UV-C Treatment Applied Alone or Combined with Orange Juice to Improve the Bioactive Properties, Microbiological, and Sensory Quality of Fresh-Cut Strawberries

The effects of UV-C treatment (5.8 kJ m(-2)) alone and combined with the addition of orange juice on the bioactive properties, microbiological, and sensory quality of fresh-cut strawberries for 12 days at 0 degrees C were studied. During storage, the contents of ascorbic acid (AA), total phenols, flavonoids, and anthocyanins were enhanced in strawberry slices only treated with UV-C (UV slices), whereas ellagic acid slightly decreased in correlation with the antioxidant capacity. After 12 days of storage, AA level in UV slices was 10% higher than those in the other samples studied. In addition, UV slices showed higher contents of phenols (about 14%), flavonoids (about 23%), and anthocyanins (11-41%) than untreated slices during storage. However, fresh-cut strawberries UV-C treated and immersed in juice showed slight but significant AA decrease due to its oxidation to dehydroascorbic acid. Also, phenolic compounds decreased that was associated with their diffusion to the juice and correlated with the antioxidant capacity. Although both UV-C treatments alone and combined with juice immersion reduced microbial load, UV-C applied alone allowed obtaining the highest microbial reductions. After 8 days of storage, the most significant reductions were found, 1.4 log units for mesophilic bacteria and 1.3 log units for molds and yeasts. In addition, UV-C applied alone allowed maintaining firmness and obtaining a product with the best sensory quality throughout storage. Hence, the irradiation at 5.8 kJ m(-2)applied alone was the most effective preserving treatment and may be useful to obtain a value-added product.