Optimization of HS-SPME combined with GC–MS for key marker volatile organic compound analysis in Kappaphycus alvarezii with a chemometric approach

Kappaphycus alvarezii is one of the most essential edible seaweeds in the global trade of marine products. The product quality will directly influence the flavor, odor, and impact on the human health of this edible seaweed. These functions are associated with volatile organic compound (VOCs) content and are controlled by seaweed cultivation sites. This study investigated VOCs using HS-SPME combined with GC–MS and multivariate analysis to determine the VOCs to be used as key markers for the quality of seaweeds from different cultivation sites. The HS-SPME factors, such as the amount of sample, extraction temperature, and extraction time, were optimized based on Box–Behnken design (BBD) and response surface methodology (RSM) for multi-response optimization (MRO). The precision of the approach varied from 1.17% (alkanes) to 6.30% (carboxylic acids) for repeatability and 3.93% (furans) to 16.64% (sesquiterpenoids) for intermediate precision. This method was applied to samples collected from nine different geographical regions in Indonesia. Principal Component Analysis (PCA) was used to determine data distribution from 48 compounds in K. alvarezii from those different cultivation sites. Based on PCA, four key marker VOCs, including heptadecane, 3-methylbutanoic acid, 2-pentyl furan, and 2-heptanone, were successfully established.