Enhancement of bromophenol levels in aquacultured silver seabream (Sparus sarba).

The effect of the addition of marine algae in fish feed on the levels of bromophenols in fish flesh was studied. These bromophenols include 2-bromophenol, 4-bromophenol, 2,4-dibromophenol, 2,6-dibromophenol, and 2,4,6-tribromophenol. Two types of algae-containing fish feeds with 30% Padina arborescens and 30% Sargassum siliquastrum were developed. The total bromophenol contents of these feeds were 132 and 340 ng/g respectively, which were significantly higher than that of the control feed (8.9 ng/g) (ANOVA, p < 0.05). Silver seabream was used as the model fish for the feeding experiment. Bromophenol contents of both fish gut and flesh were monitored at 2-week intervals throughout the 8-week period. Two-way ANOVA showed that only the 30% S. siliquastrum-containing feed significantly (p < 0.05) increased the total bromophenol content in the fish flesh with time. This also produced sensorial differences in the fish flesh.

Odor-active headspace components in fermented red rice in the presence of a monascus species.

Headspace components from rice and agar with (experimental) and without (control) inoculation with a Monascus spp. were investigated. Kinetics studies were carried out. Using rice as a substrate, 10 and 19 compounds were found for the control and the experimental groups, respectively, at day 14. Experimental group compounds were composed mainly of alcohols, ketones, and esters, whereas control group compounds were composed of aldehydes and ketones. With agar as a substrate, only five and three components were found in the control and experimental groups, respectively. Five alcohols, four esters, two ketones, and one furan with odor activity values (OAV) >1 dominated the overall flavor of the product. With liquid inoculation, the first six components with high OAVs were in the following order: 3-methyl-1-butanol (17) > ethanol (14) > ethyl acetate (10) > 2-methyl-1-propanol (15) > ethyl butanoate (11) > 3-methylbutyl acetate (13). Kinetic studies showed that most compounds reached their maximum concentrations at 10-12 days. Many compounds identified in the model red rice were reported in commercial red sufus, and several appeared to contribute solely by red rice.

Seasonal variations of bromophenols in brown algae (Padina arborescens, Sargassum siliquastrum, and Lobophora variegata) collected in Hong Kong.

Distributions and seasonal variations of the key seafood flavor compounds including 2-bromophenol, 4-bromophenol, 2,4-dibromophenol, 2,6-dibromophenol, and 2,4,6-tribromophenol in three species of brown algae (Padina arborescens, Sargassum siliquastrum, and Lobophora variegata) found in Hong Kong waters were investigated. Bromophenols were extracted by simultaneous steam distillation and solvent extraction apparatus and analyzed by gas chromatography-mass spectrometry. On a dried weight basis, the total bromophenol content (TBC) determined varied widely with seasons (from 40.9 to 7030 ng/g). The TBCs detected were higher in winter and lower in summer. Except for 2-bromophenol, the rest of the bromophenols were detected in all of the algal samples. The TBC of L. variegata was generally the highest among all of the algae collected. Relatively high concentrations of bromophenols in algae supported the fact that marine algae were major producers of bromophenols in the marine environment.