Sequential ozone and infrared pre-treatments prior to hot air drying of fruit inactivates enzymes responsible for fruit browning, and concurrently reduces microbial contamination risk and air drying time.
Both ozone usage and infrared (IR) heating have current applications as food drying and preservation techniques. However, each of these has trade-offs among food safety, the quality of the dried product, rehydration characteristics, and energy efficiency. For example, extended ozone exposure results in reduced enzyme activity of treated fruit - which helps preserve the fruit, but also affects physical and flavor profiles. Sulfur dioxide has also been used widely to reduce the microbial risk of treated fruit - but can leave undesirable residues on the finished fruit product that have raised human health concerns.
Researchers at the University of California, Davis have developed a technology to dry and preserve fruit that combines sequential ozone and infrared (IR) heating treatments with subsequent hot air drying. This technology reduces both microbial risk and total drying time significantly. It delivers several, desired, consumer preferences, increasing the dried products’ marketability. The drying technique saves energy while simultaneously improving the appearance of the final product, better preserving the light coloring associated with many fresh fruits. This technology achieves similar efficacy to current fruit preservation and drying processes. However, it minimizes the presence of unattractive physical end-product characteristics and eliminates undesirable residues that can result from current industrial-scale practices.
Food safety, Food Preservation, Fruit Drying, Ozone, Infrared Heating, IR, Microbial Reduction, Sulfur Dioxide Replacement