Commercial Apple Juice Research Articles

Single clusters of self-assembled silver nanoparticles for surface-enhanced Raman scattering sensing of a dithiocarbamate fungicide

Hydrophobic silver (Ag) nanoparticles of ∼16 nm diameter were self-assembled as building blocks in an emulsion to form large spherical clusters upon the removal of organic solvents. The self-assembled clusters of Ag nanoparticles have diameters in the range 0.5–1.0 μm and are composed of thousands of densely packed Ag nanoparticles, leading to the generation of multiple active sites or hot spots for surface-enhanced Raman scattering (SERS) in a single cluster, as clearly observed using confocal Raman microscopy. Such single clusters of Ag nanoparticles show significant SERS activity for Rhodamine-6G and dithiocarbamates such as thiram. The enhancement factor for R6G was calculated to reach 1 × 109, which is possible for the observation of SERS signals of a single molecule of R6G according to literature reports. The as-prepared individual clusters of Ag nanoparticles have been demonstrated for the SERS detection of the agricultural chemical thiram. The results show that the detection limit for thiram is as low as 0.024 ppm, which is much lower than the maximal residue limit (MRL) of 7 ppm in fruit prescribed by U.S. Environmental Protection Agency (EPA). The system also possesses the ability to selectively detect dithiocarbamate compounds over other types of agricultural chemical. Furthermore, spiked and recovery tests show that the Ag nanoparticle clusters can be used to detect thiram in natural lake water and commercial apple juice without much interference.

Development of a headspace trap HRGC/MS method for the assessment of the relevance of certain aroma compounds on the sensorial characteristics of commercial apple juice

A reliable and simple method was developed for the completely automatised analysis of apple juice aroma compounds. In total 26 flavour compounds could be measured by headspace trap gas chromatography/mass spectrometry (GC/MS). We used the method to analyse 85 commercially available apple juices, of which 67 apple juices were not from concentrate. Our results show that apple juices not from concentrate are mainly characterised by flavour compounds responsible for fruity, ripe, and sweet aroma impressions, such as 1-butanol, 2-methyl-1-butanol, ethylbutyrate, and ethyl-2-methylbutyrate. On the contrary, apple juices made from concentrate were dominated by acetaldehyde, E-2-hexenal, 3-methyl-1-butanol, ethyl acetate, and hexanal, which are mainly responsible for sensory impressions, such as ‘green, fresh, estery’. According to our data, neither of the single compounds nor indexes calculated thereof as suggested by some authors could be used for the reliable assessment of apple juice quality. Thus, these results suggest that sensory evaluation remains the ultimate mean to reliably assess apple juice quality.

Determination of patulin in apple juice by HPLC using a simple and fast sample preparation method

The goal of this work was to develop a simple and rapid preparation method for patulin analysis in apple juice without previous clean-up. This method combined sonication and liquid extraction techniques and was used for determination of patulin in 37 commercial apple juices available on the market in the South of Brazil. The method performance characteristics were determined using a sample obtained in a local market fortified at five concentration levels of patulin and done in triplicates. The coefficient of variation for repeatability at the fortification level of 20.70μg.L-1 was 3.53 % and the recovery 94.63 %, respectively. The correlation coefficient was 0.9996 and agrees with the requirements for a linear analytical method value. The detection limit was 0.21μg.L-1 and the quantification limit 0.70 μg.L-1. Only three of the analyzed samples were upper the allowed level of 50.00 μg.L-1 recommended for the World Health Organization.

HPLC Determination of Patulin in Apple Juice: A Single Center Study of Southwest Area of Iran

The aim the present study was the quantitative analysis of a potential fungal toxin, patulin in various samples of juice supplied from a commercial apple juice factory in Southwest area of Iran. For this purpose 150 samples of apple juice (local product) from the Southwest reign of Iran, were taken. Ten milliliter of each sample was dissolved in 5 mL buffer. The samples were treated by C18-SPE cartridge and analyzed by high-performance liquid chromatography (HPLC) using UV detector. Results showed level of patulin were higher than 10 μg L-1 in 90 of apple juices. Overall 13/3 of the apple juice samples had levels higher than 50 μg L-1 with maximum level of 106/01 μg L-1. The mean concentration of patulin in apple juice was 26/92 μg L-1. The results of this study showed not significant proportion of the patulin exceeding the 50 mg L-1 limit for apple juice set by WHO and certain European countries. However, constant surveillance of the patulin is strongly recommended because the available data is limited and the hot weather conditions in this area, incidence and level of this toxin could change according to factors like weather conditions, pH, type and stage of apple maturation. © 2010 Academic Journals Inc.

Simultaneous Carbohydrate Chromatography and Unsuppressed Ion Chromatography in Detecting Fruit Juices Adulteration

This paper is the first one investigating the simultaneous use of carbohydrate chromatography and ion chromatography to obtain in one run conclusive data on juice’s authenticity. A hybrid liquid chromatographic system with conductivity and differential refractive index detection, equipped with an Universal Cation 7u column for cation analysis and with a EC 250/4 Nucleodur 100-5 NH2 RP column for carbohydrate analysis, was designed for this study. In less than 18 min, this configuration can separate simultaneously six cations (lithium, sodium, ammonium, potassium, magnesium and calcium) and four carbohydrates (fructose, glucose, saccharose and maltose). Commercial orange and apple juices obtained from the Romanian market were analyzed during this research.

Experimental Measurements and Thermodynamic Modeling of CO2 Solubility at High Pressure in Model Apple Juices

High pressure carbon dioxide (HPCD) treatment can be used for the pasteurization of liquid foods. Solubility of CO2 in the liquid affects microbial inactivation. Measurement and prediction of CO2 solubility in a real or model system are of industrial relevance since the knowledge of the solubility limits will avoid the use of excess CO2. An experimental apparatus was set up to measure CO2 solubility in ternary mixtures of water−CO2−glucose and water−CO2−malic acid and in a quaternary mixture of water−CO2−malic acid−glucose at different concentrations of malic acid (0.01 and 2.68 g in 100 g of solution, corresponding to 7.5 × 10−5 and 0.02 mols in 100 mols of solution) and of glucose (4 and 12 g in 100 g of solution, corresponding to 0.02 and 0.07 mols in 100 mols of solution). CO2 solubility was also measured in a more complex solution of water−malic acid−ascorbic acid−pectin−glucose−sucrose, based on apple juice composition and in a commercial apple juice. The range of pressure tested was between 7.5 and...

Red-fleshed apple as a source for functional beverages

The potential of anthocyanin pigments in fruits and vegetables to provide protection against oxidative damage is well known. Cyanidin-3-O-galactoside is a naturally occurring red pigment commonly found in skin of apples but also present in flesh of certain crab apple and apple genotypes. The purpose of this study was to investigate the cyanidin-3-O-galactoside concentration and antioxidant capacity of juice made from 14 genotypes of red-fleshed apples in comparison to three white-fleshed apple cultivars and three commercial apple juices. Cyanidin-3-O-galactoside was found only in the juice made from red-fleshed apple genotypes with the highest concentrations (39 mg L-1) in a crab apple Roberts Crab. The antioxidant capacity measured using the Folin-Ciocalteu, the ferric reducing antioxidant power (FRAP), and the oxygen radical absorbance capacity (ORAC) assays were the greatest in juice prepared from the red-fleshed genotypes Babine and Malus pumila Niedzwetzkyana, a red-fleshed crab apple genotype. The antioxidant capacity measures were strongly correlated with each other; however, there was no correlation between the concentration of cyanidin-3-O-galactoside and the antioxidant capacity measures. The juice quality parameters °Brix and titratable acidity values were not significantly different among the juices made from the red-fleshed apples, commercial apples and commercial apple juice products.Key words: Red-fleshed apple, Malus species, antioxidants, cyanidin-3-O-galactoside, Folin-Ciocalteu, FRAP, ORAC, functional beverage

Determination of patulin in apple juice by HPLC using a simple and fast sample preparation method

The goal of this work was to develop a simple and rapid preparation method for patulin analysis in apple juice without previous clean-up. This method combined sonication and liquid extraction techniques and was used for determination of patulin in 37 commercial apple juices available on the market in the South of Brazil. The method performance characteristics were determined using a sample obtained in a local market fortified at five concentration levels of patulin and done in triplicates. The coefficient of variation for repeatability at the fortification level of 20.70µg.L-1 was 3.53 % and the recovery 94.63 %, respectively. The correlation coefficient was 0.9996 and agrees with the requirements for a linear analytical method value. The detection limit was 0.21µg.L-1 and the quantification limit 0.70 µg.L-1. Only three of the analyzed samples were upper the allowed level of 50.00 µg.L-1 recommended for the World Health Organization.

Usefulness of solute elution from frozen matrix for freeze-concentration technique

A novel freeze-concentration method was proposed to use solute elution from a frozen matrix as a concentrating operation. A batch crystallizer was made up to freeze solution with a jacket cooler, and a rod heater was set at the centre of the crystallizer in order to make the solution contact with the frozen zone. Commercial apple juice was employed as a model liquid food, and the concentration behavior was investigated with the present apparatus. It was found that the concentration clearly increased with time, and the concentrate was recovered at desirable level if the temperature of the jacket and the heater were properly selected. In fact almost all the solute could be recovered from the original apple juice. The present method would mainly be governed by the solute elution from a frozen phase to a liquid phase, therefore, would not require complicated operation.

EFFECT OF ULTRASONIC TREATMENTS ON THERMOACIDOPHILICALICYCLOBACILLUS ACIDOTERRESTRISIN APPLE JUICE

ABSTRACT The effect of ultrasonic treatments on Alicyclobacillus acidoterrestris in apple juice was investigated. In general, inactivation of the cells was more pronounced at an elevated power level and as the processing time increased. Approximately 60% of the cells were inactivated after treating the apple juice with 300-W ultrasound for 30 min. The reduction reached more than 80% when the juice was processed for 60 min. The linear inactivation rates (D values) of ultrasound on A. acidoterrestris were both process- and strain-dependent. The lowest D value at 36.18 min was found when using 600-W ultrasound to treat the A30 strain isolated from the air of a commercial apple juice processing plant, whereas the strain isolated from apple juice concentrate was found most resistant against ultrasound. Changes of sugar content, acidity, haze and juice browning were noted after ultrasonic treatments but did not adversely alter the juice quality. PRACTICAL APPLICATIONS Characterization of the effects of ultrasonic treatments on thermoacidophilic Alicyclobacillus acidoterrestris provides better understanding of how ultrasound technology could assist in alleviating the hard-to-detect spoilage caused by this spore former. Although ultrasonic technology might not be suitable as a standalone unit operation to inactivate high cell loads, the process could be integrated with other thermal or nonthermal technologies to enhance processing efficiencies, consequently preventing microbial spoilage caused by A. acidoterrestris.

Combining eugenol and cinnamaldehyde to control the growth of Alicyclobacillus acidoterrestris

This paper proposes the use of a combination of cinnamaldehyde and eugenol to control spore germination of Alicyclobacillus acidoterrestris. In the 1st phase a three variables-five levels Central Composite Design was used to study the individual and additive effects of cinnamaldehyde (0–80 ppm), eugenol (0–160 ppm) and pH (3.5–5.5). The assays were carried out in a laboratory medium (Malt Extract Broth). Cinnamaldehyde appeared as the most effective antimicrobial; otherwise, eugenol acted as a strengthening element and allowed a reduction of cinnamaldehyde amount in the system. Then, the experiments were performed in a commercial apple juice, thus highlighting that spore germination could be inhibited through the use of 80 ppm of eugenol and 40 ppm of cinnamaldehyde or alternatively through the combination of 40 ppm of eugenol with 20 ppm of cinnamaldehyde.

Determination of patulin in fruit juice and dried fruit samples by in-tube solid-phase microextraction coupled with liquid chromatography–mass spectrometry

A simple and sensitive method for the determination of patulin in fruit juice and dried fruit samples was developed using a fully automated method consisting of in-tube solid-phase microextraction (SPME) coupled with liquid chromatography–mass spectrometry (LC–MS). Patulin was separated within 5 min by high-performance liquid chromatography using a Synergi MAX-RP 80A column and water/acetonitrile (80/20, v/v) as the mobile phase. Electrospray ionization conditions in the negative ion mode were optimized for MS detection of patulin. The pseudo-molecular ion [M−H] − was used to detect patulin in selected ion monitoring (SIM) mode. The optimum in-tube SPME conditions were 25 draw/eject cycles of 40 μL of sample using a Carboxen 1006 PLOT capillary column as an extraction device. The extracted patulin was readily desorbed from the capillary by passage of the mobile phase, and no carry-over was observed. Using the in-tube SPME LC–MS with SIM method, good linearity of the calibration curve ( r = 0.9996) was obtained in the concentration range of 0.5–20 ng/mL using 13C 3-patulin as an internal standard, and the detection limit (S/N = 3) of patulin was 23.5 pg/mL. The in-tube SPME method showed >83-fold higher sensitivity than the direct injection method (10 μL injection volume). The within-day and between-day precision (relative standard deviations) were below 0.8% and 5.0% ( n = 6), respectively. This method was applied successfully for the analysis of fruit juice and dried fruit samples without interference peaks. The recoveries of patulin spiked into apple juice were >92%, and the relative standard deviations were <4.5%. Patulin was detected at ng/mL levels in various commercial apple juice samples.

Measurement of High‐Pressure Carbon Dioxide Solubility in Orange Juice, Apple Juice, and Model Liquid Foods

An experimental system to measure the carbon dioxide (CO(2)) solubility in liquids at different pressures was designed and tested. Pressure and temperature were controlled in the system, and the design assured an accurate measurement of solubility. Experimental measurements of CO(2) solubility were performed in pure water, model solutions (ascorbic acid-sugars-water, citric acid-sugars-water), and in commercial orange juice (OJ) and apple juice (AJ), as a function of pressure (7.58 to 15.86 MPa) at constant temperature (40 degrees C). Aspen simulation software was used to predict the solubility in simple cases. All experimental results and predictions from simulations were compared with literature data. Measurements of CO(2) solubility in pure water were not significantly different than the literature. CO(2) solubility (g/100 g of liquid) results in the model liquids and in the juices were lower than for pure water, due to the presence of solutes. The software simulation was able to predict the CO(2) solubility in the model systems at low pressures.

Patulin biodegradation using Pichia ohmeri and Saccharomyces cerevisiae

The effectiveness of Pichia ohmeri and Saccharomyces cerevisiae in the biodegradation of patulin was evaluated in vitro. Patulin is a toxin produced by Penicillium expansum, the predominant fungal contaminant in post-harvest apple. The biodegradation experiment was carried out in culture medium (Yeast Medium broth, YM) and commercial apple juice. These substrates were artificially contaminated with patulin previously produced by P. expansum strain 2 in malt extract broth and purified over a silica gel column. The YM broth was inoculated with P. ohmeri 158 with proved anti-P. expansum activity, whereas the apple juice was inoculated with dried Saccharomyces cerevisiae cells. The residual patulin in contaminated substrates was determined by reversed-phase HPLC. P. ohmeri 158 in YM broth degraded over 83% of the initial 223 µg (8.92 µg/ml) of patulin after incubation at 25 °C for two days under static conditions; after five days of incubation, this percentage was greater than 99%, and patulin levels fell below the limit of detection after 15 days. In the apple juices inoculated with 0.25 g/l of commercial dried S. cerevisiae cells (corresponding 1.8 x 107 cells/ml), 96% of patulin was degraded (initial contamination of 4.5 µg/ml of patulin) after 143 hours of incubation at 25 °C under static conditions. However, 90% degradation occurred when the juice was contaminated with 7.0 µg/ml under the same conditions, indicating that the biodegradation rate is concentrationdependent. The effective biodegradation of patulin using P. ohmeri 158 and S. cerevisiae demonstrates a promising application for innocuous yeast isolated from natural microbiota in the biological control, which can prevent both fruit spoilage and P. expansum mycotoxin contamination.

Development and validation of a microemulsion electrokinetic chromatography method for patulin quantification in commercial apple juice

A microemulsion electrokinetic chromatography (MEECK) method for patulin (PAT) quantification in apple juice samples has been developed. The effects of several important factors such as co-surfactant type, concentration of surfactant, acetonitrile percentage in the microemulsion, and running voltage and temperature were investigated to determine the optimum conditions. They resulted to be: a background electrolyte (BGE) composed of 25mM of sodium tetraborate, SDS (2.16%w/w), ethanol (6.49%w/w), n-octanol (0.82%w/w) and 2%v/v acetonitrile; applied voltage of +15kV; and a capillary temperature of 35°C. PAT was detected at 276nm. Quantification and detection limits (LOQ and LOD) in apple juice samples were 8.0μgL−1 and 3.2μgL−1, respectively. Patulin was extracted from apple juice using ethyl acetate with a mean recovery value of 75.3% (RSD=4.5).This method was applied to the measurement of patulin in twenty commercial apple juice samples obtained from different Danish supermarkets. The PAT apple juice mean and median levels obtained were 35.9 and 10.9μgL−1, respectively.The comparison with a previously validated micellar electrokinetic chromatography (MEKC) method for PAT analysis showed the suitability of using MEEKC for this mycotoxin analysis. However, the expectations of obtaining a higher efficiency and thus lower limits of detection and quantitation when using MEEKC were not met.

Determination of patulin in commercial apple juice by micellar electrokinetic chromatography

A novel and validated micellar electrokinetic capillary chromatography (MEKC) method using ultraviolet detection (UV) has been applied to the quantitative analysis of patulin (PAT) in commercial apple juice. Patulin was extracted from samples with an ethylacetate solution. The micellar electrokinetic capillary chromatography (MECK) parameters studied for method optimization were buffer composition, voltage, temperature, and a separation between PAT and 5-hydroxymethylfurfural (HMF) (main interference in apple juice PAT analysis) peaks until reaching baseline. The method passes a series of validation tests including selectivity, linearity, limit of detection and quantification (0.7 and 2.5 μg L −1, respectively), precision (within and between-day variability) and recovery (80.2% RSD = 4%), accuracy, and robustness. This method was successfully applied to the measurement of 20 apple juice samples obtained from different supermarkets. One hundred percent of the samples were contaminated with a level greater than the limit of detection, with mean and median values of 41.3 and 35.7 μg L −1, respectively.

Incidence and level of patulin contamination in pure and mixed apple juices marketed in Italy

A survey on the occurrence of patulin was conducted during 2005 on commercial pure apple juices (53 samples) and mixed apple juices (82 samples) marketed in Italy. The current study was undertaken to investigate the possible influence of the agro-food production process employed (conventional or organic), of the fruit percentage in the commercial product (higher or lower than 50%) and of the type of apple juice (clear or cloudy) on the occurrence and level of patulin contamination. Patulin could be quantified in 34.8% of the samples ranging from 1.58 to 55.41 μg kg −1. With the exception of one sample, the level of patulin was lower than 50 μg kg −1, the maximum permitted threshold in fruit juices according to the European legislation. Mean levels of patulin were significantly lower in mixed apple juices (4.54 μg kg −1) than in pure apple juices (9.32 μg kg −1). Levels of patulin contamination were comparable in clear and cloudy juices. A similar incidence of positive samples was found in conventional and organic apple based juices, and the magnitude between the mean contamination levels, although higher in organic (10.92 μg kg −1) than in conventional juices (4.77 μg kg −1), was not statistically significant ( p = 0.771; Mann–Whitney test). The magnitude between the means of patulin contamination in juices containing more than 50% fruit (11.26 μg kg −1) and in juices with 50% or less fruit (3.35 μg kg −1) was statistically significant ( p = 0.016; Mann–Whitney test).

Best Estimated Aroma and Taste Detection Threshold for Guaiacol in Water and Apple Juice

ABSTRACT: Alicyclobacillus acidoterrestris can produce sufficient guaiacol (methoxyphenol), a metabolic by-product of the bacterium, in apple juice to cause a detectable taint characterized by an antiseptic off-odor or distinct medicinal flavor and lingering aftertaste. Bacterial spoilage may not be visibly detectable. The objective of this study was to determine the best estimate threshold (BET) for detection of guaiacol in water and commercial pasteurized apple juice from concentrate using the forced-choice ascending concentration method of limits with an experienced 17-member sensory panel. The mean BET for aroma detection of guaiacol in water and apple juice was 0.48 ppb and 0.91 ppb, respectively. The mean BET for taste detection of guaiacol in water and apple juice was 0.17 ppb and 0.24 ppb, respectively. Individual aroma BET values ranged from 0.06 ppb to 4.71 ppb guaiacol in water and 0.17 ppb to 4.71 ppb for guaiacol in apple juice. Individual taste BET values ranged from 0.01 ppb to 4.71 ppb for guaiacol in water and apple juice. The taste BET was equal to or lower than the aroma BET for guaiacol in both water and apple juice for all panelists. There was about a 500-fold range in guaiacol taste detection between panelists, with some individuals exhibiting a BET value as low as 10 ppt (trillion). The information should be useful for developing quality assurance sensory methodology to evaluate potential apple juice flavor spoilage by Alicyclobacillus spp.

Antibacterial properties of dermaseptin S4 derivatives under extreme incubation conditions.

Antibacterial properties of the frog-derived peptide dermaseptin S4 and a series of synthetic derivatives against the food pathogen Escherichia coli O157:H7 were investigated under extreme incubation conditions. The 28-mer analog K4K20S4 (P28) displayed an MIC of 8 microM and rapid bactericidal kinetics under standard culture conditions. Potent bactericidal properties were maintained at high salt concentrations, under acidic or basic conditions, and at extreme temperatures. The N-terminal 14-mer sequence (P14) displayed higher potency (MIC, 4 microM) but only within a narrow range of incubation conditions, pointing to the importance of the C-terminal domain of P28. The potency range was reextended upon conjugation of aminododecanoic acid to P14. The resulting lipopeptide was even more potent (MIC, 2 microM) and affected bacterial viability under most of the conditions tested, including in commercial apple juice. The mechanistic implications of peptides' hydrophobicity, charge, structure, and binding to an idealized membrane were probed and are discussed here. Collectively, the data indicate interest in simple peptide-based compounds for design of antimicrobials that affect pathogens under a variable range of incubation conditions.

Determination of folic acid by capillary electrophoresis with chemiluminescence detection

A rapid and simple method is presented for the determination of folic acid (FA) by capillary electrophoresis (CE) with chemiluminescence (CL) detection. This method was based on enhance effect of FA on the CL reaction between luminol and BrO − in alkaline aqueous solution. Optimal separation and determination was obtained with an electrophoretic buffer of 35 mM sodium borate (pH 9.4) containing 0.8 mM luminol, and an oxidizer solution of 1.6 mM NaBrO in 100 mM NaCO 3 buffer solution (pH 12.0). Under the optimal conditions, the determination of FA was achieved in less than 20 min, and the detection limit was 2.0 × 10 −8 M ( S/ N = 3). The relative standard deviations (RSDs) on peak area and migration time were in the 1.5 and 1.1%, respectively. The present CE–CL method was applied to the determination of FA in commercial pharmaceutical tablets, apple juices and human urine.