New Insight into Mercury Removal from Fish Meat Using a

Overview

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Key numbers

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reduction of mercury in canned Albacore tuna by 25–35%, depending on the late, methylmercury remains a pressing
water-based sauces. Thiolated silica was chosen due to strong in the solution keeping 80 wt% of the solution and as prepared
veloped approach involves utilizing a simple, single-component umes (10–80 wt%) of the extracting solution and the variations in
known and eﬃcient mercury-binding agent (which is explained range between 1 to 12 h was also conducted. In this case, the ﬁsh
component responsible for mercury capturing. Various param- tracting solution (1.2 wt% of cysteine) the samples were stored at
glass jar and ﬁlled with the extracting solution (1.2 wt% of cys-
European reference material of ﬁsh muscles ERM-BB422 with teine) keeping the 60 wt% of the solution in each sample. Then,
was suspended in 0.5 m solution of NaOH for 1 h at room temper- obtained by storage of canned tuna in the 1.2 wt% solution of
1. reading was assessed using certiﬁed ﬁsh protein standard to the minced sample. Nevertheless, a 36% reduction of mercury
the average result was equal to 0.602 ± 0.031 mg kg−1 . S1b, Supporting Information). The 3–4% higher mercury extrac-
capacity of mercury scavenging from the ﬁsh tissue. The eﬀect of tive concentration of cysteine was found to be 1.2 wt% for both
cysteine concentration on mercury extraction from four kinds of samples of canned ﬁsh, and 1.6 wt% in the case of ﬁsh protein
lutions (80 wt% liquid content) for 1 h is presented in Figure 2. 3.2. Eﬀect of Time and Extracting Solution Content
centage of the removed mercury was between 71 and 13%. The possible eﬃciency. In this view, the duration and the working
bacore tuna, packed it in jars containing 60 wt% of the 1.2 wt%
core tuna using diﬀerent volumes of the 1.2 wt% cysteine solution for 1 h. ﬁnding since in the case of preserved products storage time does
content of 80 wt% used in our previous experiments was rela- cysteine had a chance to reach deeper trapped mercury. Another
content in water-canned tuna is typically ca. 25–30 wt% based on sarcoplasmic proteins which is possible at the pH of the applied
8% for the level of 30% solution content. For the whole pieces pacity of methylmercury adsorption from the water solution onto
of canned tuna, 45% solution content in the sample has been the base material—silica 6 h reached the level of about 100 mg
extraction mechanism is schematically presented in Figure 4. and 1.2%. The results are presented in Figure 6a as the relation-
teine solution (80 wt% of solution content, logarithmic scale of totally prevented the adsorption process. That was an expected re-
13% of mercury extraction yield was reached after 50 min, and tween mercury and sulfur-containing proteins are strong enough
no changes were observed up to 4 h of storage. Then a rapid to keep mercury stable in the solution, thereby hindering the ad-
positive eﬀects. Mercury adsorption by silica 6 h raised from 0% However, a direct comparison of the results for silica 24 h (hydr)
to 7% which is still a very low level. The next step was to look for presented in Figure 6b for canned tuna and Figure 6c for fresh
removal level was 33% (silica 24 (hydr)). Two single-point adsorp- mercury stabilization or by directly aﬀecting the adsorbent
Figure 5. Time dependence of mercury extraction from a) whole canned tuna using 1.2 wt% cysteine solution, 80% of the solution, no pH adjustments
(initial pH = 5.2); b) fresh tuna after precooking and pasteurization—black curve (1.2 wt%, no pH adjustment, 60% of solution), adsorption of Hg from
silica 6 h). b) Adsorption of mercury from the extract obtained from a whole canned ﬁsh with the solution containing 1.2 wt% cysteine using diﬀerent
The results are presented in Table 1. Based on the results, it A new simple method for the removal of mercury from tuna
like EDTA and citric acid do not exhibit this behavior. However, of 1.2 wt% cysteine solution enabled the reduction of mercury
some experiments in the laboratory of the authors of this paper content in canned albacore tuna meat by 35% and its transfer
Table 1. Mercury adsorption from the model solutions prepared according to the representative cases from the literature (Initial concentration
Cys (g L−1 ) EDTA (g L−1 ) Citric acid (g L−1 ) NaCl (g L−1 ) % Hg removed % of Hg extraction Refs.
30%. However, research on more powerful materials eﬀectively (accessed: June 2024).
tuna at least by 30% by simply separating the medium from (8) Q. Nong, H. Dong, Y. Liu, L. Liu, B. He, Y. Huang f, J. Jiang g, T. Luan,

Methods (brief)

tively reduce the methylmercury level in ﬁsh meat during the Then, the samples of ﬁsh including the whole pieces of fresh and
evidence regarding the successful application of sulfur-modiﬁed samples were stored at room temperature for 1 h. Mercury con-
The study proposes a potentially straightforward and applica- above-described experiment. In this case, the samples of whole
component responsible for mercury capturing. Various param- tracting solution (1.2 wt% of cysteine) the samples were stored at
were investigated to ascertain the most optimal conditions for tion was determined by Hg analysis in the ﬁsh samples collected
moving the collected mercury via the adsorption process using in the extracting solutions was conducted. This was to mimic the
European reference material of ﬁsh muscles ERM-BB422 with teine) keeping the 60 wt% of the solution in each sample. Then,
a certiﬁed mercury content of 0.601 ± 0.030 mg kg−1 was pur- the samples were pasteurized to avoid spoilage and enable their
deﬁned storage time (1–9 weeks), the samples were collected, the and called silica 24 h (hydr).
at 105 °C, and then the desiccated material was placed in a plastic volume and adsorbent mass. The as-prepared samples were then
conducted at 50 °C for 60 min, using a water bath shaker. Follow- ing a direct mercury analyzer (DMA-80 Direct Mercury Analysis
cysteine. For this purpose, the collected extract samples were ex-
Mercury analysis in the ﬁsh samples was conducted as follows:
process was repeated. The as-obtained samples were subjected to
comparison of the control samples that had no contact with any itating eﬀective contact between the material and the solution.
additional solutions. Generally, ﬁve types of ﬁsh samples were ex- Moreover, when the ﬁsh material is completely dry, it eﬃciently
core tuna canned in water sauce, fresh tuna steak, and fresh tuna the sample. Tests were furthermore done with real samples, ﬁrst
sis, ﬁsh samples were freeze-dried with a Labcono FreeZone tray eﬃciency was lower in comparison to the powdered proteins be-

Implications

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Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

Commit	Date	Change	Description
b01ec52c	2026-08-04	major	2 sections added
d49e450f	2026-08-03	major	5 sections added; narrative text revised