标代替主观的感官评定,研究大米(雪粳稻)、玉米粉和燕麦米的配比对食用品质和加工性质的影响。运用Design Expert软件建立了各成分配比与响应值之间的回归方程,考察了配方中各组分的相互作用。通过多目标优化得到最优的方便粥粉配方为66%雪粳稻、24%玉米粉和10%燕麦米,经验证,优化配方的溶解度、膨胀度、崩解值和碘蓝值分别为5.28%、86.16%、770 cp和0.627,与预测值相符。     

Major constituents of fusel oils distilled from Australian grape wines

Fusel oils from Australian grape wines (Vine sp. Vitis vinifera) have been found to consist substantially of ethanol, n-propanol, isobutanol (2-methyl-1-propanol), isoamyl alcohol (3-methyl-1-butanol) and active amyl alcohol (2-methyl-1-butanol). In addition there are present large numbers of aliphatic esters, believed to be of considerable importance to grape brandy and spirit flavour and quality. The quantities and occurrence of these esters have been found to follow a systematic pattern. The major esterified alcohols are related to the free alcohols present and the major esterified acids occur as a series of acids of even carbon number with a maximum concentration at the n-decanoic acid. These relationships provide a basis for calculating the approximate ester composition of fusel oil.     

Multivariate discrimination of wines with respect to their grape varieties and vintages

The primary focus of the European Union funded project entitled “Establishing a WINE Data Bank for analytical parameters for wines from Third Countries” (WINE-DB project, G6RD-CT-2001-00646-WINE-DB) was the discrimination of wine samples with respect to their geographical origin using only a few chemical parameters. Taking a step further, we have investigated the possibility of discriminating the wines in the data bank according to their harvesting seasons and grape varieties. Several chemometric methods were carefully selected and evaluated for this purpose. These were discriminant partial least squares, classification and regression trees, uninformative variable elimination discriminant partial least squares and neuro-fuzzy systems. With classification and regression trees, it was possible to identify a few chemical parameters including isotopic ratios (e.g. δ¹⁸O), biogenic amines and rare earth elements that discriminate between vintages and some grape varieties for wines produced in a particular country such as Czech Republic, Hungary, Romania or South Africa. These parameters can be used in evaluating the authenticity of wines.     

Anthocyanin pattern of several red grape cultivars and wines made from them

A high-performance liquid chromatography (HPLC) method with in-line photodiode array detection was applied to separate anthocyanins from red grape skin extracts of several Spanish cultivars, before and after winemaking, and from finished red wines. Data show that, for every cultivar studied, the anthocyanin pattern of the three materials considered (fresh grape skins, crushed grape skins after winemaking, and finished red wines) is quite different. These results may be explained by taking into account the different chemical structures of each anthocyanin and the degradation reactions that should take place during winemaking. On the other hand, the HPLC fingerprint of every material (fresh grape skins, crushed grape skins after fermentation, and wines) is related to cultivar characteristics. Thus, HPLC determination of the anthocyanin pattern of wines may be used to predict the grape cultivar from which wine was made.     

Wine vinegar production using base wines made with different yeast species

The influence of base wines obtained by the fermentation of different yeast species on acetic acid bacteria growth and on the analytical profile of vinegars was investigated. Results show that the substrates for wine vinegar production exerted a strong influence on both acetic acid bacteria growth and analytical profile of vinegars. The base wine obtained from the alcoholic fermentation of Saccharomyces cerevisiae was not always the best substrate. The fermentate made with Candida stellata positively influenced the acetic acid bacteria growth and the quality of vinegar, while the wine obtained from the fermentation of Kloeckera apiculata was a good substrate for acetic acid bacteria growth and acetic acid production and could be used for ‘ordinary’ vinegar production. © 1998 Society of Chemical Industry     

Evolution of the aroma composition of wines supplemented with grape flavour precursors from different varietals during accelerated wine ageing

The wines obtained by fermentation of a model medium supplemented with flavour precursors from different grape varieties (Muscat, Chardonnay, Grenache, Tempranillo, Merlot, Cabernet Sauvignon, Verdejo, and Syrah) were submitted to an accelerated ageing at 50 °C for 9 weeks simulating maturation in the bottle. The volatile compounds coming from grape flavour precursors were extracted by SPE and determined by GC–MS at the end of the alcoholic fermentation and after 1, 3, and 9 weeks of ageing. In general, the biggest changes were observed in the first week of accelerated ageing, most compounds showing a significant increase and a further steady decrease in their concentrations. Unexpectedly, Riesling acetal, 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN), and trans-1-(2,3,6-trimethylphenyl)buta-1,3-diene (TPB) also followed this trend. However, vanillin derivatives, furan linalool oxides, 3-oxo-β-ionone, actinidols, 4-ethylphenol, and guaiacol showed a continuous increase during the ageing process. Syrah and Muscat were the most different varieties after fermentation and also at the end of the process. Differences between the rest of the varieties increased during the accelerated ageing, and, in most cases, differences were in accordance with those observed after acid and enzymatic hydrolysis of the grape precursor extracts.     

Characterization of key-aroma compounds of botrytized wines,influence of grape botrytization

Botrytized wines (BW) are famous for their distinctive, complex aromas. To date, only a few studies have analysed the volatile compounds involved in their typical flavours. In this paper, GC–O was applied to BW and dry white wines (DW) made from the same grape varieties to characterize the main odorants responsible for their sensory differences. Surprisingly, only two odorous zones, with grapefruit or curry nuances, were apparently specific to BW. However, GC–AEDA revealed important differences in the FD values between BW and DW, making it possible to screen potent odorants of BW, such as 3-mercaptohexan-1-ol, homofuraneol^®, furaneol^®, sotolon, methional, and phenylacetaldehyde. GC–MS quantification of homofuraneol^®, furaneol^®, norfuraneol^®, phenylacetaldehyde, and methional in 14 BW, mostly at levels above their perception thresholds, confirmed their contribution to the aroma of BW. Increased concentrations of some of these odorants in BW were shown to be associated with grape botrytization, partially through the desiccation process.     

Differentiation of Greek red wines on the basis of grape variety using attenuated total reflectance Fourier transform infrared spectroscopy

Mid-infrared spectroscopy combined with appropriate software was used in an attempt to differentiate Greek red wines of different varietals origin, including the cultivars Agiorgitiko (Nemea-Peloponnesus), Xinomavro (Naousa-Central Macedonia) and Merlot from Greece. Extract of wine phenolic components were investigated by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The wine extracts were obtained by solid-phase extraction with C-18 columns and elution by methanol containing 0.01% hydrochloric acid. Libraries of spectra were created using sample from each wine variety. Spectra of unknown wine extracts were recorded and compared with those of the wine libraries and the rate of affinity (the match value) was measured automatically using the appropriate software (OMNIC ver. 7.3). The spectral region 1800–900 cm⁻¹ was used to ‘fingerprint’ wine on the basis of grape variety. This simple and fast method of analysis showed that wines from different grape varieties can be differentiated between them.     

配制法和发酵法制作姜酒的工艺比较

本文以生姜和糯米老酒为原料,分别对制取姜酒的两种常用方法--配制法和发酵法进行探讨,并对其工艺进行分析和解剖.发现此两种方法都能生姜的成份充分溶于酒体中,有效发挥姜酒功效,制作的姜酒姜香浓郁、酸甜适中、具有很多的色、香、味.     

桃红葡萄酒酿造工艺优化研究

研究利用浸渍巨峰葡萄果浆酿制桃红葡萄酒。分析果浆处理和工艺对桃红葡萄酒品质的影响。结果表明,控制果浆色度在2.5~3.0作浸渍过程终点,浸渍结束后分离不超过30%果浆量,调整含糖量为26%并加入酵母进行主发酵。按常规经后发酵、澄清、过滤与检测合格后酿造出桃红色、清亮透明、怡悦和谐的果香与酒香并具有恰当收敛性与酒体完整的桃红葡萄酒。     

Influence of grape composition and winemaking on the anthocyanin composition of red wines of Tannat

The anthocyanin composition of Tannat red wines obtained with four winemaking techniques was evaluated in different years. The wines were elaborated with traditional maceration (TM), cold pre‐fermentative maceration, delayed extraction of anthocyanins and extended maceration. Two vinifications were carried out for each technique, employing 70 kg of grapes in each one. The anthocyanin composition of wines was analysed by high‐performance liquid chromatography–diode array detection. The results confirm the fundamental role of the grape composition on the anthocyanin composition of the wines. The winemaking had an important effect on the total concentration of anthocyanins and also may modify the anthocyanic profile of wines. The wines obtained with TM had higher or similar content of anthocyanins than those elaborated with the other techniques. Canonical discriminant analysis of data showed that vintage has a greater effect on anthocyanin concentration than winemaking techniques.     

Optimization on anthocyanins extraction from wine grape skins using orthogonal test design

To optimize the extraction of anthocyanins from grape skins, orthogonal test with 4 factors and 3 levels was designed and the analysis of extracts was conducted using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The results showed that the optimal extraction for obtaining the highest amounts of anthocyanins was carried out by formic acid/methanol solvent (5/95, v/v), with ultrasonication for 10 min, extraction temperature at 25°C, and extraction time for 1.5 hr. The precision and accuracy of this method were established. This work will provide a basis for further study involving in anthocyanins of grape berries.     

Influence of grape variety and their phenolic composition on vasorelaxing activity of young red wines

Red wine has been reported to exert beneficial effects in preventing cardiovascular diseases probably due to their polyphenols constituents. The vasorelaxant capacity and phenolic composition of four monovarietal young red wines Merlot, Tempranillo, Garnacha and Cabernet-Sauvignon obtained from grapes from 2004 vintage, cultivated under the same climatic and agricultural conditions, wine-making technology and storage conditions, were determined using vascular reactivity assay in rat aortic and high-performance liquid chromatography, respectively. Primary cultures of vascular smooth muscle cells from Wistar rats were also used to evaluate their survival prevention activity as well. Every studied wine present vasorelaxation effect, but the higher value corresponds to the analyzed Merlot wine, especially rich in phenolic compounds, mainly catechins and oligomeric proanthocyanidins and anthocyanin glycosides. This study further demonstrated previous investigations about the phenolic composition of wines relation with their vasorelaxation activity.     

Ochratoxin A concentrations in Greek domestic wines and dried vine fruits.

A survey for the presence of ochratoxin A (OTA) was conducted from 1995 to 1999 on 268 locally produced commercial wines, and on 81 samples of domestic dried vine fruits (currants and sultanas) collected between 1998 and 2000 from sites of primary storage and processing. The OTA concentration in red dry wines (n = 104, median = 0.09 microgram l(-1)) was not significantly different from that for white (n = 118, median = 0.06 microgram l(-1)) and rosé (n = 20, median = 0.08 microgram l(-1)) wines. Eighteen samples of dessert wines (sweet, semi-sweet, semi-dry) and eight samples of retsina wine showed larger OTA concentrations with medians of 0.33 and 0.27 microgram l(-1), respectively. Our data indicate that the geographic region of origin influences OTA contamination for the red dry wines. In fact, a trend of increasing OTA contamination was observed for red wines from northern to southern Greece. Regarding the OTA levels in dried vine fruits, sultanas (n = 27, median = 0.6 microgram kg(-1)) were less contaminated than currants (n = 54, median = 1.3 microgram kg(-1)). Also, sultanas produced in 2000 and currants produced in 1999 showed the lowest incidence of OTA contamination, with medians of 0.3 and 0.9 microgram kg(-1), respectively.     

A review of the analytical methods to determine organic acids in grape juices and wines

The determination of low molecular weight organic acids in grape juices and wines is important because of their influence in organoleptic properties (flavour, colour and aroma) and in the stability and microbiologic control of these beverages. The analysis of these acids allows to check the process of maturation of grapes and to control the evolution of the acidity of wines during the several stages of their elaboration process (alcoholic fermentation, malolactic fermentation, aging process, etc).

In this work, a comprehensive review of the analytical methods developed for the determination of short-chain organic acids in grape juices and wines has been shown. This review included non-enzymatic spectrophotometric, enzymatic, chromatographic and electrophoretic methods. Details of the chromatographic and electrophoretic conditions of these methods have been collected in tables.     

刺葡萄汁与其它几种葡萄汁及葡萄酒的原花青素含量对比

采用铁盐催化比色法,对刺葡萄汁、巨峰葡萄汁以及几种商品葡萄汁和2种葡萄酒中的原花青素含量进行了对比测定。结果表明:刺葡萄汁中的原花青素含量为3147μg/mL,巨峰葡萄汁为1187μg/mL,Welch’s紫葡萄汁2476μg/mL,蒙娜丽莎干红葡萄酒2854μg/mL,长城干红葡萄酒2757μg/mL,可见刺葡萄汁中原花青素含量显著高于其它葡萄汁和葡萄酒中的含量。