Characterization of a Combined Treatment with Alpha-Lipoic Acid for the Control of Enzymatic Browning in Fresh-Cut Golden Delicious Apples

Enzymatic browning is the main cause of quality loss in minimally processed fresh-cut apples and this study was aimed to control it by evaluating the use of a treatment with α-lipoic acid and ascorbic acid on Golden Delicious apples. Also hexanal, an effective natural enhancer of apple odor, was added to the treatment.At the end of the preservation period, colorimetric analysis demonstrated that α-lipoic acid exerts an anti-browning effect comparable with that of ascorbic acid about 60 times more concentrated and, moreover, chemical assays demonstrated its synergistic interaction with this substance. The application of the “anti-browning mix” does not substantially change the volatile profile of the apple slices while the addition of hexanal (0.076 mmol per liter of air) improves it primarily with an increased production of hexyl acetate (about 86% of the average aromatic component), without modifying the fruit respiration.Practical ApplicationsThe combined treatment has proved to be useful to preserve and improve Golden Delicious apples quality over the span of 8 days (1 day more than the average shelf life recommended by many producers for this kind of product).The presence of hexanal makes the treatment very interesting in the context of minimally processed fruit, where apples are used in an early stage of ripening that best tolerates the processing chain but that is characterized by a low volatile biosynthesis.Moreover, the presence of α-lipoic acid gives to the fruit the connotation of “nutraceutical food.”