European Union has started a project that include ultrasound method to dehydrate fruits and vegetables. High  frequency sound waves are used in this method and and doesn’t effect nutritional value of fruits and vegetables. The project is carried out by 8 foundations from Spain, Germany, Sweden, England and Turkey. The coordinator of the project is Gokser Machine company from Turkey.

The most important property of the ultrasound method is economising energy and time. The aim is drying fruits and vegetables more effectively, quality and economically.

The most modern commercial method is Accelerated Freeze Drying (AFD) under vacuum. But this method is expensive. High Powered Ultrasound (HPU) some positive properties. These are; dependable, environment friendly, efficiently, economic and powerful technology.

Nowadays, the most important factors for consumers are food safety and durability. Another task of manufacturers is producing and developing high nutritional foods.

Generally one of the fundamental application to prolong food shelf life is stopping microbial activity. This can be possible by removing microorganisms completely, preventing their growth and killing them. Another application is controlling chemical events (enzymatic reactions, water activity, oxidative events). The most important point for food technology is food safety with the least change in food quality and nutritional value. So many conservation methods have been developed for many years.

One of these methods is Ultra High Hydrostatic Pressure (UHP) which has been searched since last of 20. century. The first food products which were applicated with UHP were launched by Japans. Apart from food industry, Ultra High Hydrostatic Pressure also gets attention of pharmacy and industrial biotechnology.

UHP consists of 100 to 1000 Mpa pressure application to packing or unpacking solid and liquid foods. Process temperature starts with  0°C and may increase to above 100°C.  Pressure vessels are enduring to high pressure and special designed. The pressure application differs between a millisecond to 1200 seconds.

According to reports, the UHP application in room temperature doesn’t change the chemical structure of food. For most efficient result UHP can be applied with the combination of heath treatment.

UHP effects equally to all parts of foods independently of food shape, size and composition, so package size, shape and composition are not the factors of UHP efficiency.

The most UHP resistant microorganism is Clostridium botulinum and its spores. It is resistant to 75°C, 30 minutes,  827 Mpa pressure application. Generally Gram-positive vegetative bacteria are more resistant to UHP than Gram-negative vegetative bacteria. Other resistant bacteria are Staphylococcus aureus, E. coli O157:H7 and Salmonella spp.

Vibrio parahaemolyticus and Listeria monocytogenes are sensitive to UHP. Byssochlamys nivea and Eupenicillum ascospores are resistant molds.

Researches have tried to find natural alternative materials to chemical food additives. The new material is chitosan.
Chitosan is the structural element in the exoskeleton of crustaceans (crabs, shrimp, etc.) and cell walls of fungi. Commercial chitosans are produced by deacetylation of chitin.

According to new findings published in Innovative Food Science and Emerging Technologies using chitosan may act as an anti-microbial ingredient for orange juice, and remove the need for pasteurization.
It is also claimed that adding one gram of chitosan to one litre of fresh orange juice reduce both enzymatic and non-enzymatic browning of the juice.

The study was carried out by Postharvest Technology Unit (PTU) and Functional Ingredient Food Unit (FiFu) at the Dublin Institute of Technology (DIT) with with chitosan in concentrations ranging from 0 to 2 grams per litre of juice. But it was found that over 1gram chitosan makes the taste of juice bitter and decrease the vitamin C content.