Abstract:

A reversed-phase high-performance liquid chromatography （HPLC） method was developed for the direct determination of docosahexaenoic acid （DHA） in sturgeon caviar extract. The assay employed n-hexane extraction combined with gradient elution （ZORBAX SB-C₁₈ column）, with data collected using a diode array detector. The content was calculated by external standard method and validated against the national standard （GB 5009.168－2016）. The study also measured DPPH free radical scavenging capacity and moisture retention rate across different DHA concentration groups. The results demonstrate that the proposed method exhibits excellent linearity （r=0.999 7）, with recovery rates ranging from 92.1% to 101.1% and relative standard deviations （RSD） of 2.23% to 3.92%. Compared to the national standard method, the relative deviation was 0.67% to 1.68%. At specific test concentrations, the high-DHA group shows significantly higher moisture retention （100.48%）, hygroscopicity （100.85%）, and DPPH scavenging efficiency （57.46%） than the low-DHA group （10.33%, 11.76%, and 3.71%）. The RP-HPLC method developed in this study simplifies DHA detection procedures with simple reagents and reliable results, making it suitable for rapid qualitative identification and quantitative analysis of target components in caviar extract quality control. The DPPH experiment further reveals the correlation between DHA content and antioxidant efficacy in sturgeon caviar extracts, providing scientific evidence for developing functional cosmetics.

Key words: reverse-phase high-performance liquid chromatography, DHA, sturgeon roe extract, moisturizing capacity, antioxidant activity, method validation