Detection of edible insect derived phospholipids with polyunsaturated fatty acids by thin-layer chromatography, gas chromatography, and enzymatic methods

Abstract

Dietary phospholipid (PL) intake from various animals and plants accounts for about 10 % of total lipids; however, the presence of PLs and their species in edible insects have yet to be fully reported. We therefore investigated the quantity and quality of PLs in edible insects (crickets, migratory locusts, and silkworms) using thin-layer chromatography (TLC), gas chromatography (GC), and enzymatic methods. Separation of PLs from total lipids extracted by a Folch method (chloroform and methanol mixture) was achieved using a two-dimensional TLC method. Based on retention factor values, this method successfully separated phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine, lysophosphatidylcholine, and cardiolipin (CL). Crickets contained higher levels of choline-binding PLs than either migratory locusts or silkworms. Fatty acid profiles of triglyceride (TG) and PL fractions from a one-dimensional TLC method reflected those of total lipids from GC analysis. Crickets were rich in TGs and PLs (PC and PE/CL), which bound n-6 polyunsaturated fatty acids (PUFAs), whereas migratory locusts and silkworms were rich in TGs and PE/CL, which bound n-3 PUFAs. A modified enzymatic quantitative PC-specific analysis showed that PC was the dominant PL in edible insects. In conclusion, edible insects, particularly migratory locusts and silkworms, may be novel sources of n-3 PUFAs containing functional PLs.