The SO2SAY project will develop a strategy to replace the application of sulphur dioxide or its releasing salts for almost all food products. Important aspect for food applications will be the maintenance of the sensory quality and shelf-life of the products produced without sulphur dioxide treatment.

The main activity of sulphur dioxide is the prevention of enzymatic and non enzymatic browning in foods, especially fruit and vegetable products. Sulphur dioxide acts as inhibitor for polyphenol oxidase, the main biocatalyst for oxidation of polyphenol to quinones, and parallel as reducing agent preventing further oxidation of the formed quinones. In addition, sulphur dioxide has strong antimicrobial power and preserves microbial spoilage.

Three approaches will enable to dispense with sulphur dioxide:

1. Inactivation of the enzyme polyphenol oxidase to prevent enzymatic browning
2. Development of plant extracts containing secondary plant metabolites with a high antioxidative capacity (e.g. plant polyphenols) and antimicrobial activity
3. Processing and packaging under an oxygen reduced atmosphere.

These strategies are planned to be successful as stand-alone technologies, but more realistic are combinations of two or three technologies, depending on the food stuff. Tailored processes and technologies will be developed to meet the requirements of fluid and solid food products. Sulphur dioxide is currently permitted for fruit and vegetable products, juices, beverages, wine, and seafood. The latter, however, is rarely produced using sulphur dioxide. Instead, organic acids and modified atmosphere packaging are used to prevent browning.

Thus, SO2SAY will focus on the most relevant food stuff currently treated with sulphur dioxide:

• Fresh and dried fruits and vegetables
• wine and beverages
• snacks and convenience products

To ensure the success of the SO2SAY project, all technological developments will be supported by an analytical work package taking care of sensorial analysis and of acceptable shelf-life of the novel developed products.

In summary, the project will develop applicable technologies to replace sulphur dioxide in food. The SO2SAY approach will be based on fundamental scientific data and will enable the complete understanding of the molecular mechanism behind the novel technological applications to be developed in SO2SAY.

Further information concerning the project start of SO2SAY: