Shrimps, a delicious seafood delicacy, are renowned for their tender and succulent texture. However, the oxidation of proteins, a natural process occurring during post-mortem storage, can lead to undesirable textural changes, diminishing the sensory appeal and consumer acceptance of shrimp.
In the pursuit of optimal preservation for seafood products, maintaining the pristine quality of shrimps is a crucial challenge. To delay the quality loss of fresh shrimps after harvest, multiple methods have been proposed, such as low-temperature preservation, modified atmosphere packaging, chemical treatments, radiation, among others.
Recently, electron beam irradiation (EBI) has garnered considerable attention for shrimp preservation due to its ability to eliminate microbial contamination.
A recent study, published by a team of researchers from Hebei Agricultural University, delves into the realm of electron beam irradiation (EBI) to explore its impact on protein oxidation and textural properties of Litopenaeus vannamei during refrigerated storage.
Electron Beam Irradiation (EBI)
Electron beam irradiation (EBI), a non-thermal food processing technology, emerges as a promising strategy to extend the shelf life of shrimp while preserving its texture.
EBI exhibits substantial capacity to enhance food safety and prolong the shelf life of food products based on its effectiveness in deactivating microbes.
Direct destruction of genetic material (DNA and RNA) and physiological metabolism of microorganisms through an electron beam can cause injuries or death to the microorganisms.
Various studies have reported that EBI is highly effective in extending the shelf life of shrimp, but its effect on protein characteristics in postmortem shrimps is not yet known.
Impact of EBI on Protein Oxidation and Textural Properties
The study delved into the effects of EBI on protein oxidation and textural properties of Litopenaeus vannamei during refrigerated storage. The researchers irradiated shrimp samples with varying doses of EBI (0, 3, 5, or 7 kGy) and stored them at 4°C for 14 days.
Protein oxidation is vital for understanding changes in other physical and chemical properties, especially textural characteristics. “Oxidative modification generally induces texture changes by affecting the structure of muscle proteins and their spatial arrangement,” cites the study.
Results indicated a dose-dependent relationship between EBI and protein oxidation levels. Shrimps irradiated with higher doses (≥7 kGy) exhibited significantly elevated levels of reactive oxygen species, turbidity, and carbonyl content, indicating increased protein oxidation. These changes are likely due to EBI-induced alterations in antioxidant systems and increased susceptibility to oxidation.
Additionally, shrimps irradiated with higher doses (≥7 kGy) showed a notable decrease in Ca2+-ATPase activity, surface hydrophobicity, solubility, and total sulfhydryl content compared to the control group (0 kGy) on the seventh day of storage.
Texture Improvements
Interestingly, the application of moderate EBI doses (3 and 5 kGy) demonstrated a beneficial effect on shrimp texture. Shrimps irradiated at these doses showed significantly higher hardness, elasticity, and chewiness compared to the non-irradiated control group. This texture improvement is attributed to EBI-induced protein cross-linking, which strengthens the network of muscle fibers.
Optimizing EBI for Shrimp Texture Preservation
The study emphasizes the importance of achieving a balance between EBI dose and its impact on protein oxidation and texture. While excessive EBI doses (≥7 kGy) promote protein oxidation, leading to softening of the texture, moderate doses (3 to 5 kGy) induce beneficial protein cross-linking, enhancing texture.
Therefore, EBI doses within the range of 3 to 5 kGy are recommended to preserve shrimp texture and extend shelf life. This finding provides valuable information for the shrimp processing industry, enabling the production of high-quality shrimp products with desirable sensory attributes.
Conclusion
EBI emerges as a versatile tool for optimizing shrimp texture and shelf life. By carefully selecting the appropriate EBI dose, processors can effectively inhibit texture softening while minimizing protein oxidation, ensuring consumers enjoy the tender and succulent texture of shrimps with every bite.
“EBI treatment is beneficial for extending the shelf life of Litopenaeus vannamei, but it also affects shrimp muscle protein and texture quality. EBI accelerated the oxidation of shrimp proteins during refrigerated storage,” concluded the researchers.
In conclusion, the study proposes a pragmatic approach to shrimp preservation through electron beam irradiation. Doses within the range of 3 to 5 kGy are recommended as they achieve a delicate balance by inhibiting texture softening through moderate protein oxidation. The research has been funded by the National Key R&D Program of China, Natural Science Foundation, and the Support Program of Seafood Deep Processing and Market Development Innovation Team in the Characteristic Seafood Industry of the Modern Agriculture Industry Technology System of Hebei Province.
Contact
Jie Wang
No.2596, Lekai South Street
Lianchi District, Baoding
Hebei Province 071000, China.
Email: wj591010@163.com
Reference (open access)
Haoran Wang, Ran Suo, Yangyang Wang, Jianfeng Sun, Yaqiong Liu, Wenxiu Wang, Jie Wang. 2023. Effects of electron beam irradiation on protein oxidation and textural properties of shrimp (Litopenaeus vannamei) during refrigerated storage, Food Chemistry: X, Volume 20, 2023, 101009, ISSN 2590-1575,
https://doi.org/10.1016/j.fochx.2023.101009.
