Detection of adulteration in commercial galactooligosaccharide by flow-injection electrospray ionization tandem mass spectrometry

- In galactooligosaccharide product, an adulteration has been detected.
- The adulterated compound was identified as maltitol by the flow-injection ESI-MS/MS.
- Content of the adulterant was 60.2%, which was not indicated on the labeled statement.
- The use of maltitol should be properly controlled for food safety and consumer confidence.

In recent years, a number of adulterants in foods, such as melamine in infant formula and horse meat in beef, have been reported. For ensuring the food safety, proper regulation of these adulterated foods is necessary. In this work, we have studied an adulteration of maltitol in a commercial galactooligosaccharide (GOS) product using the flow-injection electrospray ionization tandem mass spectrometry (ESI-MS/MS) and the MassBank database. Firstly, qualitative analysis of the adulterated maltitol in a GOS product was achieved by the flow-injection ESI-MS/MS in negative ion mode. Secondly, mass spectral data obtained from the ESI-MS/MS were compared with the MassBank database. Lastly, final confirmation and quantitative analysis of the adulterated maltitol was carried out by HPLC-RI using a reference material. As a result, content of the adulterated maltitol in a GOS product was determined to be 60.2%, which was not indicated on the label. On the other hand, unlike the labeled statement, content of raffinose was only 18.4% instead of labeled 100%. Although maltitol is generally considered to be safe, it is also known that large quantities of maltitol can have a laxative effect. Furthermore, consumers have the rights to know what are in the foods they eat. Therefore, food adulterations, including this case of maltitol, should be properly controlled by the regulatory authorities.