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Mandarine juice is one of the richest sources of β-cryptoxanthin and flavonoids, which have been positively associated with bone mineral density.

Mandarine juice is one of the richest sources of β-cryptoxanthin and flavonoids, which have been positively associated with bone mineral density. Carotenoids are lipophilic isoprenoid compounds with a complex absorption process that can be affected by different factors. In this study, we have evaluated the effect of the food matrix on the

Production of high-quality healthy foods through sustainable methodologies is an urgent necessity. High pressure homogenization (HPH) is an interesting alternative to obtain premium citrus juices, but its effects on bioactive compounds are unclear. There was studied the influence of HPH (150 MPa) and pasteurization (92 °C for 30 s and 85 °C for 15 s) processing on physicochemical properties and in vitro bioaccessibility of carotenoids and flavonoids in orange juices. Regarding fresh juice, physicochemical properties of samples remained unchanged although cloudiness was improved by homogenization. Pasteurization did not affect total carotenoids content and retinol activity equivalents (RAE) of juices whereas homogenization yielded a significant reduction (1.37 and 1.35-fold, respectively). Interestingly, particle size reduction from homogenization drastically enhanced (about 5-fold) bioaccessibility of carotenoids including hardly bioaccessible epoxycarotenoids, finding unaltered rates in pasteurized samples. Bioaccessibility of flavonoids was constant in all cases.Results can promote HPH as an efficient option to obtain health-enhanced foods., Authors thank funding from the Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía (projects CAROTINCO-P12-AGR-1287 and P11-AGR-7783). Project RTA2014-00034-C04 from the Spanish Instituto Nacional de Investigación y Tecnología Agraria supported contract of E. Sentandreu.

An analytical method was validated for the quantitative determination of isoprenoids compounds in faecal samples, based on liquid-liquid extraction from a small aliquot (0.3-0.5 g of sample) and subsequent analysis by Rapid Resolution Liquid Chromatography (RRLC) on a C30 column. An excellent linear response was observed over the range specified for all dietary isoprenoids, as confirmed by the correlation coefficient, which ranged from 0.9977 to 0.9999. LODs ranged from 0.002 μg to 0.036 μg for lutein and α-tocopherol, respectively. Depending on the compound, LOQs ranged from 0.001 μg (lutein) to 0.120 μg (α-tocopherol). For accuracy testing, spiking of faeces samples with trans-β-apo-8′-carotenal, α-tocopherol and chlorophyll a were performed (three concentration levels). Excellent recoveries were obtained in all levels (>90%). The intra-day RSD% ranged from 0.86 to 9.78%. The inter-day RSD% was not higher than 10%, except to α-tocopherol (11.34%). In order to assess the applicability of the method faecal samples from a baby fed with different purees formulated from various vegetables were analysed during a six month period. α-carotene, β-carotene, capsanthin, lycopene, lutein, phytoene, phytofluene, violaxanthin, zeaxanthin and ζ-carotene), and their isomers were identified and quantified using this method. Besides, 2 tocopherols and 9 chlorophylls and derivatives were identified and quantified in the faecal samples analysed. This method is suitable to determine dietary isoprenoids from complex matrices such as human faeces within 28 min.

High-pressure technologies are among those with increased interest in the sustainable production of quality-enhanced food products. In this work, Ortanique mandarin juices have been submitted to traditional pasteurization conditions (time/temperature of 65 °C/15 s, 85 °C/15 s and 92 °C/30 s) and energy-saving high-pressure homogenization (HPH, 150 MPa) treatments to compare the effects on the physicochemical composition and in vitro bioaccessibility of carotenoids and flavonoids. In general, physicochemical attributes of the homogenized sample were similar to those found in fresh juice, with similar ascorbic acid content and cloudiness but with significant colour differences in all cases. The bioaccessibility of total carotenoids was similar in fresh and pasteurized juices in contrast to the HPH sample that exhibited a five-fold increase, which suggests a positive effect of particle size reduction to favour the action of digestive enzymes. A clear increase in the levels of epoxycarotenoids was detected in the micellar fractions of digested HPH juices, although such carotenoids are not detected in human fluids or tissues. Regarding the bioaccessibility of flavonoids, no significant differences were found in the samples studied. Results obtained can help the implementation of HPH processing to obtain natural beverages with enhanced nutritional properties., This research was partially supported by the Andalusian Council of Economy, Innovation, Science and Employment through the projects P11-AGR-7783 and CAROTINCO-P12-AGR-1287. The Spanish Instituto Nacional de Investigación y Tecnología Agraria (INIA project RTA2014-00034-C04) supported the contract of E. Sentandreu.

Carotenoids, color and in vitro antioxidant capacity were analyzed in twenty-two genotypes of oranges produced in Spain in two consecutive seasons. The colorless carotenoids phytoene and phytofluene were also analyzed. An important influence of the genotype on the carotenoid profile was observed. In most genotypes, such profile was characterized by the predominance of xanthophylls (82.7-93.0%), except in Cara Cara, with a higher proportion of carotenes (around 70.0%). β-cryptoxanthin was the predominant carotenoid in Rohde late and Ambersweet. The samples with the lowest carotenoid contents were the ones exhibiting the lowest Trolox Equivalent Antioxidant Capacity (TEAC) and vice versa. A formula obtained by multiple regression is proposed to estimate the TEAC value from the carotenoid content. No significant correlation between TEAC values and color coordinates were obtained, suggesting that color parameters are not good predictors of TEAC values. Lastly, the samples could be classify with a high rate of success (>90%) by Linear Discriminant Analysis based on color and carotenoids.

Carotenoids are widespread isoprenoids that intervene in actions ranging from the collection of light and photoprotection to the regulation of gene expression and communication within or between species, to mention only some examples. They are, therefore, much more than natural pigments, as they are versatile compounds that are eliciting increasing interest in different disciplines, such as plant science, agriculture, food science and technology, nutrition and health, among others. Although carotenoids in humans are found almost exclusively free, in foods they can be associated with other molecules, like sugars, proteins or fatty acids. Such associations can result in substantial changes in their properties. Indeed, food xanthophylls are commonly found in the form of esters, above all in many fruits. This modification markedly influences properties such as solubility and susceptibility to oxidation, which in turn can have impacts on relevant aspects that explain their levels in foods and humans, such as their biosynthesis, deposition, stability and bioavailability, among others. The study of the esterification of carotenoids is undoubtedly gaining popularity. In this chapter, nomenclature and structural aspects related to isoprenoids, carotenoids, fatty acids and, finally, carotenoid esters are presented, with references to some physical–chemical properties and their importance at different levels.

Twenty-two commercial milk-fruit juice beverages (MFJBs) were analysed by high performance liquid chromatography with diode array detector for carotenoids, retinol and α-tocopherol content. Bioaccessibility was also investigated by in vitro enzymatic digestion. Total carotenoids content and vitamin A calculated as retinol plus pro-vitamin A carotenoids varied widely among samples as well as the bioaccessibility, depending on the formulations. The predominant carotenoid present in all the samples was β-carotene, followed by α-carotene, β-cryptoxanthin and zeaxanthin, which were not detected in all the samples. One daily consumption of MFJB (200 mL) provides on average from 5% to 11% of the Recommended Dietary Allowance (RDA) for vitamin A, depending on the age group and a slightly higher value for α-tocopherol. The bioaccessibility of bioactive carotenoids in increasing order was the following: β-carotene

Carotenoids are widespread isoprenoid secondary metabolites. They and their metabolites are thought to provide diverse health benefits. In any case, their relevance from a nutritional standpoint is unarguable, as some of them can be converted into vitamin A in animals. Animals cannot synthesize carotenoids de novo and rely on the diet as a source. Species-specific differences in the absorption and metabolism of these compounds are known to exist among livestock species. The diet is another key factor affecting the carotenoid content in biological fluids (such as plasma and milk) and tissues. The study of carotenoids in animals is also important in the context of the increasing interest of consumers in the authentication of animal diets, as they can be used as markers of pasture-fed animals. In this paper, the authors review the current knowledge on the effect of the diet on the carotenoid levels of domesticated animals and the differences in the metabolism of these compounds into vitamin A among species.

The effect of different diets on the content of carotenoids, fat-soluble vitamins (retinol and tocopherol) and color measurements in sheep tissues was assessed, to study the possible links with the livestock production system for both nutrition and traceability. Three groups of animals were considered: 15 lambs fed on pasture (G1), 15 lambs fed on concentrate (G2) and 15 suckling lambs (G3) whose mothers were grass-fed. Lutein and β-carotene appeared only in plasma from grazing lambs, so they appear useful to differentiate lambs fed on pasture. Furthermore, retinol and α-tocopherol content in fat were significantly higher ( p

Retinol and fat colour parameters in Iberian pigs fed on different carotenoid-containing diets were assessed. Thirty animals in two groups were considered: Iberian breed pigs fed on acorns and grass (Montanera) and on concentrate (Cebo). Carotenoids and retinoids were analysed in the diets and in plasma, liver and perirenal fat of the animals by HPLC and HPLC-MS. Retinol levels in plasma and fat were similar in Montanera and Cebo animals. The utility of retonids and colour parameters as traceability index was also explored. Retinoids in liver classified correctly 93% of the animals according to their diet L* and hab. CIELAB parameters of the perirenal fat discriminated correctly 78.6% of the animals according to their diet. L* values for the Montanera animals were significantly different (P0.01) from those fed on concentrate. It can be claimed that the liver retinol profile and fat colour parameters can be useful for feeding traceability purposes in Iberian pigs breed in Montanera and Cebo.

This study was aimed at training a panel of assessors to evaluate specifically orange juice colour, and to establish the colour difference threshold in orange juice for a trained and untrained panel. Panellists were first preselected using Farnsworth–Munsell 100-Hue Test and then trained with a specific method for orange juice colour. This training allowed assessors to evaluate visually orange juice samples in hue and intensity. The final selection of assessors was a panel of 8 trained observers with reproducibility and repeatability, and a significant discrimination among the samples (p On the other hand, commercial orange juices were evaluated both instrumentally by image analysis and visually by the trained panel, and the untrained panel. Instrumental colour measurements and visual evaluation were correlated. Values around 1.5 and 2.8 CIELAB units could be consider the threshold for colour differences between two orange juices for the trained and untrained panel, respectively.

Ultrafrozen orange juices are produced to preserve the nutritional and sensory quality of the fresh juices. However the effects of the thawing conditions on the nutritional quality have been scarcely studied. To gain insight into this subject we have assessed the impact of different thawing conditions (microwave, room and refrigeration temperature) on the carotenoids levels and bioaccessibility in ultrafrozen orange juices. Other related properties, such as colour, and antioxidant activity were also evaluated. The results demonstrated that the bioactive carotenoid content and the antioxidant activity were significantly affected by the microwave thawing. These juices showed the highest values for the % of relative bioaccessibility of provitamin A carotenoids, when compared to the other thawing conditions. On the other hand, thawing at room or refrigeration temperatures did not have a negative impact neither on the colour, provitamin A and macular carotenoid compounds nor in the antioxidant activity.

Summary This study was aimed to analyse the impact of the debittering process (DP) in the overall sensory properties of orange juice (OJ) (Citrus sinensis L. Var. Salustiana). The fresh industrial squeezed orange juice (FOJ) and the corresponding OJ after the DP (DOJ) were taken. No significant differences were found in acidity, pH and total soluble solids. Colour was evaluated by image analysis (DigiEye System). Hue and lightness were lower (more reddish and darker) after debittering (P

The impact of an industrial debittering process (DP) on nutritional and bioactive compounds in orange juice (OJ) was studied. The DP was aimed at removing bitter components in OJ by physical adsorption in a resin. The levels of bioactive compounds (carotenoids, ascorbic acid and phenolics), total antioxidant activity and the colour in the fresh orange juices (non-debittered) and in the debittered counterparts were measured. The results demonstrated that the carotenoid contents were not significantly affected by the treatment. However, the debittered orange juices showed a reduction (p

This study assesses the effect of background, surrounding, thickness and dilutions on the colour specifications of orange juice (OJ) analyzed by digital image and visual evaluation. A commercial OJ was diluted with distilled water to give ten levels of concentration (100, 90, 80, 70, 60, 50, 40, 30, 20 and 10 % of juice). These samples were evaluated instrumentally by digital image analysis using nine combinations of surroundings and backgrounds (black, grey and white) and three different thicknesses. Visual evaluation was also carried out on black, grey and white backgrounds. A grey surrounding, a white background and a fixed thickness are suggested to be used in future measurements of OJ colour by digital image analysis. Results of visual evaluation indicated that panellists were able to order correctly the OJ samples according to the dilution level, independently of the background chosen. The correlations between the instrumental and the visual analysis were significant (p

Tomatoes ( Solanum lycopersicum L .) are food staples that contain high levels of lycopene (LYC), a red carotenoid thought to provide health benefits. Previous studies indicate that instrumental color measurements can be harnessed to estimate carotenoid levels in a rapid and non-destructive fashion, which offers important analytical advantages. In this investigation we have assessed the different LYC isomer contents by HPLC and the color of diverse tomato genotypes and tomato derived-products by SPR and DIA with four main purposes: 1) to compare the levels of LYC isomers in processed vs fresh tomato products, 2) to evaluate the validity of DIA and SPR to ascertain the color of these products, 3) to compare the ability of both instrumental methodologies to discriminate between the two different groups of samples, and 4) to compare the utility of both methodologies for estimating LYC levels. The results indicated that the parameters obtained by SPR and DIA were significantly correlated ( p

This study was aimed at assessing the differences between industrially processed and hand-squeezed orange juices (OJs) in relation to their color, particle size, carotenoid content, and carotenoid bioaccessibility. Specifically, industrial samples of fresh squeezed OJs after the finishing steps (FISO) and the same OJs after pasteurization (PISO), as well as hand-squeezed OJs (HSO) were studied. The results showed that the HSO and PISO were different (p0.05) in terms of color (darker and more reddish vs brighter, more yellowish and colorful), particle size (volume and surface area mean diameter), and total carotenoid content (29 ± 5 and 22 ± 3 mg/L, respectively). On the other hand, the industrial extraction of OJs reduced the particle size distribution, and accordingly, the relative bioaccessibility of bioactive carotenoids increased (p0.01). Independently of the type of OJ, the bioaccessibility of carotenoids in decreasing order was the following: α-caroteneβ-cryptoxanthinβ-carotenezeaxanthinlutein.

This study was aimed at (1) finding out correlations between the instrumental and the sensory evaluation of color attributes (lightness, chroma and hue) in orange juices (OJs) and (2) evaluating consumer preferences on OJs color. Fresh hand squeezed OJs from five varieties of oranges were evaluated by image analysis (DigiEye System, VeriVide Ltd., Leicester, UK) and spectroradiometer. Eighteen trained panelists classified the OJs in increasing order of hue (yellowish–reddish), chroma (dull–vivid) and lightness (clear–dark) and scored the colorimetric parameters on a continuous scale of 10 cm, anchored at the ends. Hue and lightness were well correlated with the instrumental measurement but not chroma. One hundred eleven consumers were asked to order the five OJs according to their color liking. A significant preference (P

The color of orange juice influences consumers’ choice, hence much importance has been given to the assessment of this attribute for decades. The instrumental measurement of orange juice color can be harnessed for the rapid, quality-control oriented estimation of its carotenoids, which are health-promoting compounds. In this work we compared and analyzed different spectroscopic data that can be used for these purposes, like the reflectance spectra of orange juices and the absorption spectra of their carotenoid extracts. Additionally, we have revisited the Kubelka–Munk theory and have concluded that its parameters are suitable to assess the carotenoid content of the samples, but not as much as the CIELAB color coordinates. In this regard, we have observed that K / S is the Kubelka–Munk parameter best correlated with the carotenoid content of the orange juices surveyed ( r = −0.84), although better correlations were observed when the CIELAB coordinate a * was considered ( r = 0.86 and 0.88 for measurements with white and black background, respectively). However, in our opinion, this fact should not lead to dismissing the usefulness of the Kubelka–Munk theory to estimate carotenoid contents, since its application can lead to obtaining valuable information about the absorption and scattering properties of the samples.

This study was conducted to gain insight into the influence of the chemical structure of carotenoids in the colour of orange juices. For this purpose we correlated the colorimetric information of commercially available OJ with their carotenoid content by means of multiple regressions We have concluded that the carotenoids better correlated to the hue are not necessarily the same as those mainly related to the chroma. According to our statistical analyses, the pigments mainly related to hab were zeinoxanthin, lutein and a mixture of violaxanthin isomers, whilst those mainly related to C ab ∗ were zeaxanthin, (9Z)- or (9′Z)-antheraxanthin and zeinoxanthin. These findings are very interesting for the citrus industry, since some carotenoids are used as colorants and the colour of OJ does influence the consumers’ choices.

The vinification technique called pre-fermentative cold maceration is used to enhance the anthocyans diffusion from the skins to the must, increasing the pigments extraction. For using this technique the application of low temperatures is needed. In this study, two different refrigerating methods (dry ice and cooling of grapes) have been assessed regarding the colour and the phenolic composition of the Syrah wines elaborated by applying pre-fermentative cold maceration. Results showed more intense and stable colours when grapes were previously refrigerated in cold-storage rooms, which showed higher values of chroma and more red-bluish hues. As regards phenolic composition, the cold maceration technique used yields to significant differences among the levels of phenolics, having higher levels of anthocyanins and some non-coloured phenols as flavonols in PR wines. Regarding the colour-composition relationships, it has been highlighted the importance of the co-pigments such as flavonols and cinnamic acids for classify the two groups of samples.

The colour of orange juices is one of the main factors related to their acceptability. Their colour is mainly due to carotenoids, with the particularity that the major ones, the epoxycarotenoids, can isomerise into differently coloured isomers in the presence of acid. Since acidity is one of the main characteristics of citrus, we have carried out a simple experiment to ascertain whether large changes in this parameter can affect significantly their colour. We observed that the addition of citric acid to increase the acidity of the control by roughly 50% speeded up the isomerisations initially, although it did not lead to markedly appreciable colour changes at the end of the study. These observations may be important from a food safety point of view and in relation to the consumers’ choices. In this regard, these preliminary findings could be important for food technologists and the citrus industry in general.

The influence of externally added ascorbic acid (AA) on the deterioration of carotenoid pattern and colour of orange juices has been assessed. Regardless of the enrichment of the samples with ascorbic acid, the changes in their carotenoid profile were analogous and involved mainly the epoxycarotenoids. The decreases in the levels of the two major carotenoids, namely (9 Z )-violaxanthin and (9 Z )- or (9′ Z )-antheraxanthin, due to acid-elicited 5,6-epoxide to 5,8-furanoxide isomerizations, were markedly distinct, with the levels of the former dropping more markedly. It was observed, in any event, that the decreases were higher in the sample spiked with the higher amount of ascorbic. In view of these results it has been hypothesized that the location of (9 Z )-violaxanthin in orange cloud particles could be more accessible to the juice acids to that of (9 Z )- or (9′ Z )-antheraxanthin. In addition, the enrichment of the juices seems to promote the contact of the carotenoids and the acids during their deterioration. In terms of colour, it has been concluded that these changes in the carotenoids led to colour differences that can be discerned visually and that the use of a black background for the measurements yielded a better differentiation among the samples.

Around 30 carotenoids were detected in samples of orange juices from concentrated (OJFC) when 25 ml aliquots were analyzed, which indicated that such foodstuff is one of the most intricate sources of those pigments. The main features of the carotenoid profile were the absence or occurrence at low levels of certain isomers of the 5,6-epoxycarotenoids antheraxanthin and violaxanthin, which are major carotenoids in fresh or slightly processed juices. This fact is connected with the higher quantitative importance of their 5,8-epoxy derivatives mutatoxanthin and auroxanthin, from which it has been suggested that a rough estimation of the age of the juices can be made by considering their epoxycarotenoids content, the absence of antheraxanthin and (9Z)-violaxanthin indicating that the juice has been stored for a relatively long period. In addition, the presence, in some of the samples surveyed, of geometrical isomers of zeaxanthin and b-cryptoxanthin, which were not detectable in UFOJ, was also observed. As for the quantitative analysis, the total carotenoid contents of the OJFC analyzed fell within the bracket 1.37–5.89 mg/l, the levels of individual carotenoids being lower in comparison with those reported in the literature for slightly processed orange juices. 2008 Elsevier Ltd. All rights reserved.

In this study, we have evaluated the changes that occur in the profiles of total fatty acids and triacylglycerols during the dry-curing process (730 days) of Iberian ham. The subcutaneous adipose tissues of six hams obtained from three Iberian pigs fed on acorns were analyzed periodically during the processing time (from the raw to the dry-cured samples), including postsalting, drying, and ripening stages. The environmental conditions were also registered. The curing process significantly decreased (p < 0.01) the relative percentages of total polyunsaturated fatty acids, including C18:2n-6 and C18:3n-3 and, therefore, significantly increased (p < 0.05) the level of monounsaturated fatty acids. The triglycerides containing 0-2 double bonds showed an increase during the curing process. On the contrary, the more unsaturated ones (3-5 double bonds) suffered a significant decrease. We have postulated that these changes could also be due to polymerization and oxidation reactions that affect the triacylglycerols and besides the fatty acids. In general, most fatty acids and triacylglycerols reversed the trend by about 500-600 days of processing.

Research on the biosynthesis of carotenoid pigments, from diverse points of view, has undergone a considerable boost in recent years due to the large body of studies that highlights their beneficial effects in humans. To obtain valuable information from such surveys, it is of paramount importance to reduce the tentativeness with which some carotenoids are still identified, above all, when they are key compounds for the synthesis of other important metabolites. This is the case for neoxanthin (5′,6′-epoxy-6,7-didehydro-5,6,5′,6′-tetrahydro-β,β-carotene-3,5,3′-triol), an epoxycarotenoid which can be found in the light harvesting apparatus of plants and whose cleavage leads to the formation of xanthoxin and then of the plant hormone abscisic acid, among other compounds. Hence, this paper presents pieces of evidence that may put in doubt the presence of such a carotenoid in orange juice, as a consequence of which we propose that the compound formerly tentatively identified as neoxanthin should be referred to as “unidentified” prior to its conclusive characterization and identification.

Tomato products were analysed for their carotenoids and a-tocopherol contents to study the contribution of individual compounds to the antioxidant capacity and assess the existence of interactions. Besides, the applicability of reflectance measurements for the estimation of the Trolox Equivalent Antioxidant Capacity (TEAC) was explored. Statistically significant regression coefficients were found between TEAC values and carotenoids and a-tocopherol levels. Lycopene seemed to have the highest contribution, followed by phytofluene. The results showed that the antioxidant capacity of phytofluene warrants further investigation. It was observed that there can be interactions between lycopene and atocopherol, although just the lycopene/a-tocopherol ratio cannot be used to predict the kind of interaction. More knowledge of these interactions would supply new tools for the industry to develop more optimized ingredients. Finally, the lycopene levels and TEAC values can be estimated by considering reflectance readings at certain wavelengths, which is important for field and quality control applications

Changes in diacylglycerols, monoacylglycerols, and free fatty acid composition of subcutaneous fat of six Iberian hams during the dry-cured process were investigated. In addition, an analytical method for simultaneous quantification of diacylglycerols, monoacylglycerols, and free fatty acid by solid-phase extraction-gas chromatography was developed. The different molecular species of free fatty acids, monoacylglycerols, and diacylglycerols and 1,2- and 1,3-isomers of diacylglycerols have been described for the first time in this type of sample. A logarithmic increase of the 1,3-diacylglycerol profile throughout the processing time has been found, reaching a balance value of 62% around 500 days. The formation of diacylglycerol isomers takes place, although the 1,3-/1,2-diacylglycerol ratio increases during the process to 1.65 due to isomerization of the 1,2-form toward the 1,3-form. The profiles of monoacyl- and diacylglycerols and free fatty acids follow the same trend. The experimental values of free fatty acid are greater than theoretical prediction, probably due to phospholipid and monoacylglycerol hydrolysis.

Aside from the nutritional relevance of some carotenoids owing to their vitamin A activity, these pigments are increasingly drawing the interest of researchers as they may be somehow implicated in the prevention and/or protection against major human diseases. Orange juice is an important source of carotenoids, which, along with its nutritional importance worldwide, have stimulated the development of diverse analytical methodologies for the analysis of these isoprenoid compounds. In this paper, we review different methods used to this end, so that not only researchers but also the industry can choose the most suitable for their purposes. In addition, discussion about particular difficulties of carotenoid analysis in orange juice and research needs are also included.

Triacylglycerols of 50 samples of subcutaneous fat of Iberian pigs reared extensively on two different feeding systems: montanera (M) and cebo (C) have been analysed by gas chromatography flame ionization detector. The lipids were extracted by melting from subcutaneous fat into microwave oven. The fat was then filtered and dissolved in hexane. This analysis was performed on a column (30 m x 0.25 mm i.d.) coated with a bonded stationary phase DB-17HT (50% phenyl-50% methylpolysiloxane; 0.15 microm film thickness) with hydrogen (2.1 mL min(-1)) as a carrier gas, programmed temperature was kept at 320 degrees C, and was then raised to 350 degrees C at a rate of 2.0 degrees C min(-1) and flame ionization detector. By using the triacylglycerols as chemical descriptors, pattern recognition techniques were applied to differentiate between montanera and cebo fattening diet of Iberian pig. Triolein, palmitoyl-stearyl-oleoyl glycerol and di-oleoyl-linoleoyl glycerol were found to be the most differentiating variables.

White wines were elaborated in an experimental winery from grapes (Vitis vinifera cv. Zalema) at different degrees of maturity and grown in different soil types. The effects of these factors on the quality characteristics, in terms of colour and aroma profile, of the wines at bottling were evaluated. Two types of soils (sand and clay) and two different harvest dates (early harvest and industrial harvest) were considered. With reference to colour, the highest colour differences ( Δ E ab ∗ = 2.37 ± 1.05 ) were observed between wines from sandy soils and different harvest dates. Wines from sandy soil and early harvest date showed a more yellow-pale colour and lesser colour intensity. However, these differences were hardly appreciated by tasters. On the contrary, effects of harvest date and soil type were more marked regarding the aromatic profile of the wines. Results showed that in order to elaborate a white wine of quality, in the case of grapes from clayey soils, the harvest date should not be postponed because it would cause a decrease of fresh aromas and an increase of “ripe fruit” notes, no favourable aromatic notes for a young white wine.

Several carotenoids were isolated and their colours were ascertained objectively to establish relationships between the chemical structures of those pigments and their actual colours, considering the coordinates of the uniform space CIELAB. The results of this study revealed that the different carotenoids surveyed could be grouped in the a ∗ b ∗ plane according to the number of conjugated double bonds. For yellowish carotenoids, it was observed that a ∗ values clearly decreased from those with 11 conjugated double bonds (c.d.b.) to those with 9 c.d.b., although this trend reversed in the case of carotenoids with 7 c.d.b.. In terms of hue ( h ab ), it was seen that the decrease in conjugation of the molecules involved a slight rise in h ab . On the other hand, the aperture of the end rings or the increase in conjugation involved clear increases in hue.

The vitamin C and provitamin A carotenoids contents of 25 commercially available Spanish orange juices were studied. Large differences in the levels of these compounds were found. On average, ultrafrozen orange juices (UFOJ) and orange juices from the ecological agriculture (OJFEA) showed the highest ascorbic acid contents (518 and 412 mg/l respectively) among the different kinds of orange juices studied. Some disagreement between the declared and the actual amounts of vitamin C were found. Provitamin A carotenoids were determined by means of the corresponding standards. The monohydroxycarotenoid accompanying β-cyptoxanthin in orange juices was identified as the non-provitamin A carotenoid, zeinoxanthin, on the basis of the methylation test with acidified methanol. Unusually high contents of β-carotene (>0.5 mg/l) were found in two samples, which could indicate that substantial amounts of the pigment were added to those juices. The mandarin juice analyzed showed the highest provitamin A activity (359.3 retinol activity equivalents/l) Among the orange juices surveyed, UFO proved to be the best source of provitamin A (78.5 retinol activity equivalents/l, on average). The lowest contents were found in orange juices from concentrate (OJFC) (22.4 retinol activity equivalents/l, on average, without considering the orange juices with unusual β-carotene contents).

Nine different white wines were elaborated by applying different skin contact times (2, 4, 6, 8, 12, 18 and 24 h) and temperatures (5, 10 and 20 °C). The colour (tristimulus colour parameters) and the phenolic composition of the musts and wines were determined at different winemaking stages. Although extended skin contact (maceration time ⩾12 h) increased significantly the levels of phenolics in the final wines, some of them were important compounds as antioxidant agents, such as caffeic acid. Related to wine colour, for longer skin contact periods (12, 18 and 24 h) at low temperatures (5 and 10 °C), it was found that the wines visually had an acceptable colour (L∗ values higher than 90 CIELAB units; a∗ values ranging from −0.86 to 1.32 units; b∗ values ranging from 5.40 to 21.30 units). So an exhaustive control of the skin contact conditions (time and temperature) is really important to reduce browning in white wines due to this vinification technique.

The geometrical isomers of carotenoids are now attracting considerable interest, due in part to the fact that they are known to behave differently in terms of susceptibility to oxidation, vitamin A activity and bioavailability. The study of such isomers has been facilitated by the development of the C 30 stationary phase, which has made it possible to evaluate their occurrence in any source in a rapid fashion. In this study, the violaxanthin ((3 S ,5 R ,6 S ,3′ S ,5′ R ,6′ S )-5,6:5′,6′-diepoxy-5,6,5′,6′-tetrahydro-β,β-carotene-3,3′-diol) fraction of orange juice ( Citrus sinensis L. Osbeck) was isolated by thin-layer chromatography (TLC) to identify the different geometrical isomers occurring in it. Under the HPLC conditions described, several violaxanthin isomers were detected, of which (all- E )-violaxanthin and, above all, (9 Z )-violaxanthin, happened to be the most important in quantitative terms.

Hydrocarbons in fresh subcutaneous fat of Iberian pig have been analyzed by GC–MS after fractionation of the unsaponifiable fraction with a new off-line combination of HPLC and GC method. The new method proposed improves the recovery and simultaneous quantification of terpenic hydrocarbons in comparison to the traditional LC method. When necessary and for identification purposes, selective ion monitoring (SIM) was used as acquisition mode in GC–MS. To determine the position of the double bonds in the unsaturated hydrocarbon chain the dimethyl disulfide derivatives (DMDS) were obtained. To elucidate the structure of the branched 1-alkenes the hydrocarbon fraction was submitted to hydrogenation. Thirty-five compounds have been identified, including n -alkanes, n -alkenes, branched ( n -1, n -2-dimethyl-1-alkenes) and terpenic hydrocarbons, being the most abundant n -alkenes and n -alkanes of even chain of n -C 12 – n -C 26 . Besides the hydrocarbons already described in bibliography, a new diterpenic hydrocarbon, ent-kaurene, have been identified for the first time. The compound reported as Neophytadiene by other authors, has been identified as a 20 atoms hydrocarbon with two double bonds, the 7,11,15-trimethyl-heptadeca-1,4-diene.

The color of citrus beverages, in general, is related to the consumers' perception of flavor, sweetness, and other characteristics related to the quality of these products, so it is important to develop suitable methods for accurately assessing this attribute. In this study, the color of 2 different kinds of orange juices (ultrafrozen orange juices and orange juices from concentrate) were measured using different white references in order to demonstrate the influence of white reference measurement on the color parameters obtained. The results of this work indicated that the election of a wrong white reference measurement can affect dramatically the accuracy of the objective specification of orange juice color. Thus, the application of analysis of variance ( = 0.01) revealed that, in most cases, the parameters obtained were significantly different. In terms of color differences, the change of the background for the same white reference affected the measurements less than the changes of white references for the same background. On the other hand, important chromatic differences between the 2 types of orange juices studied were found.

This paper was aimed at optimizing the extraction conditions for the maximum yield of anthocyanins from Jaboticaba (Myricia Jaboticaba Berg.) skins. Tristimulus colorimetry was applied to evaluate quantitatively and qualitatively the process. A mixed 2 and 3 full factorial design was used (2 1 .3 3 ). The factors and levels studied were type of solvent: ethanol or methanol; solvent/water mixture: 100% v/v, 90% v/v, 80% v/v; type of acid: clorhidric acid, citric acid or acetic acid and pH: 2, 3 or 4. The estimated effect and ANOVA parameters were calculated. The yield of anthocyanins, quantified following an spectrophotometric method based on the absorbance at 535 nm was 92.92 ± mg/kg of skin. The yield of anthocyanins showed a high and significant correlation with chroma (C* ab ) (p < 0.05; r = 0.84) and lightness (L*) (p < 0.05; r = -0.85) and it was significantly (p < 0.001) affected by the type of acid used and the solvent/water% (p < 0.05).

Twelve ultafrozen orange juices obtained from the variety Valencia late were analysed to characterize the color and the carotenoid profile of this recently developed product. Reflectance color measurements were carried out by spectroradiometry, using a white and a black background. In order to study the carotenoid pigments occurring in the orange juice, HPLC with gradient elution with methanol (MeOH), methyl tert -butyl ether (MTBE) and water as mobile phase was used. Separations were performed on a C 30 column. Identification of carotenoids was made by comparison of their spectral and chromatographic characteristics with those corresponding to standards when possible. To help identify the peaks in the chromatograms, aliquots of orange juice extracts were analysed before and after treatment with hydrochloric acid (HCl) and sodium borohydride (NaBH 4 ), to check the presence of 5,6-epoxy-carotenoids on one hand, and, on the other hand, ketocarotenoids or carotenals.

The colour of 21 ultrafrozen orange juice samples was measured by spectroradiometry. Each sample was diluted with distilled water to obtain eight levels of concentration (10%, 25%, 40%, 50%, 60%, 75%, 90% and 100% of juice). Measurements were made against both a white and a black background. The results showed that the colour parameters which best correlated with orange juice concentration were different depending on the background used. The correlation between sensory and instrumental measurements was also evaluated. The mixtures were classified by 12 panellists in two cabins, one with white walls and the other one with black walls. These visual assessments revealed that the usage of a cabin with black walls led to better classifications of the samples as a function of their concentration.