Strawberry is one of the most preferred fruits all over the world due to its characteristic properties. Due to the morphological structure of fresh strawberries after harvesting, quality losses are observed during cold storage. Therefore, industrial washing of fresh strawberries is especially important for reducing microbial load and increasing shelf life. Demand for the new methods as an alternative to the chemicals used in industrial washing of fruits and vegetables is increasing due to consumer-related health concerns. Ultrasonic washing is a preferred innovative method in terms of reducing the microbial load and maintaining quality properties compared to chemical washing processes. In this study, fresh strawberries were washed with ultrasound (550 W/35 kHz) and peroxyacetic acid (40 ppm) after harvesting. The pH, total acidity, water soluble dry matter (brix), vitamin C, total phenolic content, antioxidant capacity, total viable, mold and yeast count analyses were performed in every two days during 14 days of cold storage of washed strawberries. Ultrasonic washing was found to be more effective in reducing microbial load and preserving bioactive properties of strawberries compared to other method due to its cavitation effect.

The demand of consumers to minimally processed, fresh-like foods can be meet with the non-thermal technologies, because of the undesirable effects of conventional thermal process on the quality parameters of fruit juices. Decrease in nutritional value, loss of colour pigments and vitamins, formation of some flavour defects can be reduced with ultrasound applications. Especially the advantage of ultrasound which is protecting or improving the bioactive component content have increased interest in ultrasound in recent years. In this study, the effects of ultrasound applications on bioactive components of fruit juices were reviewed and evaluated separately as the effect on ascorbic acid, anthocyanin, flavonoids and carotenoid contents. The increasing, decreasing or insignificant effects of ultrasound on bioactive content of juices which were observed in researches might be resulted from the differences between juice matrixes as well as ultrasonication parameters. Because of this, investigating ultrasound technology in different juices and optimizing the ultrasonication parameters for each fruit juice are important.