Improving the qualitative indicators of apple juice by Chitosan and ultrasound.

Today's consumers desire for tasty, nutritious, and safe food products, so researchers are looking for new ways in which little heat or no heat at all is used for processing. This study was to evaluate the effect of treatment using an ultrasonic bath (for 15, 30, and 60 min at 40 and 60°C) and ultrasonic probe (for 10, 15, and 20 min at 40 and 60°C), treatment with Chitosan, and combination of them on the quality of apple juice that includes physicochemical features (pH, acidity, total solid matter), total polyphenol, total antioxidant capacity, the cloud point, and color values of Hunter (L*, a*, b*) in the treated samples and comparing them with each other. The results showed that ultrasound has no effect on the pH and acidity, while the total solid of ultrasound treatment was higher than controls in combination with Chitosan (p < 0.05). Total polyphenols of apple juice samples treated by ultrasonic probe are higher than an ultrasonic bath (p < 0.05). The total antioxidant capacity has improved in treatments (p < 0.05). According to the results there is a significant difference between the cloud point of control samples and Chitosan (p < 0.05). The L* (brightness) increased in ultrasonic probe method and had a significant decline in Chitosantreatment (p < 0.05). Findings from this study suggest that the use of ultrasound treatment in the production of apple juice can improve quality factors, and in this regard, ultrasonic probe is more effective.