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Camu-camu (Myrciaria dubia) is a tropical fruit known for its content of bioactive compounds. This study aimed to evaluate physicochemically, morphologically, andsensorialpowders from camu-camu obtained by spray-drying at two inlet temperatures (150 °C and 180 °C) with three encapsulating agents (maltodextrin, whey protein and a 50:50 mixture of both) and by freeze-drying of whole fruit. The use of maltodextrin protected bet anthocyanins (cyanidin-3-glucoside (C3G) and delphinidin-3-glucoside (D3G)), but whey protein showed a better protective effect on ascorbic and malic acids. These facts were confirmed during the storage stability test, finding that relative humidity is a critical variable in preserving the bioactive compounds of camu-camu powders. The powders with the highest content of bioactive compounds were added to a yogurt and a white grape juice, and then sensory evaluated. The bioaccessibility studies in gastric and intestinal phases showed better recovery percentages of bioactive compounds in camu-camu powders (up to 60.8 %) and beverages (up to 90 %) for C3G, D3G, ascorbic acid, and malic acid than in the fruit juice. Dehydration of camu-camu (M. dubia) is a strategy to increase the bioactive compounds stability, modulate the fruit sensory properties, and improve their bioavailability after incorporation in food matrices.

Hyperspectral imaging is a well-known technique for quality control of food and agricultural products. This technique is often applied to the measurement of large and heterogeneous samples, where chemical imaging is extremely useful. In addition, when the amount of sample is limited by different factors (price, other analyses, sample production, etc.) hyperspectral imaging is an alternative to traditional spectroscopes for acquiring its spectral information. In this study, a new and specific methodology to acquire hyperspectral information from small amounts of granular samples has been developed. For this purpose, two different hyperspectral devices (400–1100 nm, 900–1700 nm) have been used. A statistical procedure has been followed to test the proposed method. In grape seed protein concentrates, NIR radiation (900–1700 nm) penetrates deeper into the sample than VisNIR radiation (400–1100 nm). Therefore, the minimum amount of sample needed to measure in the NIR range is larger than that needed to measure in the VisNIR range. Finally, different calibration models have been developed for the control of protein content in the tested samples. Standard errors of prediction obtained in external validation are similar to those reported in the literature when sample amount is not an issue (9–10 %).

Antioxidant activity can be evaluated using cyclic voltammetry (CV). The aim of this work is to verify the efficacy of CV in evaluating the synergistic effect of bioactive compounds, such as phenolic and amino acid compounds, on antioxidant activity. Therefore, three types of model solutions were prepared: individual model solution (phenol and amino acid), (b) binary model solutions (phenol-phenol and amino acid-amino acid) and (c) mixed phenol–amino acid solutions. Electrochemical measurement conditions were optimized for phenolic compounds (pH 3.0, 1.0 g/L and 100 mV/s) and for amino acids (pH 7.0, 2.0 g/L for amino acids and 100 mV/s), and, for each solution, the functional groups responsible of the anodic and cathodic peaks were established. The peak anodic potential (Epa) and the onset potential (Eon) were two parameters of great importance. The first one was used to classify the solutions according to their antioxidant potential. In general, all the binary and mixed solutions had lower values of Epa than the corresponding individual model solution, which indicates an improvement in the antioxidant potential. The second one was used to evaluate the synergistic effects of phenolic compounds and amino acids.

The availability of pure individual betalains in sufficient quantities which permit deeper understanding is still a challenge. This study investigates the high-yielding semisynthesis of betaxanthins using betalamic acid from a natural source (Opuntia dillenii), followed by condensation with ʟ-amino acids and further purification. Moreover, the color stability of the four synthesized individual betaxanthins, namely proline (ʟ-ProBX), alanine (ʟ-AlaBX), leucine (ʟ-LeuBX), and phenylalanine (ʟ-PheBX) betaxanthins, was investigated at different pHs. Their relative contribution to free radical scavenging was also scrutinized by TEAC and DPPH. ʟ-AlaBX and ʟ-LeuBx showed a significantly (p < 0.05) higher antioxidant activity, whereas ʟ-ProBX was the most resistant to the hydrolysis of betaxanthin and hence the least susceptible to color change. The color stability was strongly influenced by pH, with the color of ʟ-ProBX, ʟ-LeuBX, and ʟ-AlaBX at pH 6 being more stable, probably due to the easier hydrolysis under acid conditions. The semisynthesis and purification allowed us to have available remarkable quantities of pure individual betaxanthins of Opuntia dillenii for the first time, and to establish their color properties and antioxidant capacity. This study could be a step forward in the development of the best natural food colorant formulation, based on the betalain structure, which is of special interest in food technology.

Artisanal cheeses are part of the heritage and identity of different countries or regions. In this work, we investigated the spectral variability of a wide range of traditional Brazilian cheeses and compared the performance of different spectrometers to discriminate cheese types and predict compositional parameters. Spectra in the visible (vis) and near infrared (NIR) region were collected, using imaging (vis/NIR-HSI and NIR-HSI) and conventional (NIRS) spectrometers, and it was determined the chemical composition of seven types of cheeses produced in Brazil. Principal component analysis (PCA) showed that spectral variability in the vis/NIR spectrum is related to differences in color (yellowness index) and fat content, while in NIR there is a greater influence of productive steps and fat content. Partial least squares discriminant analysis (PLSDA) models based on spectral information showed greater accuracy than the model based on chemical composition to discriminate types of traditional Brazilian cheeses. Partial least squares (PLS) regression models based on vis/NIR-HSI, NIRS, NIR-HSI data and HSI spectroscopic data fusion (vis/NIR + NIR) demonstrated excellent performance to predict moisture content (RPD > 2.5), good ability to predict fat content (2.0 < RPD < 2.5) and can be used to discriminate between high and low protein values (∼1.5 < RPD < 2.0). The results obtained for imaging and conventional equipment are comparable and sufficiently accurate, so that both can be adapted to predict the chemical composition of the Brazilian traditional cheeses used in this study according to the needs of the industry.

Due to the importance of the authentication of the botanical and geographical origin of honey, this document is focused on the use of phenols as potential chemical markers in an attempt to distinguish and characterize one of the non-floral honey types, oak (Quercus sp.) honey, from other honeydew honeys produced in other regions. The development and validation of ultra-high-performance liquid chromatography with mass spectrometry detection enables the identification of 23 phenolic compounds in 58 Spanish oak honeydew honey samples. The proposed compounds, above all salicylic acid (mean = 24.31 mg 100 g−1), but also p-coumaric acid, p-hydroxybenzoic acid, syringic acid, naringenin, and galangin could further contribute as a helpful tool in the quality control of this non-floral honey, and therefore distinguish it from European honeydew honey and those from other regions. Furthermore, many positive correlations between phenolic compounds, CIELAB color parameters, and antioxidant activity are established. This research presents a complete phenolic composition and the largest sampling of one of the most appreciated honeydew honey varieties. This is also one of the singular studies that have successfully linked individual phenolic acids and flavonoids with physicochemical parameters within the same unifloral honey.

Recently, the search for alternative proteins endogenous to grapes to be used as wine colour protecting agents became an important research trend. In this study, the molecular interaction between the grape seed 11S globulin from winemaking by-product and malvidin-3-O-glucoside was investigated by fluorescence, differential colorimetry and molecular modelling. Fluorescence studies revealed the formation of grape seed protein- pigment complex whose KS was 8.5 × 104 M−1 and binding sites, n = 1.3. Malvidin-3-O-glucoside showed darker and more vivid bluish colour of in the presence of 11S globulin, suggesting the flavylium cation protection in a hydrophobic region of the protein. Docking analysis and molecular dynamics simulation indicated that malvidin-3-O-glucoside interacts mainly with the acidic subunit (40 kDa) of the 11S globulin monomer (60 kDa). An average of two hydrogen bonds and Van der Wall forces were the main interaction forces found for the protein-pigment complex, whose stability was confirmed by root-means-square deviation. © 2023 Elsevier Ltd

Colombian purple corn Zea mays L. by-products have been chemically characterized. To achieve this, after Amberlite XAD-7 purification and Sephadex LH-20 fractionation, the accurate anthocyanin and flavonol profile using UHPL-DAD-ESI-MS, total monomeric anthocyanin (TMA), polyphenols using Folin-Ciocalteau reduction capacity (FCRC), and antioxidant activity (DPPH and TEAC) of each fraction were performed. Cob and leaves illustrated a more complete flavonoid profile and a higher content of anthocyanins and flavonols, strongly related to the highest reducing power and radical scavenging activity compared to grains. Furthermore, the most antioxidant fractions corresponded to the higher molecular weight compounds. The cob and leaves were enriched in cyanidin-3-O-glucoside, cyanidin-3-O-malonyl-hexoside, and peonidin-3-O-glucoside, peonidin-3-O-(6′'-malonyl-glucoside). The purification and fractionation allowed us to establish the chemical and antioxidant characterization, and the resulting revalorization, of purple corn by-products for the first time, and to have available pure fractions of Zea mays L. for a wide diversity of industries.

A purification and fractionation process of the edible flowers of Tibouchina mollis and Tibouchina urvilleana followed by the first attempt to the anthocyanin and flavonol characterisation and identification by UHPLC-DAD-ESI-MS were developed. T. urvilleana exhibited a higher monomeric anthocyanin content, mainly due to the presence of the 3-O-(6′-p-coumaroyl)-glucoside derivatives of malvidin and petunidin. Quercetin-3-O-hexoside was the major flavonol identified in T. urvilleana, and the lack of myricetin derivatives was also exhibited. The anthocyanin and flavonol profile of T. mollis was more miscellaneous, characterised by the occurrence of cyanidin-3-O-glucoside followed by the 3-O-(6′-p-coumaroyl)-glucoside and 3-O-glucoside derivatives of malvidin and petunidin as anthocyanins, and myricetin, quercetin, and 3-O-hexosides of kaemperol and quercetin as flavonol compounds. Therefore, the anthocyanin and flavonol profile, through a process based on purification and fractionation, could be a useful tool to ensure the authenticity of the Tibouchina. Furthermore, the purification process made the antioxidant activity increase, which is greatly correlated to the reduction capacity.

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.

Wine color and limpidity are important aspects of consumer preferences. The alteration of these parameters can damage wine’s appearance but also its mouthfeel characteristics due to its relationship with attributes such as bitterness and astringency. Fining is a practice usually used in enology to modulate undesirable wine organoleptic attributes. However, there are several factors that influence this technique. In this study, the influence of wine pH and ethanol content on grape seed protein fining efficacy has been assessed. Wine clarification, total phenolic and flavanol contents, antioxidant activity, and chromatic parameters have been investigated before and after fining process. The most noticeable clarifying effects were observed for the experimental wines with a lower pH and ethanol content. Control of these factors will make it possible to modulate the main organoleptic properties of the wine, also avoiding the addition of large amounts of fining agents and thus providing greater versatility to wineries during winemaking. Furthermore, our findings indicated that grape seed protein is a potential alternative to other plant-based fining proteins commonly used in winemaking. Its effects on clarification and color quality have been found to be comparable to those of potato protein and significantly better than those of pea protein.

Wine industry produces annually a large amount of grape pomace by-products whose bioactive compounds are extracted and exploited for different technological purposes. In order to verify the efficiency of the extraction, the monitoring of each stage of the industrial processing of grape pomace, not previously considered, was carried out. For that purpose, samples of all stages of the extraction process (grape pomace, grape seed, washing waters, and defatted grape seed flour), from two grape varieties (Air´en and Tempranillo) were considered. Attention was focused on the content of protein, lipid, fiber, ash, polyphenols, and antioxidant activity. The data obtained showed that considerable amounts of protein (around 10%), fiber (20%–30%), and non-extracted phenols remain in the by-products of each stage of processing. Therefore, industrial extraction should be optimized to recover greater amounts of components of interest to other industries such as the food or pharmaceutical industry. Finally, the antioxidant activity of these samples was tested by DPPH and ABTS, and a positive correlation was found between phenols and antioxidant activity.

Our aim in this study was to outline phenolic and color characteristic that characterize the labeled unifloral resin spurge (Euphorbia resinifera) honey. With respect to phenolic composition, 17 phenolic compounds have been analyzed in the 29 honey samples. The proposed markers (syringic acid, ethyl gallate, m-coumaric acid and naringenin) might help to the enhancement of this honey type and thus, guarantee its commercial value. The color characterization by diffuse reflectance spectrophotometry revealed typical values of light amber honey (lightness ranged from 36 to 70 units, and chroma from 18 to 30 units). On the other hand, many correlations between the color attributes and phenolic acids, total phenolic compounds, caffeic acid, p- and m-coumaric acids and hesperidin have been demonstrated, also, correlation between phenols, color parameters and percentage of pollen of E. resinifera has been found. This study is one of the rare researches which have correlated the CIELAB color parameters with the individual phenolic acids and flavonoid compounds within the same unifloral honey.

After grape processing, large amounts of seeds are produced as a side product. Grape seeds are rich in proteins that could be extracted and revalorized by the wine industry due to their high techno-functional value for modulating quality features of red wines or as an alternative to the use of other stabilizers, which are also proteins but submitted to legal restrictions. Box–Behnken design and response surface methodology were used to optimize the protein extraction from defatted grape seed meal to maximize the protein purity of the isolate under practical operating conditions of pH, temperature, meal/water ratio and extraction time. The most significant factor was pH, both in the linear and quadratic forms. Additionally, the interaction between pH and temperature exhibited a significant effect on protein content. The removal of phenolic compounds from grapeseed meal, before optimizing protein extraction, led to a significant increase of 7.70% in the protein purity of grape seed protein concentrate. Therefore, grape seeds can be used as a sustainable way for protein production in the oenological sector due to the availability of grape seeds, their low cost as a grape-processing by-product, and the protein purity reached thanks to the described procedure for optimization of protein extraction.

Developing chemometric models from near-infrared (NIR) spectra requires the use of a representative calibration set of the entire population. Therefore, generally, the calibration procedure requires a large number of resources. For that reason, there is a great interest in identifying the most spectrally representative samples within a large population set. In this study, principal component and hierarchical clustering analyses have been compared for their ability to provide different representative calibration sets. The calibration sets generated have been used to control the technological maturity of grapes and total phenolic compounds of grape skins in red and white cultivars. Finally, the accuracy and precision of the models obtained with these calibration sets resulted from the application of the selection algorithms studied have been compared with each other and with the whole set of samples using an external validation set. Most of the standard errors of prediction (SEP) in external validation obtained from the reduced data sets were not significantly different from those obtained using the whole data set. Moreover, sample subsets resulting from hierarchical clustering analysis appear to produce slightly better results.

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 < 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 < 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.

“Persian” walnut (Juglans Regia L.) is one of the most consumed tree nuts in the world. It is rich in several bioactive compounds, with polyunsaturated and monounsaturated fatty acids (PUFA and MUFA) appearing at high concentrations. Walnut consumption protects against cardiovascular, carcinogenic, and neurological disorders. The fatty acid profile has usually been determined by gas chromatography, a reliable and robust tool, but also complex, polluting, and time consuming. In this study, near infrared hyperspectral imaging has been used for the screening of total fat, MUFA, PUFA, saturated, and individual fatty acids in walnuts. Five different walnuts varieties have been considered and modified partial least square (MPLS) regressions have been performed. The SEs of prediction (SEP) in external validation (ranged from 2.12% for PUFA to 13.08% for MUFA) suggest that hyperspectral imaging can be a reliable tool for controlling these parameters in a simple, non-destructive and environmentally friendly way

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.

During aging, most bottled white wines lose their distinctive organoleptic characteristics according to their storage conditions (closure, temperature, time). However, the effect of these factors on organoleptic characteristics of Torrontes Riojano wines (TRw) has not been studied yet. This study aimed at evaluating the combined effect of closure type and storage temperature on the organoleptic properties development of TRw over a 18-month aging period, during which wine was bottled with natural (C) and synthetic (SyC) corks, and screwcaps (SC). Bottles were kept 18 months in thermostatized chambers (15 °C; 25 °C). At different aging times, consumed oxygen (CO), SO2, total phenols (TP), color, and sensory properties were evaluated. CO, TP, and browning index evolutions depended on the interaction between closure and temperature, whereas CIELAB parameters (lightness, chroma, hue) depended on closure-time and temperature-time interactions. At both storage temperatures, SC had a lower hue decrease and a lower chroma increase than C and SyC. The highest temperature prompted a more yellow and darker color of TRw. Thus, it allowed discrimination throughout the process. Considering the aging process, their aromatic intensity, fresh fruit, and yellow and green nuances decreased, while brown hue, color intensity, linalool, and oxidized character rose as their storage time was increased. At the end of their aging, TRw kept to 15 °C were not differenced by closure, and they were characterized by their fresh fruit, floral, and high aromatic intensity attributes. At 25 °C, SyC presented higher color intensity and herbaceous characters, while C and SC showed a more oxidized character. In conclusion, the interaction closure type-storage temperature is critical for organoleptic stability properties of bottled TRw during aging. Thus, screwcaps and low-temperature storage conditions can preserve the TRw varietal characteristics, increasing their shelf-life significantly.

The post-fermentative double addition of Pedro Ximénez 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.

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. © 2020 Elsevier Ltd

Non-centrifugal cane sugar (NCS) samples obtained by traditional moulding and granulation, and also via a novel spray-drying powdering process without additives, were assessed to characterise their sugar and phenolic profiles, flavonoid content, as well as colour parameters. As expected, sucrose was the predominant sugar (91.9–95.5%), followed by glucose (2.9–4.6%), and fructose (1.6–3.7%). Total phenolic content was between 0.4 and 0.6% and total flavonoid content into the range of 0.2–0.4%. Six phenolic acids were found in all NCS samples: protocatechuic acid (0.36–0.94 µg/100 g), vanillic acid (0.70–1.45 µg/100 g), chlorogenic acid (2.08–3.82 µg/100 g), syringic acid (1.08–2.80 µg/100 g), p-coumaric acid (0.69–1.35 µg/100 g), and ferulic acid (0.50–0.95 µg/100 g). The thermal treatment under high temperatures required in the production of granulated products was related with darker colours and changes in phenol and flavonoid contents. In contrast, spray drying generates clearer products, but with slightly less phenol and flavonoid contents.

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.

The influence of post fermentative addition of American barrel-shoot wastes on phenolic composition and chromatic quality of Syrah red wines has been evaluated as an environmentally sustainable alternative to the conventional winemaking for avoiding the common color loss of red wines elaborated in warm climates. American oak wood byproducts added were previously classified by hyperspectral image analysis according to the amount of phenolic compounds transferred to the extraction media. After that, wines were elaborated under different maceration conditions by applying only one proportion of wood (12 g L−1) and two different maceration procedures (simple and double addition) and were compared with a traditionally macerated Syrah red wine (CW, no wood addition). Results proved the effectiveness of the moderate postfermentative addition of oak wood byproducts to stabilize the color of wines and to provoke lower color modification along the time, producing color wines chromatically more stable for a better aging. In the case of double addition, the adsorption of the pigments during the maceration presents a stronger effect on the color than copigmentation and polymerization by cause of the copigments extracted from the wood

Extraction solvent is a very important factor in the recovery of antioxidants from natural matrices. In this study, the effect of three solvents (ethanol, ethanol/water and water) on the phenolic composition, antioxidant and anti-cholinesterase activities and electrochemical behaviour of four winemaking byproducts (seeds, skins, stems, and pomace) was evaluated. Phenolic composition was determined by the Folin–Ciocalteu method and ultra-high-performance liquid chromatography (UHPLC), antioxidant activity by the capacity to scavenge 2,2-diphenyl-1-picrylhydrazyl and hydroxyl radicals, anti-cholinesterase activity by the Ellman’s method, and electrochemical behaviour by cyclic voltammetry. Eight phenolic compounds were quantified with higher content in water/ethanol extracts (e.g., epicatechin in pomace: 17 mg/100 g vs. 7 and 6 mg/100 g in ethanol and water extracts, respectively), although there were some exceptions (e.g., gallic acid in seeds was most abundant in water extracts). Moreover, the highest total phenolic content (TPC) and antioxidant activity were found in ethanol/water extracts (between 2 and 30-fold the values of the other extracts). Overall, the most active extracts in inhibiting both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes were ethanol/water and ethanol extracts from seeds (between 31.11 and 53.90%). The electrochemical behaviour allowed for differentiating the extracts depending on the solvent and the byproduct. Our findings indicate that winemaking byproducts represent a source of phenolic compounds with antioxidant and anti-cholinesterase activities and suggest that cyclic voltammetry is a promising technique to evaluate the phenolic extraction process from these byproducts.

El color es una característica sensorial que es posible describir con parámetros físicos cuantificables, mediante la Colorimetría Triestímulo, que adjudica un valor numérico al color de un estímulo visual. Este valor del color se obtiene mediante tres coordenadas en que definen un espacio tridimensional (Triestímulo), en el que cada estímulo de color viene representado por un vector, con expresión de las cantidades proporcionales de cada uno de los estímulos primarios rojo (R), verde (G) y azul (B). La dificultad en el cálculo y, sobre todo, en la interpretación de diferencias del color en este espacio RGB, condujo a que la Comisión Internacional de la Iluminación (CIE) definiera otros espacios considerados uniformes, como es el caso del espacio de color CIELAB, en 1964. Obviamente, existe una correlación entre los datos RGB y datos CIELAB. Desde 1976, la CIE publicó la fórmula para cuantificar la diferencia de color percibida basada en el espacio de color CIELAB. Existen distintos espacios de color propuestos por la CIE así como diferentes fórmulas para el cálculo de la diferencia de color percibida, aunque CIELAB es el más utilizado. La percepción del color y de la diferencia de color, dependen de múltiples factores, que se pueden medir con distintas fórmulas propuestas por la CIE. Existen escasos estudios relacionados con umbrales de percepción de diferencia de color, y sería muy interesante estandarizar las condiciones (iluminación, ángulo y distancia de observación, región del visible evaluado, capacidad de discriminación y visión del color del observador...) en las que se realiza el experimento.

New antioxidant films based on ethylene vinyl alcohol (EVOH) copolymer containing betalain-rich red beet were successfully manufactured and characterized to develop bioactive packaging for food products. Two types of red beet (powder and extract) at different proportions (0.1, 0.5, 1.0, 1.5, 2.0 and 2.5 % (w/w)) were incorporated into EVOH films, with attention focused on the optical, chemical, thermal, structural, and mechanical and antioxidant properties. The incorporation of any red beet type into EVOH resulted in purple-colored and semi-crystalline thin films, without modifying their thermal stability and mechanical properties. The addition of the beet extract led to a film with higher color intensity, antioxidant activity and lower water loss rate, whereas the addition of powdered beet resulted in an improved UV barrier compared to the extract. The results showed that new antioxidant food packaging films based on EVOH could be realized by utilizing beetroot extract or powder obtained from natural resources.

Walnut fruit (Juglans regia L.) is an internationally well-known product with an important tradition of consumption. Its health benefits and economic importance in the food industry make this nut an interesting research topic. In this feasibility study, 200 walnut samples of 5 different varieties were collected and their near infrared (NIR) spectra were recorded with 3 different devices: a benchtop Fourier transform near infrared (FT-NIR) spectrograph, a dispersive hyperspectral imaging camera and a portable NIR dispersive spectrograph. Discriminant analyses were applied and different methods for the varietal discrimination of walnuts were obtained and compared. Up to 96 and 84% of correct identification were respectively obtained in internal (training set) and external validations. Better results were obtained covering the entire shell surface than collecting a unique random spectrum per sample. Moreover, FT-NIR and hyperspectral tools produced classification models with a lower classification error in internal and external validations than the portable NIR one.

Bee pollen is a natural matrix widely studied in its nutritional and bioactive compounds, including carotenoids. That composition is usually identified by Rapid Resolution Liquid Chromatography (RRLC) coupled to UV–Vis spectrophotometry, an expensive method that requires complex sample preparation and long analysis time. In this work, a correlation between colorimetric coordinates and carotenoid composition was evaluated. Through Digital Image Analysis (DIA) by DigiEye, the color characteristics were determined, and carotenoids profile was done by RRLC. The correlations were made by multiple linear regression (MLR). From 12 carotenoids found in the samples, six had a coefficient R2 > 0.75 between reference and predict value. Heterogeneous mixtures of bee pollen samples were analyzed, and the suitability of the mathematical models could be corroborated because the relative error for most of the compounds was less than 20%. It has been demonstrated that union of Tristimulus Colorimetry and Image Analysis represent an effective tool to estimate the chemical composition in food industry.

Overripe seeds are wine by-products from grapes submitted to postharvest sun drying, which induce phenolic biosynthesis and polymerisation. Overripe seeds from Pedro Ximénez (PX) and Moscatel (MO) sun-dried grapes were compared as copigments sources to modulate grape anthocyanin (GA) colour and stability in simulated wine conditions. RRLC/MS analysis proved that overripe seeds contain specific phenolic mixtures capable of inducing positive quantitative and qualitative colour changes in GAs, evidenced by differential colorimetry. Copigmentation effects significantly varied depending on the overripe seed variety, related to their qualitative phenolic composition and content. MO extracts richer in gallic acid, catechin and procyanidin B1 led to the stronger colour intensification and perceptible qualitative changes. PX extracts richer in epicatechin, procyanidins B2, B2-GAL and B7 behaved as weak copigments. Overripe seed copigments preserved better GAs colour stability during storage leading to the formation of new anthocyanin-derived pigments, being the stabilising effect stronger with those of MO variety.

Control of coffee quality has a great importance for being one of the most important raw materials within the international trade. The extractable composition of coffee has been studied in recent decades and the use of non-destructive methodologies is being continuously promoted. In this study, near infrared hyperspectral imaging has been applied to develop non-destructive methods for the control of extractable contents of caffeine, chlorogenic acid, total phenolics and melanoidins in coffee beans. Extractable contents and trends obtained among the different coffee types analysed are similar to those obtained previously in other studies. Moreover, modified partial least square (MPLS) regressions produced prediction models with standard errors of prediction in external validation of 12.01%, 15.61% and 17.61% for caffeine, chlorogenic acid and total phenolics, respectively. Therefore, results obtained for these three parameters indicate that NIR spectroscopy has a great potential for their control in coffee beans.

Por su gran impacto medioambiental, la gestión y reutilización de residuos agrícolas es uno de los grandes retos de la sociedad actual. En el caso de la vid, uno de los cultivos más extendidos, se producen millones de toneladas de residuos cada año y la industria enológica está en permanente búsqueda de vías de aprovechamiento de los subproductos ya que, además, son residuos ricos en compuestos fenólicos de interés bioactivo. En Andalucía se elaboran vinos generosos, de alta graduación alcohólica, procedentes de uvas blancas sometidas a concentración de azúcares por exposición directa al sol en paseras, lo que conduce a características fisicoquímicas y sensoriales especiales, tanto en las uvas como en los vinos obtenidos, y cuya elaboración genera un gran volumen de orujos. Más recientemente, adaptándose a las tendencias del mercado, las bodegas de esta región de clima cálido comenzaron a elaborar vinos tintos, lo que supuso un gran reto por las altas temperaturas que se alcanzan, agravadas por los efectos del cambio climático. Se dificulta la correcta maduración de la uva tinta y se produce un desfase entre las maduraciones tecnológica (azúcares/ácidos) y fenólica, lo que pone en riesgo la obtención de vinos tintos de calidad sensorial, en especial gustativa (astringencia) y visual (intensidad y estabilidad del color). Es conocido que los vinos tintos de clima cálido frecuentemente son desequilibrados, de color inestable y, por lo tanto, poco aceptados por el consumidor. El principal objetivo de esta Memoria es integrar ambas circunstancias, por un lado, el aprovechamiento de las semillas sobremaduras procedentes de la elaboración de vinos generosos y, por otro, la mejora del color de vinos tintos de clima cálido. Se plantea establecer el valor de las semillas sobremaduras como fuente de fenoles, optimizando su aplicación en la vinificación en tinto (momento, tiempo, dosis), y evaluar su efecto en la calidad y estabilización del color a través del fenómeno de copig, Due to the environmental impact, the management and reuse of agricultural waste is one of the great challenges of today's society. In the case of vine, one of the most widespread crops, millions of tons of waste are produced each year and the oenological industry is constantly searching for ways to take advantage of byproducts since, in addition, they are rich in phenolic compounds, having bioactive interest. In Andalusia, generous wines of high alcohol content are produced from white grapes subjected to concentration of sugars by direct exposure to the sun in paseras, which leads to special physicochemical and sensory characteristics, both in the grapes and in the wines obtained, and whose elaboration generates a large volume of residues. More recently, adapting to the market trends, the wineries of this warm climate region began to elaborate red wines. This was a great challenge due to the high temperatures that are reached, aggravated by the effects of the climate change. The ripening of the red grape is inadequate being a gap between the technological (sugar/acid) and the phenolic maturation, which puts at risk the obtaining high-sensory quality red wines, mainly taste (astringency) and visual quality (intensity and color stability). Thus, it is known that warm-climate red wines are frequently unbalanced, unstable in color and, therefore, little accepted by the consumer. The main objective of this Thesis is to integrate both circumstances, on the one hand, the use of overripe seeds originated in the production of generous wines and, on the other hand, the improvement of the color of warm-climate red wines. Thus, the goal is to valorize the overripe seeds as a source of phenols, optimizing their application in red wine (moment, time, dose), and evaluate the effect on the quality and stabilization of color through the copigmentation phenomenon. By means of high efficiency liquid chromatography, the phenolic profile of seeds of three white grapes varieties commonly

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.

Cooperage byproducts are an important source of phenolic compounds that could be used for wine technology applications. The effects of the addition of two types of oak wood shavings (American, AOW, and Ukrainian, UOW) on the antioxidant activity and color of red wine anthocyanins, in a wine model solution, were evaluated by spectrophotometric and colorimetric analyses. Phenolic compounds from shavings, mainly ellagitannins, were determined by ultra-high-performance liquid chromatography/mass spectrometry (UHPLC/MS). Antioxidant and copigmentation effects varied depending on the type of shavings (AOW and UOW) and the phenolic concentration (100, 400, and 500 mg/L). Phenolic compounds from shavings improved the color characteristics (darker and more bluish color) and the copigmentation effect of red wine anthocyanins, being UOW a better source of copigments than AOW shavings. The best antioxidant activity was found for the 400 and 500 mg/L model solutions for both types of shavings. Results show a winemaking technological application based on the repurposing of cooperage byproducts, which could improve color and antioxidant characteristics of red wines.

Las características de la uva en el momento de la vendimia condicionan en gran medida la calidad del vino elaborado a partir de ellas. En regiones de clima cálido, las altas temperaturas ambientales, acentuadas en las últimas décadas por los efectos del cambio climático, originan un desfase entre la madurez tecnológica de la uva, cada vez más temprana y la madurez fenólica, cada vez más tardía, que desencadena, entre otros, problemas de estabilidad cromática en el envejecimiento. Ante esta situación se pone de manifiesto la necesidad de implementar medidas de adaptación que permitan preservar la calidad de estos vinos. En este sentido, el aprovechamiento de subproductos de la industria vitivinícola ricos en compuestos fenólicos,como pueden ser las virutas de madera cruda de las tonelerías,añadidas en etapas iniciales de la vinificación, se presenta como una estrategia enológica, nueva y sostenible, para paliar los efectos del cambio climático en la calidad de los vinos tintos.Los compuestos fenólicos de la madera, que pasarán al vino durante el proceso de maceración, junto con los compuestos fenólicos procedentes de la uva, determinarán la composición fenólica del vino y condicionarán sus características cromáticas y organolépticas. Tradicionalmente,la composición fenólica, y la facilidad de cesión de estos compuestos al vino desde diferentes matrices, se ha controlado por métodos de análisis fisicoquímicos que,en muchos casos, resultan complejos y tediosos. En las últimas décadas se han desarrollado técnicas espectroscópicas que permiten estimar de forma rápida, no destructiva y respetuosa con el medio ambiente,distintos parámetros de interés enológico. En este trabajo, inicialmente se ha evaluado el efecto que tiene la adición de chips de madera en la extracción de compuestos antociánicos del hollejo de uva tinta clasificada hiperespectralmente como uva con baja capacidadde cesión de dichos compuestos.Se ha comprobadoque la adición de copigmentos provenientes de l

Procedimiento para obtener un hidrolizado enzimático a partir de semillas sobremaduras de uva y uso del mismo. La presente invención se refiere a un procedimiento basado en la hidrólisis enzimática en medio básico de la fracción proteica de semillas de uva sobremaduras para la obtención un hidrolizado enzimático natural de peso molecular variable. La presente invención también se refiere al hidrolizado enzimático obtenido por dicho procedimiento y al uso del mismo como estabilizante del color en vinos tintos.

There is substantial variation in levels of extractable phenolic compounds of red grapes (Vitis vinifera L.). Therefore, it could be desirable to known the aforesaid parameter at least for each vine. Nowadays, interest has shifted toward the development of portable vis/NIR systems, innovation in optical system design and miniaturization for its friendly use directly in the field. Spectra of intact grapes and grapes skins were recorded at harvest time in two different vintages (2016 and 2017 respectively) using a portable micro NIR spectrophotometer (908–1676 nm). A number of chemometric approaches have been used for spectral interrogation and evaluation of the aforesaid device. Spectral data have been correlated with red grape skin extractable polyphenols (total phenolic, anthocyanins and flavanols) by modified partial least squares regression (MPLS) using a number of spectral pretreatments. Moreover, different statistics strategies have been performed to develop a qualitative analysis of the data (linear discriminant analysis, discriminant partial least square analyses and Pearson's similarity index). After an exhaustive analysis of the obtained results in two different seasons, it can be concluded that the use of the portable micro NIR device for the “in vineyard” screening of extractable polyphenols in red grape skins is hampered by a number of factors. Environmental and physiological conditions should be considered to evaluate and remove factors that hamper a good sorting the berries according to their extractable polyphenol contents.

Wood is an important source of phenolic compounds, which can be transferred to wine during aging process, improving its properties, from an organoleptic point of view. Therefore, understanding and optimizing the extractability of phenolic compounds from wood are crucial in the oenological field. The structural composition of oak wood samples has been evaluated using Raman and attenuated total reflectance Fourier transform infrared (ATR–FTIR) spectroscopies, and their main spectral features have been linked to phenolic compound extractabilities, as measured by classic chemical analyses. To support the analysis, microscopic images of the samples were also recorded using scanning electron microscopy (SEM). The applied methodology is shown to be useful to relate the wood cell wall structure to phenolic extractability levels of wood samples. It could assist in selecting oak wood suited for improving wine quality with regard to its color or/and stability through the addiction of external copigments to wine.

Malbec is the flagship variety of Argentina mainly due to its high oenological value and plasticity to obtain different wine styles. During bottled aging, the chemical and organoleptic composition of wines is subject to changes depending on the aging conditions (closure, oxygen level, temperature, time). However, the combined effect of these factors on chemical composition and organoleptic characteristics of Malbec wines has not been studied yet. Wines were bottled with screw cap and natural cork and were kept in chambers at 15 °C and 25 °C for 2 years. Sampling was performed at 2, 4, 6, 9, 12, 15, 18, 21 and 24 months. Concentrations of free sulfur dioxide, dissolved oxygen, anthocyanins, tannins, esters, volatile phenols, organic acids, and color saturation decreased during the storage process. While, the formation of polymeric pigments, the color attributes (lightness and hue) and the levels of alcohols, norisoprenoids, furanoids and terpenoids increased. At 24 months, Malbec wines were organoleptically different. Wines kept at 15 °C were associated with high sensory perceptions in color intensity and violet tint, those presented a positive correlation with free sulfur dioxide, tannins, and anthocyanins levels. On the contrary, wines aged at 25 °C were linked with high sensory perceptions of dried vegetative and dried fruit aromas. These descriptors were positively correlated with norisoprenoids, furanoids, and terpenoids. In general, the chemical composition and organoleptic attributes of bottled Malbec wines (Mendoza, Argentina) were stable respect closure type employed, but highly sensitive to the combined effect of time and storage temperature. This finding is key to making decisions about the wine style searched, and costs (e.g. refrigeration) involved in the conservation period until consumption.

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. © 2018 Elsevier Ltd

This work analyzed the use of electrocoagulation as substitute for sugarcane clarification process using sulfitation. It was evaluated technological parameters (Icumsa color and turbidity), phenolic compounds content and CIELAB color parameters. Four kinetics of reduction color from sugarcane juice were carried out. The essays were divided according to the voltage applied: 35, 45, 55 and 65 V (also based on previous tests). Higher voltage treatments achieved greater reduction of Icumsa color, turbidity and total phenolic compounds. However, none of treatments impacted simple phenolic content analyzed in this work. Tristimulus analysis presented some pattern that went beyond technological analysis, including that 65 V essay changed the pigmentation of sugarcane juice and had an early stabilization on chroma. This kind of results could be useful for industry, once they could correlate quality with different color parameters and finally improve the clarification in general with finer settings of technique according to different situations.

Anthocyanins are phenolic compounds with important technological applications due to its bioactive and color properties. In this study, pomaces from four red berries (blueberries, red raspberries, red currants and blackberries) have been analyzed as sources of anthocyanins. Anthocyanins were determined by high-performance liquid chromatography/mass spectrometry, total phenolic content (TPC) by Folin–Ciocalteu method, antioxidant activity by ABTS assay, and color by tristimulus colorimetry. A total of 15 anthocyanins were identified and quantified in the different pomaces from red berries. Pomaces exhibited different qualitative and quantitative anthocyanin profile and antioxidant activity, depending on type of red berry. The highest amounts of anthocyanins were found in blueberries (1188 mg/100 g); however, red currant pomaces exhibited the highest TPC (3447 mg/100 g) and AA (61 mmol/100 g). Color of extracts was different depending on individual and total content of anthocyanins. Results indicate that these berry pomaces are a natural source of antioxidants and pigments, and they may be useful for industrial purposes. Therefore, the exploitation of these pomaces, such as possible byproducts for their reuse in the food, cosmetics, and drug industries, could be of great interest, considering either the whole pomaces or its individual components.

Determining phenolic compounds of wood and its extractability to the hydroalcoholic medium is important in the oenological industry. The method proposed in this study copes with this issue in an in situ, non-destructive, and fast way. For this purpose, a number of oak by-product samples spectrally representative have been selected. Selected spectral data have been correlated with oak wood extractable polyphenols (extractable total phenolic content and extractable ellagitannin content) by modified partial least squares regression (MPLS) obtaining coefficients of determination (RSQ) greater than 0.9 and standard errors of prediction (SEP) between 13.68 and 23.51% for all parameters evaluated. The obtained results are comparable with those obtained using bench-top devices and present the advantage of its eventual friendly use out of lab. Development of applicable models in situ will allow a greater versatility and efficiency for the decision-making in the winemaking process on the adequacy and/or dosage of these by-products according to the requirements of the wine. The use of cooperage by-products as the source of copigments for wine leads to a sustainable and competitive cooperage industry, through waste reduction and by-product valorization.