Ozone-high hydrostatic pressure synergy for the stabilization of refrigerated pitaya (Stenocereus pruinosus) juice

摘要

The synergistic effect of ozone (24 mg/O-3/L/min) and high hydrostatic pressure (HHP, 179-321 MPa) combination was evaluated with regard to individual effects of these over the microbial population in pitaya juice by using a response surface methodology and a repeated measures design with Tulcey test. Treatment with 300 MPa/5 min reduced 6.89-log(10) and 0.89-log(10) CFU/mL of Saccharomyces cerevisiae and Listeria innocua population, respectively; and treatment with 9.6 min of ozonation time reduced 0.47-log(10) and 2.51-log(30) CFU/mL of S. cerevisiae and L. innocua population respectively; however, L. innocua was reduced 5.1-log(10) CFU/mL with exposure to ozone for 7 min followed by 316 MPa/5 min. Likewise, these treatment conditions kept native tnicrobiota of the juice at non-detectable levels and achieved the highest sensory preference (79%) as compared to untreated juice at 30 d (5 +/- 2 degrees C). Ozone-HHP reduced bacterial counts suggesting a microbiologically safe pitaya juice, contrary to what was obtained with individual application of these technologies.