Changes in Volatile Compound Profiles in Cold-Pressed Oils Obtained from Various Seeds during Accelerated Storage

Abstract

Cold-pressed oils are highly valuable sources of unsaturated fatty acids which are prone to oxidation processes, resulting in the formation of lipid oxidation products, which may deteriorate the sensory quality of the produced oil. The aim of the study was to determine the main volatile compounds which differentiate examined oils and could be used as the markers of lipid oxidation in various oils. In the experiment, cold-pressed oils—brown flaxseed, golden flaxseed, hempseed, milk thistle, black cumin, pumpkin, white poppy seed, blue poppy seed, white sesame, black sesame and argan oils from raw and roasted kernels—were analyzed. To induce oxidative changes, an accelerate storage test was performed, and oils were kept at 60 °C for 0, 2, 4, 7 and 10 days. Volatile compound profiling was performed using SPME-GC-HRToFMS. Additionally, basic measurements such as fatty acid composition, peroxide value, scavenging activity and phenolic compound contents were carried out. Multivariate statistical analyses with volatile compound profiling allow us to differentiate oils in terms of plant variety, oxidation level and seed treatment before pressing. Comparing black cumin cold-pressed oil with other oils, significant differences in volatile compound profiles and scavenging activity were observed. Compounds that may serve as indicators of undergoing oxidation processes in flaxseed, poppy seed, milk thistle and hemp oils were determined.

Intestinal, liver and lipid disorders in genetically obese rats are more efficiently reduced by dietary milk thistle seeds than their oil

“…From the study design perspective, a very important question was that the fatty acid profile of the milk thistle seeds and milk thistle seed oil was similar. The main PUFA of the seeds and oil was linoleic acid (53.0% and 55.1%, respectively), and these results were generally in agreement with the literature 13 , 32 . Moreover, the seeds and oil were a relatively poor source of α -linolenic acid (0.12% and 0.13%, respectively) and similar proportions of this fatty acid were determined by Zarrouk et al 32 and Rokosik et al 30 .…”

“…Interestingly, Zhang et al 31 also reported that the milk thistle seed oil can be a good source of MUFAs, which can comprise over 30% of total fatty acids, and this proportion was higher than that of the present study both for the seeds and oil (24.7% and 23.7%, respectively). According to the literature, the main MUFA in the milk thistle seed oil is oleic acid 13 , which equaled 24.1% of total fatty acids, and comparable proportions of this acid was also determined in this study (23–24%).…”

“…Milk thistle seeds also contain significant amounts of oil (20–23%), which is considered as a by-product of silymarin industrial production 11 . This oil is rich in unsaturated fatty acid and can also be a valuable foodstuff 12 , because it is rich in linoleic acid and oleic acid, the proportions of which can be up to 54% and 24% of total fatty acid, respectively 13 . Furthermore, some authors have reported the presence of other bioactive compounds in the oil fraction of this seeds, such as phytosterols ( β -sitosterol, δ -7-stigmasterol, stigmasterol, campesterol) and α -tocopherol 12 , 14 .…”

Physicochemical Properties, Fatty Acid Composition, Volatile Compounds of Blueberries, Cranberries, Raspberries, and Cuckooflower Seeds Obtained Using Sonication Method

“…Oil deterioration is mainly associated with volatile compounds such as aldehydes, ketones, esters, and furan derivatives, which are formed as a result of lipid oxidation processes [47,48], especially the auto-oxidation of unsaturated fatty acids. Several compounds, including hexanal or nonanal, are used as markers to detect the oxidation of lipids [49,50].…”

Effect of Frying and Roasting Processes on the Oxidative Stability of Sunflower Seeds (Helianthus annuus) under Normal and Accelerated Storage Conditions

“…Similar results were reported for sunflower seeds [34] with 5.00-6.10% of palmitic, 2.53-3.24% of stearic, 54.1-54.1% of oleic, and 32.3-41.0% of linoleic fatty acids. Additionally, other seeds such as hemp, pumpkin, brown flaxseed, golden flaxseed, blue poppy seed, and white poppy seed oils have shown similar fatty acid composition [35][36][37]. Regarding fried samples, linoleic acid (77.40 ± 0.02%) was the highest fatty acid at the beginning of the storage period followed by oleic (14.31 ± 0.02%), palmitic (4.56 ± 0.19%), and, finally, stearic (3.73 ± 0.15%) acids.…”