Concentrated Orange Juice Research Articles

Detection of the Addition of Citrus reticulata and Hybrids to Citrus sinensis by Flavonoids

In some European countries there is a legal barrier against the marketing of some citrus juice mixtures under the denomination “orange juice”, as allowed under certain conditions by the FDA for pasteurized and canned orange juice and for frozen concentrated orange juice. For this reason methods have to be developed to determine a juice addition of up to 10% Citrus reticulata and hybrids thereof and up to 5% Citrus aurantium. Using HPLC equipped with a photodiode array (PDA) detector we could establish that a combination of the flavanone glycoside (FG) and polymethoxylated flavone (PMF) pattern offers possibilities. For the flavanone glycosides the method is based on the presence of some specific compounds, on the didymin content, on a divergent ratio of hesperidin on narirutin, and/or on an unidentified component. In other cases, however, an F test applied on the relative PMF pattern offers a better solution calculating the % adulteration probability. We could conclude that, for all examined citrus sample...

Citrus Tissue Extracts Affect Juice Cloud Stability

ABSTRACTSalt extractable proteins were isolated from hand expressed juice, rag and peel of Valencia oranges. Each tissue extract was divided into dialysis supernatant (DS) and precipitate (DP) (forms during dialysis). DP, DS and DS heated for 2 min at 80°C (HDS) were added to pasteurized, reconstituted frozen concentrated orange juice at 5 U · mL−1 of pectinmethylesterase. Samples were incubated either at 25°C for 14 days or 4°C for 28 days and periodically sampled to determine the effects of tissue extracts on juice cloud stability. Tissue specific differences were observed for the rate of juice cloud precipitation and among the HDS, DS, and DP fractions of a given tissue. HDS fractions destabilized juice cloud more rapidly than DS or DP at both 25 and 4°C.

Export demand for US orange juice: Impacts of US export promotion programs

Export demand for US frozen concentrated orange juice (FCOJ) was estimated with special focus on the impacts of export promotion programs based on annual observations from 1984 to 1992. The study was based on exports to France, Germany, Japan, the Netherlands, and the United Kingdom. Results indicate that own-price, real exchange rate of the importing country in most cases, and trend had a negative relationship with US FCOJ exports; while the price of Brazilian FCOJ exports, the real income (GNP) of the importing country, and export promotion programs were positively related to US FCOJ exports. © 1997 John Wiley & Sons, Inc.

Ultra high pressure treatment of orange juice: a kinetic study on inactivation of pectin methyl esterase

Ultra high pressure treatments ranging from 0 to 720 min were applied to freshly squeezed, non-pasteurized orange juice and reconstituted frozen orange juice at pressures in the range 100 to 400 MPa to investigate the pressure inactivation kinetics of pectin methyl esterase (PME) activity. Freshly squeezed orange juice was adjusted to pH 3.7 or 3.2 (12.6 ° Brix) while the reconstituted frozen concentrate orange juice was adjusted to 10, 20, 30 and 40 ° Brix at pH 3.7. The frozen concentrated orange juice was initially heat treated to inactivate the natural enzymes and then fortified with commercial PME prior to inactivation studies. Analyses of kinetic data revealed the presence of a dual-effect of pressure inactivation: the first one, designated as an instantaneous pressure kill (IPK), which depended only on the pressure level; and a second one, which depended on the holding time at each pressure level, described by first-order reaction kinetics (characterized by a rate constant, k, or by the more familiar decimal reduction time, D). The associated IPK were higher and D values were lower at the lower pH and lower soluble solid contents. The pressure sensitivity of D values were adequately described by a z p value which represented the range of applied pressure between which the D values change by a factor of 10.

Orange juice classification with a biologically based neural network

Dystal, an artificial neural network, was used to classify orange juice products. Nine varieties of oranges collected from six geographical regions were processed into single-strength, reconstituted or frozen concentrated orange juice. The data set represented 240 authentic and 173 adulterated samples of juices; 16 variables [8 flavone and flavanone glycoside concentrations measured by high-performance liquid chromatography (HPLC) and 8 trace element concentrations measured by inductively coupled plasma spectroscopy] were selected to characterize each juice and were used as input to Dystal. Dystal correctly classified 89.8% of the juices as authentic or adulterated. Classification performance increased monotonically as the percentage of pulpwash in the sample increased. Dystal correctly identified 92.5% of the juices by variety (Valencia vs non-Valencia).

Conversion of Ferulic Acid to 4-Vinylguaiacol by Yeasts Isolated from Frozen Concentrated Orange Juice

Yeasts were isolated from frozen concentrated orange juice, grown in Sabouraud dextrose broth at 25°C, and tested for the ability to cometabolize ferulic acid. Strains of Rhodotorula sp., Candida lambica, Trichosporon pullulans, and Candida intermedia decarboxylated ferulic acid nonoxidatively to an off-flavor compound, 4-vinylguaiacol. By decarboxylating naturally occurring ferulic acid, these and other yeasts have the potential to contribute to off flavors in improperly stored fruit juices.

Kinetics of aseptic concentrated orange juice quality changes during commercial processing and storage

SummaryAseptically concentrated orange juice (COJ) was processed commercially at three holding temperatures (84, 87 and 90°C, 72 s) and stored for up to 7 weeks at 32°C and 15 weeks at 22°C. No differences were found in nonenzymic browning (NEB), vitamin C, sucrose, fructose and glucose, furfural, HMF (5‐hydroxymethyl furfural), and DMHF (2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furanon) concentrations due to the different thermal treatment. the dominating factors affecting vitamin C retention and NEB were time and storage temperature. A lag‐time was observed in NEB formation and its length depended on storage temperature. Furfural concentration was below 1 ppm. HMF reached c. 11 ppm after 7 weeks at 32°C. DMHF concentration decreased throughout the storage period. Sensory evaluation showed a nonsignificant preference for COJ processed at the lower temperature.

The potential of NIR spectroscopy for the detection of the adulteration of orange juice

AbstractNear‐infrared spectroscopy was used to investigate the adulteration of 65 authentic concentrated orange juice samples obtained from Brazil and Israel. These samples were adulterated with 100 g kg−1 additions (ie 100 g added to 900 g) of (1) orange pulpwash, (2) grapefruit juice, and (3) a synthetic sugar/acid mixture and with 50 g kg−1 additions (ie 50 g added to 950 g) of (4) orange pulpwash, and (5) grapefruit juice. All samples were scanned on the NIR systems 6500 spectrophotometer over the 1100‐2498 nm wavelength range. Principal component analysis was used to reduce each spectrum to 20 principal components. Factorial discriminant analysis was used to distinguish between the different sample groups. Using orange juice and orange juice adulterated at the 100 g kg−1 level, accurate classification rates of 94–95% were obtained. To classify samples adulterated at the 50 g kg−1 level, the calibration development sample set had to be augmented by the inclusion of samples adulterated at this lower level—after this augmentation, an accurate classification rate of 94% was obtained. The results demonstrated that the application of principal component and factorial discriminate analysis to NIR reflectance spectra can detect the adulteration of orange juice with an average accuracy of 90%. Furthermore, not one adulterated sample was predicted as being an authentic orange juice throughout the entire test regime.

ChemInform Abstract: Synthesis of L‐Ascorbic Acid and Its 2‐Phosphate and 2‐Sulfate Esters and Its Role in the Browning of Orange Juice Concentrate

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

OPTIMISATION OF SOLIDS RECOVERY IN CONCENTRATED ORANGE JUICE (COJ) PROCESSING

Conventional procedure for producing concentrated orange juice through evaporation often causes thermally induce gelation with difficulties in raising brix to optimum level. The objective of this study was to determine the effects of mixed pectinase treatment on solids extraction, recovery and pulp wash from selected sweet orange fruit cultivars. Enzyme use level, depectinization time were varied and pertinent rheological parameters determined on concentrate samples towards standardising quality control protocols. The enzyme treatment improved juice circulation in the climbing film evaporator and solids content raised to ≥ 60 Brix.

RETENTION OF FRESH ORANGE JUICE FLAVOR AND AROMA IN AN AQUEOUS DISTILLATE FROM VALENCIA ORANGE JUICE1

ABSTRACTFreshly squeezed Valencia orange juice, distilled at low temperature and reduced pressure, yielded an aqueous distillate with the necessary balance of volatile flavor and aroma constituents to retain the fresh juice characteristics. Flavor comparisons by an experienced sensory panel determined that orange juice reconstituted by combining the aqueous distillate with the residual juice solids had significantly more fresh juice character than reconstituted commercial frozen concentrated orange juice; commercial not pasteurized single strength orange juice (SSOJ); pasteurized SSOJ, not from concentrate; canned SSOJ, from concentrate; or aseptically packed SSOJ, from concentrate. The panel also found no significant difference in fresh juice characteristics between freshly squeezed orange juice and distillate and residual solids recombined from the same juice sample. Fifty four volatile constituents were identified from the aqueous distillate of freshly squeezed orange juice.

δ18 Measurements in Water for Detection of Sugar Beet-Derived Syrups in Frozen Concentrated Orange Juice: Collaborative Study

Abstract Stable isotope ratio mass spectrometry has shown that pure frozen concentrated orange juices (FCOJ) of 63-67° brix possess a mean δ18 value of +14.28%o, with a standard deviation of 1.80. Beet invert syrups, which are produced using ground water, possess negative values. As a result, δ18 values decrease on addition of such syrups to FCOJ. Samples with values less than +8.9%o (3 standard deviations from the mean for pure FCOJs) can confidently be considered as adulterated. A collaborative study was conducted in which a pure FCOJ and 4 samples adulterated to various levels with medium beet invert syrup were sent to each of 6 collaborators. In all but 2 instances, juices containing more than 10% beet syrup would have been classified as adulterated by the collaborators; none would have classified pure juice as adulterated. The plot of mean δ18 values for all collaborators at each adulteration level has a correlation coefficient >0.999. The method has been adopted first action by AOAC International.

The Application and Economic Interpretation of Selectivity Models

AbstractSubstantial differences in economic interpretations may be inferred from the estimated selectivity model results. Using the demand for frozen concentrated orange juice (FCOJ) as an example, the study suggests that the consumption patterns are quite similar between national brand and private label when the marginal effects and elasticities are evaluated based on actual observations rather than unobserved latent variables. Results show that private label FCOJ is considered as a normal (inferior) good if the income effect is assessed based on actual (potential) purchases. The estimated cents‐off elasticities for private label FCOJ also vary substantially depending on which approach is used.

Chemical Changes during Storage of an Alcoholic Orange Juice Beverage

ABSTRACTChemical stability of a pasteurized, noncarbonated, alcoholic orange juice beverage, (8% ethanol and 30% reconstituted Valencia frozen concentrated orange juice), was investigated. It was hot‐filled into clear glass bottles under nitrogen and subjected to 14‐wk storage at 4, 25, and 40°C. pH, °Brix, titratable acidity, and % alcohol remained constant throughout storage. Accumulation of furfural and darkening paralleled ascorbic acid degradation. The beverage exhibited 25 times more browning at 40°C and 9 times more at 25°C than at 4°C after 14‐wk. d‐Limonene decreased at all temperatures. Nitrogen headspace slightly improved stability at 40°C. Time and temperature were most significant in storage and long‐tem shelf‐life could only be achieved with refrigeration.

Effects of heat, radiation and their combination on the thiamin content of concentrated orange juice

Effects of heat, radiation and their combination on the thiamin content of concentrated orange juice

Nutrient content and nutrition labeling of several processed Florida citrus juice products

From February 1986 to January 1988, samples of several processed Florida citrus juice products--frozen concentrated orange juice, orange juice from concentrate, pasteurized orange juice, grapefruit juice, and grapefruit juice from concentrate--were surveyed regularly during production. Samples were assayed for sodium, potassium, ascorbic acid, thiamin, calcium, iron, folic acid, phosphorus, magnesium, zinc, and copper primarily for the purpose of nutrition labeling. Means, standard deviations of the means, and maximum and minimum values of each nutrient are expressed in mg/6 fl oz for each product. In addition, the estimated percentage of the U.S. Recommended Daily Allowance (U.S. RDA) for each nutrient claimable at time of packing is given. (To be claimed on a nutrition label, a nutrient must occur at a minimum level of 2% of the U.S. RDA per serving, according to U.S. Food and Drug Administration [FDA] regulations.) The estimated percentage of the U.S. RDA claimable for ascorbic acid ranged from 90% to 100% in the orange juice products and was 70% for the grapefruit juice products. These juices are all considered significant sources of vitamin C. In the orange juice products, the percentage of the U.S. RDA for thiamin ranged from 6% to 8% and was 8% for folic acid. Significantly smaller amounts of each vitamin were noted in the grapefruit juices. Small but claimable levels of magnesium, calcium, copper, and phosphorus were found in one or more of the products tested. Neither zinc nor iron was found at the U.S. RDA minimum level of 2%. Significant amounts of potassium, for which there is no established U.S. RDA, were found in all the citrus juice products.(ABSTRACT TRUNCATED AT 250 WORDS)

Flavor and compositional comparison of orange essences and essence oils produced in the United States and in Brazil

One commercial sample of each of aqueous orange essence and orange essence oil from Brazil was compared with three samples of each product produced in Florida. Brazilian and U.S. products were qualitatively identical, but minor quantitative differences were found. Sensory panels noted aroma differences between aqueous essences and essence oils produced in the United States and Brazil; similar aroma differences were found between these products produced by two different U.S. suppliers. When the products were used to flavor frozen concentrated orange juice (evaporator pumpout), however, no flavor differences were noted between any of the aqueous essences or essence oils.

Ascorbic and dehydroascorbic acid contents of canned food and frozen concentrated orange juice

A sensitive high-performance liquid chromatography method was used to estimate ascorbic and dehydroascorbic acid in canned foods and in frozen concentrated orange juice. Canned foods were found to be an unreliable and variable source of vitamin C; only orange and fortified apple juices were excellent sources of the vitamin. The proportion of dehydroascorbic acid to ascorbic acid in some products was high but the total vitamin C amount was low. Unlike the canned foods tested, frozen concentrated orange juice was an excellent source of vitamin C and dehydroascorbic acid was very low. These results indicate that the levels of dehydroascorbic acid are low in canned foods, and that these canned foods are not a health concern from the perspective of dehydroascorbic acid intake.

Effect of Storage Temperature on the Stability of Aseptically Packaged Concentrated Orange Juice and Concentrated Orange Drink

ABSTRACTCommercial orange drink concentrate and two orange juice concentrates were aseptically packed in flexible bags and stored at 4°, 15°, 22°, and 30°C for 6 months. Ascorbic acid, nonenzymatic browning and sensory quality were measured monthly. Sensory characteristics for drink concentrate deteriorated after 3 and 4 months at 30°C and 22°C, respectively. Juice concentrates were unacceptable after 2 and 5 months at 30°C and 22°C, respectively. Drink concentrate ascorbic acid loss was greater than juice concentrates at 4°, 15°, and 22°C. Changes in nonenzymatic browning as measured by Hunter color and by absorbance at 420 nm were similar to changes in other containers. The quality of refrigerated aseptic drink (15°C) and juice (4°C) was similar to frozen concentrates (−18°C).

C18 solid-phase isolation and high-performance liquid chromatography/ultraviolet diode array determination of fully methoxylated flavones in citrus juices.

A new analytical methodology for the determination of fully methoxylated flavones (FMFs) in citrus juices is described. Isolation of the FMFs is carried out by percolation of 30 mL of clarified citrus juice (to which tetramethyl-o-kaempferol is previously added as internal standard) through a C18 Sep-Pak cartridge, washing with 3 mL of water followed by 5 mL of water/acetonitrile (3:1), and selective elution of the retained FMFs with 5 mL of water/acetonitrile (9:11). Determination of the isolated FMFs is carried out by reversed-phase high-performance liquid chromatography (HPLC) and UV diode array detection (DAD). Signals at wavelengths 320, 335, and 345 nm (bandwidth 4 nm) are simultaneously acquired, stored, plotted, and integrated. The column used is a microbore (200 x 2.1-mm) Hypersil ODS 5 microns. Elution is in gradient mode, using a ternary mobile phase (water/acetonitrile/tetrahydrofuran). Column temperature is 40 degrees C. Recovery yields are nearly 100% for all the FMFs detected and identified: isosinensetin, hexamethyl-o-gossypetin, sinensetin, tetramethyl-o-isoscutellarein, hexamethyl-o-quercetagetin, nobiletin, tetramethyl-o-scutellarein, heptamethoxyflavone, and tangeretin. Chromatographic separation of the FMFs is extremely dependent upon the minor changes of the mobile phase composition and percentages, gradient rate, and temperature. The UV spectra (230 to 400 nm) of the FMFs obtained under chromatographic conditions are given. The FMFs relative response factors at 320, 335, and 345 nm and their concentrations in hand-squeezed and commercial concentrated orange and mandarin juices are tabulated. The FMF concentration differences found among samples are discussed.