Effect of Induced Germination of Alicyclobacillus acidoterrestris on the Quality of Ultra-high Pressure Treated ‘Hanfu’ Apple Juice during Storage

Abstract

In this study, the optimal conditions for inducing the spore germination of Alicyclobacillus acidoterrestris were determined, and the effect of spore induction pretreatment on the quality of ultra-high pressure (UHP) treated ‘Hanfu’ apple juice was explored. Meanwhile, the changes of nutritional quality and volatile flavor during storage were investigated. The results showed that the optimal induction conditions were as follows: activation temperature of 41 ℃, activation time of 15 min, L-alanine concentration of 38 mmol/L, induction temperature of 40 ℃, and induction time of 20 min. Induced spore germination of A. acidoterrestris combined with UHP treatment reduced the microbial load of ‘Hanfu’ apple juice to less than 1 (lg(CFU/mL)), and improved the phenolic content and total antioxidant capacity compared with UHP treatment. Electronic tongue analysis showed that the taste of ‘Hanfu’ apple juice subjected to the combined UHP treatment was well preserved during refrigeration. Compared with UHP treatment, the combined treatment significantly increased the types and amount of aroma compounds as determined by solid phase microextraction (SPME) coupled to gas chromatography-mass spectrometry (GC-MS). This study provides an important theoretical basis for the cold sterilization of ‘Hanfu’ apple juice and provides a new idea for the industrial application of ‘Hanfu’ apple deep processing.

Keywords

• alicyclobacillus acidoterrestris; ‘hanfu’ apple juice; ultra-high pressure; phenolic compounds; aroma components