Researchers at the Zurich University of Applied Sciences (ZHFAW) have for the first time used rhubarb juice as a natural antioxidant in food production. These not only do without ascorbic acid and sulfur, but also stay fresh much longer. Now various varieties of rhubarb are being examined.
For the first time, rhubarb juice was used as a natural antioxidant in the industrial processing of fruits. ZHAW researchers, together with the industrial partner Agrofrucht-Inn, have made apple chips and frozen apples stay fresh for longer through natural means only. While the fruits, conventionally treated with ascorbic acid, turned brown after only a few hours, those treated with rhubarb were permanently protected from oxidation."This gives the industry a great advantage in time-critical processes and makes rhubarb juice particularly interesting in convenience products, dried fruit, frozen fruits or fruit juices, but in salad dressings as well," says ZHAW researcher Martin Häfele from the Institute for Food and Beverage Innovation. The ZHAW project is supported by the Association of Swiss Vegetable Producers and the Swiss Fruit Association.
Rhubarb fits into the current trends
The antioxidizing effect of rhubarb juice had already been discovered in the mid-1990s: rhubarb has a high oxalic acid content, which protects against oxidation. Ascorbic acid or sulfur are most commonly used to preserve foods. The process with the rhubarb juice, however, has never been adapted into practice. "Today, however, rhubarb as a natural antioxidant corresponds to the spirit of the times," Häfele claims. "In addition to a 'Clean Label', the product would have its value added in Switzerland, which also allows the predicate 'Swiss'. This increases its attractiveness."
The rhubarb plant suits Switzerland well, due to its particular demands on soil and climate. Due to the early harvest period, from April to the end of June, it is possible to go without pesticides. With up to 30 tonnes per hectare of land, rhubarb perennials can produce cost-effectively in biological cultivation. Since the use of ascorbic acid is prohibited for organic products, rhubarb offers a natural enzyme control option. Rhubarb juice could be used as an antioxidant even with kosher or halal products.