The effect of ultrasound and pure apple vinegar as pretreatments on the functional and antibacterial properties of dried garlic slices in the hot air

Drying is one of the effective ways to increase shelf life and preserve the useful compounds of materials, which can be improved by using different methods and materials. The use of bioactive compounds as a pre-treatment can be one of the effective methods to increase functional and antibacterial properties. This research was conducted to simultaneously apply ultrasonic pretreatment and pure apple vinegar before drying garlic slices, and investigate their effect on the functional and antibacterial properties of dried garlic slices by hot air. Before drying, the slices were floated in pure apple vinegar and distilled water under ultrasonic treatment (frequency of 40 kHz) for 10 minutes at 35oC, and also in pure apple vinegar for 10 minutes at 35oC. Then they dried using a hot air circulation dryer at a temperature of 50oC to reach a moisture content of 6% (wet basis). The chemical properties of samples including total phenolic and flavonoid content, functional properties, antioxidant capacity, and antibacterial properties were evaluated. The results showed that the use of ultrasound pretreatment together with pure apple vinegar had the greatest effect in the increase of bioactive compounds and antibacterial properties of samples compared with the control one. The results showed that the use of ultrasonic and pure apple vinegar improved the quality, functional, and antibacterial properties of dried sliced garlic samples.