Aspartame Degradation Research Articles

Isolation and characterization of the aspartame-degrading strain Pseudarthrobacter sp. AS-1

Aspartame is one of the main varieties of artificial sweeteners. Although it has been approved as a food additive, the environmental hazards and ecological risks posed by aspartame are attracting more and more attention. In the present study, strain Pseudarthrobacter sp. AS-1 was isolated and characterized as an efficient aspartame degrader. Strain AS-1 was capable of degrading 200 mg L−1 aspartame within 10 h under conditions optimized at 30 °C and pH 8.0. At the same time, it was found that enzymes degrading aspartame in strain AS-1 were induced and secreted extracellularly. Degradation of aspartame in Pseudarthrobacter sp. AS-1 was identified as following: it was first demethylated to aspartyl-phenylalanine, then degraded to phenylalanine and aspartate, and finally the two amino acids were further degraded. In addition, strain AS-1 was able to remove more than 85% of aspartame in soil and river water. It is the first time that pure bacterial cultures were reported to have the capability of aspartame degradation. These findings add to our knowledge of the microbial metabolic mechanisms of aspartame.

Stability of aspartame in the soft drinks: Identification of the novel phototransformation products and their toxicity evaluation

Photolytic transformation of aspartame – a widely used artificial sweetener – under the simulated sunlight was studied for the first time. The experiments were conducted in pH range of 2.5 – 7.0 and in eight soft drinks available in the market. The highest degradation rate in the tested buffered solutions was observed under the neutral pH conditions. Irradiation of the soft drinks resulted in significantly (up to tenfold) faster degradation of aspartame, regardless of its initial concentration in the beverage. Such considerable acceleration of decomposition, not reported for aspartame so far, was ascribed to influence of the co-occurring ingredients, which can act as the photosensitizers. These findings indicate that some formulations may be particularly unfavorable in the context of aspartame photostability. Qualitative analysis of the studied processes revealed formation of six phototransformation products including three previously not described. In silico estimation of toxicity showed that some of the identified photoproducts, including the novel phenolic derivatives, may be more harmful than the parent compound. Taking into account relatively extensive formation of those products in the soft drinks, such finding may be particularly important from the food safety point of view.

Comparative study of aspartame and neotame stability in Ice cream and Cake

The suitability of artificial sweeteners aspartame and neotame for the incorporation in products like ice cream and cake was studied. These sweeteners were compared for their stability during processing and storage and the effect of addition ond ifferent physico-chemical properties were also considered. The recovery of the HPLC method used for the estimation of aspartame and neotame from ice cream and cake was 96.22-98.57% and 96.08-98.62%, respectively. During pasteurization of ice cream mix (68°C/30 min), 25% of aspartame was degraded, however, no loss of neotame was observed. Aspartame and neotame content decreased significantly from 74.55 to 62.97% and 99.42 to 89.93%,respectively during storage (-18°C/90 days) of ice cream. During baking (180°C/20 min), the degradation of aspartame and neotame was about 50 and 13%, respectively. However, aspartame and neotame content decreased significantly from 49.90 to 24.61%and 87.20 to 62.40%, respectively during storage (25°C/20 days)of cake.

High-efficiency electrochemical decomposition of artificial sweetener aspartame using a Ti3+ self-doped TiO2 nanotube arrays anode

Artificial sweeteners have attracted growing concern considering their large usage, wide detection and ecological toxicity in the last decade. In this work, high-efficiency decomposition of artificial sweetener aspartame was investigated by using a Ti3+ self-doped TiO2 nanotube arrays electrode. Effects of current density, initial concentration and inorganic anions on the degradation kinetics were studied. Results showed that the electrochemical degradation of aspartame followed pseudo-first-order kinetics, and the rate constant was 0.039 min−1 at a current density of 2 mA cm−2. The electrochemical degradation was not susceptible to nitrate, and the degradation was significantly enhanced by chloridion. Twenty-four transformation products were identified by UPLC-Orbitrap-MS/MS, and possible electrochemical degradation pathway was proposed. The degradation process of aspartame mainly included hydroxylated, demethylation, dehydrogenation, dehydration condensation and side-chain cleavage. Quantitative structure-activity relationship model revealed that the potential risks in electrolysis process should not be ignored before complete mineralization of aspartame. Energy consumption was greatly reduced in the presence of Cl-, and the lowest value for 90% aspartame degradation was 0.07 Wh L−1. The findings presented here demonstrate that electrocatalysis exhibits high efficiency in degrading aspartame and is potentially suitable for eliminating artificial sweeteners from wastewaters.

Environmentally Evaluated New HPLC/UV Method for the Simultaneous Determination of Acesulfame-K, Butylated Hydroxytoluene, and Aspartame and Its Degradant in Chewing Gum

Abstract Background: Acesulfame-K (ACE), butylated hydroxytoluene (BHT), and aspartame (ASP) are a common combination of food additives added to chewing gums. The abuse of these additives results in severe adverse health effects; however, they are still extensively used owing to their high performance and low cost. Objective: The development and optimization of a simple, cheap, sensitive, and eco-friendly HPLC/UV method for the simultaneous determination of ASP, ACE, and BHT along with aspartame degradation product phenylalanine (PHEN) in chewing gum. Methods: The method was optimized using a 5 μm C18 column and an eluent consisting of methanol and 0.1 M phosphate buffer (pH 5.0) according to a suitable gradient elution program. Simple sample preparation, consisting of dilution, homogenization, and sonication followed by centrifugation and filtration, was optimized and used for the extraction of chewing gum. The greenness of the method was evaluated. Results: The proposed method exhibited excellent linearity (R2 > 0.9996), low LOQ (0.08–0.95 μg/mL), and recoveries between 85.3 and 98.83% with relative SD (RSD) ≤ 2.7%. High resolution was obtained with <25 min run times with excellent precision (RSD: 0.28–1.33%). This method was successfully applied for the simultaneous determination of ACE, ASP, and BHT in commercial chewing gum; PHEN was not detected. Furthermore, our method is considered to be environmentally acceptable. Conclusions: The results demonstrate that the developed method can be used to detect ACE, BHT, ASP, and PHEN in chewing gum. Highlights: A new sensitive, green HPLC/UV method is developed to be used as a minimal-cost routine analysis procedure for commercial chewing gum.

Environmentally Evaluated New HPLC/UV Method for the Simultaneous Determination of Acesulfame-K, Butylated Hydroxytoluene, and Aspartame and Its Degradant in Chewing Gum.

Background: Acesulfame-K (ACE), butylated hydroxytoluene (BHT), and aspartame (ASP) are a common combination of food additives added to chewing gums. The abuse of these additives results in severe adverse health effects; however, they are still extensively used owing to their high performance and low cost. Objective: The development and optimization of a simple, cheap, sensitive, and eco-friendly HPLC/UV method for the simultaneous determination of ASP, ACE, and BHT along with aspartame degradation product phenylalanine (PHEN) in chewing gum. Methods: The method was optimized using a 5 μm C18 column and an eluent consisting of methanol and 0.1 M phosphate buffer (pH 5.0) according to a suitable gradient elution program. Simple sample preparation, consisting of dilution, homogenization, and sonication followed by centrifugation and filtration, was optimized and used for the extraction of chewing gum. The greenness of the method was evaluated. Results: The proposed method exhibited excellent linearity (R² > 0.9996), low LOQ (0.08-0.95 μg/mL), and recoveries between 85.3 and 98.83% with relative SD (RSD) ≤ 2.7%. High resolution was obtained with <25 min run times with excellent precision (RSD: 0.28-1.33%). This method was successfully applied for the simultaneous determination of ACE, ASP, and BHT in commercial chewing gum; PHEN was not detected. Furthermore, our method is considered to be environmentally acceptable. Conclusions: The results demonstrate that the developed method can be used to detect ACE, BHT, ASP, and PHEN in chewing gum. Highlights: A new sensitive, green HPLC/UV method is developed to be used as a minimal-cost routine analysis procedure for commercial chewing gum.

Removal of artificial sweetener aspartame from aqueous media by electrochemical advanced oxidation processes

The degradation and mineralization of aspartame (ASP) in aqueous solution were investigated, for the first time, by electrochemical advanced oxidation processes (EAOPs) in which hydroxyl radicals were formed concomitantly in the bulk from Fenton reaction via in situ electrogenerated Fenton's reagent and at the anode surface from the water oxidation. Experiments were performed in an undivided cylindrical glass cell with a carbon-felt cathode and a Pt or boron-doped diamond (BDD) anode. The effect of Fe2+ concentration and applied current on the degradation and mineralization kinetics of ASP was evaluated. The absolute rate constant for the reaction between ASP and OH was determined as (5.23 ± 0.02) × 109 M−1 s−1 by using the competition kinetic method. Almost complete mineralization of ASP was achieved with BDD anode at 200 mA constant current electrolysis. The formation and generation of the formed carboxylic acids (as ultimate end products before complete mineralization) and released inorganic ion were monitored by ion-exclusion high performance liquid chromatography (HPLC) and ion chromatography techniques, respectively. The global toxicity of the treated ASP solution during treatment was assessed by the Microtox® method using V. fischeri bacteria luminescence inhibition.

Stability of aspartame and neotame in pasteurized and in-bottle sterilized flavoured milk

Analytical high performance liquid chromatography (HPLC) conditions were standardized along with the isolation procedure for separation of aspartame and neotame in flavoured milk (pasteurized and in-bottle sterilized flavoured milk). The recovery of the method was approximately 98% for both aspartame and neotame. The proposed HPLC method can be successfully used for the routine determination of aspartame and neotame in flavoured milk. Pasteurization (90°C/20min) resulted in approximately 40% loss of aspartame and only 8% of neotame was degraded. On storage (4–7°C/7days) aspartame and neotame content decreased significantly (P<0.05) from 59.70% to 44.61% and 91.78% to 87.18%, respectively. Sterilization (121°C/15min) resulted in complete degradation of aspartame; however, 50.50% of neotame remained intact. During storage (30°C/60days) neotame content decreased significantly (P<0.05) from 50.36% to 8.67%. Results indicated that neotame exhibited better stability than aspartame in both pasteurized and in-bottle sterilized flavoured milk.

Investigations on the degradation of aspartame using high-performance liquid chromatography/tandem mass spectrometry

Abstract Aspartame is a widely used sweetener, the long-term safety of which has been controversial ever since it was accepted for human consumption. It is unstable and can produce some harmful degradation products under certain storage conditions. A high-performance liquid chromatography/tandem mass spectrometry method was developed for the simultaneous analysis of aspartame and its four degradation products, including aspartic acid, phenylalanine, aspartyl-phenylalanine and 5-benzyl-3,6-dioxo-2-piperazieacetic acid in water and in diet soft drinks. Aspartame and its four degradation products were quantified by a matrix matched external standard calibration curve with excellent correlation coefficients. The limits of detection were 0.16–5.8 μg/L, which exhibited higher sensitivity than common methods. This method was rapid, sensitive, specific and capable of eliminating matrix interferences. It was also applied to the study of the degradation of aspartame at various pH and temperatures. The results indicated that aspartame was partly degraded under strong acidic or basic conditions and the extent of degradation increased with increasing temperature.

The development of burfi sweetened with aspartame

Sucrose was successfully replaced with the sweetener aspartame for the preparation of the indigenous dairy product burfi. Analytical conditions were standardised for the solid phase extraction of aspartame and its degradation products from burfi followed by their reverse phase HPLC. Recovery using this method was 90–97%. Aspartame at a level of 0.065% of milk w/w scored highest in terms of sweetness perception and resembled control burfi in sweetness. Storage studies at 6–8°C revealed that aspartame‐sweetened burfi resembled the control burfi in retaining the sensory profile, but showed an increase in acidity and microbial load and could not retain the texture. High‐performance liquid chromatography analysis revealed no degradation of aspartame in burfi, establishing its stability and hence its sweetness on storage.

Effect of the temperature and pH on methanol release in coffee brew sweetened with aspartame

Methanol is an alcohol which is metabolized to folmaldehyde in humans. It is a very toxic substance, responsible for blindness in cases of methanol intoxication. This study shows the production of methanol when aspartame is used to sweeten coffee brew. The temperature versus pH binomium was also tested. When assayed at 90 °C coffee brew+aspartame and aspartame solution showed an increase in methanol release of 17.8 and 19.3%, respectively, as compared with coffee brew. At 180 °C, the increase was 32.5 and 26.3%, respectively. Our data revealed a protective effect of the pH of coffee on the degradation of aspartame and formation of methanol; an important fact, mainly for specific populations that use aspartame, like diabetics.

Kinetics of an Acid‐Base Catalyzed Reaction (Aspartame Degradation) as Affected by Polyol‐Induced Changes in Buffer pH and pKa Values

The kinetics of an acid-base catalyzed reaction, aspartame degradation, were examined as affected by the changes in pH and pK(a) values caused by adding polyols (sucrose, glycerol) to phosphate buffer. Sucrose-containing phosphate buffer solutions had a lower pH than that of phosphate buffer alone, which contributed, in part, to reduced aspartame reactivity. A kinetic model was introduced for aspartame degradation that encompassed pH and buffer salt concentrations, both of which change with a shift in the apparent pK(a) value. Aspartame degradation rate constants in sucrose-containing solutions were successfully predicted using this model when corrections (that is, lower pH, lower apparent pK(a) value, buffer dilution from the polyol) were applied. The change in buffer properties (pH, pK(a)) from adding sucrose to phosphate buffer does impact food chemical stability. These effects can be successfully incorporated into predictive kinetic models. Therefore, pH and pK(a) changes from adding polyols to buffer should be considered during food product development.

Sweetening ruthenium and osmium: organometallic arene complexes containing aspartame

The novel organometallic sandwich complexes [(eta(6)-p-cymene)Ru(eta(6)-aspartame)](OTf)(2) (1) (OTf = trifluoromethanesulfonate) and [(eta(6)-p-cymene)Os(eta(6)-aspartame)](OTf)(2) (2) incorporating the artificial sweetener aspartame have been synthesised and characterised. A number of properties of aspartame were found to be altered on binding to either metal. The pK(a) values of both the carboxyl and the amino groups of aspartame are lowered by between 0.35 and 0.57 pH units, causing partial deprotonation of the amino group at pH 7.4 (physiological pH). The rate of degradation of aspartame to 3,6-dioxo-5-phenylmethylpiperazine acetic acid (diketopiperazine) increased over threefold from 0.12 to 0.36 h(-1) for 1, and to 0.43 h(-1) for 2. Furthermore, the reduction potential of the ligand shifted from -1.133 to -0.619 V for 2. For the ruthenium complex 1 the process occurred in two steps, the first (at -0.38 V) within a biologically accessible range. This facilitates reactions with biological reductants such as ascorbate. Binding to and activation of the sweet taste receptor was not observed for these metal complexes up to concentrations of 1 mM. The factors which affect the ability of metal-bound aspartame to interact with the receptor site are discussed.

Interactions between aspartame, glucose and xylitol in aqueous systems containing potassium sorbate

The interaction between aspartame, glucose and xylitol in aqueous model systems of pH 3.00 and containing potassium sorbate was studied. Potassium sorbate degradation diminished with the increment of aspartame level from 0.050 to 0.500 g/100 g of system. Xylitol was the humectant that minimized aspartame degradation and non-enzymatic browning development. In general, as expected, presence of aspartame, xylitol or glucose and their mixtures increased the sweetness and they also diminished the sourness of the systems. The addition of 0.050 g of aspartame/100 g of system to the system containing xylitol produced a synergistic effect on sweetness intensity. Based on that trend, it could be concluded that the use of more than one sweetener might allow diminishing the amount of each one of them to assure a specific sweet level. These results stand out the advantage of the use of xylitol as well as the importance of an appropriate choice of the additives and food ingredients to use in the formulation of modified products with lower sugar content to optimize their quality.

Study of thermal degradation of aspartame and its products of conversion in sweetener using isothermal thermogravimetry and HPLC

Aspartame (APM) has been a center of discussion due to the toxicity of its metabolism products. This work studied the thermal degradation of aspartame and its products of conversion in a sweetener using isothermal thermogravimetry (TG), infrared (FTIR) and high-performance liquid chromatography (HPLC). The TG curves were performed using a Shimadzu Thermobalance, under air atmosphere, flow rate of 20 mL min −1 and heating rate of 10 °C min −1. The chromatograms were performed using a Shimadzu Chromatograph with diode-array detector at 210 nm, C18 column, water–acetonitrile (90:10) and 0.1% trifluoroacetic acid. The 5-benzyl-3,6-dioxo-2-piperazineacetic acid (5BZ) was identified as only one product of thermal conversion from aspartame (APM). The 5BZ and APM have been identified and quantified through the comparison of areas and retention time established with standards. The chromatograms had presented limits of quantification (LOQ) and detection (LOD) of 5; 2 μg mL −1 and 10; 5 μg mL −1 for 5BZ and APM, respectively. The samples have indicated recovery of 100.42 ± 1.34%. The content of APM in the sweetener was 19.08 mg ± 2.22%, this amount is within specifications (19 mg ± 10%). The standard APM was heated at 80–220 °C in TG-isothermal and chromatograms have indicated the total conversion of APM to 5BZ, which showed a maximum rate of conversion in a temperature range of 140–160 °C. In the sweetener the APM was converted to 5BZ in a temperature range of 120–140 °C. The TG-isothermal indicated a decrease in the temperature of conversion to 5BZ and its intensity, probably due to interaction with the lactose excipient contained in the sweetener.

The Influence of High Pressure on the Formation of Diketopiperazines And Pyroglutamate in Peptides and Peptide Esters

The effects of pressurization on several short chain peptides were examined. Leucylleucine methyl ester was rapidly degraded under pressure at 60 °C. Results were comparable to the pressure induced degradation of aspartame, meaning that the ester bond is largely high pressure sensitive: The structure of such peptides is consequently modified. Glutamine in model systems underwent cyclization to pyroglutamate under pressure only at conditions unrealistic for industrial purposes: 50 °C, pH 9, and holding times exceeding 30 min. No cyclization of peptides with glutamine at the C-terminus was observed.

Aspartame Degradation in Solutions at Various pH Conditions

ABSTRACT: This study of aspartame degradation in phosphate‐citrate buffer solutions of pH2,4,6, 7,8,10, and 12 using reverse‐phase high‐performance liquid chromatography (HPLC) showed different major degradation products for different pH ranges. The major degradation product found at pH 2 to 6 was L‐phenylalanine methyl ester (PME). The major degradation product found at pH 7 to 10 was 3,6‐dioxo‐5‐phenylmethylpiperazine acetic acid (diketopiperazine, DKP). L‐aspartyl‐phenylalanine (Asp‐Phe) was the major product detected at pH 12.

Photodecomposition of aspartame in aqueous solutions

Photodecomposition of aspartame in aqueous solutions under different conditions of light intensity and pH were studied. The effects of photosensitizers (riboflavin and methylene blue) and ascorbic acid on aspartame stability in aqueous solutions at different pH under light were also studied. Light illumination significantly increased aspartame degradation in an aqueous solution (pH 7), indicating that aspartame was very unstable under the illuminated conditions. In the dark, 91% of aspartame in an aqueous solution at pH 7 remained after 10 h of storage. Under 5500 1x of light, however, 39% of aspartame in the solution was destroyed after 10 h of storage. Aspartame degradation under light followed simple zero-order reaction kinetics. The higher the light intensity, the greater the degradation of aspartame. The relative reaction rate for the destruction of aspartame under 0, 1100, 3300 and 5500 1x was 1:1.42:2.80:4.61. The photodecomposition rate of aspartame varied with the pH of the system. Aspartame degradation was fastest at pH 7.0, followed by pH 4.0 and pH 6.0, in decreasing order. Addition of 4.8 ppm riboflavin or 4.8 ppm methylene blue significantly accelerated the aspartame decomposition at pH 7 in the presence of light. There were, however, no significant photosensitizing effects of these sensitizers on aspartame destruction at pH 6 and pH 4. Addition of 1.2 × 10 −4 M ascorbic acid greatly increased the aspartame degradation at pH 7.0, but did not affect the destruction rate of aspartame at pH 6.0 and pH 4.0.

Aspartame Degradation in Solution As Impacted by Buffer Type and Concentration

Aspartame (APM) is a high-intensity sweetening agent incorporated into a variety of diet beverages along with some type of buffer to control the beverage pH. However, data on the effects of individual buffer types and their concentrations on APM degradation rates do not exist. This project evaluated the rate of aspartame degradation in phosphate and citrate buffer solutions at pH 3 and 7 over a concentration range of 0.01-1.0 M ; experiments were performed at 25 °C. APM degradation rate constants were less at pH 3 than at pH 7 as reported previously. The reaction rates increased significantly as buffer concentration increased in both phosphate and citrate buffers. The degradation rate in phosphate buffer was significantly faster than in citrate buffer at pH 7. However, at pH 3, the difference between the rates in citrate and phosphate buffers was diminished. These results suggest that using citrate buffer rather than phosphate buffer would reduce the loss of APM in diet beverages, especially in higher pH beverages. Thus, diet beverages formulated with citrate buffer would have longer shelf lives than those formulated with phosphate buffer. In addition, this study provides general insight as to the mechanisms by which buffers may destabilize food ingredients.

Differentiating between the Effects of Water Activity and Glass Transition Dependent Mobility on a Solid State Chemical Reaction: Aspartame Degradation

Recent debates have emerged on whether it is water activity (a W ) or the state of the system as dictated by the glass transition temperature (T g ) that impacts the rates of chemical reactions in reduced-moisture solid systems. Previously, model systems could not evaluate the effects of water activity and glass transition independently. By using poly(vinylpyrrolidone) (PVP) of different molecular weights, the effect of water activity and glass transition on chemical reactions can be studied independently and at a constant temperature. The kinetics of aspartame degradation, via its rearrangement into diketopiperazine, was evaluated in the PVP model system. Reaction rates at constant water activity, but different T g values, were not significantly different