Microwave roasting effects on the physico‐chemical composition and oxidative stability of sunflower seed oil

Abstract

The purpose of the present study was to explore the influences of microwave heating on the composition of sunflower seeds and to extend our knowledge concerning the changes in oxidative stability, distribution of FA, and contents of tocopherols of sunflower seed oil. Microwaved sunflower seeds (Helianthus annuus L.) of two varieties, KL-39 and FH-330, were extracted using n-hexane. Roasting decreased the oil content of the seeds significantly (P < 0.05). The oilseed residue analysis revealed no changes in the contents of fiber, ash, and protein that were attributable to the roasting. Analysis of the extracted oils demonstrated a significant increase in FFA, p-anisidine, saponification, conjugated diene, conjugated triene, density, and color values for roasting periods of 10 and 15 min. The iodine values of the oils were remarkably decreased. A significant (P < 0.05) decrease in the amounts of tocopherol constituents of the microwaved sunflower oils also was found. However, after 15 min of roasting, the amount of α-tocopherol homologs was still over 76 and 81% of the original levels for the KL-39 and FH-330 varieties, respectively. In the same time period, the level of δ-tocopherol fell to zero. Regarding the FA composition of the extracted oils, microwave heating increased oleic acid 16-42% and decreased linoleic acid 17-19%, but palmitic and stearic acid contents were not affected significantly (P > 0.05).

Effect of microwave and oven roasting on chemical composition, bioactive properties, phenolic compounds and fatty acid compositions of sunflower seed and oils

“…However, partial changes were detected in the amount of fatty acids depending on the applied processes. While the our results obtained were similar to the results of Kiczorowska et al (2019) and Mohammed et al (2017), results were found to be partially lower than the results of Anjum et al (2006). It was determined that there was no difference in the fatty acid compositions of rice and sesame seed oils, which were heat treated at different roasting temperatures, over time (Kim et al, 2002).…”

Effect of microwave and oven roasting on chemical composition, bioactive properties, phenolic compounds and fatty acid compositions of sunflower seed and oils

“…However, partial changes were detected in the amount of fatty acids depending on the applied processes. While the our results obtained were similar to the results of Kiczorowska et al (2019) and Mohammed et al (2017), results were found to be partially lower than the results of Anjum et al (2006). It was determined that there was no difference in the fatty acid compositions of rice and sesame seed oils, which were heat treated at different roasting temperatures, over time (Kim et al, 2002).…”

Effect of roasting on oxidative and tocopherol stability of walnut oil during storage in the dark

“…The values of retention of tocopherols in different oils reported on previous study was comparable to this study; the retention of γ‐tocopherol was >80% in sesame oil 32. Anjum et al 30 reported that α‐tocopherol in two varieties of sunflower oil was retained from 76 to 81% whereas γ‐tocopherol was not retained in both varieties of sunflower oil. However, the tocopherol contents increased by roasting in different oils such as safflower (α‐tocopherol from 386 to 441 and 520 µg/g during roasting at 140 and 180°C, respectively), rice germ (α‐tocopherol from 1307.6 to 1457.5 and γ‐tocopherol from 115.3 to 137.9 during roasting at 160°C for 15 min), mustard (total tocopherol from 602.09 to 641.78 µg/g) due to release of tocopherol by rupturing membrane, and also by breaking the bond between tocopherol and phospholipid or protein 14, 26, 29.…”

Physico‐chemical, Sensory and Aromatic Properties of Cold Press Produced Safflower Oil

“…Although the amount of a-tocopherol measured in this study is in good agreement with the previous studies, other tocopherols and tocotrienols were not quantified. In addition, similar to the finding of Anjum et al [34] for sunflower seed oils, microwave treatment caused a significant decrease in the tocopherol level of the oil. The sterol composition of the samples is also shown in Table 4.…”

Effect of microwave and oven roasting on chemical composition, bioactive properties, phenolic compounds and fatty acid compositions of sunflower seed and oils

“…However, partial changes were detected in the amount of fatty acids depending on the applied processes. While the our results obtained were similar to the results of Kiczorowska et al (2019) and Mohammed et al (2017), results were found to be partially lower than the results of Anjum et al (2006). It was determined that there was no difference in the fatty acid compositions of rice and sesame seed oils, which were heat treated at different roasting temperatures, over time (Kim et al, 2002).…”

Effect of roasting on oxidative and tocopherol stability of walnut oil during storage in the dark

“…The values of retention of tocopherols in different oils reported on previous study was comparable to this study; the retention of γ‐tocopherol was >80% in sesame oil 32. Anjum et al 30 reported that α‐tocopherol in two varieties of sunflower oil was retained from 76 to 81% whereas γ‐tocopherol was not retained in both varieties of sunflower oil. However, the tocopherol contents increased by roasting in different oils such as safflower (α‐tocopherol from 386 to 441 and 520 µg/g during roasting at 140 and 180°C, respectively), rice germ (α‐tocopherol from 1307.6 to 1457.5 and γ‐tocopherol from 115.3 to 137.9 during roasting at 160°C for 15 min), mustard (total tocopherol from 602.09 to 641.78 µg/g) due to release of tocopherol by rupturing membrane, and also by breaking the bond between tocopherol and phospholipid or protein 14, 26, 29.…”

Physico‐chemical, Sensory and Aromatic Properties of Cold Press Produced Safflower Oil

“…Although the amount of a-tocopherol measured in this study is in good agreement with the previous studies, other tocopherols and tocotrienols were not quantified. In addition, similar to the finding of Anjum et al [34] for sunflower seed oils, microwave treatment caused a significant decrease in the tocopherol level of the oil. The sterol composition of the samples is also shown in Table 4.…”

Effect of microwave and oven roasting on chemical composition, bioactive properties, phenolic compounds and fatty acid compositions of sunflower seed and oils

“…However, partial changes were detected in the amount of fatty acids depending on the applied processes. While the our results obtained were similar to the results of Kiczorowska et al (2019) and Mohammed et al (2017), results were found to be partially lower than the results of Anjum et al (2006). It was determined that there was no difference in the fatty acid compositions of rice and sesame seed oils, which were heat treated at different roasting temperatures, over time (Kim et al, 2002).…”

Effect of roasting on oxidative and tocopherol stability of walnut oil during storage in the dark

“…The values of retention of tocopherols in different oils reported on previous study was comparable to this study; the retention of γ‐tocopherol was >80% in sesame oil 32. Anjum et al 30 reported that α‐tocopherol in two varieties of sunflower oil was retained from 76 to 81% whereas γ‐tocopherol was not retained in both varieties of sunflower oil. However, the tocopherol contents increased by roasting in different oils such as safflower (α‐tocopherol from 386 to 441 and 520 µg/g during roasting at 140 and 180°C, respectively), rice germ (α‐tocopherol from 1307.6 to 1457.5 and γ‐tocopherol from 115.3 to 137.9 during roasting at 160°C for 15 min), mustard (total tocopherol from 602.09 to 641.78 µg/g) due to release of tocopherol by rupturing membrane, and also by breaking the bond between tocopherol and phospholipid or protein 14, 26, 29.…”

Physico‐chemical, Sensory and Aromatic Properties of Cold Press Produced Safflower Oil

“…Although the amount of a-tocopherol measured in this study is in good agreement with the previous studies, other tocopherols and tocotrienols were not quantified. In addition, similar to the finding of Anjum et al [34] for sunflower seed oils, microwave treatment caused a significant decrease in the tocopherol level of the oil. The sterol composition of the samples is also shown in Table 4.…”