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Grape seed flour by-product (GSBP) is an economic and renewable source of proteins, increasingly being explored due to interesting technological application such as colour protection in rich-anthocyanins beverages. Globulin-like proteins from GSBP were characterised by proteomic and computational studies. MALDI TOF/TOF analysis revealed the presence of two 11S globulins (acid and basic), whose 3D structures have been elucidated for the first time in Vitis vinifera L. grape seeds by using homology models and molecular dynamics. The secondary structure showed 11 α-helices and 25 β-sheets for acid and 12 α-helices and 24 β-sheets for basic 11S globulins. Molecular docking results indicate that both grape seed 11S globulins could establish different types of non-covalent interactions (π-π) with malvidin 3-O-glucoside (wine anthocyanin), which suggest a possible colour protection similar to that occurring in copigmentation phenomenon. These findings provide valuable information of globulin family proteins that could be relevant in food industry applications. España Ministerio de Economía y Competitividad (Project AGL2017- 84793-C2 and FPI grant PRE2018-087184) Programa Operativo FEDER 2014-2020/Consejería de Economía y Conocimiento de la Junta de Andalucía (Project US-1261752)

Bee pollen (BP) is a natural product with remarkable nutritional and bioactive composition. Some of the compounds of interest are carotenoids with provitamin A activity, possessing an excellent antioxidant capacity and positive health effects. For that, the objective of this work was to characterize the botanical origin and carotenoid profile in two particle sizes of Colombian BP by Rapid Resolution Liquid Chromatography (RRLC). The carotenoid profile and α-tocopherol content were obtained, and ANOVA analysis was employed to explore data. The main carotenoids found were 9Z-zeaxanthin (65.15 ± 7.41–1104.98 ± 113.41 μg/g pollen), zeaxanthin (35.29 ± 2.08–354.30 ± 29.91 μg/g pollen), two zeaxanthin isomers (18.23 ± 3.73–227.69 ± 19.00 μg/g pollen) and β-cryptoxanthin (8.67 ± 1.27–34.25 ± 2.25 μg/g pollen). The statistical analysis showed significant differences between harvest time and particle size, proving the influence of climatic and botanic factors. The high content of macular and provitamin carotenoids was highlighted, which proposes BP as a significant source of important bioactive compounds. The carotenoids found allows characterizing BP in a complete seasonal cycle (January–December), research conducted for the first time in this product. Also, the information reported can be used to select harvest time of BP in order to include it as an ingredient, supplement, or raw material in the food industry, according to the carotenoid composition needed.

The quality of 27 Moroccan Spurge (Euphorbia) honey samples was assessed. Eight physicochemical parameters and mineral composition were analysed and the CIELAB colour parameters (L∗, a∗, b∗, Cab∗ and hab) were determined. Results show no significant differences between the two Euphorbia honey types (Euphorbia officinarum subsp. echinus and Euphorbia regis-jubae honeys) regarding the physicochemical parameters. Sodium and magnesium show average values that can help to differentiate between E. officinarum subsp. echinus and E. regis-jubae honeys. Potassium was quantitatively the most important mineral (66% of the total minerals quantified), while sodium and calcium were present in moderate amounts (20% and 11% of the minerals, respectively). The colour parameters also have shown significant differences between E. officinarum subsp. echinus and E. regis-jubae honeys.Considering the total information from physicochemical, mineral and colour data, Principal Component Analysis (PCA) and Stepwise Discriminant Analysis (SDA) were carried out to distinguish between the two Euphorbia honey types. PCA showed that the cumulative variance was approximately 56%. The results of SDA showed that parameters with a higher discriminant power were Na, Mg, L∗, Cab∗ and hab, and almost 100% of the samples were properly classified in their corresponding group, except for one sample. Keywords: Unifloral honey, Euphorbia officinarum subsp. echinus, Euphorbia regis-jubae, PCA, SDA

Sacha inchi oil is a high-quality product with market potential and a wealth of bioactive compounds beneficial for food and health. The main objective of this work was to evaluate three quality parameters, stability, chromatic parameters and total carotenoids of commercial oils obtained from Sacha inchi seeds. The free acidity and peroxide value of all samples studied were in ranges of 0.16–1.86 (% α-linolenic acid) and 1.87–17.47 (meq O2/kg), respectively. While K232 value for the samples ranged from 1.96 to 2.29, the K270 value was between 0.08 to 0.20 and ∆K in the range of − 0.005 to 0.005. Regarding color, Sacha inchi oils showed high hab and low $$ C^{*}_{\text{ab}} $$ values, and the L* values were from 91 to near 100 units. Samples were located in the second quadrant of the CIELAB a*b*-color diagram. These characteristics corresponds to low-vivid light-yellow colors. Carotenoid content of Sacha inchi oils was 0.31–9.10 mg/kg. The oxidative stability using Rancimat (100 °C, 20 L/h air flow rate) of these oils presented an average value of 5.6 h. Pearson’s coefficients indicate a very high correlation coefficient between the values of Car (carotenoid) versus b* (yellow area) (r = 0.991). The results of this study provide better understanding of the quality, stability, chromatic intensities and carotenoid contents of Sacha inchi oil that is marketed in Peru.

The usefulness of digital image analysis in estimating sensory attributes of grape seeds in relation to maturation level was evaluated for the first time. Seeds from Syrah grapes harvested throughout the ripening period were grouped according to maturity using the DigiEye® system. The discriminant ability, homogeneity, repeatability, and uniformity of a sensory panel were assessed after training on grape seeds. The aim was to evaluate the use of digital image techniques in order to accurately establish the maturity level of grape seeds, based on sensory and textural features. All sensory attributes (color, hardness, cracking, vegetal, bitterness and astringency) showed significant (p &lt, 0.05) correlations with the chemical maturity stage. Color and vegetal (sensory attributes), together with deformation energy (instrumental texture parameter) (De), allowed for the classification of the seeds into four real maturity stages, hence their usefulness as grape seed ripening indicators. Significant (p &lt, 0.05) and high-correlation factors were also found between instrumental and sensory attributes. Therefore, digital analysis can be a useful tool to better define the maturity stage in the vineyard, and to dispose of grape seeds with well-defined sensory profiles for specific oenological applications. This could help to determine the optimal harvest date to manage winemaking, in order to produce high quality wines in warm climates.

Overripe seeds from sun-dried grapes submitted to postharvest dehydration constitute a scarcely investigated class of vinification byproduct with limited reports on their phenolic composition and industrial applications. In this study, Raman spectroscopy was applied to characterize a selection of overripe seed byproducts from different white grapes (cv. Moscatel, cv. Pedro Ximénez and cv. Zalema) submitted to postharvest sun drying. The Raman measurements were taken using a 1064 nm excitation laser in order to mitigate the fluorescent effect and the dispersive detection scheme allowed a compactness of the optical system. Spectroscopic data were processed by a prin-cipal component analysis to reduce the dimensionality and partner recognition. The evolution of the Raman spectrum during the overripening process was compared with the phenolic composition of grape seeds, which was determined by rapid resolution liquid chromatography/mass spectrom-etry (RRLC/MS). A multivariate processing of the spectroscopic data allowed the classification of overripe seeds according to the grape variety and the monitoring of stages of the postharvest sun drying process. Ministerio de Economía y Competitividad AGL2017-84793 Universidad de Sevilla SOL2019-12566

The grape pomace industry produces large quantities of protein-rich seeds, which can be a sustainable nonanimal protein source; their techno-functional properties could be exploited to improve the colour stabilisation and modulating the astringency of red wines in warm climates. This study aims to optimise the methodology of obtaining protein hydrolysates from defatted grape seed meal residue. Five assays using different quantities of enzyme and raw materials were considered. Based on the protein purity, hydrolysates yield, colour and molecular weight distribution achieved, optimal conditions were the hydrolysis of the alkaline protein concentrate with the highest amount of enzyme. The products obtained showed the lowest colour parameters, with the lightness contributing the most to the colour differences, which were visually perceptible (ΔE*ab > 3). The hydrophobic amino acids remained within the peptide sequence, leaving polar and charged amino acids in terminal positions, which could affect the wine equilibrium related to colour stabilisation. FEDER, Ministerio de Ciencia e Innovación, Agencia Estatal de Investigación AGL2017-84793- C2

The post-fermentative double addition of Pedro Ximenez cv seeds obtained from natural matured grapes (ripe seeds, RS) and postharvest sun-dried grapes (overripe seeds, OS) were studied as sustainable enological alternatives to conventional vinification (CW) to improve the stability of Syrah wines produced in a warm climate. The phenolic composition was assessed by rapid resolution liquid chromatography, copigmentation/polymerization processes by spectrophotometry, and color quality and stability by Differential Colorimetry. OSW and RSW wines enriched their total phenolic content, being the effect more pronounced with overripe seeds (by 23% versus 10%). OSW differences were found for gallic acid, monomeric flavan-3-ols, and procyanidins compared to CW, and for (+)-catechin, procyanidin B2-3-O-gallate and the tetramer to RSW. Phenolic changes were related to higher color intensity in seed-added wines. OSW having higher percentage of polymeric pigments maintained for longer time the chromatic improvement, being visually darker and more intense than final CW and RSW.

With the purpose of modulating the copigmentation equilibria of red wines, an environmentally sustainable process was performed based on post-fermentative addition of overripe seeds (OS). Simple (SW) and double (DW) addition were performed to produce different enrichment of phenolics from seeds, hence different copigmentation/polymerization ratios. The determination of the phenolic composition showed different global increases in OS-macerates wines (catechin, epicatechin, gallic acid and procyanidins B1 and B2). The double post-maceration (DW) was more effective than the simple post-maceration addition to improve the phenolic structure of wines. The application of Differential Tristimulus Colorimetry could assess the effects of this practice on the color characteristics and stability of wines. Results highlighted that both simple and double assays underwent colorimetric improvements against the control wines (CW, no seeds addition). DW led to the highest chromatic stability, showing lower lightness, higher chroma values and bluish hues than CW. This color difference was visually detectable.

Currently, the wine industry has an increasing interest in developing alternative solutions to traditional animal proteins fining agents. In this study, the impact of different protein fining agents on the turbidity, phenolic composition and color of 2-month and 12-month Syrah red wines was assessed. Wines fined with egg albumin and plant-based proteins from potato, pea, and grape seed as recent alternative, were compared to unfined control wines. Changes on turbidity, phenolic composition and color (by Differential Colorimetry) showed that animal and plant proteins differed in their clarifying efficiency and ability to interact with colorless phenolics and anthocyanins, depending on the age of wine, with important consequences on color quality and stability. Plant proteins showed lower effectiveness to reduce wine turbidity than egg albumin but modified in different way the phenolic composition, inducing lower color differences with respect to control wine and similar stability, especially potato and grape seed proteins.

Grape skins or their by-products from wine production are rich sources of anthocyanins and various colorless phenolics, depending on the grape variety. Phenolics have strong antioxidant and anthocyanin stabilizing properties and help to produce functional anthocyanin colorants with improved stability. This study aimed to assess differences in color expression and stability of anthocyanin colorants from red grape varieties naturally copigmented and with different levels of purity and to compare them to synthetic FDC Red No. 3. Model juice systems were prepared at pH 3.5 with anthocyanins and phenolic copigments extracted from four Vitis vinifera grape varieties ('Tempranillo', 'Syrah', 'C. Sauvignon', and 'Graciano') both crude and purified by C18 solid phase extraction. Attention was focused on differential colorimetry and phenolic composition related to the color. Degradation kinetics of total color were also studied during storage of 17 days in darkness at 25 °C. Grape variety significantly influenced pigment yield, proportion of acylation, and proportion of copigments:pigments ratios in crude extracts; purification modulated the copigment:pigment ratios. This proportion was related to perceptible color variability among colorants and to different stabilities. With the same pigment content, grape varieties richer in skin copigments and higher copigment/pigment ratios ('Syrah' and 'Tempranillo') produced more intensely colored crude extracts whose tonalities ranged from reddish ('Graciano') to red-bluish ('Syrah'), depending on the proportion of acylation. Increasing the purity of the pigments diminished the color variability due to variety, making them less vivid and visually more similar to one another and also to the synthetic colorant. Degradation kinetic studies showed that unpurified grape colorants had higher color stability over time, with the greatest stabilizing effects achieved with varieties richer in skin flavonols ('Tempranillo' and 'Syrah').

The chemical composition of wine grapes changes qualitatively and quantitatively during the ripening process. In addition to the sugar content, which determines the alcohol content of the wine, it is necessary to consider the phenolic composition of the grape skins and seeds to obtain quality red wines. In this work, some imaging techniques have been used for the comprehensive characterisation of the chemical composition of red grapes (cv. Tempranillo and cv. Syrah) grown in a warm-climate region during two seasons. In addition, and for the first time, mathematical models trained with laboratory images have been extrapolated for using in field images, obtaining interesting results. Determination coefficients of 0.90 for sugars, 0.73 for total phenols, and 0.73 for individual anthocyanins in grape skins have been achieved with a portable hyperspectral camera between 400 and 1000 nm, and 0.83 for total and individual phenols in grape seeds with a desktop hyperspectral camera between 900 and 1700 nm. Junta de Andalucía US-1261752 Ministerio de Ciencia e Innovación AGL2017- 84793-C2

The effect of the fermentative addition of overripe seeds by-product (Pedro Ximenez white grapes, 3 g/L) on the phenolic composition and colour of red wines was studied by rapid resolution liquid chromatography (RRLC-MS) and Differential Colorimetry. Overripe seeds summited to postharvest dehydration by sun drying directly demonstrated were rich in phenolics such as gallic acid, epicatechin, and procyanidin B2 3- O -gallate, and hence a source of copigments capable to stabilize wine anthocyanins. The fermentative addition of overripe seeds led to Syrah wines with significant higher content of anthocyanins and procyanidins than traditional macerated wines, which had a positive effect on colour quality and stability. With respect to the colour quality, visually perceptible colour differences were found respect to the traditional macerated wines (ΔE* ab > 3), getting overripe seeds macerated wines with bluish hues and higher chroma values. Moreover, Differential Colorimetry demonstrated that the addition of overripe seeds induces lower colour modification in wines during stabilization and, in consequence, higher colour stability.

Imaging techniques have revolutionised the way quality is assessed in food products. Using cameras, it is possible to estimate not only the chemical composition of a product but also its geometric distribution. However, the limited range of detectors implies the use of different measuring equipment. The presence of small and discrete samples or very heterogeneous samples makes joining both sets of data a complicated task. This work arises from the need to merge images with colour information and NIR spectral information on grape samples and derivatives. An application has been created under MATLAB to join this type of images so that it is possible to simultaneously extract the colour and/or spectral information of each pixel or object present in the image. Although the software can be used in a wide range of applications, it has been successfully applied to grape and grape seed samples. In red grape bunches, it was possible to evaluate individually grapes and notice differences due to changes in visible and infrared regions at the same time. In the case of white grape seeds, it was proved that merged images were better to discriminate between varieties than the single CIELAB or spectral images.

Spanish MINECO grant BES-2012-060192 Spanish MINECO project AGL2014- 58486-C2 Universidad de Sevilla (España) Plan VI (VPPI-US)

The effect of salt stress (200 mM NaCl for 28 days) on physiological characteristics of Hibiscus rosa-sinensis, such as abscisic acid (ABA) content, electrolyte leakage, and photochemical efficiency in leaves, and its influence on biomass production, anthocyanin composition, and color expression of flowers were evaluated. Salinity significantly increased electrolyte leakage and ABA content in leaves and reduced the flower fresh weight. Chlorophyll fluorescence parameters were lower in salt stress condition, compared to control. Moreover, salt stress negatively affected the content of anthocyanins (mainly cyanidin-3-sophoroside), which resulted in a visually perceptible loss of color. The detailed anthocyanin composition monitored by HPLC-DAD-MS and the color variations by digital image analysis due to salt stress showed that the effect was more noticeable at the basal portion of petals. A forward stepwise multiple regression was performed for predicting the content of anthocyanins from appearance characteristics obtained by image analysis, reaching R-square values up to 0.90.

Different white winemaking byproducts (pomace, skins, seeds, and stems) were compared as natural sources of phenolic compounds having biological and sensory properties of enological interest. Antioxidant and copigmentation effects of these byproducts were studied in a wine-like model solution. RRLC-DAD was used to establish differences in the phenolic composition, and the ABTS method was used to compare the antioxidant activities. Spectrophotometric and colorimetric analyses were performed to assess the magnitude of copigmentation and the changes induced in the color expression of red wine anthocyanins. Antioxidant and copigmentation properties significantly varied depending on the type of byproduct, which was related to their qualitative and quantitative phenolic composition. Seeds and pomace showed the highest antioxidant potential, whereas skins and pomace led to the strongest and visually perceptible color effects on red wine anthocyanins by multiple copigmentation (darker, more saturated, and vivid bluish colors). Results open the possibility of technological applications for the wine industry based on reusing winemaking byproducts to improve the biological value and color characteristics of red wines.

Graphical abstractDisplay Omitted The method for evaluating heterogeneous colours in foodstuffs has been improved.An algorithm that adjusts point clouds to ellipsoids in CIELAB colour space has been introduced.The methodology presented can be useful in studies that use 'Chemical Imaging'. The use of computer vision for estimating composition in food products has become wide spread in recent years, especially for products where by measuring colour or other spectral features, we are able to estimate the composition, variety, or ripeness. On the other hand, the appearance is one of the most worrying issues for producers due to its influence on quality and consumer preferences. Computer vision is the best option to satisfy the need of measuring colour and heterogeneity in these products. Previous studies have expressed the heterogeneity with the standard deviation or other magnitudes that do not explain accurately the distribution of colour in CIELAB colour space. Graphing the scatterplot of the a*b* values belonging to the pixels of the image helps to explain the shape of the point cloud, but currently there is not an objective procedure to quantify these point clouds. This work has established a method for improving the illustration of colour measurements by image analysis. The proposed algorithm classified the point clouds by clustering methods and established the methodology for fitting the resulting clusters into ellipsoids. Their geometric features described the shape of the clouds in a quantitatively manner and they could be useful in multivariate statistical techniques for classifying and predicting chemical properties.

[EN] The aim of this work was to conduct a detailed colorimetric study, using transmittance and reflectance measurements, to evaluate the possible interactions occurring among the different families of pigments comprising to colour matter of red wines and their contribution to the colour in aged red wines. To accomplish this, the phenolic material of monovarietal red wines obtained from Tempranillo and Graciano varieties, and their blends, were fractionated by gel permeation chromatography in order to separate the coloured fractions with different chemical compositions. The binary blends at different concentrations of the fractions having higher anthocyanin monoglucoside proportions with fractions having higher pyranoanthocyanin derivative contents and direct flavanol-anthocyanin condensation products were carried out in order to determine the effect of adding these derivatives on the colour of the anthocyanin monoglucosides, the major wine pigments. It was observed that the addition of derived pigments to the anthocyanin monoglucosides fraction resulted in colour differences perceptible by the human eye. These variations were mainly quantitative (changes in chroma and lightness), and were also qualitative (changes in hue) in monovarietal wines. Studying the phenolic fractions of wines implies an approach to the chemical reality of the wines, more than the studies on model solutions, since they can lead to the knowledge of those components having more influence on the final colour of the wine. With these results the wineries could conduct the vinifications towards a higher extraction of the components or families of components more important for the intensity and stability of colour.

The experimental study presented shows how optical spectroscopy can be used innovatively as a rapid and non-destructive tool for differentiating distinctive single-malt Scotch whiskies with respect to commercial-grade blends, and for classifying them according to the region of production. During the study, absorption and fluorescence spectroscopies are carried out without any sample treatment or handling. Spectroscopic data have been processed by means of multivariate analysis in order to design a discriminating map. The map shows that the cluster representing the single-malt whiskies from selected Scottish distilleries distinctly separates from the cluster of the commercial-grade blended whiskies. Moreover, the cluster of single-malt whisky is split into two subgroups, which represent samples from two main macro-areas: the “islands” and the “highlands”, respectively.

Digital imaging has become a powerful tool for the characterization and quality control of foodstuff. Because of the need to automate processes, faster tools are needed and Computer Vision is a good alternative to chemical analysis of many products in quality control. Appearance of grape seeds and grape berries change during the ripeness. These changes are closely related to the chemical composition, especially phenolics, which are very important compounds due to their implications on the intensity and stability of red wine colour. In this study, a complete characterization of grape seeds and grape berries by digital image analysis is described. The size of grapes and the veraison has been determined by image analysis and it has been also established an objective Browning Index of seeds. Morphological differences between varieties were studied by applying discriminant analysis models which allowed us to classify the grape seeds with high accuracy.

The appearance of most of the commercialized olive oils involves both their color and turbidity depending on the different technologies used for their elaboration. This research has been carried out to study the filtration impact on the colorimetric changes of virgin olive oils. Naturally turbid olive oils were blended at different proportions (100, 80, 60, 40, 20 and 0%) with their corresponding filtered replicates to obtain a scale of six levels of turbidity and simulating different turbidity grades. Tristimulus colorimetry, particularly the CIELAB uniform color, was used to follow color changes. As turbidity of the oil increased in the blend, yellowish oils, darker, and less saturated were obtained. Univariate correlations between the colorimetric parameters and turbid content were achieved with second degree polynomial equations, being chroma ( $$ C_{{_{\text{ab}} }}^{ *} $$ ) and hue (h ab) the best correlated parameters. The color differences ( $$ \Updelta E_{{_{\text{ab}} }}^{ *} $$ ) calculated between turbid oils (100%) and the consecutively decreasing turbid oils blends ranged from 3.18 to 18.72 CIELAB units, revealing differences in color visually perceptible to the human eye.

The influence of different storage conditions on the volatile composition of young white wine was evaluated during 1 year of storage. The wine was bottled and stored under different conditions of temperature, position and illumination. During storage, a significant increase in total content esters (mainly due to the increase in ethyl butyrate, ethyl acetate and diethyl succinate) and total content acids was detected. Also total content alcohols and carbonyl compounds decreased during storage. Storage time, temperature and illumination have a significant effect on esters content, whereas carbonyl compounds are affected by temperature, and alcohols content is affected by illumination. Stepwise linear discriminant analysis was applied to the experimental data. The results showed that the samples were well classified as a function of storage temperature. On the other hand, a certain trend was observed when the wine samples were classified according to storage time. The samples corresponding to two and four months of storage were well differentiated from the rest. PRACTICAL APPLICATIONS From a sensory point of view, the aroma influences greatly the quality of wines. The loss of aromatic characteristics in young white wine, as well as browning, take place over a variable period of time which ranges from one month to several years, depending on wine type and storage conditions. Assessment of possible factors affecting the useful lifespan of young white wine is of great interest for the wine making industry. Knowing the chemical composition of wine, specifically aromas, and its evolution relating to different storage and preservation conditions is an important tool in quality control.

The stabilization of red wine color by the copigmentation phenomenon is a crucial process that does not always proceed favorably under natural conditions during the first stages of vinification. The impact of the prefermentative cold maceration technique on the phenolic composition and magnitude of the copigmentation level of organic Tempranillo wines elaborated in a warm climate have been studied as an enological alternative to the traditional maceration for obtaining highly colored wines. Tristimulus colorimetry was applied to study the color of wines during vinification, and a high-performance liquid chromatography (HPLC) procedure was used for the analysis of phenolic compounds. Spectrophotometric and colorimetric analyses were also performed to evaluate the copigmentation level of the wines. Significant chemical and color differences were found depending on the maceration technique applied. Prefermentative cold macerated wines were richer in those compounds accounting directly for the color of red wine (anthocyanins) and those involved in anthocyanin stabilization through copigmentation reactions (phenols), which was in accordance with the higher copigmentation degree and darker, more saturated and vivid bluish colors. The evaluation of the copigmentation based on colorimetric parameters in the CIELAB color space showed that prefermentative cold maceration caused greater effectiveness of copigmentation than traditional maceration since it induces more important and hence more easily perceptible color changes.

Changes in colour and stability of anthocyanins have been evaluated over pH range 2.0–8.7. The study was made on crude extract (XAD-7 Amberlite-retained fraction) as well as on the following pure pigments isolated from tamarillo fruit ( Solanum betaceum Cav.): delphinidin 3- O -(6″- O -α-rhamnopyranosyl-β-glucopyranosyl)-3′- O -β-glucopyranoside, delphinidin 3- O -(6″- O -α-rhamnopyranosyl)-β-glucopyranoside, cyanidin 3- O -(6″- O -α-rhamnopyranosyl)-β-glucopyranoside and pelargonidin 3- O -(6″- O -α-rhamnopyranosyl)-β-glucopyranoside. The relationships between the colour and the hydroxylation degree of the B ring and the pH have been studied for the first time on rutinosides. The peel extract showed much more colour stability than the jelly extract at all the pH values studied. The replacement of the 3′-OH with a glycosyl group increased the stability of the colour to pH changes, although this substitution yields a less colourful (higher L ∗ and lower C ab ∗ ) compound (Dp 3-rut-3′-glc), having both hypsochromic and hypochromic shifts relative to the non-glycosylated molecule (Dp 3-rut). Moreover, the influence of the hydroxylation degree of the B ring on the quality and stability of colour, as well as on the antioxidant activity, was determined.

Different quality attributes and chemical components of wines change during storage as a function of a series of factors. Thus, in young white wines, changes in phenolics, that lead to modifications of their colour as a result of oxidation processes, are well-known. These reactions can also alter their volatile profile giving rise to the appearance of new aromas, which in some cases are undesirable. In this study we have carried out a thorough evaluation of the changes in the colour, volatiles and phenolics of Zalema and Colombard wines during 1 year of storage under different conditions of temperature and position. The phenolics and colour were more affected than was the volatiles profile and wines kept in the cold could be clearly distinguished from the others, whilst the position of the bottles onlt slightly affected the wines during storage. Results showed that the blending of Zalema wines with Colombard wines may be an appropriate means of enhancing the acidity of the former without dramatically affecting its character.

Apart from the need to assess the color of foods due to its preponderant role in their acceptability, there is currently a new trend consisting in the study of the relationships between the color and the pigments accounting for it. The color of five strawberry varieties cultivated in two different soilless systems has been studied, and an array of multivariate statistical methods have been performed to single out the color parameters that best discriminate among the different samples surveyed and to correlate them with the pigment content. It is concluded that there is not a direct relationship between the external and flesh colorations of the berries. Additionally, after discriminant methods were applied, it was noticed that, taking into account the strawberry varieties, >90% of the cases could be correctly classified, a noticeably lower percentage of correct classification (around 60%) being obtained when the type of cultivation system was selected as the criterion for discrimination. The best correlations of pigment-color coordinates were found between pelargonidin-3-rutinoside and the external a *( r ) -0.87) followed by pelargonidin-3-glucoside and the internal L *( r )- 0.72).

A quick and simple method to obtain the colour of honeys with minimum error is proposed. Characteristic vector analysis has been tested and proved to be applicable to the reconstruction of honey reflectance spectra. Expressions for tristimulus values are obtained as function of reflectance measurements at a few wavelengths. Different sets of reflectance were tested (from 3 to 6 wavelengths) showing better results as the number of characteristic vectors (wavelengths) increases. The measures were made both over white and over black backing. Results showed that, when spectrophotometric measurements are made with 10 mm pathlength cells, the determination of reflectance at four wavelengths (443, 530, 554, and 618 nm for white backing; 439, 488, 555 and 636 nm for black backing) is adequate to reconstruct the spectrum and to obtain the tristimulus chromatic characteristics. The black backing measurements showed better results, being 74% and 57% (black and white backing measurements, respectively) the percentage of samples giving colour differences less than 1 CIELAB unit between the calculated coordinates and those obtained from the whole visible spectra.

The evolution of colour and free anthocyanins during the pre-fermentative cold maceration and alcoholic fermentation of Syrah musts was studied. Colour was measured by Tristimulus Colorimetry and anthocyanins were determined by HPLC. The results showed that the most significant changes were produced during the first two days of cold-maceration and no decrease in the anthocyanin extraction was observed during the whole cold maceration period. Quantitatively, malvidin derivatives were the most abundant anthocyanin compounds. With respect to the colour, pre-fermentative cold maceration has proved to be an useful technique to obtain darker, more saturated and more bluish wines. From a study of the colour-composition relationships using forward stepwise multiple linear regression, the colorimetric parameters L∗, b∗, hab and s uv ∗ were predicted from different individual anthocyanins, the 3-monoglucoside of malvidin being the most important free anthocyanin to predict the wine colour.

[EN] Oak chips-related phenolics are able to modify the composition of red wine and modulate the colour stability. In this study, the effect of two maceration techniques, traditional and oak chips-grape mix process, on the phenolic composition and colour of Syrah red wines from warm climate was studied. Two doses of oak chips (3 and 6 g/L) at two maceration times (5 and 10 days) during fermentation was considered. Changes on phenolic composition (HPLC–DAD–MS), copigmentation/polymerisation (spectrophotometry), and colour (Tristimulus and Differential Colorimetry) were assessed by multivariate statistical techniques. The addition of oak chips at shorter maceration times enhanced phenolic extraction, colour and its stabilisation in comparison to the traditional maceration. On contrast, increasing chip dose in extended maceration time resulted in wines with lighter and less stable colour. Results open the possibility of optimise alternative technological applications to traditional grape maceration for avoiding the common loss of colour of wines from warm climate.

The phenolic composition (by HPLC-DAD-MS) and color characteristics (by Imaging Tristimulus Colorimetry) of four strawberry cultivars that have shown good climate adaptation to subtropical area (Nikte, Zamorana, Jacona and Pakal) have been assessed. 24 monomeric phenolics were identified, including 15 anthocyanins, 5 phenolic acids, 1 flavanol and 4 flavonols. Nikte and Zamorana showed the highest phenolic potential mainly due to their higher content of anthocyanins, while Pakal was richer in phenolic acids. Regarding color, Nikte and Zamorana were the more similar cultivars having the lowest values of lightness and hue. On the contrary, the color of Pakal was quite different from all the rest, due to the specific distribution between pelargonidin and cyanidin. The inclusion of both phenolic and colorimetric information in the Linear Discriminant Analysis allowed reaching very good discriminations among cultivars.

A chromatic analysis by tristimulus colorimetry and a pollen analysis (pollen grains contained in each honey sample, considering their volume and geometrical shape) were carried out on 33 Eucalyptus unifloral honeys; the colour of the pollen grains was also considered. Multiple linear regression (MLR) and partial least squares regression (PLSR) were used to establish equations relating the chromatic variables to the pollen data, ie number and morphology of the pollen grains, thus allowing the prediction of the ultimate colour from the botanical characteristics. The results obtained show that lightness (L*) is significantly (p < 0.05) related to the pollen type Olea europaea; on the other hand, the variable that better relates to the chroma is the Zea mays pollen type. Copyright © 2004 Society of Chemical Industry

The combined effect of anthocyanin−flavanol−flavonol ternary interactions on the colorimetric and chemical stability of malvidin-3-glucoside has been studied. Model solutions with fixed malvidin-3-glucoside/(+)-catechin ratio (MC) and variable quercetin-3-β-D-glucoside concentration (MC+Q) and solutions with fixed malvidin-3-glucoside/quercetin-3-β-Dglucoside ratio (MQ) and variable (+)-catechin concentration (MQ+C) were tested at levels closer to those existing in wines. Color variations during storage were evaluated by differential colorimetry. Changes in the anthocyanin concentration were monitored by HPLC-DAD. CIELAB color-difference formulas were demonstrated to be of practical interest to assess the stronger and more stable interaction of quercetin-3-β-D-glucoside with MC binary mixture than (+)-catechin with MQ mixture. The results imply that MC+Q ternary solutions kept their intensity and bluish tonalities for a longer time in comparison to MQ+C solutions. The stability of malvidin-3-glucoside improves when the concentration of quercetin-3-β-D-glucoside increases in MC+Q mixtures, whereas the addition of (+)-catechin in MQ+C mixtures resulted in an opposite effect

peer-reviewed The use of hyperspectral imaging to (a) quantify and (b) localise total glucosinolates in florets of a single broccoli species has been examined. Two different spectral regions (vis–NIR and NIR), a number of spectral pre-treatments and different mask development strategies were studied to develop the quantitative models. These models were then applied to freeze-dried slices of broccoli to identify regions within individual florets which were rich in glucosinolates. The procedure demonstrates potential for the quantitative screening and localisation of total glucosinolates in broccoli using the 950–1650 nm wavelength range. These compounds were mainly located in the external part of florets. Universidad de Sevilla J.M. Hernández-Hierro thanks the Spanish MICINN for the Juan de la Cierva contract (JCI-2011-09201) and Universidad de Sevilla for the mobility Grant (Universidad de Sevilla Research Plan). Spanish MICINN Project AGL2011-30254-C02 and Junta de Andalucia PGC Project AGR 6331.

Chemical composition of seeds changes during grape ripening and this affects the sensory properties of wine. In order to control the features of wines, the condition of seeds is becoming an important factor for deciding the moment of harvesting by winemakers. Sensory analysis is not easy to carry out and chemical analysis needs lengthy procedures, reagents, and it is destructive and time-consuming. In the present work, near infrared hyperspectral imaging has been used to determine flavanols in seeds of red (cv. Tempranillo) and white (cv. Zalema) grapes (Vitis vinifera L.). As reference measurements, the flavanol content was estimated using the p-dimethylaminocinnamaldehyde (DMACA) method. Not only total flavanol content was evaluated but also the quantity of flavanols that would be extracted into the wine during winemaking. A like-wine model solution was used for this purpose. Calibrations were performed by partial least squares regression and they provide coefficients of determination R2=0.73 for total flavanol content and R2=0.85 for predicting flavanols extracted with model solution. Values up to R2=0.88 were reached when cultivars were considered individually.

The effect of adding American oak wood chips during fermentation on Tempranillo red wines elaborates in a warm climate has been studied. Our attention was focused on the tristimulus colorimetry, differential colorimetry and phenolic compounds related to wine colour. This technique was applied as an oenological alternative to the conventional winemaking for avoiding the common fall of colour of red wines elaborated in warm climates. The addition of oak wood chips promoted the colour enhancement and stabilisation, producing wines with a notably darker colour and with more bluish tonality. This fact was also related to the significantly higher content of some phenolic compounds. On the basis of the results, it could be affirmed that the addition of oak wood chips during fermentation induced visually perceptible colour changes (by the analysis of Δ E ab ∗ , %Δ2L, %Δ2C and %Δ2H), mainly in a quantitative way, and also a lower percentage of diminution of colour.

New colorimetric variables have been defined in the uniform CIELAB color space to assess the quantitative and qualitative color changes induced by copigmentation and their incidence on visual perception. The copigmentation process was assayed in model solutions between malvidin 3-glucoside and three phenolic compounds (catechin, epicatechin, and caffeic acid) as a function of the pH and the pigment/copigment molar ratio. Along the pH variation, the greatest magnitude of copigmentation was obtained at pH 3.0, being significantly higher with epicatechin and caffeic acid. At high acidic pH, the main contribution of copigmentation to the total color was qualitative, whereas between pH 2.0 and 4.0, the main colorimetric contribution was quantitative. The contribution of epicatechin and caffeic acid to the color changes was more marked for the quantitative characteristics. On contrast, particularly at higher pH values, the qualitative contribution was more important in catechin copigmented solutions. Increasing copigment concentration induced perceptible color changes at molar ratios higher than 1:2, consisting in a bluish and darkening effect of the anthocyanin solutions. Among the different CIELAB attributes, hue difference was the best correlated parameter with the increase of copigment concentration, proving the relevance of this physicochemical phenomenon on the qualitative changes of anthocyanin color.

The aim of the present work was to determine whether there is any relationship between measurement by transmission and reflection (in the latter case, with and without contact with the sample). We also evaluated which methodology used would offer a better interpretation of the results in visual terms. For this purpose, different colorimetric techniques such as transmission spectrophotometry, diffuse reflectance spectrophotometry and spectroradiometry were applied. The samples consisted of increasing dilutions (0, 20, 40, 60, 80 and 100%) of the phenolic fractions obtained from 4 wines: Tempranillo (T) and Graciano (G) monovarietal wines, and two 80:20 mixtures: M (wine elaborated by blending grapes) and W (a blend of the T and G wines) (9 fractions per wine). Fractionation was performed using gel permeation chromatography with a Toyopearl HW-40S column, and the dilutions of the fractions were performed with synthetic wine (pH = 3.6). The spectroradiometric measurements permitted the differences due to the dilution effect on the fractions to be established more clearly than with the results obtained using diffuse reflectance and spectrophotometry. Thus, this technology is very suitable for use in comparative interpretations by the human eye. In turn, we assessed the changes in colour due to the effect of dilution on the fractions, observing that the effect of dilution led to an increase in the values of lightness (L*), while the chroma values (C* ab ) followed the opposite trend, in agreement with its role as a variable related to chromatic intensity or vividness of the sample. In contrast, hue (h ab ) did not seem to be affected by dilution of the fractions, in consonance with the qualitative nature of this parameter.

[EN] The applications of computer vision technology for acquiring and analysing images have been extended to the quality evaluation in food industry. This technique involves great advantages for the objective, rapid, non-contact and automated quality inspection and control. The aim of this work was to evaluate the potential of the computer vision to determine the phenolic maturity stage of grape seeds. Up to 21 phenolic compounds were determined by HPLC–DAD-MS in order to obtain reference values to develop the model. The CIELAB parameters, area, aspect, roundness, length, width and heterogeneity of seeds were analysed using a DigiEye® system. The technique reported in this work can be a good and rapid tool for taking decisions at harvest time. Notwithstanding, a comprehensive study should be made in order to develop more robust models.

One nonanthocyanin-accumulating (Ailsa Craig) and three anthocyanin-accumulating tomato genotypes (Anthocyanin fruit type, Atroviolaceum, and Sun Black) were analyzed to assess differences in their carotenoid and anthocyanin levels and color and to evaluate the effects of nutrient solutions with different salt concentrations on these parameters. The carotenoid content of control Atroviolaceum tomatoes was ca. 2-2.5-fold higher relative to the other two types, and the color of its puree could be visually distinguished from those of other genotypes. Salinity stress led in some cases to a 2-3-fold increase in the lycopene content. Saline treatment increased the accumulation of total anthocyanins in fruits of Sun Black (2-fold increase), while it reduced it in fruits of Anthocyanin (10-fold decrease). In general, the treatment increased the differences in color of different purees. These results indicate that salinity stress can lead to similar or higher increases in tomato carotenoids than those achieved by genetic engineering. In addition, these changes were accompanied by visually discernible color differences in tomato products. Our findings show the considerable potential of exploiting saline soils to obtain tomatoes with higher levels of secondary metabolites like carotenoids and anthocyanins.

The phenolics from different strawberry cultivars (Aromas, Camarosa, Diamante, Medina, and Ventana) cultivated in two different soilless systems (with and without recycling nutrient solution) were quantified to assess differences in their profiles as a function of both the variety and the cultivation system. Considering groups of phenols, it was found that either anthocyanins (including pelargonidin-3-glucoside, cyanidin-3-glucoside, pelargonidin-3-rutinoside, pelargonidin-3-acetylglucoside, and two unidentified pelargonidin derivatives) or phenolic acids (including caffeic, ferulic, p-coumaric, p-hydroxybenzoic, and ellagic acid) were quantitatively more important than those of flavonols (quercetin and kaempferol); the ranges of values were 78.81-198.88, 49.77-128.37, and 12.85-43.04 microg/g, respectively. Considering individual compounds and after applying relevant pattern recognition techniques, it was concluded that the contents of cyanidin-3-glucoside, pelargonidin-3-rutinoside, p-coumaric acid, and pelargonidin-3-glucoside were the most appropriate variables to discriminate among varieties, whereas those of p-hydroxybenzoic acid and pelargonidin-derivative 1 were the most appropriate to discriminate between cultivation systems. The first factor of PCA was mainly linked to anthocyanins and quercetin, whereas the second principal component (PC) was related to kaempferol and p-coumaric acid.