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Enrique Sentandreu - One of the best experts on this subject based on the ideXlab platform.

  • pulsed electric fields versus thermal treatment equivalent processes to obtain equally acceptable Citrus Juices
    Journal of Food Protection, 2006
    Co-Authors: Enrique Sentandreu, L Carbonell, D Rodrigo, J.v. Carbonell
    Abstract:

    Pulsed electric field treatment has been claimed to produce more acceptable chilled Citrus Juices than those obtained by conventional thermal treatment. The pectin methylesterase activity and the acceptability of nine Juices obtained from Clementine mandarins, Valencia oranges, and Ortanique fruits (hybrid of mandarin and orange), untreated, pasteurized (85°C for 10 s), and treated by pulsed electric fields (25 kV/cm for 330 μs), were evaluated. The treatments, selected to reach a similar level of pectin methylesterase inactivation, produced Juices that did not differ in acceptability from each other for the three varieties and in all cases were less acceptable than the untreated juice.

  • reduction kinetics of the free stable radical 2 2 diphenyl 1 picrylhydrazyl dpph for determination of the antiradical activity of Citrus Juices
    European Food Research and Technology, 2006
    Co-Authors: José M. Sendra, Enrique Sentandreu, José L. Navarro
    Abstract:

    There is vast epidemiological evidence for the beneficial effects that the consumption of Citrus Juices exerts on human health. These effects are attributed to their content in substances exhibiting free radical scavenging and antioxidant activities, mainly ascorbic acid, flavonoids, carotenoids and polyphenolic derivatives. This work describes an approximation to the reduction kinetics of the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH•) by the free radical scavenging activity of Juices from sweet orange (Citrus sinensis L.), clementine (Citrus reticulata Blanco) and satsuma (Citrus unshiu K. Marc), as well as the deduction of a kinetic equation to fit the experimental data. This equation contains two contributions. The first contribution accounts for the concentration of DPPH• reduced by the cumulative antiradical activity of those Citrus juice components that are capable of fast hydrogen atom transfer (fast-kinetics), mainly ascorbic acid and some polyphenolic derivatives; the second accounts for the concentration of DPPH• reduced by the cumulative antiradical activity of those Citrus juice components that are capable of slow hydrogen atom transfer (slow-kinetics), mainly flavanone-7-O-glycosides and some polyphenolic derivatives. This methodology thus permits the determination of the total antiradical activity of a Citrus juice (expressed as molar equivalents of ascorbic acid), as well as the partial contributions of the cumulative antiradical activities (also expressed as molar equivalents of ascorbic acid) due to both fast-kinetics and slow-kinetics.

  • Reduction kinetics of the free stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH • ) for determination of the antiradical activity of Citrus Juices
    European Food Research and Technology, 2006
    Co-Authors: José M. Sendra, Enrique Sentandreu, José L. Navarro
    Abstract:

    There is vast epidemiological evidence for the beneficial effects that the consumption of Citrus Juices exerts on human health. These effects are attributed to their content in substances exhibiting free radical scavenging and antioxidant activities, mainly ascorbic acid, flavonoids, carotenoids and polyphenolic derivatives. This work describes an approximation to the reduction kinetics of the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH•) by the free radical scavenging activity of Juices from sweet orange (Citrus sinensis L.), clementine (Citrus reticulata Blanco) and satsuma (Citrus unshiu K. Marc), as well as the deduction of a kinetic equation to fit the experimental data. This equation contains two contributions. The first contribution accounts for the concentration of DPPH• reduced by the cumulative antiradical activity of those Citrus juice components that are capable of fast hydrogen atom transfer (fast-kinetics), mainly ascorbic acid and some polyphenolic derivatives; the second accounts for the concentration of DPPH• reduced by the cumulative antiradical activity of those Citrus juice components that are capable of slow hydrogen atom transfer (slow-kinetics), mainly flavanone-7-O-glycosides and some polyphenolic derivatives. This methodology thus permits the determination of the total antiradical activity of a Citrus juice (expressed as molar equivalents of ascorbic acid), as well as the partial contributions of the cumulative antiradical activities (also expressed as molar equivalents of ascorbic acid) due to both fast-kinetics and slow-kinetics.

A Sasskiss - One of the best experts on this subject based on the ideXlab platform.

  • physical chemical and sensory properties of pulsed electric field and high hydrostatic pressure treated Citrus Juices
    Innovative Food Science and Emerging Technologies, 2011
    Co-Authors: Piroska Hartyani, Zs Cserhalmi, M Tothmarkus, Istvan Dalmadi, David B Kantor, A Sasskiss
    Abstract:

    Abstract The consumers have increasing desire towards fresh, long shelf-life and healthy products by consisting favourable sensory properties. As an ambivalent fact appears that the product should meet all these requirements and should be consumable long time. All these demands lead to the importance of the minimal processing methods. The properties of widely common Citrus Juices (100% orange, – grapefruit, – and tangerine juice) were analyzed by measuring the possible changes in the physical–chemical parameters (pH, Brix°, electric conductivity, colour) respectively the aroma and acid content. The applied technology was pulsed electric field (in furthers: PEF) treatment with the parameters of 28 kV/cm with 50 pulses; respectively high hydrostatic pressure (HHP) technology with the parameter of 600 MPa pressure for 10 min treatment time. The sensory properties of the Juices were analyzed with electronic-nose and -tongue to measure the possible changes of the treated Juices compared to the untreated (control) samples with the help of these electronic tools, which can serve as a potential detection system for the differentiation of the treatments mentioned above. Industrial relevance Fruit Juices are preserved mainly by heat treatment which can change many prosperous flavour- , acid and sensory properties. The present work shows in case of Citrus Juices the application of pulsed electric field treatment and high hydrostatic pressure techniques as non-thermal preservation possibilities and the use of electronic tongue and – nose as a new method for sensory testing.

  • study of pulsed electric field treated Citrus Juices
    Innovative Food Science and Emerging Technologies, 2006
    Co-Authors: Zs Cserhalmi, A Sasskiss, M Tothmarkus, N Lechner
    Abstract:

    Abstract The effect of pulsed electric field (PEF) treatment, applied in a continuous system, on physical and chemical properties of freshly squeezed Citrus Juices (grapefruit, lemon, orange, tangerine) was studied. The aim of the present work was to investigate the effect of PEF technology on pH, Brix°, electric conductivity, viscosity, nonenzymatic browning index (NEBI), hydroxymethylfurfurol (HMF), color, organic acid content, and volatile flavour compounds of Citrus Juices. The Juices were treated by 50 pulses at 28 kV/cm. The treatment temperature was less than 34 °C. The pH, Brix°, electric conductivity, viscosity, NEBI and HMF of Citrus Juices practically did not change. At most of samples there was no or slightly visible difference in the color. In all cases the absorbance spectra of treated and untreated samples were similar to each other. There was no significant change in organic acid content of Juices. The volatile flavour compounds of treated Juices are essentially equal to those present in unprocessed juice as shown by SPME GC-MS results. Industrial relevance Pasteurization of fruit Juices by pulsed electric fields (PEF) has received considerable attention during the last years and will most likely be the first industrial application of PEF. Consequently, for legal approval of such a process, an indepth product characterisation of treated product is required. This paper found limited differences in key quality characteristics between untreated and PEF treated Citrus Juices. However, in agreement with the authors, more work regarding the mechanisms of changes during PEF treatment and during subsequent storage are required.

Shin Hasegawa - One of the best experts on this subject based on the ideXlab platform.

  • Biosynthesis of Limonoids in Citrus
    Phytochemistry, 2001
    Co-Authors: Shin Hasegawa, John E. Hoagland
    Abstract:

    Limonoids represent a group of chemically related triterpenes found in the Rutaceae and Meliaceae. Bitterness due to limonoids in a variety of Citrus Juices is a major problem in the Citrus industry. Among 38 limonoids isolated from Citrus and its hybrids, limonin, a bitter member of the group, occurs widely in Citrus Juices and is the major cause of the bitterness. Recently, limonoids have been shown to be present as glucoside derivatives in the Rutaceae1–6. These glucosides are one of the major secondary metabolites present in Citrus 7–9. Limonoids have also been found to possess biological activities, such as anticarcinogenic activity in laboratory animals10–12 and antifeedant activity against insects13–19. Recently, the biochemistry of limonoids in Citrus 20–21 and the removal of bitter limonoids from Citrus Juices by adsorption22–24 and biological means24–25 have been reviewed. This review summarizes the biosynthetic pathways of the major limonoids in Citrus and the alternative pathways occurring in Ichang Chie (C. ichangensis), sour orange (C. aurantium) and calamondin (C. reticulata x Fortunella sp). Also included is a review of the sites of biosynthesis in Citrus tissues and information on when limonoids are biosynthesized during fruit growth and maturation.

  • Limonin Bitterness in Citrus Juices
    Flavor Chemistry, 1999
    Co-Authors: Shin Hasegawa
    Abstract:

    Bitterness due to limonin in a variety of Citrus Juices, generally referred to as delayed bitterness, is a major problem of the Citrus industry worldwide and has a significant negative economic impact. Significant progress has been made during the past 30 years in understanding the flavor chemistry and biochemistry of Citrus limonoids. The mechanisms of the delayed bitterness and a naturally occurring limonoid debittering process have been established. Biosynthetic pathways of limonoids, and sites of the biosynthesis and accumulation have been well established. The delayed bitterness can be controlled to a semi-acceptable level by chemical, biochemical and physical means. Genetic engineering approaches to the problem will be an area of interest in the future. Research on Citrus limonoids has recently extended to their biological functions including anticarcinogenic and insect antifeedant activities, and their chemotaxonomy.

  • Biosynthesis of limonoid glucosides in navel orange
    Phytochemistry, 1991
    Co-Authors: Zareb Herman, Chi H. Fong, Shin Hasegawa
    Abstract:

    Using radioactive tracers, nomilin was converted to nomilin 17-β-d-glucopyranoside in the mature albedo tissue of a navel orange. The reaction utilized UDP-glucose as a substrate. Application of 2-chloroethylphosphonic acid to small green navel oranges initiated the formation of limonoid glucosides in the fruit. Nomilin glucoside was not metabolized in the mature albedo tissue. The formation of limonoid glucosides represent a natural pathway for the debittering of Citrus Juices. © 1991.

Luigi Mondello - One of the best experts on this subject based on the ideXlab platform.

  • a nano lc uv method for the analysis of principal phenolic compounds in commercial Citrus Juices and evaluation of antioxidant potential
    Electrophoresis, 2014
    Co-Authors: Anna Rocco, Chiara Fanali, Laura Dugo, Luigi Mondello
    Abstract:

    In this study, a simple and rapid methodology to analyze and quantify principal flavanones in Citrus fruit Juices through the use of a nano-LC/UV-Vis apparatus, employing a 75 μm id capillary column packed with sub-2 μm particles C18 stationary phase for 10 cm, was developed. All compounds were baseline resolved working with a step gradient elution mode in 10 min. The developed analytical method was validated and the resulting RSD% for intra- and interday repeatability, related to retention time and peak area, were <4.7 and 5.5%, respectively. LOD and LOQ values corresponded to 0.40 and 1.56 μg/mL for didymin, hesperitin, and narinegenin, while for the other flavanones were 0.78 and 3 μg/mL, respectively. Good linearity with acceptable determination coefficients R(2) was obtained in the range between LOQ concentration and 200 μg/mL (500 μg/mL naringin and hesperidin). Good recovery values were also obtained. Then, the method was applied to the analysis of selected hand-squeezed and commercial Citrus Juices. Further, the nano-LC system was coupled to a mass spectrometer to confirm analyte identification. Antioxidant capacity of selected samples was also evaluated measured by Folin-Ciocalteu assay and Trolox equivalent antioxidant capacity assay. Results were compared to determine total flavanones concentrations.

  • determination of flavanones in Citrus Juices by means of one and two dimensional liquid chromatography
    IEEE Journal of Solid-state Circuits, 2011
    Co-Authors: Marina Russo, Paola Dugo, Luigi Mondello, Francesco Cacciola, Ivana Bonaccorsi
    Abstract:

    1-D and 2-D comprehensive (LC×LC) liquid chromatography methods have been developed and compared for the separation and quantification of flavanones in various Citrus Juices. 1-D analyses were carried out on a superficially porous C18 column, whereas the 2-D LC approach was composed of a polyethylene glycol silica narrow-bore column packed with totally porous particles in the first dimension (D1) and a superficially porous C18 column in the second dimension (D2). Low-selectivity correlations were ensured by the complementary separation mechanisms offered by the D1 and D2 columns. Quantification was carried out both manually and by means of a software capable of detecting and quantifying each peak from the 2-D plot. Limit of detection (LOD) values as low as 0.023 μg/mL were obtained for hesperidin used as reference material for 1-D LC analyses, whereas values as high as 0.432 μg/mL were obtained by comprehensive LC. This discrepancy can be traced back to the minor sensitivity experienced in comprehensive LC due to both sample dilution in D1 and the high flow rates employed in D2. On the other hand, the separation capabilities of the LC×LC approach allowed to reduce the interferences coming from the matrix and to achieve the separation of some critical pairs, e.g. hesperidin/naringin difficult to accomplish in 1-D LC.

  • determination of flavonoids in Citrus Juices by micro hplc esi ms
    IEEE Journal of Solid-state Circuits, 2005
    Co-Authors: Paola Dugo, Maria Lo Presti, Marcus Ohman, Alessia Fazio, Giovanni Dugo, Luigi Mondello
    Abstract:

    Flavonoids are a large class of naturally occurring aromatic secondary plant metabolites. They constitute one of the most characteristic classes found in nature and more than 4000 flavonoids have been identified and divided into several subclasses. Flavonoids have several effects on human health, mainly related to their antioxidant activity. As a result of the increased interest in the biologically active compounds in food, many research studies have investigated the detection and quantification of antioxidants. Citrus plants are of great interest since they accumulate large amounts of flavonoids and fruit and Juices of these species are consumed in large quantities. Despite the extensive research performed on Citrus flavonoids, many compounds still remain unidentified. In this work, flavonoids of five Citrus Juices: lemon, grapefruit, bergamot, orange, and mandarin were analyzed by microHPLC coupled on-line with an MS detector equipped with an ESI source operating in negative mode. The use of microcolumn HPLC greatly enhanced detection performance. In total, 20 flavonoids of two different subclasses (flavanone and flavone glycosides) were identified with the help of retention data and MS spectral information.

Corrado Caristi - One of the best experts on this subject based on the ideXlab platform.

  • Flavonoid composition of Citrus Juices
    Molecules, 2007
    Co-Authors: Giuseppe Gattuso, Davide Barreca, Claudia Gargiulli, Ugo Leuzzi, Corrado Caristi
    Abstract:

    In the early nineties the presence of flavonoids in Citrus Juices began to attract the attention of a number of researchers, as a result of their biological and physiological importance. This short review will explore two different aspects. The first part will focus on analytical techniques for the characterization of Juices from different Citrus fruits regarding their flavonoid content (even if present in only trace amounts), concentrating on the most widely used methods (LC-MS and LC-MS-MS). The second part analyzes data reported in the literature regarding the composition of Citrus Juices. The main components that have been detected so far are flavanone-O-glycosides and flavone-O- or -C-glycosides. The presence of such derivatives in various hand-squeezed and industrial Juices is discussed, with special emphasis on their correlation to different species.

  • flavone di c glycosides in Citrus Juices from southern italy
    Food Chemistry, 2006
    Co-Authors: Corrado Caristi, Claudia Gargiulli, Ersilia Bellocco, Giovanni Toscano, Ugo Leuzzi
    Abstract:

    6,8-Di-C-glucopyranosylapigenin and 6,8-di-C-glucopyranosyldiosmetin were detected by HPLC–DAD–ESI–MS–MS in a variety of Southern Italian Citrus Juices (orange, lemon, bergamot, citron, mandarin, clementine). In some Juices, the amounts of C-glycosides detected were significant. 6,8-Di-C-glucopyranosylapigenin is characteristic of orange juice, while 6,8-di-C-glucopyranosyldiosmetin is the most important C-glycoside in lemon and citron juice. In bergamot juice the concentrations of 6,8-di-C-glucopyranosylapigenin and 6,8-di-C-glucopyranosyldiosmetin are similar. Clementine juice is distinctive as the amounts of both C-glycosides present are negligible.