Valencia Orange Juice Research Articles

Characterization of volatile compounds from healthy and citrus black spot-infected Valencia orange juice and essential oil by using gas chromatography–mass spectrometry

Citrus black spot (Phyllosticta citricarpa, CBS) is an important fungal disease that causes rind blemishes and affects quality of citrus fruits. The response of citrus to CBS in terms of volatiles was evaluated using molecular sensory science approaches. Fifty and twenty-one volatiles were identified in the orange juice and essential oil samples, respectively, via gas chromatography–mass spectrometry (GC–MS). The total volatile content in the samples increased after CBS infection, especially in the severe-infection group (SEG) juice and moderate-infection group (MOG) essential oil, which reached the highest levels. CBS enhanced floral, fruity, and off-flavor aromas and decreased the green aroma in citrus juice. Citrusy, floral, and green aromas increased in the CBS-infected essential oil. Six/five potential markers were screened in citrus juice/essential oil, respectively using the orthogonal partial least-square discriminant analysis (OPLS-DA) model. The changes in aroma profile and the difference in infection levels in citrus were attributed to these odorants.

Ultrafiltration of Moroccan Valencia orange juice: juice quality, optimization by custom designs and membranefouling

Ultrafiltration of Moroccan Valencia orange juice: juice quality, optimization by custom designs and membranefouling

Changes in quality parameters of orange juice deacidified by ion exchange resins

In this study, the effectiveness of five different ion exchange resins (Amberlite-IRA96,-FPA51,-FPA53,-FPA54 and Lewatit-S4528) in reducing the acidity of Valencia orange juice and effects on juice quality were determined. The greatest decrease in titratable acidity (65%) and increase (23%) in pH were determined in the juices deacidified using Amberlite-FPA51. The greatest color change (ΔE*=4.89) was identified by treatment of Lewatit-S4528. Ascorbic acid contents were decreased between 12 and 28% by deacidification. Changes ((-4.43)–(+8.18)%) in the carotenoid contents were also assessed in juices treated with different resins. The changes in amount of hydroxycinnamic, hydroxybenzoic acids, flavanones, flavonol and flavone were determined. The largest decrease (ca.28%) in total phenolics was observed with Amberlite-FPA54. The most abundant organic acids in juices were citric acid followed by quinic, malic, ascorbic, tartaric, succinic and oxalic acid, which were decreased after deacidification. Lowest color change and highest carotenoid content were obtained with Amberlite-FPA54.

Changes in the Key Odorants and Aroma Profiles of Hamlin and Valencia Orange Juices Not from Concentrate (NFC) during Chilled Storage.

Application of the aroma extract dilution analysis (AEDA) on the volatiles isolated by extraction/SAFE distillation from NFC (not from concentrate) juice from Hamlin oranges revealed 51 odor-active constituents in the flavor dilution (FD) factor range of 8 to 8192 among which vanillin, wine lactone, and ( R)-linalool appeared with the highest FD factors. The AEDA applied on the volatile fraction of the same batch of juice stored at 0 °C for 10 months under aseptic conditions showed clear changes in the aroma profile as well as in the FD factors of key odorants. The reduction in the intensity of the citrus-like, pungent, green odor attributes in the aroma profile correlated with the loss of 1-penten-3-one, acetaldehyde, and ( Z)-3-hexenal and a clear decrease in hexanal, octanal, nonanal, decanal, and ( E, E)-2,4-decadienal. Quantitation done by stabile isotope dilution assays followed by a calculation of odor activity values (ratio of concentration to odor thresholds in citrate buffer) confirmed that the quick loss of 1-penten-3-one and acetaldehyde already within a few weeks and a significant reduction in nearly all aldehydes over the storage time of 10 months were responsible for the changes in the overall aroma profile of the juice. The same approach applied on Hamlin juice from the next harvest year as well as on chilled stored NFC juice from Valencia oranges confirmed the results for another harvest year and another orange variety.

Kinetics of ascorbic acid thermal degradation in Valencia orange juices and evaluation of its shelf life

Ascorbic acid is a well-known natural antioxidant which is widely distributed in nature, especially in green plants. Its traditionally known sources are citrus fruits like orange. This vitamin acts as an efficient radical inhibitor and it has been used as a food additive. Moreover, it presents antioxidant activity and contributes for the prevention of certain types of cancer. Ascorbic acid is also used as an index of nutritional quality of fruits and vegetables, due to its sensibility to different kinds of degradation in food processing and subsequent storage. Thus, the study of ascorbic acid degradation kinetics is important to raise information that allows estimating the quality changes that occur during the storage of food products. The purpose of this research was to evaluate the thermal degradation kinetics of ascorbic acid in Valencia orange juices and to quantify the effect of water activity on its rate of loss upon storage. Ascorbic acid content was determined by titration with 2,6 dichlorophenol indophenol. Its degradation as a function of storage time was studied at different temperatures during a period of 14 days of storage. Reaction constant rates (k) and the order of reaction (n) were determined through regression analysis of experimental data. Higher coefficient of determination (R2) indicated that a first-order reaction model fits closely well to data obtained in this study. In general, it was observed that increasing temperature and water activity led to increasing losses of ascorbic acid. A direct equation for the estimation of the shelf life of the juice with respect to ascorbic acid losses at any specified temperature and degradation rate has been derived.

Characterisation of the flavonoid composition and total antioxidant capacity of juice from different citrus varieties from the Western Cape region

Four citrus varieties, clementine mandarin, satsuma mandarin, navel orange and Valencia orange, grown in the Western Cape of South Africa, were evaluated in terms of their total polyphenol content (TPC), total flavonoid content (TFC), major phenolic compounds and total antioxidant capacity (TAC) of the juice, taking into account seasonal variation (2011, 2012 and 2014). The results indicated that juice from satsuma mandarin had the highest TFC level (748mg/L naringin equivalents) and Valencia orange had the lowest TPC (115mg/L gallic acid equivalents). The data indicated that varieties grown in the same geographical region differed in terms of TPC and TFC content of the juice and that seasonal influence was not significant. Contrary to these results, the major phenolic compounds showed great variation between different seasons. Hesperidin and narirutin were the predominant flavanone-C-glycosides in navel orange and Valencia orange juice, with vicenin-2 and ferulic acid-O-hexoside also present in high quantities. The juice from satsuma mandarin had the highest quercetin-3-O-rutinoside-7-O-glucoside, narirutin and rutin concentrations, whilst clementine mandarin had the lowest in terms of the sum of individual phenolic compounds quantified. Overall the citrus fruit juice samples, collected in 2014, irrespective of variety, had the highest TAC.

Physico-Chemical changes in valencia orange concentrate during commercial scale vacuum concentration

Changes in the refractometric solids (Brix), viscosity, spectral reflectance (color), pH, acidity, Brix/acid ratio, color, true ascorbic acid and carotene during commercial scale vacuum concentration of Valencia orange juice in a forced circulation, single-pass, falling-film Evaporator have been reported. With the advancing concentration, there was a gradual increase in Brix, acidity, viscosity, color, ascorbic acid and carotene, no change in Brix/acid ratio but a slight fall in pH. Upto 4-fold concentration of the Juice, the increase in viscosity was comparatively slight, but after 5-fold concentration, there was a steep rise in viscosity. There were negligible losses in carotene while the losses in true ascorbic acid were well within 5% during concentration up to 63Degree Brix. Use of mid-season, healthy ripe oranges for juice extraction and concentration of the flash-heated juice (195Degree-200DegreeF for 10-12 seconds) upto 5-fold concentration are suggested.

PRODUCTION AND EVALUATION OF NONTRADITIONAL PRODUCTS FROM LEMON GRASS

This study was carried out to produce products having high nutritional value from lemon grass with valencia orange, Egyptian lime and cantaloupe juices available all the year besides studying the factors affecting on quality of products after processing and during storage. Blends were prepared from lemon grass extract with orange, lime and cantaloupe juices at a ratio of 1:1, 2:1 and 3:1(wt:wt), respectively .Results indicate that total carbohydrates, fat, ash, total phenols and ascorbic acid contents of lemongrass leaves were 75.73, 4.15, 9.47, 3.76% and 175.11 mg/100g (on dry weight basis) , respectively. Results illustrate that total soluble solids (T.S.S.) of blends ranged from 15 -15.3%, total sugars from 79.51 to 88.86%, ash content (1.83-2.56%), total phenols content (0.410 -0.812%) and ascorbic acid content (23.02-152.4mg/100g) on a dry weight basis. Results show that statistical analyses for sensory evaluation of nectars were accepted for orange juice at a ratio of 2:1 and lemongrass extract: lime juice at a ratio of 3:1.The chemical composition of products was slightly affected by storage, while statistical analyses for sensory evaluation of nectars ascertained that they were accepted till 9 months of storage at room temperature. Also, results show that total bacterial count was less than 10 cfu/gfor nectars during storage.

Determination of volatile, phenolic, organic acid and sugar components in a Turkish cv. Dortyol (Citrus sinensis L. Osbeck) orange juice

Orange flavour is the results of a natural combination of volatile compounds in a well-balanced system including sugars, acids and phenolic compounds. This paper reports the results of the first determination of aroma, organic acids, sugars, and phenolic components in Dortyol yerli orange juices. A total of 58 volatile components, including esters (nine), terpenes (19), terpenols (13), aldehydes (two), ketones (three), alcohols (four) and acids (eight) were identified and quantified in Dortyol yerli orange juice by GC-FID and GC-MS. Organic acids, sugars and phenolic compositions were also determined by HPLC methods. The major organic acid and sugar found were citric acid and sucrose, respectively. With regard to phenolics, 14 compounds were identified and quantified in the orange juice. Terpenes and terpenols were found as the main types of volatile components in Dortyol yerli orange juice. In terms of aroma contribution to orange juice, 12 compounds were prominent based on the odour activity values (OAVs). The highest OAV values were recorded for ethyl butanoate, nootkatone, linalool and DL-limonene. When we compare the obtained results of cv. Dortyol orange juice with the other orange juice varieties, the composition of Dortyol orange juice was similar to Valencia and Navel orange juices.

Kinetic study of high pressure microbial and enzyme inactivation and selection of pasteurisation conditions for Valencia Orange Juice

SummaryKeeping quality of fresh orange juice is highly dependent on pectinolytic enzyme activity and the growth of spoilage microorganisms. The inactivation kinetics of indigenous pectin methylesterase (PME) and of the two more pressure resistant species of spoilage lactic acid bacteria (LAB) Lactobacillus plantarum and L. brevis in freshly squeezed Valencia orange juice under high hydrostatic pressure (100–500 MPa) combined with moderate temperature (20–40 °C) was investigated. PME inactivation followed first order kinetics with a residual PME activity (15%) at all pressure–temperature combinations used. The values of activation energy and activation volume were estimated at each pressure and at each temperature, respectively. Values of 90 kJ/mol and −30 mL/mol at reference pressure of 300 MPa and reference temperature of 35 °C were estimated respectively. The corresponding zT and zP values of LAB inactivation were also estimated at all conditions tested. Values of 19.5 °C and 95 MPa at reference pressure of 300 MPa and reference temperature of 30 °C were estimated respectively for L. plantarum, while the corresponding values for L. brevis were 40 °C and 82 MPa, respectively, at the same reference conditions. Pressure and temperature were found to act synergistically both for PME and LAB inactivation. The PME and LAB inactivation rate constants were expressed as functions of the temperature and pressure process conditions. These functions allow the determination of the pressure/temperature conditions that achieve the target enzyme and microbial inactivation at a selected processing time. The process conditions of 350 MPa at 35 °C for 2 min are proposed as effective for Valencia orange juice cold pasteurisation.

Effect of thermal pasteurization and concentration on carotenoid composition of Brazilian Valencia orange juice

Changes in carotenoid pigment content of Brazilian Valencia orange juices due to thermal pasteurization and concentration were studied. Total carotenoid pigment content loss was not significant after thermal pasteurization and concentration. However, thermal effects on carotenoid pigment contents, especially violaxanthin and lutein, were clearly observed and significant ( P < 0.05). Pasteurization reduced the content of violaxanthin by 38% and lutein by 20%. The concentration process resulted in loss of lutein (17%). With the loss of lutein, β-cryptoxanthin became the major carotenoid in the pasteurized and concentrated juices. The provitamin A content of the juice (β-carotene, α-carotene and β-cryptoxanthin) and the amount of zeaxanthin, which are considered to be active against age-related macular degeneration and cataracts, did not significantly decrease after pasteurization and concentration.

Major carotenoid composition of Brazilian Valencia orange juice: Identification and quantification by HPLC

The carotenoid composition of Brazilian Valencia orange juice was determined by open column chromatography (OCC) and high-performance liquid chromatography. Carotenoid pigments were extracted using acetone and saponified using 10% methanolic potassium hydroxide. Sixteen pigments were isolated by OCC and identified as α-carotene, ζ-carotene, β-carotene, α-cryptoxanthin, β-cryptoxanthin, lutein-5,6-epoxide, violaxanthin, lutein, antheraxanthin, zeaxanthin, luteoxanthin A, luteoxanthin B, mutatoxanthin A, mutatoxanthin B, auroxanthin B and trollichrome B. Thirteen carotenoid pigments were separated using a ternary gradient (acetonitrile–methanol–ethyl acetate) elution on a C 18 reversed-phase column. Among these, violaxanthin, lutein, zeaxanthin, β-cryptoxanthin, ζ-carotene, α-carotene, and β-carotene were quantified. The total carotenoid content was 12 ± 6.7 mg/l, and the major carotenoids were lutein (23%), β-cryptoxanthin (21%), and zeaxanthin (20%).

Protoplast transformation and regeneration of transgenic Valencia sweet orange plants containing a juice quality-related pectin methylesterase gene

Valencia orange [Citrus sinensis (L.) Osbeck] is the leading commercial citrus species in the world for processed juice products; however, the presence of thermostable pectin methylesterase (TSPME) reduces its juice quality. A long-term strategy of this work is to eliminate or greatly reduce TSPME activity in Valencia orange. Previous work resulted in the isolation of a putative TSPME gene, CsPME4, associated with a thermostable protein fraction of Valencia orange juice. To begin research designed to overexpress CsPME4 to verify the thermostability of the protein product and/or to downregulate the gene, a sense gene cassette containing a gene-specific sequence from a putative TSPME cDNA and the enhanced green fluorescent protein (GFP) as a selectable marker was constructed (M2.1). In the work reported here, M2.1 plasmid DNA was transformed (polyethylene glycol-mediated) into protoplasts isolated from an embryogenic suspension culture of Valencia somaclone line B6-68, in an effort to obtain transgenic Valencia lines. A vigorous transformed line was identified via GFP expression, physically separated from non-transformed tissue, and cultured on somatic embryogenesis induction medium. One transgenic proembryo expressing GFP was recovered and multiple shoots were regenerated. The recovery of multiple transgenic plants was expedited by in vitro grafting. Polymerase chain reaction analysis revealed the presence of the PME gene in transgenic plants, and subsequent Southern blot analysis confirmed the presence of the eGFP gene. These transgenic plants show normal growth and minor morphological variation. The thermostability of PME in these plants will be assessed after flowering and fruit set. This is the first successful transfer of a target fruit-quality gene by protoplast transformation with recovery of transgenic plants in citrus. This method of transformation has the advantage over Agrobacterium-mediated transformation in that it requires no antibiotic-resistance genes.

Toward Validation of Process Criteria for High-Pressure Processing of Orange Juice with Predictive Models

Mathematical models were developed to predict time to inactivation (TTI) by high-pressure processing of Salmonella in Australian Valencia orange juice (pH 4.3) and navel orange juice (pH 3.7) as a function of pressure magnitude (300 to 600 MPa) and inoculum level (3 to 7 log CFU/ml). For each model, the TTI was found to increase with increasing inoculum level and decrease with increasing pressure magnitude. The U.S. Food and Drug Administration Juice Hazard Analysis and Critical Control Point Regulation requires fruit juice processors to include control measures that produce a 5-log reduction of the pertinent microorganism of public health significance in the juice. To achieve a 5-log reduction of Salmonella in navel orange juice at 20°C, the models predicted hold times of 198, 19, and 5 s at 300, 450, and 600 MPa, respectively. In Valencia orange juice at 20°C, a 5-log reduction of Salmonella was achieved in 369, 25, and 5 s at 300, 450, and 600 MPa, respectively. At pressures below 400 MPa, Salmonella was more sensitive to pressure in the more acidic conditions of the navel orange juice and TTIs were shorter. At higher pressures, little difference in the predicted TTI was observed. Refrigerated storage (4°C) of inoculated navel orange juice treated at selected pressure/time/inoculum combinations showed that under conditions in which viable Salmonella was recovered immediately after high-pressure processing, pressure-treated Salmonella was susceptible to the acidic environment of orange juice or to chill storage temperature. These TTI models can assist fruit juice processors in selecting processing criteria to achieve an appropriate performance criterion with regard to the reduction of Salmonella in orange juice, while allowing for processing flexibility and optimization of high-pressure juice processing.

Identification and Aroma Impact of Norisoprenoids in Orange Juice

Four norisoprenoids, alpha-ionone, beta-ionone, beta-cyclocitral, and beta-damascenone, along with their putative carotenoid precursors, were identified in Valencia orange juice using time-intensity GC-O, GC-MS, and photodiode array HPLC. alpha-Ionone and beta-cyclocitral are reported in orange juice for the first time. GC-O aroma peaks were categorized into seven groups with similar sensory qualities: citrus/minty, metallic/mushroom/geranium, roasted/cooked/meaty/spice, fatty/soapy/green, sulfury/solventy/medicine, floral, and sweet fruity. The four norisoprenoids contributed approximately 8% of the total aroma intensity and 78% of the total floral aroma category. The putative carotenoid norisoprenoid precursors, alpha- and beta-carotene, alpha- and beta-cryptoxanthin, and neoxanthin, were identified in the same orange juice using photodiode array HPLC retention times and spectral characteristics.

Involvement of Volatile Sulfur Compounds in Ionizing Radiation‐induced Off‐odor of Fresh Orange Juice

ABSTRACT: The influences of ionizing radiation on volatile sulfur compounds in fresh Valencia orange juice were analyzed using gas chromatography (GC)‐pulsed flame photometric detection and sensory evaluation. Methyl sulfide (MS) and methanethiol (MT) were induced most, followed by dimethyl disulfide and dimethyl trisulfide. Carbon disulfide was reduced by irradiation, while hydrogen sulfide was not consistently affected. Sensory evaluation indicated that the odor of irradiated juice differed from the nonirradiated samples at 0.5, 1, 2, or 3 kGy. Addition of the 2 major irradiation‐induced sulfur compounds (MS and MT) into fresh juice changed the juice odor, indicating that those 2 compounds were probably involved in the development of irradiation‐induced off‐odor.

The effect of high pressure processing on the microbial, physical and chemical properties of Valencia and Navel orange juice

The quality and shelf-life of high pressure processed (HPP) Valencia and Navel orange juices were compared to fresh and thermally pasteurized juices. The juices were pressure processed at 600 MPa, 20 °C for 60 s and stored at 4 and 10 °C for up to 12 weeks. The microbiological, physical, chemical and nutritional properties of the juices and pectin methyl esterase (PME) activity were analyzed at regular intervals. HPP of the juices reduced the microbial load to non-detectable levels immediately after processing. Storage of the juices at 4 °C kept the microbial load below the limit of detection for at least the first 4 weeks of storage, and then to less than 2 log 10 cfu/ml for up to 12 weeks. PME was not completely deactivated in the Valencia juice (pH 4.3) by HPP or thermal treatment (65 °C, 1 min). In the Navel juice (pH 3.7), PME was reduced significantly with thermal treatment (85 °C for 25 s) and with HPP. Other orange juice quality parameters (°Brix, viscosity, titratable acid content, alcohol insoluble acids, browning index and color), ascorbic acid and β-carotene concentrations of the juices were not significantly affected by HPP.

OPTIMIZING STABILITY OF ORANGE JUICE FORTIFIED WITH WHEY PROTEIN AT LOW pH VALUES

Abstract The influence of temperature, heating time and pH on the stability of whey protein‐fortified Valencia orange juice was determined by uronic acid content, degree of esterification (DE), % transmission measurements (%T) and capillary electrophoretic analysis of the juice‐protein supernatants. Uronic acid content and charge of pectins showed no significant change in heat‐treated samples with added proteins. The %T decreased with decreasing pH and increasing temperature and heating time for α‐lactalbumin (α‐lac), β‐lactoglobulin (β‐lg) and whey protein isolate (WPI). The lowest transmission values were shown at pH 3.0 and 85C. Capillary electropherograms confirmed more extensive juice‐protein interactions in WPI and β‐lg added juices than in those containing α‐lac, especially at low pH, resulting in more stable juice‐protein mixtures.

Effect of Thermal Processing and Carbon Dioxide‐assisted High‐pressure Processing on Pectinmethylesterase and Chemical Changes in Orange Juice

ABSTRACT: The effects of high‐pressure processing (HPP), CO2‐assisted high‐pressure processing (HPP + CO2), and thermal processing on the chemical and physical properties of single‐strength Valencia orange juice were evaluated over 4 mo of storage at 4 and 30 °C. The HPP + CO2 juice had the greatest cloud stability and highest ascorbic acid retention. Volatile compound losses were lowest in the HPP juice and lower in the HPP + CO2 juice compared to the thermally processed juice (p &lt; 0.05). HPP + CO2 produced a cloud‐stable orange juice with more ascorbic acid and flavor volatiles than thermally processed juice (p &lt; 0.05).

Floc Formation and Changes in Serum Soluble Cloud Components of Fresh Valencia Orange Juice

ABSTRACT: The pH of pulp‐free juice (PFJ) from Valencia oranges was adjusted, ultracentrifuged to produce serum (UCS) and pellet (UCP), and stored at 4 °C for 11d. The UCS and PFJ had no pectinmethylesterase (PME) activity. Floc (UCF) in the UCS appeared at the same time as the %T increase in PFJ. Presumptively, PME peptides at 13‐, 20‐, 27‐, and 36‐kDa were in UCF and UCP. The UCS had no protein. Soluble (in UCS) and insoluble (in PFJ) proteins are involved in clarification. Steric stabilization and charge repulsion at pH 7 delays clarification. Increased charge, loss of steric stabilization, and loss of charge repulsion of juices readjusted from pH 7 to natural pH led to accelerated clarification.