Characterisation of traditional Macedonian edible oils by their fatty acid composition and their volatile compounds

Abstract

The fatty acid composition and volatile compounds of selected traditional Macedonian edible oils of several varieties, including sunflower seeds, pumpkin seeds, flax seed, rapeseed and sesame seeds, were analysed. The fatty acid (FA) composition was determined by GC-FID analysis after transesterification into the corresponding methyl esters. α-Linolenic acid (C18:3) was the main unsaturated fatty acid in flax seed oil (56.2% of total FA), oleic acid (C18:1) dominated in rapeseed and sesame seed oils (65.3 and 43% of total FA, respectively), and linoleic acid (C18:2) was the dominant compound in sunflower and pumpkin seed oils (59.2 and 59.5% of total FA, respectively). The volatile flavour compounds were determined using headspace solid phase microextraction (HS-SPME) using a DVB/Carboxen/PDMS fibre, coupled with gas chromatography-mass spectrometry (GC-MS). In total 97 volatile compounds were detected revealing a very complex aroma profile of the oils, composed of acids, alcohols, aldehydes, alkanes, alkenes, esters, furans, pyrazines, sulphur compounds and terpenes. Among them, aldehydes presented the highest proportion of the overall volatiles in rapeseed oil (76.8% of the total volatiles), followed by sesame seed oil (25% of the total volatiles), pumpkin seed (5.45% of the total volatiles), flax seed oil (2.5% of the total volatiles) and sunflower seed oil (0.95% of the total volatiles). Terpenes (41 detected) were the dominant compounds in sunflower seed oil and pumpkin seed oil (93.9 and 87.8% of the total terpenes, respectively), followed by flax seed oil (47.6% of the total terpenes), sesame seed oil (21.5% of the total terpenes) and rapeseed oil (10% of total the terpenes). Sunflower seed and pumpkin seed oil showed the highest number of volatile compounds identified, with the highest number of terpenes and esters within the investigated products.

Reaction pathway mechanism of thermally induced isomerization of 9,12-linoleic acid triacylglycerol

“…Poyato et al reported that aldehydes are formed during edible oil degradation even at temperatures as low as 180 °C, and the amount of aldehydes increase with temperature and time. Ivanova‐Petropulos et al further confirmed that the exact composition of aldehydes in edible oils includes alkanals, alkenals and alkadienals. Our results show that the increase in absorption at 1714 cm −1 in trilinolein and trilinoelaidin is not obvious at 180 and 240 °C (Fig.…”

Effects of Aromatic Herb Flavoring on Carotenoids and Volatile Compounds in Edible Oil From Blue Sweet Lupin (Lupinus angustifolius)

“…Further, phytochemicals are reported to act as pro‐oxidants at very high concentrations, which can explain the different VOC profiles of sage and thyme flavored oils. Previous studies performed on edible oils correlated the presence of C6 aldehydes such as hexanal with green, apple, or grass aroma . Within the group of alcohols, sage was the only flavored oil to lack of hexanol, which was a major compounds of the other oils.…”

Influence of thermal treatment on the stability of vegetable “milk” obtained by ultrafiltration of aqueous oil body extracts from various sources

“…Likewise to H‐U, α ‐pinene was the main terpene, representing ∼41% of the total amount, followed by β ‐pinene, limonene, 3‐carene, trans ‐ β ‐ocimene, as well as linalool. The last compound has been identified as dominant in SS oil . Furthermore, nine carbonyl compounds (e.g., hexanal, nonanal, heptanal, 4‐methyl‐2‐hexanone, etc.…”