Impact of microwave treatment on polyphenols in safflower seeds and oil

Abstract

This study aimed to evaluate the effects of microwave (MW) treatment on polyphenol forms in safflower seeds and polyphenol compositions in safflower seed oil (SSO) extracted using pressing and subcritical dimethylether extraction (SDE) methods. Results revealed that polyphenols in safflower seeds were predominantly present in free forms (89.51 %), followed by insoluble- (6.19 %) and soluble-bound (4.30 %) forms. MW treatment resulted in a significant increase in the content of free-form phenolics and total phenolic content (TPC). In the untreated and MW-treated samples, 58 phenolics were identified, with45 polyphenols detected in both types of samples. After the MW treatment, N-(p-coumaroyl) serotonin content increased but N-feruloyl serotonin content decreased in safflower seeds. MW treatment significantly increased the acacetin content, TPC, and oxidative stability of SSO. Additionally, the combined effect of MW treatment and SDE significantly improved polyphenol content in SSO, addressing the issue of poor oxidative stability that limits its applications.