Maltobionate has an antioxidative effect in food and feed products. The antioxidant can be produced directly from starch or maltose already present in the food product, using enzymatic catalyzed processes. The antioxidant production can be performed on an isolated fraction of a food product from which it can be added back to the food production process or the final food product. Alternatively, the antioxidant can be produced as an integrated part of the food production process by adding the relevant enzymes to the process.