Using MALDI MS for rapid analysis of food lipids

Abstract

Matrix-assisted laser desorption/ionization (MALDI) is an ionization method that produces intact lipid molecule species that can be separated and characterized by mass spectrometry. Recent research has concentrated on using rapid MALDI MS lipid analysis that employs little sample cleanup, simple sample preparation, no chemical derivatization, and minimal chromatography. This article takes a look at selected MALDI MS applications for edible oils and lipid rich foods, such as meat and eggs, and explores potential uses in food and lipid science.

Synthesis of EPA- and DHA-Enriched Structured Acylglycerols at the sn-2 Position Starting from Commercial Salmon Oil by Enzymatic Lipase Catalysis under Supercritical Conditions

“…Thus, they show a different behavior from that observed in the initial oil, according to the fact that visualization of the compounds requires the use of a matrix, which would be one of the factors that favor the fragmentation of the compounds [ 14 , 46 ]. Additionally, the ionization process, although corresponding to a soft type, can induce the fragmentation of TG to originate DG or FFA, artificially increasing the content of the samples [ 47 , 48 ]; this fact would explain the difference between values observed in TLC of EPA/DHA sAG and Extraction 3. However, the possibility of greater compounding with DHA and EPA in the sn -2 position is an advantage with respect to the initial oil, since it shows that the extraction conditions in a supercritical fluid (temperature, time and pressure) can be manipulated to exert changes in the positioning of EPA and DHA.…”

Acylglycerol synthesis including EPA and DHA from rainbow trout (Oncorhynchus mykiss) belly flap oil and caprylic acid catalyzed by Thermomyces lanuginosus lipase under supercritical carbon dioxide

“…MALDI-TOF is an important technique that has been used in the characterization of triacylglycerols in different types of oils [37][38][39][40][41], in the determination of oil adulterations [42][43][44] and even in the relative quantification with results comparable to those obtained by gas chromatography [45]. Schiller et al [46], Calvano et al [37] and Picariello et al [42] found that an advantage of MALDI-TOF is the minimal sample preparation, the discrimination ability of the components in the absence of chromatographic separation and the high sensitivity, whereas Shinn et al [40] and Yener and Van Valenberg [40] suggest that the lack of chromatographic separation has the disadvantage of an important suppression effect, for example, polar lipids interfere in the ionization of non-polar lipids, or the more abundant forms of saturated TAGs affect the ionization of less abundant unsaturated TAGs, which would explain the low intensity of the identified signals shown in the Fig. 3 (a) at m/z 685.4177 and m/z 691.3700.…”

“…3 (a) at m/z 685.4177 and m/z 691.3700. Additionally, the ionization process, although of a soft type, can induce the fragmentation of the TAGs to originate DAGs or free fatty acids, artificially increasing the own content of the samples, this explaining the large amount of signals observed in the range m/z 580-650 of the spectrum [37][38][39][40]48] and the DAG with EPA and DHA seen in the purified TAG sample Fig.…”

“…On the other hand, the visualization of the compounds requires the use of a matrix, which would be one of the factors that favor the fragmentation of the compounds, as well as providing signals to the spectrum up to m/z 500, thus making the identification more complex [37][38][39][40][41][42][43][44][45][46][47][48][49]. Interestingly, identification by MALDI-TOF can be considered as tentative where the high resolution provided ensures a high certainty in the identification; however, the structural confirmation of the position of the fatty acids in the structure of the TAGs would only be possible through fragmentation [37, 39, 43 and 45].…”