Variability of Essential and Nonessential Fatty Acids of Irish Rapeseed Oils as an Indicator of Nutritional Quality

Abstract

The low saturated fatty acid content of rapeseed oil has resulted in it being classed as one of the most health-benefiting culinary oils. This study determines whether Irish rapeseed oils contain identical fatty acid profiles or whether distinct profiles exist between producers and producers’ successive oil batches. The fatty acid content of Irish rapeseed oils was determined in terms of the desirable MUFA and PUFA and saturated content of these oils. The fatty acid composition demonstrated significant differences in individual unsaturated fatty acid content, while total saturation had insignificant differences. Saturated fatty acid content ranged from 6.10 to 15.8%, while unsaturated fatty acids ranged from 84.20 to 90.10%. Moreover, individual fatty acid content exhibited significant differences ( p < 0.05 ). Oleic acid (C18:1), linoleic acid (C18:2), and stearic acid (C18:0) contents were considered significantly different from other fatty acids detected. The third successive batch from each producer exhibited lower oleic acid content, and the third batch contained higher linoleic acid content, at the same time maintaining a desirable unsaturated fatty acid composition. Studies suggest that differences in the fatty acid composition may be due to cultivation practices such as climate, soil composition, sowing and harvesting, processing techniques, and oxidation reactions.

Analysis of volatile organic compounds in Irish rapeseed oils

“…Specific aldehydes are formed through lipid oxidation, hexanal is generated through oxidation of linoleic acid while octanal and nonanal, which are present in low amounts in rapeseed oils, are oleic acid derivatives ( Ivanova-Petropulos et al, 2015 ). Furthermore, it has been established that the Irish rapeseed oils tested here are abundant in linoleic acid and oleic acid which can justify the higher aldehyde content observed ( Coughlan et al, 2022 ).…”

“… Jing et al (2020) states that the roasted and nutty descriptors of rapeseed oils is derived from octanal, butanal and nonanal (via fatty acid degradation) which have high OAV resulting in the rapeseed possessing these sensory qualities ( Jing et al, 2020 ). Thus, the difference in “nuttiness” between the rapeseed oils may be attributed to the variations observed in the linolenic acid content of these oils ( Coughlan et al, 2022 ).…”

“…These differences may be attributed to pre-processing techniques, seed variety, or fatty acid composition ( Zhang et al, 2019 ). Coughlan et al, 2022 , previously proved that these Irish rapeseed oils do not contain the same fatty acid profile, which may be a significant contributor to the variation observed in the volatile profile due to individual fatty acid differences which may have given rise to the differentiation between the oils in terms of sensory properties. The Irish rapeseed oils in this study demonstrated variance in fatty acid composition whereby the individual fatty acids were statistically significant with respect to abundance (p=<0.050) demonstrating variability between producers and batches alike ( Coughlan et al, 2022 ).…”

“…Oleic acid (C18:1) ranged from 34.17% to 66.03%, linoleic acid (C18:2) content ranged from 13.00% to 40.99% and stearic acid (C18:0) content ranged from 1.48% to 4.34%. These fatty acids were considered statistically significant with respect to abundance (p=<0.050) demonstrating variability between producers and batches alike ( Coughlan et al, 2022 ). Hence, fatty acids of different concentrations may be a significant contributor to the variance in VOCs such as aldehydes, ketones, and alcohols.…”

A Comprehensive Review of Health-Benefiting Components in Rapeseed Oil

“…Rapeseed oil is also known as canola oil or Brassica oil. Brassica is widespread in various conditions all over the world [ 6 ]. It is reported that Canada, Europe, and China are the leading producers of rapeseed oil in the world.…”