Removal of heavy metals and enhancement of flavor from Sargassum fusiforme through sequential processing involving steaming, citric acid, and fermentation

This study investigated the effects of steaming, citric acid washing, and microbial fermentation on heavy metal content and flavor in Sargassum fusiforme. The optimal processing combination (M-5 %ST-5)-sequential steaming (2 h), 0.64 % citric acid (70 °C, 2 h), and 5 % S. thermophilus fermentation (5 days) -significantly reduced As, Cr, and Cd contents from 97.2 ± 4.4, 47.4 ± 3.4, and 4.7 ± 0.1 mg/kg to 5.3 ± 0.8, 3.1 ± 0.2, and 3.3 ± 0.4 mg/kg, achieving removal rates of 94.5 %, 93.5 %, and 29.8 %, respectively. GC-IMS analysis identified 44 volatile compounds, revealing a decrease in aldehydes and ketones (fishy odor) and distinct flavor profiles during processing. Electronic tongue and sensory evaluation indicated that the M-5 %ST-5 processed sample developed a whitish appearance, softened texture, and pleasant floral and fatty aromas, with a dominant sweet taste that received the highest sensory score. These findings demonstrate an effective strategy for improving the safety and consumer acceptance of S. fusiforme.