Discovery of Unexpected Sphingolipids in Almonds and Pistachios with an Innovative Use of Triple Quadrupole Tandem Mass Spectrometry

Abstract

The densely packed storage of valuable nutrients (carbohydrates, lipids, proteins, micronutrients) in the endosperm of nuts and seeds makes the study of their complex composition a topic of great importance. Ceramides in the total lipid extract of some ground almonds and pistachios were searched with a systematic innovative discovery precursor ion scan in a triple quadrupole tandem mass spectrometry, where iso-energetic collision activated dissociation was performed. Five descriptors were used to search components with different C18 long chain bases containing different structural motifs (d18:0, d18:1, d18:2, t18:0, t18:1). The presence of hexoside unit was screened with a specific neutral loss experiment under iso-energetic collision activated dissociation conditions. The discovery scans highlighted the presence of two specific hexosyl-ceramides with a modified sphingosine component (d18:2) and C16:0 or C16:0 hydroxy-fatty acids. The hexosyl-ceramide with the non-hydroxylated fatty acid seemed specific of pistachios and was undetected in almonds. The fast and comprehensive mass spectrometric method used here can be useful to screen lipid extracts of several more seeds of nutraceutical interest, searching for unusual and/or specific sphingosides with chemically decorated long chain bases.

From untargeted metabolomics to the multiple reaction monitoring‐based quantification of polyphenols in chocolates from different geographical areas

“…On the basis of their molecular mass, these signals were associated to sphingolipids derivatized with oligosaccharide chains of different length. Recently, other authors reported the unexpected occurrence of sphingolipids in almonds and pistachios samples with intense signals at 714.6 m/z (GlcCer(t18:2/16:0)) and 698.6 m/z (GlcCer(d18:2/16:0)) 25 . In the pooled chocolate samples, an additional hydroxylation signal was observed at 730.9 m/z with a further mass increment of 16 m/z (Table 2).…”

LC–MS based metabolic fingerprinting of apricot pistils after self-compatible and self-incompatible pollinations

“…This compound was proposed to be a plant sphingolipid, a member of the hydroxy sphingosine family. Sphingosine compounds were shown to take part in signalling pathways (Luttgeharm et al 2016) and the presence of such compounds was also confirmed in Prunus, i.e., almond kernels (Rubino et al 2020). The biosynthesis of plant sphingosine compounds includes the transportation of ceramide to Golgi apparatus, where ceramidases hydrolyse them to yield sphingosine and fatty acid.…”

“…This compound was proposed to be a plant sphingolipid, a member of the hydroxy sphingosine family. Sphingosine compounds were shown to take part in signalling pathways (Luttgeharm et al 2016 ) and the presence of such compounds was also confirmed in Prunus , i.e., almond kernels (Rubino et al 2020 ).…”

Preservation of Phytonutrients, Antioxidants, and Minor Lipids in Palm Oil through Mild Thermal Processing

“…Sphingolipids were not detected as markers of mild-heat pressed CPO in the crude fraction of palm oil, possibly due to the removal of neutral lipids and fatty acids through SPE of the polar lipid analysis. Rubino et al also reported that triglycerides could interfere with fragment ions of sphingosine ceramides, preventing the detection of sphingolipids . Despite the minute differences in lipid profiles between mild-heat and high-heat pressed CPO, the lipidomic analysis revealed that mild-heat pressed CPO contains 4–8 times higher levels of specific galactolipids and 3–4 times higher level of sphingolipids.…”