LAUSR

BACKGROUND Ultrasound has a potential to increase microbial metabolic activity, so this study explored the stimulatory effect of ultrasound pre-treatment on the degradation of four common pesticides (fenitrothion, chlorpyrifos, profenofos, and dimethoate) during milk fermentation by Lactobacillus plantarum and its effect on yogurt quality. RESULTS Proper ultrasound pretreatment significantly enhanced the growth of L. plantarum. The degradation percentages of pesticides increased by 19-38% under ultrasound treatment. Ultrasonic intensity, pulse duty cycle, and duration time were key factors affecting microbial growth and pesticide degradation. Under the optimal ultrasonic pre-treatment conditions, the degradation rate constants of four pesticides were at least 3.4 times higher than those without sonication. In addition, such ultrasound pretreatment significantly shortened the yogurt fermentation time, increased the water holding capacity, hardness and antioxidant activity of the yogurt, and improved the flavor quality of the yogurt. CONCLUSION Ultrasonic pretreatment significantly accelerated the degradation of the four pesticides during yogurt fermentation. In addition, such ultrasound pretreatment increased the efficiency of yogurt making and improved the quality of yogurt in terms of water holding capacity, firmness, antioxidant activity and flavor. These findings provide a basis for the application of ultrasound to the removal of pesticide residues and quality improvement of yogurt. This article is protected by copyright. All rights reserved.