Optimization of vacuum infusion and incubation time for enzymatic peeling of ‘Thomson’ and ‘Mollar’ oranges

A study to determine the optimum conditions for enzymatic peeling of two morphologically different oranges varieties (Thomson and Mollar) was carried out. The potential enzymatic saturation of albedo (PESA) was determined by submerging the orange fruit (with perforated flavedo) in an enzymatic solution with Chinese ink and applying several vacuum pressures for different times. The PESA was evaluated using percentage of weight increase and percentage of albedo surface dyed with ink. The incubation time with the enzymatic solution (Peelzym II) necessary to obtain a final product with good quality was also optimized. After each incubation time, the evaluation of peeling efficiency was carried out. The means of visual assessment for five characteristics were chosen and scaled for peeling and final product quality. Results showed that vacuum application in pulses was more effective than in continuum. For obtaining peeled segments from the Mollar variety the best conditions were three pulses of 80 kPa with the enzymatic solution and 30 min of incubation at an atmospheric pressure of 40 °C. The best condition to obtain peeled entire orange from Thomson variety were two pulses of 53 kPa with the enzymatic solution and 40 min of incubation at an atmospheric pressure at 40 °C.