Sweetness acceptance of novices,experienced consumers and winemakers in Hunter Valley Semillon wines

The consumer preference of Hunter Valley Semillon (HVS) with varying amounts of glucose was investigated. The respondents were divided into three categories; novice (consumer), experienced (consumer) and winemakers. Experienced drinkers preferred wines with less added glucose than did the novice group. Winemakers preferred a lower level of glucose addition again. This study has also defined levels of residual sugar within which winemakers can aim to produce wine in order to fulfil the desires of the consumer, allowing winemaking decisions for residual sugar levels to be quantitatively based.     

Evolution of esters in aged Chardonnay wines obtained with different vinification methods

BACKGROUND: During wine ageing on lees yeast lysis takes place and some enzymes from the yeast cells, such as esterases, may be released. These enzymes might determine ester synthesis and could be also involved in their breakdown. In this study, the evolution of esters in Chardonnay wine fermented in stainless steel tanks and aged in bottles (conventional vinification) was compared with the evolution of esters in the same wine fermented and aged in barrel on lees. In this way, it was hoped to determine the influence of distinct methods of vinification on the evolution of esters in Chardonnay wine. RESULTS: The concentration of acetate esters of higher alcohols decreased in all the wines independently of the vinification method. However, the ethyl esters of fatty acids decreased in wine aged in barrel and increased in wine aged in bottle, so it would seem that these compounds interact with the lees present in the barrels and/or with the wood of the barrel. The ethyl esters of organic acids increased during ageing both in barrel and bottle. CONCLUSION: The ageing of Chardonnay wine in barrel on lees did not favour the formation of esters compared to the same wine aged in bottle. Copyright © 2009 Society of Chemical Industry     

Inducing malolactic fermentation in Chardonnay musts and wines using different strains of Oenococcus oeni

Malolactic fermentations (MLF) were induced in a commercially prepared Washington State Chardonnay must to evaluate the influence of timing of inoculation and pre-culture conditions of Oenococcus oeni strains MCW, EQ-54, and WS-8. The must (pH 3.62, 21.5°Brix) was divided into lots and inoculated with Saccharomyces cerevisiae strain CY3079. Strains of O. oeni were pre-cultured by growing in diluted juice or by re-hydration of freeze-dried strains. Bacteria were inoculated into the musts before (Day 0) or after completion of the alcoholic fermentation (Day 22). Yeast populations exceeded 10⁷cfu/mL in all fermentations that proceeded to dryness. However, the viability of most strains of O. oeni quickly declined after inoculation regardless of the timing of inoculation or the strain used. MLF was induced in the wines inoculated with strains EQ-54 and WS-8 but not with MCW, and the rate depended on the time of inoculation. The method used to prepare bacterial starter cultures had no apparent influence on the completion of MLF. Values for volatile acidity were slightly higher (P< 0.05) in wines inoculated with O. oeni before alcoholic fermentation compared with those inoculated after alcoholic fermentation.     

Changes in headspace volatile attributes of apple cider resulting from thermal processing and storage

One attribute that frequently reflects a product's organoleptic impact is its aroma. In research presented here, a Fox-3000 Electronic Nose was used to determine and compare the aromatic profiles of samples of apple cider subjected to various thermal treatments. Initial results have indicated that exposure to temperatures of up to 90 °C for approximately 28 s acts to stabilize the aromatic properties of apple cider over a 7-day period. In contrast, there are significant changes in the aromatic profiles of fresh apple cider having no such thermal treatment over the same time period. A comparison of samples thermally treated at 60, 70, and 80 °C to non-processed cider showed minimal statistical difference on the basis of similarity indices obtained after 24-h of storage of the samples at 4 °C. Treatment at 90 °C showed significant differences from the unprocessed samples in the same test sequence. After storage for 7-days, samples that were thermally treated exhibited minimal differences from each other, however, were quite different from the non-processed sample on the basis of similarity index analysis. GC analysis was done to confirm potential differences between the samples measured using the electronic nose. Sensory testing is required to determine whether these differences affect the overall quality perception by consumers.     

Volatile composition and sensory characteristics of Chardonnay wines treated with American and Hungarian oak chips

Toasted or non-toasted chips of oak woods of different geographical provenances were macerated in Chardonnay wines (4 g/l) during a period of 25 days. Oak lactones were detected in significant quantities in wines treated with American oak. Only trace amounts of oak lactones were detected in the wines treated with Hungarian oak. Toasting of the oaks increased the quantities of the compounds derived from the thermal degradation of lignin: vanillin, eugenol, guaiacol and its derivatives and the pyrolysis of cellulose and hemicellulose: furfural and 5-methyl furfural, and decreased the concentrations of the two isomers of oak lactones. The concentrations of the majority of the volatile compounds did not present statistically significant differences between 15 and 25 days. However, the wines preferred by the tasters and with maximum intensity of the sensory attributes acquired were those treated with oak chips for 25 days. Chemical and sensorial analyses of wines revealed that the effect of the toasting of oak chips on wine characteristics was greater than the type of oak used. All wines studied were positively evaluated by the panellists.     

宁夏贺兰山东麓产区霞多丽、贵人香干白葡萄酒呈味特征差异及相关性分析

运用电子舌、常规指标检测法对宁夏贺兰山东麓产区霞多丽、贵人香干白葡萄酒的呈味特征差异及相关性检测分析,并结合主成分分析(principal component analysis,PCA)、聚类分析及因子分析等分析方法,对不同酒样进行分析测定,从而为宁夏贺兰山东麓产区霞多丽、贵人香干白葡萄酒呈味相关特征提供理论指导。结果表明:经主成分分析得出,鲜味、咸味、酸味、丰厚度指标对呈味特征贡献较大;经聚类分析得出,对葡萄酒呈味特征影响因素中,品种差异较年份影响具有优势;经雷达图得出,不同酒样中,除苦味、涩味值相差较大外,鲜味、咸味、丰厚度等指标强度基本一致,且品种间区别较明显;经因子分析对常规理化指标分析得出,酒样中干浸出物与总酚贡献度较大,且酸味优于甜味的贡献度。经过以上多种分析处理法,以上酒样得到了较好区分。     

Increased flavour diversity of Chardonnay wines by spontaneous fermentation and co-fermentation with Hanseniaspora vineae

Discovery, characterisation and use of novel yeast strains for winemaking is increasingly regarded as a way for improving quality and to provide variation, including subtle characteristic differences in fine wines. The objective of this work was to evaluate the use of a native apiculate strain, selected from grapes, Hanseniaspora vineae (H. vineae) 02/5A. Fermentations were done in triplicate, working with 225 L oak barrels, using a Chardonnay grape must. Three yeast fermentation strategies were compared: conventional inoculation with a commercial Saccharomyces cerevisiae strain, ALG 804, sequential inoculation with H. vineae and then strain ALG 804 and spontaneous fermentation. Yeast strain identification was performed during fermentation, in which the apiculate strain was found to be active, until 9% of alcohol in volume, for the co-fermentation and the spontaneous fermentation was completed by three native S. cerevisiae strains. Basic winemaking parameters and some key chemical analysis, such as concentration of glycerol, biogenic amines, organic acids, and aroma compounds were analysed. Sensory analysis was done using a trained panel and further evaluated with professional winemakers. Sequential inoculation with H. vineae followed by S. cerevisiae resulted in relatively dry wines, with increased aroma and flavour diversity compared with wines resulting from inoculation with S. cerevisiae alone. Wines produced from sequential inoculations were considered, by a winemaker’s panel, to have an increased palate length and body. Characteristics of wines derived from sequential inoculation could be explained due to significant increases in glycerol and acetyl and ethyl ester flavour compounds and relative decreases in alcohols and fatty acids. Aroma sensory analysis of wine character and flavour, attributed to winemaking using H. vineae, indicated a significant increase in fruit intensity described as banana, pear, apple, citric fruits and guava. GC analysis of the relative accumulation of 23 compounds to significantly different concentrations for the three fermentation strategies is discussed in relation to aroma compound composition.     

宁夏贺兰山东麓产区霞多丽、贵人香干白葡萄酒香气成分分析

研究宁夏贺兰山东麓产区霞多丽、贵人香干白葡萄酒地域特性的主要香气特点,运用固相微萃取技术提取霞多丽、贵人香干白葡萄酒的香气组分,用内标法对检测峰予以定量分析,并结合气相色谱-质谱、计算机检索技术对分离香气化合物进行分析测定,共检测出49种香气物质。结果表明,干白葡萄酒香气成分主要有酯、醇、酸、酚、萜烯5类化合物,其中酯类、醇类、酸类分别为18种、16种、4种;两品种酒样(霞多丽与贵人香)干白葡萄酒香气成分含量显著不同,有关香气成分含量多少与其贡献度大小并不成正比,与气味活度值(Odor Activity Value,OAV)大小关系较为密切;贵人香新酒主要香味成分与霞多丽相当,霞多丽酒样具有一定的青苹果、草莓果香,贵人香则有较明显的花香、水果的味道,经过陈酿的贵人香酒样表现出香蕉、椰子等热带水果及奶酪等乳制品的味道;经气相色谱-质谱联用仪(Gas Chromatograph-Mass Spectrometer,GC-MS)检测,在定量出酒样中的49种香气成分中,高含量化合物中酯类香气贡献率明显高于醇类和酸类,微量成分中酚类和萜烯类贡献率高,微量香气成分中,虽然一些物质含量较低,但具有较高贡献率;经聚类分析得出,新酒香气成分含量表现出年份影响较品种差异明显,但经过陈酿酒样,则品种差异占主要优势。     

Determination of geosmin and 2,4,6-trichloroanisole in white and red Austrian wines by headspace SPME-GC/MS and comparison with sensory analysis

This paper describes the development and application of a fast and simple headspace solid phase microextraction GC–MS method for simultaneous determination of geosmin and 2,4,6-trichloroanisole (2,4,6-TCA), two main contributors to off-flavors in wine. The compounds were adsorbed onto a polydimethoxysiloxane (PDMS) fiber at 35 °C for 40 min without prior equilibration, thermally desorbed and analyzed by GC–MS in the selected ion monitoring mode. The parameters for adsorption onto and desorption from the fiber were optimized. This method was applied to analysis of 118 Austrian white and red wines, which were also characterized by sensory analysis. Geosmin was above the limit of detection (0.5 ng/L) in 110 wines (93%) and additionally quantified (>2 ng/L) in 65 wines (55%). It could be detected in wines of each off-flavor (moldy, corky, damp, musty, rotten, woody, grassy) in concentrations up to 16.7 ng/L and even in 90% of the sensorially faultless wines (up to 6.5 ng/L). On the other hand, 2,4,6-trichloroanisole was detected only in 24 wines (20% of all investigated wines) and above the limit of quantitation (2 ng/L) only in 5 wines (4%) sensorially classified as corky; corky and moldy plus other defects; or faultless in concentrations up to 14.3 ng/L. These results show that geosmin is more prevalent than 2,4,6-TCA and that chemical analysis is required especially when other wine characteristic flavors cover beginning off-flavors.     

Gas chromatographic analysis of volatile sulfur compounds from heated milk using static headspace sampling.

An investigation was conducted to test the feasibility of using gas chromatography with static headspace sampling as an objective tool to measure milk flavor quality. Heated milk off-flavor was chosen for study. Different strategies were tried for increasing the sensitivity of a commercially available headspace method, including salting out with sodium sulfate, cryofocusing during injection, and applying backpressure to the sampling loop. With the aid of a sulfur-specific detector, the resulting system was sufficiently sensitive to detect the sulfur volatiles, H2S and dimethyl sulfide, at the concentrations found in pasteurized skim milk. Milk that was heated to varying degrees was analyzed, and the analytical results were compared with the intensity of heated flavor as determined by a sensory panel. For skim milk, correlations were moderately strong: Spearman's correlation coefficients for H2S and dimethyl sulfide were .75 and .60, respectively. Correlations were weak for whole milk.     

Analysis of indole compounds in edible Basidiomycota species after thermal processing

Methanolic extracts of processed fruiting bodies of six edible mushroom species (Basidiomycota) - Armillaria mellea, Boletus badius, Boletus edulis, Cantharellus cibarius, Lactarius deliciosus collected from natural habitats and Pleurotus ostreatus of commercial origin - were analysed for the presence of non-hallucinogenic indole compounds. Thermal processing was designed in such a way that it mimicked conditions used for cooking of mushroom dishes, since only a narrow group of mushrooms can be eaten raw, while indole compounds are thermolabile. All processed extracts were shown to contain l-tryptophan (up to 8.92 mg/100 g dw). The contents of the remaining compounds, 5-methyltryptophan, tryptamine, melatonin, indoleacetonitrile and indole, varied in different species (from 0.71 to 6.55 mg/100 g dw). Extract of processed C. cibarius fruiting bodies contained l-tryptophan, 5-methyltryptophan, tryptamine, melatonin, indoleacetonitrile and indole (1.96-4.94 mg/100 g dw) whereas l-tryptophan (2.78 mg/100 g dw) and tryptamine (2.77 mg/100 g dw) were the only indole compounds identified in the processed fruiting bodies of A. mellea.     

"赛美蓉"与"长相思"葡萄汁挥发性风味物质的分析

通过顶空固相微萃取结合气相色谱-质谱联用技术分析赛美蓉和长相思澄清葡萄汁挥发性风味物质组成,初步定性77种挥发性风味物质,二者共有组分46种。其中醇类物质的种类最多,所占比例最高,分别达到了72.76%和77.69%;酯类物质的种类数量居第二,但所占比例较低,分别为3.67%和2.12%;醛类物质虽然只有8种,但其比例却分别达21.99%和18.82%。主要挥发性组分感官特征分析显示:表现为果香的物质种类最多,表现为清香的物质总离子流量和比例最高。     

Dairy foods and novel thermal and non-thermal processing: A bibliometric analysis

Processing dairy products by conventional methods, such as pasteurization, can induce chemical reactions and physicochemical alterations, compromising nutritional and sensory quality. Thus, there is a growing worldwide demand for studies related to emerging processing technologies. This study aims to describe trends related to dairy processing through the application of emerging technologies. In this sense, articles published in this area of research in the last decade were retrieved from scientific databases, and their findings were analyzed through a bibliometric study. Reviews and original articles expressed 40 and 60% of publications, respectively, and novel thermal and non-thermal processing studies showed multidisciplinary approaches. Ohmic heating and microwave heating were the most discussed novel thermal technologies in the processing of dairy products. Among non-thermal technologies, there was a more significant trend in studies on ultrasound, high hydrostatic pressure, and pulsed electric fields. The impact of the application of novel food technologies concerning quality, safety, and energy efficiency compared to traditional methods and the influence of critical operating conditions for process control were the most studied areas. Furthermore, the impact of novel non-thermal food processing technologies from the consumer's point of view is emerging. These results can be used for future innovations by the dairy industry.Industrial relevanceDairy foods are important food matrices considering a nutritional and functional point of view and recommended in a regular diet for consumers of all ages. Therefore, a bibliometric analysis was performed considering dairy foods and novel thermal and non-thermal processing. A higher number of publications considering non-thermal technologies was reported, highlighting the need for food processing without applying high temperatures. High hydrostatic pressure, ultrasonication, and pulsed electric fields were the most discussed non-thermal technologies. At the same time, ohmic heating and microwave heating were the most reported thermal technologies. Furthermore, the most used applications, critical process parameters, and food properties to be evaluated are highlighted and discussed. The results could be used as a basis for the dairy processors to implement non-conventional technologies as an option at their production lines, as they demonstrate the most relevant process parameters and food characteristics to be evaluated, helping them to choose the parameters with higher impact and firstly consider them. Furthermore, consumers studies are important and should evaluate consumer perception about the products and the perceived benefits and risks of the novel technologies.     

Gas Chromatographic Analysis of Sugars in Granola Cereals

Fourteen granola cereals from seven different manufacturers were analyzed for sugars with a gas chromatographic technique that determines the type and amount of all the common food sugars. The total sugar content of the cereals ranged from 22–32% of dry weight. Sucrose was the predominant sugar, along with varying amounts of fructose and glucose. Several cereals also contained lactose. New sampling procedures have been developed for these heterogeneous mixtures.