Sodium metabisulfite is an approved food additive in China (included in GB2760-2011). Therefore, in principle, the used standards comply with the requirements (i.e., do not harm human health in any form, do not use adulteration, falsification, or forgery to cover up corrupt and spoiled food, do not cover up quality defects, etc.). The study of using sodium metabisulfite to process abalone has been extremely extensive.

Sodium metabisulfite reacts with water to produce sodium bisulfite:

NaSO+ HO → 2NaHSO

Sodium bisulfite decomposes to produce sulfur dioxide (gas):

2NaHSO→ 2SO+ HO + 2Na

The conversion rate of sulfur dioxide depends on temperature, pH, time, and the ratio of abalone to water. Control these parameters to meet the required sulfur dioxide indicator standard, which is less than or equal to 1000mg/Kg.

The use of sulfur dioxide in abalone has been approved by WHO, JECFA, and CODEX. Government food safety authorities, including but not limited to New Zealand, Singapore, Australia, the United States, and Hong Kong, have accepted the recommendations of these international organizations to produce abalone products and gain consumer recognition. Other compounds such as coenzyme Q10, ellagic acid, nicotinamide purine dinucleotide, and hydrogen peroxide have also been evaluated, but a product with both taste and visual enjoyment has not been successfully produced.

Sodium Metabisulfite Used in Canned Aquatic Products

Remarks:

-WHO: World Health Organization

-JECFA: Joint FAO/WHO Expert Committee on Food Additives

-CODEX: International Codex Alimentarius Commission

The Role of Sulfur Dioxide in Canned Aquatic Products (Canned Abalone)

The purpose of using sulfur dioxide in canned aquatic products (canned abalone) is to produce high-quality products with taste and visual enjoyment. The use of sulfur dioxide in canned abalone produced in Australia and New Zealand will not exceed the proposed maximum allowable usage limit. The recommended maximum usage is 1g/Kg.

Many abalone varieties in the world belong to the Haliotis genus, and each variety differs in its meat and shell. Therefore, the processing process required to achieve the desired finished product will vary depending on the initial color of abalone meat. New Zealand abalone is the only abalone in the world with black feet.

In order to obtain acceptable colors for commercial products, various oxidants and reducing agents are applied to achieve ideal colors, flavors, odors, and textures. However, only sulfite compounds can successfully provide the sensory properties required for abalone products.

In the processing of abalone, sulfite releases electrons through chemical decomposition, reducing the quinine group in abalone melanin. The product of decomposition is sulfur dioxide.

Therefore, in order to maintain color, sodium metabisulfite (maximum usage based on residual sulfur dioxide) is used as an antioxidant. If sulfur dioxide is not present in the finished product, the color of abalone will change to greenish brown. Sulfur dioxide reacts with a wide range of food ingredients, including nucleotides, disulfide bonds, and others. The following chemical reaction explains how proteins bind to sulfur dioxide, which breaks when heated, indicating the release of sulfur dioxide from the final product:

R.S-S.R+ SORS.SO+ RS

Sodium Metabisulfite Used in Canned Aquatic Products-1

Canned abalone is mainly used for festive occasions. Sulfur dioxide is a byproduct of the reaction between sulfite salts and water during the treatment of abalone, and is therefore referred to as a food additive for canned abalone (INS 220). This process is to produce a product of acceptable quality and color. Consumers’ preferences for canned abalone have a creamy/yellow appearance without discoloration (Brown et al., 2008).

Sulfur dioxide has been used for the treatment of canned abalone for over 40 years. Abalone is packaged in sealed containers, including but not limited to metal and plastic cans, glass bottles, bag packaging, and technical modified atmosphere packaging. The types of abalone include but are not limited to the following:

-Haliotis rubra

-Haliotis conicopora

-Haliotis laevigata

-Haliotis roei

-Haliotis iris

-Haliotis australis