1.Development of an HPLC Method with an ODS Column to Determine Low Levels of Aspartame Diastereomers in Aspartame.
Ohtsuki T1, Nakamura R2, Kubo S2, Otabe A2, Oobayashi Y2, Suzuki S3, Yoshida M3, Yoshida M3, Tatebe C1, Sato K1, Akiyama H1. PLoS One. 2016 Mar 25;11(3):e0152174. doi: 10.1371/journal.pone.0152174. eCollection 2016.
α-L-Aspartyl-D-phenylalanine methyl ester (L, D-APM) and α-D-aspartyl-L-phenylalanine methyl ester (D, L-APM) are diastereomers of aspartame (N-L-α-Aspartyl-L-phenylalanine-1-methyl ester, L, L-APM). The Joint FAO/WHO Expert Committee on Food Additives has set 0.04 wt% as the maximum permitted level of the sum of L, D-APM and D, L-APM in commercially available L, L-APM. In this study, we developed and validated a simple high-performance liquid chromatography (HPLC) method using an ODS column to determine L, D-APM and D, L-APM in L, L-APM. The limits of detection and quantification, respectively, of L, D-APM and D, L-APM were found to be 0.0012 wt% and 0.004 wt%. This method gave excellent accuracy, repeatability, and reproducibility in a recovery test performed on five different days. Moreover, the method was successfully applied to the determination of these diastereomers in commercial L, L-APM samples. Thus, the developed method is a simple, useful, and practical tool for determining L, D-APM and D, L-APM levels in L, L-APM.
2.Conformational Flexibility of Aspartame.
Toniolo C1, Temussi P2,3. Biopolymers. 2016 Apr 2. doi: 10.1002/bip.22847. [Epub ahead of print]
L-Aspartyl-L-phenylalanine methyl ester, better known as aspartame, is not only one of the most used artificial sweeteners, but also a very interesting molecule with respect to the correlation between molecular structure and taste. The extreme conformational flexibility of this dipeptide posed a huge difficulty when researchers tried to use it as a lead compound to design new sweeteners. In particular, it was difficult to take advantage of its molecular model as a mold to infer the shape of the, then unknown, active site of the sweet taste receptor. Here, we follow the story of the 3D structural aspects of aspartame from early conformational studies to recent docking into homology models of the receptor. This article is protected by copyright. All rights reserved.
3.Aspartame, a bittersweet pill.
Paolini M1, Vivarelli F2, Sapone A2, Canistro D2. Carcinogenesis. 2016 Feb 24. pii: bgw025. [Epub ahead of print]
For the first time, the aspartame case shows how a corporation decided to ban an artificial ingredient in the wake of public opinion notwithstanding the regulatory assurance claims that it is safe. PepsiCo Inc. made an unprecedented decision most likely based on life-span carcinogenicity bioassay studies from the Cesare Maltoni Cancer Research Center of the Ramazzini Institute (CMCRC/RI), which provide consistent evidence of aspartame's carcinogenicity in rodents. Although CMCRC/RI experiments have been criticized for not complying with Organisation for Economic Co-operation and Development (OECD) guidelines, the newly launched aspartame-free soft drink may not be an isolated case. In the light of vinyl chloride-, formaldehyde- or benzene-associated carcinogenicity discovered for the first time by CMCRC/RI in the same way, it seems the guidelines need to be re-evaluated to avoid the credibility of international regulatory agencies being compromised by consumer opinion.
