Lipidomic Profile of <i>Rhodotorula toruloides</i> by GC/MS and Antioxidant Capacity of the Oil by DPPH and TLC-Plate Methods

Abstract

This work was undertaken to evaluate the antioxidant capacity of Rhodotorula toruloides lipid extract in TLC plate, using the (DPPH) (1,1-diphenyl-2-picril-  hydrazine) method as an innovative way to visualise lipid groups that comprise this activity. Similarly, carotenoids and crude oil were analysed for  antioxidant capacity by the DPPH and β-carotene/linoleic acid methods. The lipidomic profile extract analysis was performed by GC/MS and HPLC/DAD.  The sample preparation for the GC/MS analysis was made by ultrasound-assisted transesterification. Free compounds were silylated with BSTFA (N,O-Bis  (trimethylsilyl) trifluoracetamide) + 1% TMCS (Trimethylchlorosilane). The analysis of the lipid extract showed that in the saponifiable fraction saturated  fatty acids (SFA) and monounsaturated fatty acids (MUFA) were present; and in the unsaponifiable fraction were steroids and carotenoids. The antioxidant  capacity was expressed as IC₅₀ reaching 6.4 mg/L that means relative efficiency. The oil profile, using TLC, shows the chemical groups:  carotenoids, acylglycerols, free fatty acids and steroids. Similarly, the GC/ MS analysis shows the fatty acids and steroids. The HPLC analysis describes the  carotenoids profile, highlighting b-carotene as the majority and the presence of β-carotene-5,8-epoxide, zeaxanthin and b-cryptoxanthin, characterising  the lipidomic study of this yeast.