Measurement of the colour of white and rosé wines in visual tasting conditions

We have designed a colour measurement method that reproduces the conditions found during visual colour assessment of wines. In particular the illumination, background, wine sampler and the relative positions of sampler, illumination and observer have been controlled. Using this method, the colour of 33 white wines and 33 rosé wines was measured and expressed in terms of the CIELAB colour coordinates. Colour of wine samples was also assessed by expert wine tasters. White wines were classified into three colour categories: Straw-yellow, Yellow-gold and Yellow-green. Rosé wines were classified into four colour categories: Raspberry, Strawberry, Redcurrant and Salmon. The performance of CIELAB colour coordinates to reproduce the observed classification has been established using discriminant analysis. The central region of the wine surface gives the best results having lower measurement errors and higher classification performance. For white wines a*, b* and h _ab are the relevant colour coordinates scoring 84.8% of correctly classified samples. In rosé wines L*, a* and h _ab in the central region correctly classify 100% of the samples. This study demonstrates that colour of white and rosé wines can be measured in the same conditions that are found in the visual colour assessment when precise information on the visual colour appearance of wines is required.     

Simultaneous Determination of Biogenic Amines and Methylxanthines in Foodstuff—Sample Preparation with HPLC-DAD-FL Analysis

Chromatographic system for simultaneous determination of levodopa, biogenic amines, and methylxanthines in food has been developed. Chromatographic column and pre-column with octadecylsilane phase and simultaneously fluorescence and DAD detectors have been used. Gradient elution with acetate buffer (pH?=?4.66) with acetonitrile has been applied. Examination included levodopa, norepinephrine, dopamine, normetanephrine, tyramine, and serotonin as well as caffeine, theophylline, and theobromine. Limit of detection (LOD) and limit of quantitation (LOQ) have been determined for all compounds with signal to noise ratio (S/N) equal to 3 and 10, respectively. LOD of 10 ng/mL and LOQ of 30 ng/mL for levodopa and biogenic amines as well as LOD of 70 (60)?ng/mL and LOQ of 210 (180)?ng/mL for methylxanthines have been determined. Authors have also developed method for simultaneous separation of all analytes from food matrix. Developed chromatographic system with sample preparation method has been applied for determination of examined compounds in cocoa products, vegetables, and fruits.     

Plant protection product residues in white grapes and wines of “Malvasia Istriana” produced in Istria

Monitorting of plant protection product residues was performed in 12 grape and 66 wine samples of “Malvasia Istriana” variety, produced in Istria winegrowing region of Croatia and Slovenia. The samples were analysed for the presence of 169 different active compounds using two multiresidual analytical methods: gas chromatography coupled with mass spectrometry and liquid chromatography coupled with tandem mass spectrometry. Residues were found in 58.3% of all the inspected grape samples and in 28.8% of all the inspected wine samples. Beside that contents of residues in grapes were below 10% of maximum residue level values and they should not represent any risk for “Malvasia Istriana” grape or wine consumers.     

Sensory and chemical characteristics of ‘dry’ wines awarded gold medals in an international wine competition

The objective of this work was to identify the sensory attributes associated with the highest awards given to wines in large competitions. Data from the Mundus Vini annual wine competitions (editions) from 2014 to 2016 were used. The chemical analysis and sensory attributes were subjected to cluster analysis and logistic ridge regression to identify predictors of grand gold and gold medal awards. High ethanol levels and sugar concentrations, mainly in red wines, were observed. For both red and white wines, three clusters were identified which broadly separated grand gold from gold medal awarded wines. The discrimination of G wines was mainly due to higher scores of bitterness and green/vegetative characters in both red and white wines, and with barnyard attributes only in red wines. The prediction regression for white wines showed that the exotic fruit was the most valued sensory attribute along with the quality indicators of body and complexity. Red wines had a higher number of predictors, including positive attributes like dried fruits and spicy or negative attributes like green/vegetative and red berries. This study identified the most relevant sensory features most valued by competition jurors, which were broadly consistent with the so-called international commercial wine style.     

Heavy metals in cow’s milk and cheese produced in areas irrigated with waste water in Puebla,Mexico

The aim of this work was to determine Ni, Cr, Cu, Zn, Pb, and As levels in raw milk and Oaxaca and ranchero type cheeses, produced in areas irrigated with waste water from Puebla in Mexico. Milk results showed a mean Pb level of 0.03 mg kg^?1, which is above the maximum limit as set by Codex Alimentarius and the European Commission standards. For As a mean value of 0.12 mg kg^?1 in milk was obtained. Mean As and Pb levels in milk were below the Mexican standard. Milk whey and ranchero cheese had mean Pb levels of 0.07 and 0.11 mg kg^?1, respectively. As was higher in Oaxaca and ranchero cheese at 0.17 and 0.16 mg kg^?1, respectively. It was concluded that cheeses made from cow’s milk from areas irrigated with waste water are contaminated with Pb and As, which may represent a health risk.     

4-Ethylphenol and 4-ethylguaiacol contents in bottled wines from the German ‘Württemberg’ region

The 4-ethylphenol (4-EP), 4-ethylguaiacol (4-EG), and 4-ethylcatechol (4-EC) concentrations were determined in 1.312 bottled wine samples from the German ‘Württemberg’ region by means of HPLC coupled with fluorescence detection. 4-EC was not detected in quantifiable concentrations in any of the samples analysed. 6.4% of the wines showed 4-EP and 4-EG concentrations over the detection limit of 16 μg/L for 4-EP and 7 μg/L for 4-EG. 1.8% of all wines were over the odour threshold. For white wines it was shown that 4-EG is the only tainting compound and that 0.3% of the wines contain 4-EG above the sensory threshold. The 4-EP and 4-EG contents averaged 17.7 and 4.7 μg/L in red wine and 2.2 and 1.0 μg/L in white wine, respectively. Based on the analytical results a statistical evaluation was performed to assess the impact of various parameters, such as wine type, storage, residual sugar content, etc., which are known to influence ethylphenol concentration. A significant difference between white wine and wine made from red grape varieties was observed. Wine stored for a long time period in wooden casks showed especially high ethylphenol content. Only a slight tendency was observed regarding the residual sugar, alcohol, total acidity and SO₂ content. Based on our data, we cannot confirm the results published by some authors that varieties show significant differences with regard to their ethylphenol ratios.     

Determination of Free Arginine, Glutamine, and β-alanine in Nutritional Products and Dietary Supplements

A method for the determination of free arginine, glutamine, and β-alanine in nutritional products and dietary supplements is described. The amino acids are derivatized with the fluorescent tag 9-fluorenylmethoxycarbonyl (FMOC), and the derivatives are then determined by reversed phase HPLC. Method suitability was defined by experimental assessments of linearity (R ² > 0.999), precision (day-to-day RSD ≤ 1.0%), accuracy (spike recoveries=98.7%–101.8%, n = 18), and selectivity (baseline resolution from the other common amino acids). The method provides for an accurate and precise quantification of the three amino acids, when present at concentrations >0.2% (w/w) in nutritional products and dietary supplements. Assessments of free l-glutamine stability in three different reconstituted powder products, as performed by the method, found recoveries >97% through 24 h at room temperature.     

Astringency sub-qualities of red wines and the influence of wine–saliva aggregates

Astringency is a sensory attribute, related to the quality and mouthfeel of red wines. However, the origin of astringency sub-qualities, such as the typical drying astringency found in immature grapes, is still unknown. Astringency of red wines with similar tannin content but different astringency sub-qualities, from different harvest dates, is studied. Astringency was characterised in terms of friction coefficient, polyphenol content, sensory analysis and tannin/salivary–proteins aggregates characterisation. A different evolution during ripening was found for both Cabernet Sauvignon and Carménère, and tannin–protein aggregates showed differences in size, shape and surface. The velvety sub-quality appears to be related to aggregates with low precipitation, and with specific surface characteristics as roundness and Feret diameter. Results from this work propose an effect of aggregates on sensory perception and opens the possibility to explore their effect on oral lubrication.     

Determination of cashmere and wool contents in textile by near infrared spectroscopy北大核心

A quantitative analysis model was established to determine the contents of cashmere and wool in textile by near infrared spectroscopy (NIRS). 101 calibration samples were mixed by weighing and measured by NIRS, which were combined to establish the calibration model by partial least squares (PLS) method. The correlation coefficient between the predictive result and true value was 0.99, and the root mean standard error of prediction was 2. 8% . The results demonstrated that NIRS could be a rapid and nondestructive technique for quantitative analysis of cashmere and wool. However, extensive sample collections were suggested in the future work to set up a representative database and to establish a mathematical model with better stabilization, precision and dependability.     

Determination of thermal oxidation and oxidation products of β-carotene in corn oil triacylglycerols

A reversed phase HPLC-DAD coupled to APCI-MS method is reported for the determination of the degradation of β-carotene and characterization of the oxidation products in corn oil. Corn oil containing β-carotene was oxidized in the Rancimat at 110 °C from 1 to 14 h. A significant degradation of β-carotene was observed in corn oil during accelerated thermal oxidation. A total of eight different oxidized products of β-carotene were identified, which includes 8′-apo-β-carotenal, 6′-apo-β-carotenal, 5,6-epoxy-8′-apo-β-carotenal, β-carotene-2,2′-dione, 13-Z-5,6,5′,6′-diepoxy-β-carotene, all-E-5,8-epoxy-β-carotene, all-E-5,6-epoxy-β-carotene, and 15-Z-5,6-epoxy-β-carotene. Corn oil triacylglycerols (TAGs) oxidation products were also identified using isocratic HPLC–ESI-MS. It was found that β-carotene promoted oxidation of TAGs especially at longer exposure times. For the first time two new classes of oxidized TAGs have been identified in corn oil, which were epidioxy bis-hydroperoxides and hydroxy bis-hydroperoxides. Other oxidation products of TAGs were mono-epoxides, mono-hydroperoxides, and epoxy hydroperoxides. It was found that complementing the HPLC-DAD method for β-carotene with ESI-MS method for TAGs oxidation provides a comprehensive set of analytical tools to characterize carotenoids and triacylglycerols oxidation and degradation in edible oils.     

Determination of alkylphenol residues in breast and commercial milk by solid-phase extraction and gas chromatography–mass spectrometry

This study presents a feasible and sensitive method to determine alkylphenol residues (i.e., 4-t-octylphenol (4-t-OP) and the isomers of 4-nonylphenols (4-NPs)) in breast milk samples and commercial cow milk products. The matrix interference associated with the constituents in the milk was reduced by extraction with n-hexane and dilution with 50% methanolic solution (v/v, methanol/water), then followed by the Oasis-HLB SPE extraction. The analytes were determined by a GC–MS system in full-scan and selected ion monitoring modes simultaneously. Limit of quantitation was less than 0.05 ng/g in a 20 g (wet weight) milk sample. The 4-NPs were detected in 19 of the 20 breast milk samples at concentrations ranging from 1.7 to 11.6 ng/g, while 4-t-OP was detected in 8 samples at concentrations ranging from 0.4 to 1.1 ng/g. The 4-NPs were detected in all the testing commercial cow milk products at concentrations ranging from 2.9 to 8.8 ng/g.     

Effectiveness of starch removal in a Bath-Substrate-Flow (BSF) device using surfactants and α-amylase

The effectiveness of the removal process of starch from different surfaces was studied using a laboratory device called Bath-Substrate-Flow. To do this, experiments were performed using the following solutions as washing bath: (a) the commercial nonionic surfactant Glucopon^® 650; (b) the commercial anionic surfactant, linear alkylbenzene sulfonate LAS, and (c) the enzyme α-amylase (obtained from the microorganism Bacillus licheniformis). The washing efficiency was related to the temperature of the process, the washing bath composition and the substrate used. The highest detergency was detected with the glass spheres presented, followed by the polyurethane discs. The cleaning process with the polyurethane discs is strongly dependant on the viscosity of the starch film, because their porous structure determines milder shear conditions inside them. The effect of temperature on starch removal was related to the properties of the washing bath (interfacial tension, viscosity, etc.) as well as to the solubility and viscosity of the soiling agent. The use of surfactants or enzymes under the appropriate conditions of concentration and/or temperature proved to be an interesting option for clean-in-place processes of starchy soils in the food industry, guaranteeing cleaning with a reduced risk of contamination.     

Genetic traceability of Asti Spumante and Moscato d’Asti musts and wines using nuclear and chloroplast microsatellite markers

The final characteristics of a wine are strongly influenced by must varietal composition. Further, wine quality and value can be heavily modified if grape varieties other than those expected/allowed are used, especially in the case of monovarietal wines. ??Moscato bianco??, which is one of the main grape varieties grown in Piedmont (north-western Italy), is used for the production of two renowned monovarietal sparkling wines: Asti Spumante and Moscato d??Asti. Here, the genetic traceability of these wines was assessed using a simple sequence repeat (SSR or microsatellite) DNA-based method. Must and wine samples from two local wineries were collected at different winemaking steps: after grape crushing and pressing, without the skins (must sample 1, M1); after static clarification or flotation (M2); halfway through fermentation (M3); and finished wines. A DNA extraction protocol was developed, and samples were analysed using a set of 9 nuclear (nSSR) and 7 chloroplast (cpSSR) markers. The application of nSSR markers was successful for M1 and M2, but was inadequate for M3 and wines. CpSSR gave better results as amplifications were achieved using DNA extracted from M1, M2 and wines, despite the lack of amplification in M3. Furthermore, the amplified cpSSR loci showed high polymorphism, allowing the identification of 5 distinct chlorotypes among 7 muscat-flavoured and 2 non-aromatic grapevines. Altogether, these results suggest that this technique could be extended to wine quality and authenticity control, as well as origin protection.     

Addition of milk to tea infusions: Helpful or harmful? Evidence from in vitro and in vivo studies on antioxidant properties

Tea consumption is practised as a tradition, and has shown potential to improve human health. Maximal uptake of tea antioxidants and milk proteins without a negative impact on tea flavor is highly desired by consumers. There is a conflicting evidence of the effect of milk addition to tea on antioxidant activity. Differences in the type of tea, the composition, type and amount of milk, preparation method of tea–milk infusions, the assays used to measure antioxidant activity, and sampling size likely account for different findings. Interactions between tea polyphenols and milk proteins, especially between catechins and caseins, could account for a decrease in antioxidant activity, although other mechanisms are also possible, given the similar effects between soy and bovine milk. The role of milk fat globules and the milk fat globule membrane surface is also important when considering interactions and loss of polyphenolic antioxidant activity, which has not been addressed in the literature.     

Determination and validation of D-values for Listeria monocytogenes and Shiga toxin–producing Escherichia coli in cheese milk

Certain cheeses can be legally produced in the United States using raw milk, but they must be aged for at least 60 d to reduce pathogen risks. However, some varieties, even when aged for 60 d, have been shown to support growth of Listeria monocytogenes or survival of Shiga toxin–producing Escherichia coli (STEC). Thermization, as a subpasteurization heat treatment, has been proposed as a control to reduce the risk of pathogens in raw cheese milk while retaining some quality attributes in the cheese. However, the temperature and time combinations needed to enhance safety have not been well characterized. The objective of this research was to determine and validate decimal reduction values (D-values) for L. monocytogenes and STEC at thermization temperatures 65.6, 62.8, and 60.0°C; a D-value at 57.2°C was also determined for L. monocytogenes only. Nonhomogenized, pasteurized whole-milk samples (1 mL) were inoculated with 8-log cfu/mL L. monocytogenes or STEC (5- or 7-strain mixtures, respectively), vacuum-sealed in moisture-impermeable pouches, and heated via water bath submersion. Duplicate samples were removed at appropriate intervals and immediately cooled in an ice bath. Surviving bacteria were enumerated on modified Oxford or sorbitol MacConkey overlaid with tryptic soy agar to aid in the recovery of heat-injured cells. Duplicate trials were conducted, and survival data were used to calculate thermal inactivation rates. D_65.6°C-, D_62.8°C-, and D_60.0°C-values of 17.1 and 7.2, 33.8 and 16.9, and 146.6 and 60.0 s were found for L. monocytogenes and STEC, respectively, and a D_57.2°C-value of 909.1 s was determined for L. monocytogenes. Triplicate validation trials were conducted for each test temperature using 100 mL of milk inoculated with 3 to 4 log cfu/mL of each pathogen cocktail, A 3-log reduction of each pathogen was achieved faster in larger volumes than what was predicted by D-values (D-values were fail-safe). Data were additionally compared with published results from 21 scientific studies investigating L. monocytogenes and STEC in whole milk heated to thermization temperatures (55.0–71.7°C). These data can be used to give producers of artisanal raw-milk cheese flexibility in designing thermal processes to reduce L. monocytogenes and STEC populations to levels that are not infectious to consumers.     

Effects of hyper-oxygenation and storage of Macabeo and Airén white wines on their phenolic and volatile composition

The effects of hyper-oxygenation and storage period of Macabeo and Airén white wines on color characteristics, phenolic, and volatile composition have been evaluated. Hyper-oxygenation treatment provoked a significant decrease in virtually all individual phenolic compounds in must, young wine, and one-year-aged wines, above all hydroxycinnamic acid derivatives, flavonols, and the new GRP derivatives compounds (derived from 2-S-glutathionyl-caftaric acid or grape reaction product). Despite this fact, the contribution of the yellow color component (b*) of white wines derived from hyper-oxygenated musts was significantly higher in comparison with untreated ones, even after 1 year of bottle storage. On the other hand, the concentration of major volatile compounds and some alcohols (namely, C₆ alcohols, terpenes, and lactones) was higher in wines derived from hyper-oxygenated musts, but the hyper-oxygenation effect on volatile profile deeply depended on the grape variety. After 1 year of bottle storage, the significant differences were maintained and the content of some long-chain esters increased as a consequence of oxygen addition.