Salmonids are highly valued for their flavor and health benefits. But did you know that there’s more to salmon than meets the eye? This article dives into the fascinating world of salmonids, exploring the hidden variations in nutrition, flavor, and the science behind identifying different types.
A team of scientists from Dalian Polytechnic University (China) analyzed the general sensory characteristics and low molecular weight compounds to achieve discrimination of different commercial salmon (“Atlantic salmon” Salmo salar, “rainbow trout” Oncorhynchus mykiss, “sockeye salmon” O. nerka, “pink salmon” O. gorbuscha, “Pacific coho salmon” O. kisutch, and “Japanese salmon” O. masou) and investigate the sensory and nutritional quality of salmonids.
The Rise of Aquaculture and the Need for Transparency
With the growing consumer demand for salmon, wild resources are being depleted. This has led to the rise of salmon fish farms, significantly boosting production. However, a hidden challenge arises: different species of salmonids (such as rainbow trout and sockeye salmon) are sometimes simply labeled as “salmon,” despite variations in flavor, texture, and nutritional content.
This not only economically harms consumers but also disrupts the market. Therefore, a reliable method to distinguish between different types of salmon is essential.
Unveiling the Spectrum of Salmonids
Current research is delving into these differences. Studies show that salmonid species vary significantly in lipid content, with phospholipid profiles being a potential fingerprint for identification. Additionally, fatty acid and protein composition can differ, affecting flavor and nutritional value. Wild sockeye salmon and king salmon, for example, are known for their high omega-3 content.
However, consuming salmonids is not just about health; it’s a sensory experience. Different species offer unique textures, flavors, and colors. Coho and chum salmon, for example, tend to be firmer and less fatty than others.
Science Steps In: Revealing Salmon’s Fingerprint
Traditionally, salmonid identification relied on physical characteristics. Now, science offers more precise tools. Researchers are exploring the potential of low molecular weight compounds, specific metabolites, and even protein profiles as unique identifiers for each salmon species.
This study employed metabolomics to create a unique “fingerprint” for six commercially available salmon varieties. These fingerprints, along with sensory evaluation, provide a complete picture of each salmon’s quality, encompassing both its nutritional profile and sensory characteristics (flavor, texture, aroma). This paves the way for a more transparent and reliable labeling system.
The Results?
- A Podium of Champions: Oncorhynchus mykiss (rainbow trout), Salmo salar (Atlantic salmon), and Oncorhynchus kisutch (coho salmon) stood out the most for their desirable texture and flavor. This paves the way for greater consumption of these varieties.
- Distinctive Aroma: Alcohols and sulfur compounds were key in the typical aroma of Oncorhynchus masou (masu salmon) and Oncorhynchus gorbuscha (pink salmon). Their presence exceeds that of other salmon by 147% to 167%!
- Chemical Fingerprints: Oligopeptides and phospholipids present in salmon act as biomarkers, allowing differentiation between different species.
- The Science of Umami Flavor: Oligopeptides are also closely related to the taste of salmon. Using molecular coupling techniques, 17 oligopeptides with potential umami activity were identified, with Arg-Val and Ser-Asn being the main contributors to this characteristic in salmon.
Importance for the Salmonid Breeding Industry
This research empowers both consumers and the aquaculture industry. Consumers gain access to comprehensive information about different salmon options, enabling them to make informed decisions based on taste and nutritional preferences. For producers, this knowledge translates into better labeling practices and contributes to responsible resource management.
Conclusion
According to the sensory evaluation results, O. mykiss, S. salar, and O. kisutch were the salmonids that most satisfied the panel with their desirable texture and flavor; and the scientists highlighted that rapid discrimination of these salmon could be achieved through oligopeptide and phospholipid profiles.
In summary, this research brings us closer to a deeper understanding of salmon, allowing us to appreciate the subtle differences between varieties and highlighting their nutritional value.
The study was funded by the National Key Research and Development Program of China, the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study, and the Basic Scientific Research Project of Colleges and Universities of Liaoning Provincial Department of Education.
Contact
Lei Qin
School of Food Science and Technology, State Key Laboratory of Marine Food Processing & Safety Control, National Engineering Research Center of Seafood, Dalian Polytechnic University
Dalian 116034, China
Email: qinlei@dlpu.edu.cn
Reference
Dong, M., Zhang, Z., Wang, H., Huang, X., Wang, X., & Qin, L. (2024). Discrimination and evaluation of commercial salmons by low-molecule-weight compounds: Oligopeptides and phosphatides. Food Chemistry, 139777. https://doi.org/10.1016/j.foodchem.2024.139777
