Does oyster sauce contain shellfish? (how is oyster sauce made)

In this article, we answer the following question: “Does oyster sauce contain shellfish?” and discuss what are the ingredients in oyster sauce, the benefits and drawbacks of oyster sauce and how to use oyster sauce.

Does oyster sauce contain shellfish?

Yes, the oyster sauce contains shellfish. The traditional method to produce oyster sauce is, in simple words, by boiling oysters with water and adding soy sauce and other spices (2).

Traditional oyster sauce is obtained by the concentration and fermentation of oyster water extracts, followed by a purification process (1).

How is oyster sauce traditionally produced?

In the traditional method to produce oyster sauce, oysters are collected and their soluble solids contents are washed with fresh water and concentrated with the use of membranes.

In the sequence, the concentrated liquid is added with 12 % salt, and 2 % koji meal (rice inoculated with Aspergillus oryzae, a fungal species) and incubated at 25 °C (77 °F) for 3 months (1).

During the fermentation process, the proteins in the oyster sauce are hydrolysed and converted to amino acids enhancing the biological value of the product (2).

Many aromatic compounds are produced, such as 5´-inosine monophosphate, 5´- guanosine monophosphate and 5´- adenosine monophosphate, which are nucleotides and give the characteristic umami taste to the oyster sauce (1, 2).

The fermented liquid is filtrated and added with 8 % sugar, 5 % cornstarch, 4 % wheat flour, 0.1 % monosodium glutamate and 4 % caramel and packed into autoclavable bottles.

The bottles are then sterilised at 121 °C (250 °F) under a pressure of 15 psi for 15 minutes to produce a shelf-stable product with a long shelf life.

What are the benefits of consuming oyster sauce?

The benefits of consuming oyster sauce are the presence of hydrolysed amino acids and nucleotides in the composition of oyster sauce, in addition to the possibility of substituting table salt, thus favouring the ingestion of sodium (1, 2, 3).

The hydrolysis and fermentation processes occurring in the production of oyster sauce result in the breakdown of proteins from the oysters and the generation of amino acids, such as taurine and nucleotides, such as 5´- inosine (1, 2).

While taurine has important biological functions in the body, including brain development and cytoprotection activities, nucleotides favour cell proliferation through the production of RNA and the recovery of the liver cells (4).

According to studies, condiments, such as oyster sauce, can be used as a strategy to reduce the use of table salt or salt as a food ingredient, thus contributing to the reduction of sodium in the diet.

The ingestion of high amounts of sodium in the diet is related to the high incidence of hypertension and health-related diseases, such as cardiovascular disease and the risk of osteoporosis and gastric cancer (3).

The use of condiments that are high in the umami taste, such as oyster sauce, can compensate for the sodium in the food (4).

What are the drawbacks of consuming oyster sauce?

The drawbacks of consuming oyster sauce are the high concentration of salt in its composition (1, 2, 3) and the risks of allergic reactions in individuals who are allergic to fish protein and seafood protein (5).

About 10 % of the world’s population suffers from seafood allergies, due to the different proteins in fish and seafood, which can cause Immunoglobulin-E mediated allergic reactions (5).

The main symptoms related to seafood allergic reactions are hives, urticaria, swelling of the throat or other organs, breathing difficulties, lowering of blood pressure and dizziness.

Individuals who are allergic to fish or seafood should not consume oyster sauce.

How to use oyster sauce?

Oyster sauce is commonly used as a condiment to prepare vegetables, meats, soups and salads, or in place of table salt, soy sauce or fish sauce (4).

The characteristic flavour of seafood is highly appreciated, as well as the umami taste of oyster sauce, which results from the fermentation process (1, 2).

Asians are the main consumers of oyster sauce, especially in Southeast Asian countries (2).

Conclusions

In this article, we answered the following question: “Does oyster sauce contain shellfish?” and discussed what are the ingredients in oyster sauce, the benefits and drawbacks of consuming oyster sauce and how to use oyster sauce.

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References

1.-

Shiau CY, Chai TJ. Protein rRcovered from Oyster Wash Water by Ultrafiltration and Their Utilization as Oyster Sauce Through Fermentation. Journal of Marine Science and Technology. 2009;7(2):6.

4.-

Sanchez-Pozo A, Gil A. Nucleotides as semiessential nutritional components. British Journal of Nutrition. 2002 Jan;87(S1):S135-7.

5.-

Nugraha R, Ruethers T, Johnston EB, Rolland JM, O’Hehir RE, Kamath SD, et al. Effects of Extraction Buffer on the Solubility and Immunoreactivity of the Pacific Oyster Allergens. Foods [Internet] 2021;10(2):409. Available from: http://dx.doi.org/10.3390/foods10020409