Y. Sedat Velioglu

Ozone Applications in Fruit and Vegetable Processing

Ozone, a powerful oxidant, is effective against various kinds of microorganisms on fruits and vegetables. Promising results have been revealed in solving the problems of the food industry like mycotoxin and pesticide residues by ozone application. Spontaneous decomposition without forming hazardous residues in the treatment medium makes ozone safe in food applications. If improperly used, ozone can cause some deleterious effects on products, such as losses in sensory quality. Treatment conditions should be specifically determined for all kinds of products for effective and safe use of ozone.

Mycotoxins: contamination of dried fruits and degradation by ozone

Dried fruits are susceptible products for mold contamination and growth, and consequent mycotoxin production. Numerous studies revealed high incidences or high levels of contamination of these products with mycotoxins. Once the product is contaminated, decontamination procedures are inevitable. Ozonation, a recently approved process in the food industry, has revealed promising results in detoxifying contaminated products. This review presents the results of recent studies conducted on mycotoxin contamination in economically important dried fruits and gives some information about contamination steps, mechanisms, and possible prevention methods for each product. The potential of ozone application in mycotoxin degradation was reviewed and finally data obtained from recent studies about the properties of degradation products after the reaction between ozone and mycotoxins was discussed.

Effects of Some Metals and Chelating Agents on Patulin Degradation by Ozone

The efficiency of ozone treatment for degradation of the mycotoxin patulin in the presence of various metal ions was evaluated in model systems. An initial patulin concentration of 250 μg/L was ozonated and residual ozone concentration was about 0.17±0.01 mg/L at the end of the experiment. Patulin showed a weak resistance to ozone, because up to 98% of this toxin was oxidized in only one minute. Degradation rates in the presence of calcium, aluminum, copper and zinc were almost the same in the absence of these metals. However, degradation of patulin was reduced from 98 to 37% when the concentration of manganese increased from 0 to 3 mg/L. Patulin was almost completely degraded in the absence of iron, while the degradation was only 8.5% in the presence of 0.5 mg/L of iron. These results have revealed that manganese and iron significantly reduce the detoxification of patulin by ozone. Agents such as ethylenediaminetetraacetic acid and sodium polyphosphate effectively chelated iron and increased the degradation rate of patulin. None of the tested agents were able to chelate manganese and to enhance patulin degradation by ozone.