Effect of roasting temperature on bioactive compounds, antioxidant activity, phenolic profile, chemical properties, and oil extraction method on fatty acids composition of chia (Salvia hispanica L.) seeds and oil

Abstract

AbstractIn this study, the effects of roasting chia seeds at different temperatures (90 and 120 °C) on total phenol, flavonoid, and carotenoid contents and antioxidant activities were examined. Additionally, the effects of different extraction methods on the phenolic components of chia seeds and the chemical properties and fatty acids of chia seed oils were investigated. Chia seed oil was extracted via Soxhlet without roasting as control, yielded 29.62%. The oils from seeds roasted at 90 °C and 120 °C had yields of 32.65% and 33.85%. The control oil had an acidity value of 4.70%. In comparison, the acidity values were 4.20% and 3.61% for the oils from seeds roasted at 90 °C and 120 °C. The total phenol result of the control sample was found to be 2.55 mg GAE/g, while the total phenol contents in Chia samples roasted at 90 °C and 120 °C are determined as 2.34 mgGAE/g and 2.14 mg GAE/g, respectively. Also, the flavonoid contents of the roasted chia samples (90 °C and 120 °C) were reported as 13.71 mgCE/g and 12.91 mgCE/g, respectively. It was observed that the application of roasting caused a decrease in quercetin and resveratrol values (p < 0.01). The highest antioxidant value (80.13%) was established in chia sample roasted at 90 °C. Quercetin, catechin, resveratrol, kaempferol and izorhamnetin were the main phenolic components of chia seeds. Other phenolic components such as syringic acid, p-cuoumeric acid, caffeic acid, and gallic acid were found at quite low levels. It was observed that of roasting application caused a decrease in quercetin and resveratrol values. The highest fatty acids in chia seeds were linoleic and linolenic acids. Linolenic and linoleic acid results of chia oils were recorded to be between 64.58 and 68.10% to 17.30 and 18.44%, respectively. The palmitic, stearic, oleic, linoleic and linolenic (except sonication) acid contents of the chia oils obtained by Soxhlet and sonication systems from roasted seeds were found high compared to the control.