The main problems occurring during fresh-cut papaya shelf-life are the loss of weight, loss of texture, depletion of nutritional value and microbial load increase. Scientists have evaluated the total phenolic content, the ascorbic acid, the antioxidant capacity, and the microbial load of fresh-cut papaya cubes after exposure to 9.2±0.2µl/L ozone for 10, 20 and 30 minute sessions.
For the study, fruits were peeled, seeds were removed, the pulp was cut into cubes of 2.5 cm3, the cubes were placed in plastic trays and then were put inside the ozone chamber.
Comparing the cubes treated with ozone for 20 min with untreated cubes resulted that in the former the total phenolic content increased by 10.3% while the ascorbic acid decreased by 2.3%.
The initial counts of mesophilic and coliform bacteria were 2.67 log10 CFU/g and 1.81 log10 CFU/g, respectively. The treatment with ozone significantly reduced the microbial load, especially the ozone resulted more effective against coliforms (reduction from 0.39 to 1.12 log10 CFU/g) than against mesophilic bacteria (reduction from 0.22 to 0.33 log10 CFU/g).
Tab. The effects of different exposure time of 9,2±0,2µl/L ozone on the antioxidants and populations of mesophile and coliform bacteria on fresh-cut papaya. Values in columns not followed by the same letter are significantly different (P<0.05) using Duncan's test. Each value is the mean ± standard error of 4 replicates.
Click here to enlarge the table.
The results suggest that treating the fresh-cut papaya cubes with 9.2±0.2µl/L ozone for 20 min can reduce the microbial load without depleting its major antioxidants, except for ascorbic acid
Source: Yeoh W.K., Ali A., Forney C.F., ‘Effects of ozone on major antioxidants and microbial populations of fresh-cut papaya’, 2014, Postharvest Biology and Technology, Vol. 89, pagg. 56-58. Further info: http://www.sciencedirect.com/science/article/pii/S0925521413003475