Lipidomic Analysis for Discriminating Fermented and Non-Fermented Pearl Millet (Pennisetum Glaucum L.) Grains during Storage using Multivariate Data Analysis

Fatty acids (FAs) are the building block of fats or lipids and the key indicator for rancidity during grain storage. The pearl millet grains were subjected to lactobacillus (LAB) fermentation and changes in their lipidomic profile with respect to different storage conditions were analysed. This study scrutinised the effect of storage period and temperature (5, 25, and 45 °C) on the lipidomic profile of raw and fermented pearl millet grains stored for 120 days through the FA analysis. A total of 23 FA compounds were identified in raw and fermented grains during storage. The predominant FAs identified in both the control and fermented pearl millet grains are linoleic, oleic, palmitic, alpha-linolenic, and steric acids. It can be observed that the unsaturated FAs such as linoleic and oleic acids are prone to oxidation during storage, contribute to rancidity of the grains. Multivariate data analysis shows that the oPLS-DA and sPLS-DA could distinctly classify the lipidomic data as compared to PLS-DA with respect to various storage conditions. A high value of the variable importance in projection score (VIP> 1) indicates a significant contribution of the FAs to cluster separation. The idea of the lipidomic profile of FA analysis at a particular time period will be helpful for the endorsement of applicable remedial measures so as to minimize grain quality loss and recommending a use-by-date.