A Comparative Lipidomic Analysis of Wild Rice Versus White and Brown Rice

Objectives As a staple food in the Native American diet, wild rice (Zizania spp.) is an edible grass native to the Great Lakes region. Wild rice contains about one % of lipids. Previous studies have determined its fatty acid composition, but the composition of its lipidome was not examined in detail. This study sought to examine the lipidome of wild rice and provide a comparison to the lipidomes of white and brown rices. Methods In this study, lipid fractions of six commercially available wild rice samples (Zizania spp.), one traditionally-harvested wild rice sample (Zizania spp.), three white rice samples (Oryza spp.), and three brown rice samples (Oryza spp.) were extracted by hexane and ethyl acetate, dried in nitrogen gas, and then reconstituted in n-butanol for liquid chromatography-mass spectrometry (LC-MS)-based lipidomic analysis. Multivariate data analysis was performed using principal components analysis and orthogonal partial least squares-discriminant analysis. Models visualized the distinguishing features of each rice and provided information for a database search of selected markers and subsequent comparison to authentic standards. Results The multivariate model constructed by the LC-MS data of these samples showed clear separation of wild rice samples from white and brown rice samples, suggesting different lipid profiles of wild versus white and brown rice. Wild rice contained higher abundances of linolenic acid-containing triacylglycerol species, but less palmitic acid- and stearic acid-containing triacylglycerol species. Subtle differences between wild rice harvested in Minnesota versus wild rice harvested outside of Minnesota were also observed through lipidomic comparison. Interestingly, 10-demethylsqualene emerged as a prominent feature separating wild rice from white and brown rice through specific analysis of the phytosterol content of wild rice. Conclusions LC-MS-based lipidomic analysis of in-tact triacylglycerol species as well as a comprehensive profiling of the wild rice lipidome in comparison to that of white and brown rice was performed. These insights provide a compelling rationale for increasing consumer awareness of the benefits of wild rice consumption. Funding Sources W. Mosher was supported by the University of Minnesota CFANS Diversity Scholars Fellowship.

Comparative Analysis of Milk Triglycerides Profile between Jaffarabadi Buffalo and Holstein Friesian Cow

Milk lipids are known for a variety of biological functions, however; little is known about compositional variation across breeds, especially for Jaffarabadi buffalo, an indigenous Indian breed. Systematic profiling of extracted milk lipids was performed by mass spectrometry across summer and winter in Holstein Friesian cow and Jaffarabadi buffalo. Extensive MS/MS spectral analysis for the identification (ID) of probable lipid species using software followed by manual verification and grading of each assigned lipid species enabled ID based on (a) parent ion, (b) head group, and (c) partial/full acyl characteristic ions for comparative profiling of triacylglycerols between the breeds. Additionally, new triacylglycerol species with short-chain fatty acids were reported by manual interpretation of MS/MS spectra and comparison with curated repositories. Collectively, 1093 triacylglycerol species belonging to 141 unique sum compositions between the replicates of both the animal groups were identified. Relative quantitation at sum composition level followed by statistical analyses revealed changes in relative abundances of triacylglycerol species due to breed, season, and interaction effect of the two. Significant changes in triacylglycerols were observed between breeds (81%) and seasons (59%). When the interaction effect is statistically significant, a higher number of triacylglycerols species in Jaffarabadi has lesser seasonal variation than Holstein Friesian.

Chemical characterization and thermal properties of kernel oils from Tunisian peach and nectarine varieties of Prunus persica

A comparative study was conducted to determine the fatty acids, triacylglycerol compositions and thermal properties of Tunisian kernel oils from the Prunus persica varieties, peach and nectarine, grown in two areas of Tunisia, Gabes and Morneg. Qualitatively, the fatty acids composition and triacylglycerol species were identical for all samples. Oleic acid (67.7-75.0%) was the main fatty acid, followed by linoleic (15.7-22.1%) and palmitic (5.6-6.3%) acids. The major triacylglycerol species were triolein, OOO (38.4-50.5%), followed by OOL (18.2-23.2%), POO (8.3-9.7%) and OLL (6.3-10.1%). The thermal profiles were highly influenced by the high content of triolein due to the importance of oleic acid in these oils. Moreover, the fatty acids distribution in TAG external positions was determined as corresponding to an α asymmetry coefficient that was between 0.10 and 0.12, indicating a high asymmetry in the distribution of saturated fatty acids in the position sn-1 and sn-3 in the TAG species of all samples.