Quality evaluation of cold‐pressed edible oils from Macedonia

Abstract

The chemical composition and quality of eight pure cold‐pressed oils and two blend oils from Macedonia were examined in this work. The highest level of oleic acid was determined in apricot kernel oil and rapeseed oil with abundance of 70.9 and 59.2%, respectively. The highest level of polyunsaturated fatty acids was seen for flaxseed and hemp seed oil with abundance of α‐linolenic acid of 55.1% for flaxseed oil and linoleic acid of 57.4% for hemp seed oil. Apricot kernel oil and roasted sesame seed oil had the highest oxidative stability with induction times of 7.6 and 10.9 h. Apricot oil, hemp seed oil, and flaxseed oil had the highest level of total vitamin‐E‐active compounds with 58.8, 58.1, and 69.7 per 100 g of oil with predomination of γ‐tocopherol. The highest peroxide number was detected in blend oils (oil 2 and oil 8) with values over 10 meq O2/kg of oil. The highest FFA was detected in rapeseed oil (1.57%). Roasted and unroasted sesame seed oils had relatively high specific extinction (K232 values 3.55 and 3.33, respectively). However, the highest UV extinction had a blend of pumpkin seed oil and sunflower oil with a value of 3.84. Practical applications: The results of this study can be applied for determination of the most important major and minor components responsible for quality evaluation of cold‐pressed oils. Statistical results indicated a strong relationship between the level of monounsaturated fatty acids in the oil and their oxidative stability. The level of tocopherols and other vitamin‐E‐related compounds was in strong relationship with the antioxidant activity of the oils measured by the DPPH method. Phytosterols, as minor compounds present in the oils, did not contribute significantly to the total antioxidant potential of the oils but, their levels in particular oils, together with fatty acids, can be useful and reliable markers for the purity of the oils and determination of the composition of blends. Score plot of fatty acid profile, induction time, peroxide number, FFA, specific extinction, total phenolic compounds, total flavonoids, DPPH and TEAC assay, vitamin‐E‐active compounds, and phytosterols of ten cold‐pressed edible oils from Macedonia.

Cold-pressed pumpkin seed (<em>Cucurbita pepo</em> L.) oils from the central Anatolia region of Turkey: Characterization of phytosterols, squalene, tocols, phenolic acids, carotenoids and fatty acid bioactive compounds

“…Trace amount of the fatty acids were also identified and these data are similar to those reported by Kostadinovic Velickovska et al, 2015. On the other hand, there are insignificant differences in fatty acid profiles between these results and those reported by Nederal et al, (2014). The differences in profile and amount of certain fatty acids depended on the origin of specific pumpkin (Cucurbita pepo L.) seed oil cultivars, climatic conditions, and post-harvest management (Rabrenovic et al, 2014).…”

“…Significantly higher contents of total phytosterols were determined and total phytosterol contents for the PSO samples which ranged from 782.1 ±9.7 to 805.2 ±11.3 mg/100 g oil. Total phytosterol content in the studied samples is significantly higher than the data reported in the literature (Rabrenovic et al, 2014;Kostadinovic Velickovska et al, 2015). Thus, the high total phytosterol contents in the PSO samples from different regions of Turkey may also be related to the species of pumpkin, although the techniques used for oil extraction from seeds and the isolation procedure of phytosterols from oil may also considerably influence data.…”

“…The quantities of phytosterols in vegetable oils have been used for the classification and assessment of their quality (Rabrenovic et al, 2014;Kostadinovic Velickovska et al, 2015). The cultivation and environmental conditions influence the concentration of phytosterols.…”

Characteristics and Antioxidant Potential of Cold-Pressed Oils—Possible Strategies to Improve Oil Stability

“…The data regarding the flavonoid content in cold-pressed oils are very limited. Macedonian flaxseed oil has been shown to contain about three times more flavonoids than samples analyzed in this study [43]. Interestingly, for flaxseed oils from New Zealand, much higher flavonoid levels values (up to 256 mg LE/kg) were noted than values obtained in this study [26,44].…”

Physicochemical characterization and quality of cold-pressed peanut oil obtained from organically produced peanuts from Macedonian “Virginia” variety

“…Statements in our work are very similar to those made by Tuberoso et al (2007); Kostadinović Veličkovska and Mitrev (2013) and Kostadinović Veličkovska et al (2015) who concluded that free radical scavenging was mainly influenced by the tocopherol content and polyunsaturated fatty acids in oil.…”