Simultaneous optimization of Alicyclobacillus acidoterrestris reduction, pectin methylesterase inactivation, and bioactive compounds enhancement affected by thermosonication in orange juice

Abstract

Thermosonication (TS) was applied to optimize the quality characteristics of orange juice and to inactivate Alicyclobacillus acidoterrestris vegetative cells using the Box–Behnken design by varying temperature (45–75°C), time (20–40 min), and frequency (20–60 kHz). Results from the response surface methodology showed that the optimal conditions for TS were 47°C, 30 min, and 20 kHz. The models generated were highly significant (p < .001) with the coefficient of determination of 0.986–0.996. The optimal conditions demonstrated high total phenolic contents (TPC) (490.85 mg GAE/100 ml), pectin methylesterase (PME) enzyme inactivation (94.77%) as well as low A. acidoterrestris vegetative cells’ load (1.00 log reduction). In addition, total flavonoids contents (38.50 mg/100 ml ER), ascorbic acid (441.70 mg/ml), color change ΔE (1.85), polyphenol oxidase enzyme (56%), and antioxidant capacity (FRAP, 107.33 g/100 ml AEAC, DPPH, 85.90%) of treated orange juice showed a significant (p < .05) difference compared to the control. Thus, TS significantly enhanced the quality of the natural orange juice. Practical applications The negative impact of Alicyclobacillus acidoterrestris is a major concern for the food industry. Reducing their amount in food by thermosonication is gaining much attention lately. This kind of green technology represents a quick, efficient, and economical substitute to improve the quality of fruit juices.