Smoke-derived taint in wine: effect of postharvest smoke exposure of grapes on the chemical composition and sensory characteristics of wine

Although smoke exposure has been associated with the development of smoke taint in grapes and subsequently in wine, to date there have been no studies that have demonstrated a direct link. In this study, postharvest smoke exposure of grapes was utilized to demonstrate that smoke significantly influences the chemical composition and sensory characteristics of wine and causes an apparent 'smoke taint'. Verdelho grapes were exposed to straw-derived smoke for 1 h and then fermented according to two different winemaking treatments. Control wines were made by fermenting unsmoked grapes. Sensory studies established a perceivable difference between smoked and unsmoked wines; smoked wines were described as exhibiting 'smoky', 'dirty', 'earthy', 'burnt' and 'smoked meat' characteristics. Quantitative analysis, by means of gas chromatography-mass spectrometry, identified guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-ethylphenol, eugenol, and furfural in each of the wines made from smoked grapes. However, these compounds were not detected in the unsmoked wines, and their origin is therefore attributed to the application of smoke. Increased ethanol concentrations and browning were also observed in wines made from grapes exposed to smoke.     

Magnetic resonance imaging for nondestructive analysis of wine grapes

Magnetic resonance imaging (MRI) was used to study the growth and ripening of grape berries for three varieties. The results show that this technique allows the visualization of internal characteristics of berries using noninvasive procedures in order to obtain the volume and degrees Brix distribution within a cluster. Samples of Cabernet Sauvignon, Carmenère, and Chardonnay varieties collected over the 2002 season were analyzed. Calibration models were developed to correlate soluble solids (degrees Brix) against spin-lattice relaxation time t(1) and spin-spin relaxation time t(2). The correlation of degrees Brix and t(1) was R(2) = 0.75 for Cabernet Sauvignon, R(2) = 0.8 for Carmenère, and R(2) = 0.65 for Chardonnay. In the case of t(2) the correlation was significantly lower. Reconstruction techniques for the three-dimensional representation of clusters were developed, allowing an interactive visualization of the bunches. The method also provides volume measurements of single berries and their distribution within the cluster with an accuracy of 3% and R(2) = 0.98. These results show the potential of MRI in the wine industry for both monitoring and research. Not only does it provide quantitative information about the berries such as volume and degrees Brix distributions, but it can also be used to support the sampling procedures by providing a better cluster characterization.     

Determination of ethylenethiourea in grapes and wine

Residues of ethylenethiourea (ETU) in grapes and wine were determined by capillary gas chromatography and paper chromatography, without a cleanup step, and after derivatization to S-benzyl-ETU. The detection limit was 0.0002 mg/kg for flame ionization detection, 0.008 mg/kg for paper chromatography with photodensitometric evaluation of the detected spot. Results were compared with a generally used GC method specifying electron capture detection of trifluoroacetylated S-benzyl-ETU. The recoveries of ETU in grapes and wine at different concentration levels were determined. ETU residues were determined in treated grapes but no residues were detected in wine.     

基于Weibull分布函数的葡萄干燥过程模拟及应用

为了探究Weibull分布函数中各参数的影响因素及其在干燥中的应用,该文以不同干燥方法（气体射流冲击干燥、真空脉动干燥）、干燥温度（50、55、60和65℃）以及烫漂预处理（30、60、90、120 s）的葡萄干燥过程为研究对象,利用Weibull分布函数对其干燥动力学曲线进行模拟并分析。研究结果表明：Weibull分布函数能够很好的模拟葡萄在试验条件下的干燥过程;尺度参数α与干燥温度有关,并且随着干燥温度的升高而降低;形状参数β与干燥方式和物料状态有关,但干燥温度对形状参数β的影响很小。计算了葡萄在干燥过程中的水分扩散系数Dcal在0.2982×10-9~2.7700×10-9 m2/s 之间,并根据阿伦尼乌斯公式计算出热风干燥和真空脉动干燥方法的干燥活化能分别为72.87和61.43 kJ/mol。研究结果为Weibull分布函数在葡萄干燥过程的应用提供参考。     

采用轻量级网络MobileNetV2的酿酒葡萄检测模型

为提高高分辨率田间葡萄图像中小目标葡萄检测的速度和精度,该研究提出了一种基于轻量级网络的酿酒葡萄检测模型（Wine Grape Detection Model,WGDM）。首先,采用轻量级网络MobileNetV2取代YOLOv3算法的骨干网络DarkNet53完成特征提取,加快目标检测的速度;其次,在多尺度检测模块中引入M-Res2Net模块,提高检测精度;最后,采用平衡损失函数和交并比损失函数作为改进的定位损失函数,增大目标定位的准确性。试验结果表明,提出的WGDM模型在公开的酿酒葡萄图像数据集的测试集上平均精度为81.2%,网络结构大小为44 MB,平均每幅图像的检测时间为6.29 ms;与单发检测器（Single Shot Detector,SSD）、YOLOv3、YOLOv4和快速区域卷积神经网络（Faster Regions with Convolutional Neural Network,Faster R-CNN）4种主流检测模型相比,平均精度分别提高8.15%、1.10%、3.33%和6.52%,网络结构分别减小了50、191、191和83 MB,平均检测时间分别减少了4.91、7.75、14.84和158.20 ms。因此,该研究提出的WGDM模型对田间葡萄果实具有更快速、更准确的识别与定位,为实现葡萄采摘机器人的高效视觉检测提供了可行方法。     

快速脱水抑制葡萄干制过程中膜脂过氧化及褐变

为探索脱水速度对无核白葡萄干制过程中膜脂过氧化作用及褐变的影响,以新疆无核白葡萄为试验材料,经过葡萄促干剂处理后,采用快速脱水和缓慢脱水2种处理,质量每减轻10%进行取样,测定脱水过程中果实干基含水率、干燥速率、褐变度、细胞膜透性、丙二醛(malonaldehyde,MDA)含量、脂氧合酶(lipoxygenase,LOX)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)、过氧化物酶(peroxidase,POD)、多酚氧化酶(polyphenol oxidase,PPO)活性以及总酚含量的变化。结果表明:与缓慢脱水相比,快速脱水处理显著(P0.05)降低了无核白葡萄褐变度的上升,减少MDA生成量以及膜透性的增加,抑制LOX活性的升高,保持较高的活性氧清除酶SOD、CAT及POD活性及较高的总酚含量,且使PPO活性保持在一个较低的水平。因此认为,快速脱水可以有效地抑制无核白葡萄的膜脂过氧化作用对细胞膜的破坏,保持细胞的完整性,且PPO活性较低,从而减少无核白葡萄脱水褐变的发生。研究结果为快速脱水在无核白葡萄干制中的应用提供参考。     

Immunodetection of proteins from grapes and yeast in a white wine

The objective of this study was to analyze the origin of proteins of a Chardonnay wine. Three various polyclonal antibodies raised against must, yeast, and bacteria proteins were produced. For microorganisms, only the secreted macromolecules were used. To this end, yeast and bacteria were cultured in a model medium under conditions close to those of winemaking. Results obtained using these specific antibodies indicate that most of the wine proteins came from grapes and many of them were glycoproteins. Some proteins of this Chardonnay wine came from the yeast; they were released during the alcoholic fermentation and consisted of high molecular weight mannoproteins. In contrast, no bacteria proteins were detected in this Chardonnay wine.     

马铃薯薄片干燥过程形态变化三维成像

为研究马铃薯薄片在干燥过程中形态变化规律,该文利用Kinect传感器搭建了图像采集平台,研究其在不同干燥温度下(50、60、70、80℃)的形态变化规律。通过图像采集平台获取马铃薯薄片深度图像和彩色图像,利用彩色图像确定感兴趣区域,对对应区域的深度图像进行灰度值拉伸、阈值分割、边缘去噪处理,进而提取特征,计算出正投影面积的收缩率、深度均值及标准差,以表征马铃薯干燥过程中表面卷曲及平整度等形态指标的变化规律。对不同干燥时间点马铃薯片进行三维图形显示可观察其变化规律明显。统计结果表明:低温(50、60℃)与高温(70、80℃)对马铃薯薄片干燥时的收缩率、卷曲程度具有显著影响(P0.05)。50℃时收缩率为54.97%,80℃时收缩率升高为64.55%;干燥温度与马铃薯片卷曲程度呈先升后降的关系,60℃时卷曲度最大,其深度均值为27.81 mm,80℃时降低到18.86 mm。而四组温度下,马铃薯薄片的平整度具有显著性差异(P0.05),50℃时马铃薯片深度值的标准差为7.99 mm,80℃时降低至5.71mm,说明平整度随着干燥温度升高而增加。该研究可为马铃薯薄片干燥过程中形态变化的检测提供参考,同时为干燥工艺的智能化控制提供技术依据。     

干制黄花菜工业化生产工艺技术

为改进干制黄花菜传统生产方法并实现工业化生产,采用带式汽蒸生产线对黄花菜进行前处理,在干制过程中将全自动隧道式干燥生产线与工业微波生产线相结合,利用正交试验设计对干制黄花菜工业化生产工艺技术条件进行了较为详尽的研究。结果表明,在蒸汽温度95℃,汽蒸时间60s;隧道式干燥生产线装载量5.0kg/m2,热风温度85℃,风速1.5m/s;微波干燥生产线铺料厚度15mm、干燥功率16kW、干制时间90s的条件下,所生产的干制黄花菜经农业部食品质量监督检验测试中心检测其感官、理化和微生物指标均达到了《无公害食品—干制金针菜》NY5186-2002所规定的一级品标准。     

The extraction of anthocyanins and proanthocyanidins from grapes to wine during fermentative maceration is affected by the enological technique

The effect of three enological techniques (low temperature prefermentative maceration, must freezing with dry ice, and the use of a maceration enzyme) on the extraction of anthocyanins and proanthocyanidins from must to wine during fermentative maceration was studied to determine the extent to which these compounds are extracted and to assess the changes on their qualitative composition due to enological technique applied. The results showed that the dry ice treatment led to wines with high color intensity and high anthocyanin content, the maximum rate of extraction being observed the first 6 days of fermentative maceration. Regarding the effect of the different techniques on the quantitative and qualitative composition of proanthocyanidins, only the dry ice treatment seemed to favor the extraction of high molecular weight skin proanthocyanidins. The low temperature prefermentative maceration treatment led to the highest concentration of proanthocyanidins at the moment of pressing; however, this treatment, contrary to expectations, led to wines with the highest content of seed-derived proanthocyanidins. The use of the maceration enzyme also increased the concentration of proanthocyanidins during all of the fermentative process, as compared to a control wine, although the increase was not only due to skin proanthocyanidins but also seed proanthocyanidins. We have demonstrated in this study that maceration enzymes also facilitate seed phenolic extraction.     

碳纤维红外板辐射特性及其农产品物料干燥试验

为将碳纤维红外板的辐射加热技术应用于农产品物料的干燥中,探究其辐射加热特性和干燥特点。在介绍其制作工艺的基础上,以碳纤维红外板作为辐射热源搭建干燥试验台,对胡萝卜块、苹果块、香蕉块、木耳等4种常见果蔬物料进行干燥。通过实时采集、检测干燥过程中物料内部温度、干燥室温度、相对湿度变化情况了解干燥进程;并对红外干燥过程中物料升温情况、物料厚度、辐射间距、干燥方式进行探讨。结果表明:1)碳纤维红外板可作为红外干燥热源,辐射功率1.1 k W/m2时,能发射1~30μm的中、长波红外线,且主要集中在5~15μm,红外板表面温度范围为84~92℃。辐射间距8 mm条件下,4种物料从水分比1干燥到水分比0.1时,耗时为270~300 min,且20 mm×20 mm×11 mm的胡萝卜片内部温度升高到60℃仅需20 min。2)胡萝卜片长宽20 mm×20 mm,厚度5~11 mm范围内,在干燥中期近似恒温段,物料中心温度随厚度的增加而增加。3)辐射间距为4~12 mm范围内,辐射间距越大,干燥时间越长。4)与普通热风干燥相比,红外—热风联合干燥可有效缩短40%干燥时间,能耗约为普通热风干燥的49.39%;干燥前期排湿、干燥过程较小的风速均有助于红外干燥的进行。综上所述,碳纤维红外板可作为干燥热源。研究结果可为碳纤维在干燥领域的实际应用提供理论依据。     

Fate of quinoxyfen residues in grapes, wine, and their processing products

Quinoxyfen is a new fungicide that belongs to the family of the quinolines, recently introduced to control powdery mildew (Uncinula necator). In this paper the fate of quinoxyfen residues from vine to wine and in their processing products was studied. After the last of four applications at the recommended rate, 0.38 mg/kg of residue was found on the grapes, which is under the legal limit fixed in Italy (0.5 mg/kg). The degradation rate was according to a pseudo-first-order kinetics (r = 0.964) and the half-life was 7.24 days. Vinification was carried out with and without maceration. During the vinifications without maceration <50% of the residues passed from the grapes to the musts. Separation of the lees (8%) from the must by centrifugation caused no detectable residues in centrifuged must. At the end of fermentation with and without maceration no quinoxyfen residues were determinable in the wine. No effect on the alcoholic or malolactic fermentation was observed even in the presence of higher quinoxyfen concentrations than those found in the grapes at harvest time. During fermentation, the yeasts partially degraded the pesticides and completly adsorbed them. Bacteria, on the other hand, do not have any degradative effect on the pesticides. The raisins obtained by sun-drying did not contain any residues, whereas those obtained by oven-drying show the same amount of residues as in the fresh grapes. During the sun-drying process the fruit weight decreased by a factor of 4; the decrease in the oven-drying was equivalent. Samples of dregs and liquid lees, fortified with high levels of quinoxyfen. were double-distilled. The first dregs distillate, with an alcohol content of 32.1%, did not show any residues, whereas the first lees distillate, with an alcohol content of 34.5%, showed 7% of the initial residues. After the second lees distillation, the obtained product showed an alcoholic content of 81.2% and no residues of quinoxyfen (<0.01 mg/kg).     

Effect of postharvest ultraviolet irradiation on resveratrol and other phenolics of cv. Napoleon table grapes

In the skin of cv. Napoleon table grapes, the anthocyanins malvidin 3-glucoside (and its acetyl and p-coumaroyl derivatives), cyanidin 3-glucoside, peonidin 3-glucoside, cyanidin 3-glucoside, petunidin 3-glucoside, and delphinidin 3-glucoside were identified by HPLC-DAD-MS. In addition, quercetin 3-glucoside and 3-glucuronide, caffeoyltartaric, piceid, and resveratrol were also detected. The content of most phenolics remained quite constant during postharvest refrigerated storage (10 days at 0 degrees C) while the resveratrol derivatives increased 2-fold. Postharvest treatments of grapes with UVC and UVB light induced a large increase in resveratrol derivatives (3- and 2-fold, respectively). This means that a serving of mature Napoleon grapes (200 g) provides approximately 1 mg of resveratrol, which is in the range of the amount supplied by a glass of red wine. This can be increased to 2 or 3 mg of resveratrol per serving in grapes that have been irradiated with UVB or UVC, respectively. These results show that refrigerated storage and UV irradiation of table grapes can be beneficial in terms of increasing the content of potentially health-promoting phenolics.     

广式腊肠干燥及贮藏过程中主要理化特性的变化

为了准确把握和控制广式腊肠加工贮藏过程中脂肪氧化和水解反应引起的理化指标和风味等变化,本文系统研究了烘烤和传统日晒两种加工方式生产出的广式腊肠的酸价、过氧化值、含水率等理化指标的变化。结果表明:加工过程中烘烤肠含水量、酸价及过氧化值的变化速度较日晒肠大,而贮藏过程中,日晒腊肠的酸价及过氧化值的变化速度高于烘烤腊肠。真空包装对酸价无明显抑制,但对过氧化值有明显的抑制作用。贮藏温度与酸价和过氧化值呈正相关,但在100d的贮藏期内广式腊肠的过氧化值均未超过国家标准,而无论是日晒肠还是烘干肠的酸价,即使在10℃抽真空包装的理想贮藏条件下,在60d和80d时分别超过了国家标准。烘烤腊肠在30℃散装贮藏条件下保质期为20d,添加0.15%瓜尔豆胶及0.15%硬脂酰乳酸钠可使腊肠保质期延长到60d左右。     

Determination of rotundone, the pepper aroma impact compound, in grapes and wine

Shiraz, also known as Syrah or Hermitage, is one of Australia's most popular red wine varieties both domestically and internationally. Black pepper aroma and flavor are important to some Australian Shiraz red wine styles. Recently, rotundone (a bicyclic sesquiterpene) was identified as the potent aroma compound responsible for pepper aromas in grapes, wine, herbs, and spices, including peppercorns. Here the development, optimization, and validation of the analytical method for the quantitative determination of rotundone in grapes and wine are described and discussed. The method is precise, accurate, robust, and sensitive with a subpart per trillion limit of quantitation. The method uses stable isotope dilution analysis with d(5)-rotundone as internal standard, solid-phase extraction and microextraction, and gas chromatography-mass spectrometry.     

基于GF-6卫星影像多特征优选的酿酒葡萄精准识别

多源遥感信息和特征优选是提高农作物识别精度的重要支撑,高分六号(GF-6)卫星作为首次引入红边波段的国产卫星,其丰富的光谱信息为作物识别提供了新的思路和解决途径。该研究基于宁夏回族自治区银川市永宁县2018年6月—2019年3月的GF-6数据,充分利用红边优势提取光谱特征、纹理特征和植被指数特征,构建多种特征组合方案,并根据随机森林算法对特征重要性进行度量,选取最优特征组合对酿酒葡萄进行精准识别。结果表明,与单一特征相比,多源遥感特征的增加显著改善了酿酒葡萄分类效果,其中,植被指数贡献程度最大,光谱特征次之;基于随机森林的优选特征组合分类效果最佳,其中,总体分类精度为94.15%,酿酒葡萄用户精度为94.23%,制图精度为92.59%;以实地调查的4个酒庄为验证区,将酿酒葡萄提取结果与统计数据进行对比,面积相对精度均在70%以上,其中优选特征结果相对精度在90%以上,研究结果将为国产卫星红边波段在植被分类和识别方面的应用提供数据参考。     

Detailed characterization of proanthocyanidins in skin, seeds, and wine of Shiraz and Cabernet Sauvignon wine grapes (Vitis vinifera)

The distribution of proanthocyanidin (PA) polymer lengths, proanthocyanidin concentration at each polymer length, and polymer composition were determined in the seed, skin, and wine of Shiraz and Cabernet Sauvignon grape berries grown in southeast Australia. PA was fractionated by semipreparative high performance liquid chromatography (HPLC) and analyzed by phloroglucinolysis and HPLC to report the degree of polymerization (DP), concentration, and composition at 11 DP values in seed and wine and 21 DP values in skin. In skin, the highest PA concentration was observed at a DP of 31 in Shiraz and 29 in Cabernet Sauvignon representing 15% of the total PA in both varieties. The distribution of seed PA had the highest concentration at a DP of 7 in Shiraz and 6 in Cabernet Sauvignon representing around 30% of the total PA. In the wine PA distribution, the highest concentration was observed at a DP of 11 in Shiraz and 9 in Cabernet Sauvignon representing around 26 and 32% of the distribution, respectively. A second peak in wine PA concentration was observed at the largest DP of 18 in Shiraz and 15 in Cabernet Sauvignon representing around 20% of the distribution. The composition in wine did not vary at different DP, but the proportion of epicatechin gallate varied in seed PA less than 4 DP. The proportion of epigallocatechin increased with increasing DP in skin PA. Wine PA had a DP range and composition similar to the distribution of skin PA between DP 4 and 18 suggesting that larger skin PAs are not extracted into wine. This study provides information that could be used to target the important PA fractions in grapes that need to be measured to understand (or predict) PA extraction into wine and eventual mouthfeel.     

叶面补施糖醇钙对酿酒葡萄品质及产量提升的影响

针对宁夏贺兰山东麓葡萄酒地理标志产区风土特征中存在的矿质营养元素有效性低导致的产区葡萄酒特色不鲜明、风味与香气不足等问题.以6年生赤霞珠为研究对象,设置5个不同糖醇钙喷施水平:?1.2 L·hm-2(T1)、2.4 L·hm-2(T2)、3.6 L·hm-2(T3)、4.8 L·hm-2(T4)和6.0 L·hm-...