Stability Of Aspartame Research Articles

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 stability of aspartame and neotame in yoghurt

The comparative stability of aspartame and neotame was monitored in yoghurt during its processing, fermentation and storage. A solid‐phase extraction method was suggest changing it to developed for the isolation of aspartame and neotame. Pasteurisation (85 °C/30 min) resulted in approximately 47% and 3% loss of aspartame and neotame, respectively. During fermentation, 3% loss of aspartame was observed, but no loss of neotame. There was no significant effects on the stability of either aspartame or neotame during storage (4–7 °C/15 days). The results indicated that neotame was more stable than aspartame under both pasteurisation and fermentation conditions; however, during storage, both sweeteners exhibited excellent stability.

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.

Storage Stability of Aspartame in Orange Flavored Soft Drinks

In this study, “orange flavored soft drink” samples sweetened with 100% aspartame (0.5 g/L) were stored in three different pH values and temperatures. The samples with the pH values of 2.75, 3.25, and 4.57 were kept in 20, 30, and 40°C temperatures over a period of 5 months. The remaining aspartame was determined at the 1st, 2nd, 3rd, 4th, and 5th months by HPLC. In the same pH groups, it was clearly observed that stability of aspartame decreased with increasing storage temperature. It was also determined in each of the same pH groups that aspartame stability increased as the pH value was raised from 2.75 to 4.57. Aspartame was the least stable at pH 2.75 when stored in 40°C, whereas it was the most stable at pH 4.57 and 20°C. At the end of 5th month in 40°C, stability tests could not be performed and remaining aspartame could not be determined.

Structure, dynamics, and stability of beta-cyclodextrin inclusion complexes of aspartame and neotame.

Studies of the high-intensity sweetener aspartame show that its stability is significantly enhanced in the presence of beta-cyclodextrin (beta-CyD). At a 5:1 beta-CyD/aspartame molar ratio, the stability of aspartame is 42% greater in 4 mM phosphate buffer (pH 3.1) compared to solutions prepared without beta-CyD. Solution-state (1)H NMR experiments demonstrate the formation of 1:1 beta-CyD/aspartame complexes, stabilized by the interaction of the phenyl-ring protons of aspartame with the H3 and H5 protons of beta-CyD. Inclusion complex formation clearly accounts for the observed stability enhancement of aspartame in solution. The formation of inclusion complexes in solution is also demonstrated for beta-CyD and neotame, a structural derivative of aspartame containing an N-substituted 3,3-dimethylbutyl group. These complexes are stabilized by the interaction of beta-CyD with both phenyl-ring and dimethylbutyl protons. Solid-state NMR experiments provide additional characterization, clearly demonstrating the formation of inclusion complexes in lyophilized solids prepared from solutions of beta-CyD and either aspartame or neotame.

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 Stability In Commercially Sterilized Flavored Dairy Beverages

The objective of this research was to evaluate the stability of aspartame in commercially sterilized skim milk beverages that contained different buffer salts, buffer concentrations, and flavor. The effects of pH and temperature on aspartame stability in these dairy beverages were also studied. The pH and storage temperature appeared to be the two most important factors for a successful dairy beverage sweetened with aspartame. The half-lives were 1 to 4 d at 30°C and 24 to 58 d at 4°C. Decreasing the pH from 6.7 to 6.4 doubled the stability of aspartame. The type and concentration of buffer had only a minor influence on the aspartame stability. The addition of vanilla did not enhance the degradation of aspartame in dairy beverages.

Influence of Dairy Proteins on Aspartame Stability in the pH 6–7 Range

ABSTRACTThe effect of three commercial milk protein products on aspartame degradation was studied as a function of temperature (4, 30, 70, 80°C), pH (6 and 7), phosphate buffer concentration (0.01 M/L, 0.1 M/L) and protein (0–3%). Caseinates significantly decreased the pseudo‐first order loss rate at low buffer concentration and higher temperature (70–80°C), whereas the rate was faster in the presence of a casein/ whey mixture. At high buffer concentration, the loss rate was not affected by protein. The protective effect may have been due to either a buffering capacity decrease caused by a protein/aspartame interaction that lowered pH or some unknown protein interaction. At 4 and 30°C, the loss rate was not affected by calcium caseinate.

Effect of Sundae-Style Yogurt Fermentation on the Aspartame Stability in Fruit Preparation

We assessed the stability of aspartame during fermentation of milk to manufacture yogurt with fruit on the bottom (sundae-style yogurt) using different direct-set cultures and incubation temperatures. Aspartame recovery based on original amount was determined using HPLC. Aspartame recovery was 95 or 90% in yogurts produced using a 6-h incubation at 43.3°C and 13h at 32.2°C, respectively. Aspartame, therefore, has excellent stability in fruit preparation during the manufacture of sundae-style yogurt.

Stability of Aspartame in Water:Organic Solvent Mixtures with Different Dielectric Constants

In order to examine the influence of solvent composition on the stability of aspartame (N-α-L-aspartyl-L-phenylalanine-1 -methyl ester) in solution (5 mg/mL), the degradation of aspartame was carried out in water:methanol, water:ethanol, and water:glycerine mixtures with dielectric constant values of 45, 55, and 65, respectively. The rate of disappearance of aspartame was measured by a sensitive HPLC assay. The degradation rate of aspartame increased as the dielectric constant of the solvent mixture decreased in all three solvents systems. For example, at 60 °C, the degradation rate constants were 4.1, 5.9, and 8.4 × 10-3 h-1 at dielectric constant of 65, 55, and 45, respectively. From these results, it can be concluded that the stability of aspartame in aqueous solutions cannot be enhanced by the replacement of water by solvents of lower dielectric constant.

Stability of Aspartame in Fruit Preparations Used in Yogurt

ABSTRACTStability of aspartame (APM) in three fruit preparations stored 6 months at three temperatures was assessed monthly. Remaining aspartame, microbiological quality, objective color and pH were determined; sensory acceptance tests were conducted with the fruit added to a commercial yogurt. pH or microbiological counts did not change during storage. About 60% of original APM remained after 6 months at 21.1°C. APM level was a function of pH, temperature and time. Based on the tests, shelf life estimates for the fruit preparations were 1½ months at 32.2°C, 4–6 months at 21.1°C, and &gt; 6 months at 4.4°C.

Measurement and Stability of Aspartame in a Fruit Spread

A procedure was developed for extraction and quantitation of aspartame from a fruit spread. Quantitation was by HPLC using a reverse phase column with ion pairing and detection at 260nm. Coefficients of variation for paired extractions at different aspartame levels ranged from 2.7 to 7.1. The standard curve prepared in fruit media had R2 values of 0.98 or 0.99 (p ≥ .01). The method was applied in a 6-month storage trial of an aspartame sweetened apricot spread (pH 3.2). Aspartame storage losses were modeled as a first order reaction with an average half life of 168 days.