Acid In Apple Juice Research Articles

Suppressive Effect of Apple Juice Intake on Urinary Excretion of Ascorbic Acid: Unblinded Randomized Crossover Study in Healthy Japanese Subjects.

Ascorbic acid is essential for human health. As this vitamin is water-soluble, it cannot be stored in the body for a long time and is easily excreted in urine; therefore, it is necessary to ingest it in sufficient amounts every day. The fact that apples retain ascorbic acid in human bodies are known; however, this has not been experimentally demonstrated/documented. In this study, to clarify the effect of apple juice ingestion on the urinary excretion of ascorbic acid, we compared urinary ascorbic acid excretion in healthy women administered ascorbic acid alone or with apple juice. The experimental design was an unblinded randomized crossover study. Subjects ingested ascorbic acid in apple juice or ascorbic acid with water. Urine was collected after ingestion, and urinary ascorbic acid was measured. When ascorbic acid was ingested with apple juice, urinary excretion of ascorbic acid was significantly suppressed compared to when ascorbic acid was ingested alone. This suggests that apple juice intake can help retain ascorbic acid in the body.

Ultrasonic and other sterilization methods on nutrition and flavor of cloudy apple juice

Sterilization plays an important role in extending the shelf-life of apple juice; however, it also affects the nutritional and flavor profile of the juice. This study was initiated to evaluate the effects of several common sterilization methods (conventional pasteurization, microwave sterilization, ultrasonic sterilization, and ultra-high-pressure sterilization) on some important quality parameters of apple juice. The results showed that the content of soluble pectin and soluble protein in juice decreased significantly after ultra-high-pressure sterilization. Sonication was found to be effective in increasing the level of ascorbic acid in apple juice. The sugar:acid ratio increased significantly after pasteurization, microwave sterilization, and ultra-high-pressure sterilization, which changed the taste of juice. Microwave sterilization caused the highest volatile compound loss, while ultra-high-pressure sterilization led to a higher retention rate of volatile compounds in juice. This study could be helpful in seeking suitable sterilization methods retaining the quality of cloudy apple juice.

The content of ascorbic and dehydroascorbic acids and vitamin C in non-preserved juices, depending on their type and storage time.

Vitamin C is one of the most important water-soluble vitamins. It is responsible for many important functions in the body, including: it has a positive effect on maintaining immunity, protects the body against free radicals, and also participates in the synthesis of hormones. Juices can be a good source of this vitamin. Most of the juices available on the market are processed products. Untreated juices, which do not contain added preservatives, sugar and are not pasteurized, constitute a smaller group on the market. Therefore, this group of juices can be a valuable product in human nutrition. The aim of the study was t o analyze the content of ascorbic acid (AA), dehydroascorbic acid (DHAA) and vitamin C (TAA) in non-preserved juices, depending on their type and storage time. The analysis of T AA, AA and DHAA content in juices was carried out in ten types of nonpreserved juices from two companies (A and B), purchased in a chain of retail outlets. The analyzed juices in company A were: sauerkraut and carrot, grapefruit, orange, apple and mandarin, while in company B: orange, apple, apple and quince, grapefruit and mandarin. In test 1, the first ten juices were analyzed, in test 2 - another ten juices after one month, in test 3 - juices from test 2 were used, and three days after opening the package and storing the juices in standard refrigeration conditions, the stability test of AA was analyzed. The AA and TAA contents were determined using the high performance liquid chromatography (HPLC) method. The DHAA content was calculated by subtracting the AA content from the TAA content. The highest TAA content was found in citrus juices, i.e. grapefruit, orange and mandarin, and the lowest in sauerkraut and carrot juices and apple juice. Moreover, ascorbic acid in apple juice was characterized by the lowest durability. In the production of non-preserved apple juice, consideration should be given to the natural protection of ascorbic acid by the addition of citrus or other fruit juice, vegetable juice or by using a mild technology in the production process.

Cover Image, Volume 99, Issue 14

The cover image is based on the Short Communication Hydrolysis of chlorogenic acid in apple juice using a p‐coumaryl esterase of Rhizoctonia solani by Mareike Siebert et al., https://doi.org/10.1002/jsfa.9940. image

Synthesis of CdTe Quantum Dots-based Imprinting Fluorescent Nanosensor for Highly Specific and Sensitive Determination of Caffeic Acid in Apple Juices

A facile method for the synthesis of molecularly imprinted polymers (MIPs) onto CdTe quantum dots (CdTe-QDs@MIPs) was successfully developed, and for the first time used as a sensitive fluorescent nanosensor for specific and rapid determination of caffeic acid (CA) in apple juices. Sol—gel polymerization was selected to fabricate hydrophilic MIPs layer using 3-(aminopropyl) triethoxysilane, tetraethyl orthosilicate, and CA as functional monomer, cross-linker and template, respectively. Under optimum experimental conditions, smaller CdTe-QDs@MIPs particles (48 nm) were synthesized with polymerization time at 2 min, which showed fast fluorescence quenching with response time at 3 min and high sensitivity with a limit of detection at 0.73 μg L−1. The fluorescence intensity of CdTe-QDs@MIPs presented excellent linearity with the concentration of CA in the range from 2 to 100 μg L−1 (R2, 0.9980). Te developed method showed good repeatability with batch-to-batch relative standard deviation at 3.31%, and excellent selectivity over structural analogues. The practicability of the as-prepared CdTe-QDs@MIPs was confirmed by the analysis of CA in apple juices with satisfactory recoveries from 93.3% to 108.3%, and precisions <2.1%. Results demonstrated that a rapid, selective, and sensitive fluorescent method was successfully developed to detect CA in food samples.

Stability of the phenolic compounds and antioxidant capacity of five fruit (apple, orange, grape, pomelo and kiwi) juices during in vitro‐simulated gastrointestinal digestion

SummaryThe in vitro digestive stability of phenolic compounds and the antioxidant capacity of five kinds of commonly consumed fruit juices in the daily diet, including apple juice (AJ), orange juice (OJ), grape juice (GJ), pomelo juice (PJ) and kiwifruit juice (KJ), were studied. Following in vitro digestion, the total phenolic (TP) content of fruit juices decreased to different extents by 35%, 25.3%, 23.5%, 22.2% and 7.8% for KJ, OJ, PJ, GJ and AJ, respectively. The individual phenolic content showed similar changes to the TP content, showing reductions of naringenin‐trisaccharide in OJ and PJ, epicatechin in GJ, and chlorogenic acid in AJ by 43.74%, 27.59%, 47.11% and 33.28%, respectively. Conversely, the antioxidant capacity of fruit juices during digestion measured by ABTS assay increased from 4.79% to 35.53%, except in KJ, which decreased by 19.34%. These results show the health benefits of fruit juices after processing and contribute towards establishing suitable dietary recommendations.

NMR detected metabolites in complex natural fluids. Quinic acid in apple juice

Abstract Different types of 1D and 2D NMR experiments were used to completely characterize quinic acid and demonstrate its presence in complex mixtures. The identification of quinic acid in apple juice was done without any separation step. The NMR experiments presented in this study can be used to analyze other metabolites in different complex natural fluids, of vegetal or biological origin.

Determination of fumaric and maleic acids with stacking analytes by transient moving chemical reaction boundary method in capillary electrophoresis

The paper presents an on-line transient moving chemical reaction boundary (MCRB) method for simply but efficiently stacking analytes in capillary electrophoresis (CE). The CE technique was developed for a rapid determination of fumaric and maleic acid. Based on the theory of MCRB, Effects of several important factors such as the pH and concentration of running buffer and the conditions of stacking analytes were investigated to acquire the optimum conditions. The optimized separations were carried out in a 20 mmol/L sulphate neutralized with ethylenediamine to pH 6.0 electrolytes using a capillary coated with poly (diallyldimethylammonium chloride) and direct UV detection at 214 nm. The optimized preconcentrations were carried out in 50 mmol/L borax (pH 9.0). The calibration curves were linear in the concentration range of 1.0 × 10 −7–1.0 × 10 −4 mol/L and 5.0 × 10 −7–1.0 × 10 −4 mol/L for fumaric and maleic acid with correlation coefficients higher than 0.9991. The detection limits were 5.34 × 10 −8 mol/L for fumaric acid and 1.92 × 10 −7 mol/L for maleic acid. This method was applied for determination of fumaric acid in apple juice and of fumaric and maleic acid in dl-malic, the recovery tests established for real samples were within the range 95–105%. This work provided a valid and simple approach to detect fumaric and maleic acid.

Quantitative determination of formic acid in apple juices by 1H NMR spectrometry

A quantitative determination method of formic acid in apple juices is proposed by means of the proton nuclear magnetic resonance ( 1H NMR) technique. Formic acid gives a singlet signal at the 8.2–8.4 ppm interval of the spectrum, and its area is used to determine the concentration of the acid. 1,3,5-Benzenetricarboxylic acid is added to the juice as an internal standard. Since the chemical shift of both species varies with the pH, ascorbic acid is also added to adjust it at 2.74 and to avoid the overlapping of the signals. Recoveries between 95 and 109% are obtained when the standard addition method is applied to the juices of five different cider apple varieties. The coefficient of variation obtained is 3.9% for intra-day repeatability ( n = 5), and 4.6% for inter-day repeatability ( n = 10). The limit of detection is 1.49 mg/l, calculated from “3 S y/ x + intercept”. The described method is direct and no previous derivatization is needed.

Fumaric acid in apple juice: a potential indicator of microbial spoilage of apples used as raw material

The effects of heat treatment (evaporation and excessive heating), and microbial contamination (Rhizopus stolonifer, Penicillium expansum and Lactobacillus plantarum) as sources of fumaric acid formation in apple juice concentrates were investigated. Fumaric acid formed in apple juice did not exceed 1.0 mg l−1 during both commercial-scale evaporation and laboratory-scale excessive heat treatment, indicating that malic dehydration is not the primary source of fumaric acid formation. However, R. stolonifer and L. plantarum produced 18.23 ± 0.82 and 5.39 ± 0.31 mg l−1 fumaric acid as determined in the raw juice obtained from contaminated apples after 5 days of incubation. The mean fumaric acid content of apple juice concentrates manufactured in 2000, 2001 and 2002 were determined as 4.9 ± 1.9, 5.7 ± 2.8 and 4.1 ± 2.6 mg l−1, respectively. The overall results suggest that the primary source of fumaric acid in apple juice concentrate is the use of apples decayed by certain microorganisms capable of producing fumaric acid.

Determination of phenolic compounds using high-performance liquid chromatography with Ce 4+-Tween 20 chemiluminescence detection

A novel method for the simultaneous determination of phenolic compounds such as salicylic acid, resorcinol, phloroglucinol, p-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, and m-nitrophenol by high-performance liquid chromatography (HPLC) coupled with chemiluminescence (CL) detection was developed. The procedure was based on the chemiluminescent enhancement by phenolic compounds of the cerium(IV)-Tween 20 system in a sulfuric acid medium. The separation was carried out with an isocratic elution or with a gradient elution using a mixture of methanol and 1.5% acetic acid. For six phenolic compounds, the detection limits (3 σ) were in the range 1.40–5.02 ng/ml and the relative standard deviations ( n=11) for the determination of 0.1 μg/ml compounds were in the range 1.9–2.9%. The CL reaction was well compatible with the mobile phase of HPLC, no baseline drift often occurred in HPLC–CL detection was observed with a gradient elution. The method has been successfully applied to the determination of salicylic acid and resorcinol in Dermatitis Clear Tincture and p-hydroxybenzoic acid in apple juices.

Quantitation determination of chlorogenic acid in cider apple juices by [formula omitted] NMR spectrometry

This article introduces a method for the determination of chlorogenic acid in apple juices by measuring its signal at 7.20 ppm in the 1 H NMR spectrum. The method is direct and does not need any previous derivatization. The addition to the juice of 1,3,5-benzenetricarboxylic acid as internal standard allows the determination of the absolute concentration of chlorogenic acid. Ascorbic acid is also added to prevent enzymatic oxidation of the phenolic compounds and to adjust the pH to 2.74, since the chemical shifts of some compounds vary with the pH. A standard addition method performed with the juices of three different varieties of apples gave recoveries between 91 and 107%. The precision of the method was tested for repeatability ( n=5) and reproducibility ( n=15), obtaining coefficient of variation of 5.7 and 7.5%, respectively, for a sample of Gezamina apple juice (586 mg l −1 chlorogenic acid).

Direct chiral resolution of malic acid in apple juice by ligand-exchange capillary electrophoresis using copper(II)-L-tartaric acid as a chiral selector.

Chiral resolution of native DL-malic acid was achieved by ligand-exchange capillary electrophoresis using copper(II)-L-tartrate as a chiral selector. Factors affecting chiral resolution, migration time, and peak area of malic acid were studied. The running conditions for optimum separation of malic acid were found to be 1 mM copper(II) sulfate-1 mM L-tartrate (pH 5.1) with an effective voltage of -20 kV at 30 degrees C, using direct detection at 280 nm, and resolution (Rs) of racemic malic acid was approximately 4. With this system, D- and L-malic acids in apple juice were analyzed successfully.

Enantiomeric purity determination of malic acid in apple juices by multi-beam circular dichroism detection

A multi-beam circular dichroism (CD) detector which is easily constructed by inserting inexpensive optics into a conventional photo-diode array detector has an advantage of simultaneous detection of the absorbance and CD. The enantiomeric purity determination of malic acid in beverages was performed by this detection system. Malic acid when complexed with Cu(II) was found to have an absorbance maximum at around 750 nm. The l-malic acid–Cu(II) complex showed a positive Cotton effect in its absorbance band and its anisotropy factor (Δ ε/ ε) was relatively large at about 1/170. This complex was retained on a reversed-phase column with the addition of racemic 2-hydroxy-3-methylbutyric acid to the mobile phase as the ligand. A plot of the relative peak areas between the CD and the absorption (Δabs/abs) versus optical purity showed good linearity with a correlation coefficient of 0.999, and the precision expressed as the relative standard deviation of the errors from the regression line was ±2.7% (2 σ). The accuracy of the proposed method was assessed by capillary electrophoresis. Eight commercially available juice products were analyzed using this method. Five of them were thought to be adulterated with synthetic malic acid.

Determination of fumaric acid in apple juice by on-line coupled capillary isotachophoresis–capillary zone electrophoresis with UV detection

An on-line coupled capillary isotachophoresis–capillary zone electrophoresis (cITP–CZE) method for the determination of the fumaric acid content in apple juice is presented. A clear separation of fumaric acid in real samples is achieved within 20 min. The leading, terminating and background electrolyte of the employed system consist of 10 m M HCl+β-alanine+5 m M β-cyclodextrin+0.05% hydroxypropylmethylcelullose (HPMC), pH 3, 10 m M citric acid and 20 m M citric acid+β-alanine+5 m M β-cyclodextrin+0.1% HPMC, pH 3.3, respectively. The linearity, recovery, repeatability and detection limit of the developed method are 25–1000 ng/ml, 1.07%, 95.4±3.5 (± s)% and 10 ng/ml, respectively. Low laboriousness (no sample pretreatment), sufficient sensitivity and low running cost are the important attributes of the cITP–CZE method which was successfully applied to analyses of real samples of apple juices.

An investigation into the formation of fumaric acid in apple juice concentrates

In this study, apples inoculated with pure cultures of Rhizopus stolonifer, Penicillium expansum and Lactobacillus plantarum were utilised as the raw material to produce apple juice concentrate. The effects of microorganisms and various processing treatments on the fumaric acid, lactic acid and patulin contents of apple juice were investigated. R. stolonifer was found to be the most responsible causative agent of fumaric acid and lactic acid. L. plantarum also produced certain amounts of lactic acid, but not as much as R. stolonifer. L. plantarum caused a significant decrease in L-malic acid content indicating the occurrence of malolactic fermentation. During this complicated biochemical pathway, a small amount of fumaric acid was also formed by L. plantarum. P. expansum produced only patulin, but did not affect the fumaric acid and lactic acid contents. Fumaric acid contents of the samples decreased throughout the processing steps excepting evaporation. The fumaric acid contents of the samples increased just after evaporation depending on the heat applied. The patulin and lactic acid contents of the samples also showed a decreasing trend throughout processing. However, L. plantarum caused a significant increase in lactic acid content just after depectinization depending on whether the appropriate time-temperature conditions for incubation were available during depectinization.

Kinetic Model of Folate Metabolism in Nonpregnant Women Consuming [2H2]Folic Acid: Isotopic Labeling of Urinary Folate and the Catabolite para-Acetamidobenzoylglutamate Indicates Slow, Intake-Dependent, Turnover of Folate Pools

In a 10-wk study of folate metabolism in nonpregnant women (21–27 y, n –6 per group), subjects were fed a diet containing ∼68 nmol/d (30 μg/d) folate from food. The remainder of the ingested folate was provided as folic acid in apple juice (as nonlabeled during wk 1–2, as [2H2]folic acid during wk 3–10) to yield a constant intake of 454, 680 or 907 nmol/d (200, 300 or 400 μg/d). Isotopic enrichment of total urinary folate and the primary catabolite para-acetamidobenzoylglutamate (ApABG) was determined. Isotopic enrichment of ApABG served as an indicator of labeling of tissue folates. A kinetic model consisting of fast- and slow-turnover nonsaturable pools and a saturable slow-turnover pool, with provisions for urinary and fecal excretion, catabolism and enterohepatic circulation, yielded a close fit to the data. Mean residence times for total body folate were 212, 169 and 124 d for folate intakes of 454, 680, and 907 nmol/d, respectively. The model predicted that variation in folate intake over this range had little effect on the mass of the large saturable folate pool; however, the fast-turnover nonsaturable pools increased in proportion to folate intake, whereas the slow nonsaturable pool also tended to increase. This model will aid in evaluation of folate turnover and in predicting kinetic consequences of physiologic conditions associated with altered folate requirements.

Urinary Excretion of [2H4]Folate by Nonpregnant Women Following a Single Oral Dose of [2H4]Folic Acid Is a Functional Index of Folate Nutritional Status

In a 10-wk study with nonpregnant women (21–27 y, n = 5–6 per group), subjects were fed a diet containing ∼68 nmol/d (30 μg/d) folate from food that was supplemented with folic acid in apple juice to yield a constant intake of 454, 680 or 907 nmol/d (200, 300 or 400 μg/d) to evaluate folate status and long-term in vivo kinetics. Reported here is an additional phase of this protocol conducted to determine the relationship between short-term urinary excretion after a single isotopically labeled dose and various measures of folate nutritional status. It was hypothesized that urinary excretion from a single [glutamate-2H4]folic acid ([2H4]folic acid) dose would increase in proportion to folate nutritional status due to saturable cellular uptake and retention processes along with saturation of renal reabsorption. Each subject was given 1.13 μmol (500 μg) of [2H4]folic acid orally on the morning of d 70 of the study, followed by a complete 24-h urine collection. Urine was analyzed to determine the isotopic enrichment of urinary folate by gas chromatography-mass spectrometry and the concentration of urinary folate by HPLC. Urinary excretion of [2H4]folate was greatest at the 907 nmol/d intake and was positively correlated with serum folate concentration but was not correlated with erythrocyte folate. Excretion of [2H4]folate tended to be greatest when plasma homocysteine concentrations were low (<8 μmol/L), although this relation was not significant. These results suggest that 24-h urinary excretion after a single oral dose of isotopically labeled folate is a functional indicator of folate nutritional status that complements other measures of folate nutriture.

DIFFUSION OF OXYGEN INTO A PACKAGED PRODUCT (APPLE JUICE) WITH SIMULTANEOUS OXIDATION OF ASCORBIC ACID

ABSTRACTOne and three dimensional mathematical models to predict loss of quality in packaged apple juice were developed. The models were based on the mass transfer of oxygen through the wall of the package and into the apple juice, and mass transfer of ascorbic acid within the apple juice with simultaneous oxidation of ascorbic acid in the packaged apple juice. Computer programs were developed to solve the mathematical model, using the finite difference method. Concentration of the ascorbic acid in the apple juice was checked using high performance liquid chromatography. Mathematical models and computer programs were successfully validated by experimentation. The model can predict the loss of ascorbic acid in apple juice up to 50% ascorbic acid remaining. The three dimensional mathematical model is valid on block type geometric packages. The mathematical model and computer program can be modified for other geometric shapes, product morphology, and oxygen diffusion, and for other forms of product oxidation.

Determination of D-Malic Acid in Apple Juice by Liquid Chromatography: Collaborative Study

Eleven laboratories collaboratively studied a liquid chromatographic (LC) method for determination of D-malic acid in apple juice. The mobile phase consisted of mM L-valine and 8 mM copper acetate adjusted to pH 5.5 with NaOH. The UV detector was set at 330 nm, and a single reversed-phase LC column was used. Seven paired samples containing various amounts of D-malic acid ranging from 0 to 188 mg/100 mL of 12 Brix pasteurized apple juice were tested by each collaborator. Repeatability and reproducibility coefficients of variation ranged from 1.0 to 3.5% and 7.7 to 11.7%, respectively, within the range of 26 to 188 mg D-malic acid/100 mL of 12 Brix apple juice. The collaborative study results demonstrated that the method could quantitate the economic adulteration of apple juice with DL-malic acid at lower levels than those reported with previous methods. The LC method for determination of D-malic acid in apple juice has been adopted first action by AOAC INTERNATIONAL.