Influence of controlled atmospheres and antioxidants on enzymatic browning and shelf life of fresh-cut persimmon 'Rojo Brillante'

Persimmon fruit 'Rojo Brillante' can be marketed as a fresh-cut commodity after removal of astringency by application of high levels of CO₂. However, the shelf life is reduced due to enzymatic browning. Therefore, the objective of this work was to study the effect of antioxidants combined with controlled atmosphere storage extending the shelf life of fresh-cut persimmons. Fruits were harvested with an external color index (CI) of 8.3 (where, CI = 1,000*a/L*b). Persimmon pieces were dipped in two different antioxidant solutions (1% ascorbic acid (AA) and 1% citric acid (CA)) or in water as control. Fruit slices were placed under continuous flow of air (Atm-A) or 3 different controlled atmospheres of 21 kPa O₂ + 10 kPa CO₂ (Atm-B), 21 kPa O₂ + 20 kPa CO₂ (Atm-C), 5 kPa O₂ + 10 kPa CO₂ (Atm-D) during 8 days at 5°C. Color (CIE L*a*b*), firmness and visual quality were determined during storage. Persimmon pieces stored in Atm-D had higher L* and lower a* values than pieces stored in the other atmospheres. 1% CA was more effective controlling enzymatic browning of fresh-cut persimmons than 1% AA, showing the lowest a* values in all the controlled atmospheres studied. However, samples treated with CA had the lowest firmness. Samples stored in Atm-A showed the highest firmness values during storage; whereas, samples in Atm-D showed the lowest firmness. Storage of persimmon pieces in high CO₂ concentrations induced an internal browning of the tissue, different from enzymatic browning, that has been related in whole fruit to preharvest nutritional deficiencies, mechanical injury, and/or the effect of the treatment used to eliminate fruit astringency. This non-enzymatic browning limited the shelf life of the fresh-cut persimmon reducing the limit of commercialization significantly. The results show that atmospheres with low O₂ could reduce the enzymatic browning, whereas high CO₂ concentrations affect tissue internal browning of the samples.