et al. Chemistry Central Journal (2018) 12:30
The eﬀect of melanin-free extract
from Sepia esculenta ink on lipid peroxidation,
protein oxidation and water-holding capacity
of tilapia ﬁllet during cold storage
, Hua‑Zhong Liu
, Ping Luo
, Yi‑Peng Gu
and Yan‑Qun Li
Background: Preservative eﬀect of melanin‑free extract of Sepia esculenta ink (MFESI) on Sparus latus ﬁllet has been
veriﬁed in our previous work. This study aims to further approach the mechanism of MFESI for extending the shelf‑
life of ﬁsh ﬁllet during cold storage. Tilapia ﬁllets were treated with diﬀerent dosage of MFESI (0, 15, 25 and 35 mg/
ml) and packed with preservative ﬁlm for succedent cold‑storage at 4 °C for scheduled time. Contents of total volatile
basic nitrogen and sulfydryl and carbanyl groups were measured for evaluating protein oxidation. Malondialdehyde
contents were measured for estimating lipid peroxidation and loss of water was used to determine water‑holding
capacity of ﬁllet.
Results: The data indicated that MFESI not only possessed certain degree of antioxidant capacity in vitro, also
lengthened shelf‑life of tilapia ﬁllet in cold‑storage condition. Apart from 15 mg/ml, both 25 and 35 mg/ml of MFESI
obviously prevented lipid and protein from oxidation and reduced loss of water from tilapia ﬁllets, and the latter was
more eﬀective than the former.
Conclusion: MFESI can repress lipid peroxidation and protein oxidation and reduce water loss, maintain the tilapia
ﬁllets quality and, thus, it could be an eﬀective and natural preservative for extending the shelf‑life of tilapia ﬁllets dur‑
ing cold storage.
Keywords: Antioxidation, Cold storage, Sepia esculenta ink, Tilapia ﬁllets
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As a delicious food and a good resource of proteins in
human diet, ﬁsh plays an important role in the global
food supply. However, ﬁsh is diﬃcult to keep fresh and
even highly perishable due to the actions of microorgan
isms and enzymes naturally present and rancidity of the
lipids. In order to keep the quality of ﬁsh, a lot of tech
niques to reduce the deterioration have been developed.
Although the chemical preservatives are eﬃcient and
cheap, their health hazards are the concerns of consum
ers and regulations and the addition of synthetic preserv-
atives has been restricted. Nowadays, the applications
of safe and natural-source preservatives in the ﬁsh pro
cessing are still limited. erefore, it is an urgent task to
develop eﬃcient, safe and natural preservatives for ﬁsh
Sepia ink is a marine material with multifunctional
roles based on its bioactive components, including pro
tein, melanin and glycosaminoglycan . Regrettably
sepia ink is generally discarded during the ﬁsh process.
To fully utilize the by-product of squid processing,
attempts have been made by researchers. e poten
tial fresh-keeping eﬀects of sepia ink were approached
in shiokara and peeled shrimp in earlier studies [2–6].
*Correspondence: firstname.lastname@example.org; email@example.com
College of Chemistry & Environment, Guangdong Ocean University,
Zhanjiang 524088, China
College of Food Science & Technology, Guangdong Ocean University,
Zhanjiang 524088, China
Full list of author information is available at the end of the article