Effect of 4-hexylresorcinol on post-cut browning and quality of minimally processed 'Fuji' apple fruits

Demand for minimally processed apples (MPA) is growing, as it is an easy-to-consume food rich in vitamins, minerals, fiber and phenolic compounds that benefit consumer health. However, MPA perishability is a hindrance in meeting this demand due to enzymatic browning of the pulp. To minimize this problem, the effectiveness of different concentrations (0.1%, 0.2% and 0.3%) of 4-hexylresorcinol (4-HR) were tested on MPA (sliced Fuji apples) for up to nine days at 4.0 degrees C. Distilled water (DW) andl-cysteine chloride (LC) 0.6% (m v(- 1)), were used as negative control and positive control, respectively. The color, mass loss, pulp firmness, bioactive compounds, enzymatic activity and sensorial characteristics were evaluated. After the evaluations, it was found that the different concentrations of 4-HR exerted undesirable effects on the color variables (L *, a *, oHue and browning index), because it did not effectively inhibit the browning of the apple pulp. During storage, fruits treated with 4-HR gradually lost weight without affecting quality; had greater firmness and their total phenolic content and antioxidant activity remained superior to controls (DW and LC). Although the activity of the peroxidase and polyphenol oxidase enzymes was decreased, the sensorial analysis revealed that dark spots formed in the endocarp, and also in the mesocarp, impairing the purchase intention of the MPA. Based on these considerations, immersion in 4-hexylresorcinol was considered not suitable for controlling pulp darkening of 'Fuji' apples minimally processed during refrigerated storage.