Effects of infrared treatment on some constituents and properties of safflower (Carthamus tinctorius L.) seed

Safflower (Carthamus tinctorius L.), a member of Asteraceae/Compositae family, is a herbaceous annual oilseed crop. Safflower seeds, with their phenolic and flavonoid components, as well as serotonin derivatives, can exhibit health-beneficial effects such as antidiabetic, antimicrobial and anti-inflammatory effects, antioxidant activity, α-glucosidase inhibitory and tyrosinase inhibitory effects. Infrared (IR) treatment has obtained a great interest in the food industry, due to its advantages (short processing time, direct heat penetration, homogeneous temperature distribution, energy saving and low cost) over conventional heating. Infrared treatment has been used for roasting, drying, cooking, sterilization, enzyme inactivation, and for enhancing extraction of many bioactive components (polyphenols, flavonoids, etc.) by disintegrating the structure. To the best of our knowledge, in literature there is no study about the effects of infrared treatment on some components and properties of safflower seeds. Therefore, in this study, safflower seeds (cv. Hasankendi) were infrared treated at different powers (800W, 1000W and 1200W) and times (10 and 20 min). Effects of infrared treatment on protein, ash, color, total phenolic content, total flavonoid content, antioxidant activity (DPPH and CUPRAC), phenolic profile (chlorogenic acid, p-coumaric acid, ferulic acid, rutin, quercetin, luteolin and acacetin), serotonin derivatives (N-(p-coumaroyl) serotonin and N-feruloyl serotonin), tannin content, α-glucosidase inhibitory and tyrosinase inhibitory effects of safflower samples were investigated. Infrared treatment caused a gradual increase (except 800W-10min) in total phenolic content, as the power and time increased. For total flavonoid content, a gradual increase up to 1000W-20min and then a slight decrease at 1200W was observed. As compared to control, infrared treatment at 800W caused an increase in the radical scavenging activity while infrared treatment at 1000W and 1200W caused a decrease. For total antioxidant capacity, lower values were observed for safflower samples infrared treated at 800W, 1000W and 1200W-10min while a higher value was observed for 1200W-20min, as compared to control. Infrared treatment did not cause a significant change in chlorogenic acid, ferulic acid, luteolin (except 1000W-20min and 1200W) and rutin (except 800W-20min and 1200W-20min) content, as compared to control. For other infrared treatments, a significant decrease was observed. A gradual significant decrease in quercetin content was observed for 800W and 1000W-10min treatments. For other infrared treatments, quercetin was not detected. p-coumaric acid was not detected in all samples. Acacetin was first detected at 1000W-20min, and a significant increase was observed as the infrared power and time increased. A significant increase in N-(p-coumaroyl) serotonin content was observed for 800W-20min, 1000W, and 1200W-10min, as compared to control. A slight increase in N-feruloyl serotonin content was observed for 800W and 1000W-10min, and this increase was found to be significant for 800W-20min. For other infrared treatments, a slight decrease was observed for both serotonin derivatives, but this decrease was significant only for 1200W-20min. α-glucosidase inhibition of control sample was 74.23% and decreased to 74.22–69.15% by infrared treatment. Infrared treatment (except 800W-10min) caused an increase in tyrosinase inhibition of safflower samples, and this increase was found to be significant for 1000W-20min and 1200W. Tannin content of safflower samples increased by infrared treatment.