Combination of Hydrocolloid and Ultrasound Assistance to Improve the Stability of Lemon Juice After Thawing

In order to reduce the delamination and flocculation of frozen lemon juice after thawing, this study investigated the effect of ultrasound-assisted hydrocolloids on the stability of lemon juice after thawing. By comparing the effects of different hydrocolloids, it was found that pectin, xanthan gum, and konjac gum significantly improved the stability of lemon juice, whereas other hydrocolloids such as gum arabic and acacia bean gum were not effective in improving the stability and even exacerbated the flocculation and delamination phenomenon in some cases. In addition, the effects of pectin, xanthan gum, and konjac gum were studied in depth. The effects of different combinations of concentrations and hydrophilic colloids were evaluated by determining parameters such as particle size, zeta potential, viscosity, and cloud stability of the juices using one-way and response surface tests. The results showed that the use of any one hydrocolloid alone could not completely solve the problems such as delamination and flocculation of fruit juice. The hydrophilic colloids were more effective when used in combination, and the optimal composite stabilizer additions were when the additions of pectin, xanthan gum, and konjac gum were 0.32%, 0.25%, and 0.15%, respectively, at which time the stability of lemon juice after thawing was better. In addition, the use of ultrasound-assisted treatment also significantly improved the stability of lemon juice, and the use of 1500 W ultrasound for 10 min resulted in a 15.4% increase in its cloud stability. Practical Application: This study provides a simple and novel method to improve the stability of frozen lemon juice after thawing. Using the addition of hydrophilic colloids combined with ultrasonic treatment, the stability of lemon juice after thawing can be improved, which provides a new method to improve the quality of fruit juice products.