Determination of guaiacol produced by Alicyclobacillus acidoterrestris in apple juice by using HPLC and spectrophotometric methods, and mathematical modeling of guaiacol production

In this study, easy detection of Alicyclobacillus acidoterrestris was performed by determination of guaiacol in apple juice. Guaiacol produced by A. acidoterrestris was determined by using HPLC, UV-Vis spectrophotometer, and Minolta spectrophotometer. Statistical analysis showed that the methods used for measuring the guaiacol concentrations were not significantly different (p > 0.05). Guaiacol formation in apple juice spiked with different levels of A. acidoterrestris spores was also analyzed using Gompertz, Logistic, and Richards models. In all cases, a good agreement between experimental data and fitted values was obtained. Using the modified Gompertz model, the derived biological parameters were calculated. Guaiacol formation rates (μ) and final guaiacol concentrations (A) were very similar in all cases, regardless of the initial A. acidoterrestris spore counts. However, lag phase durations (λ) were found to be dependent on the initial bacterial counts, and increased from 28.4 to 37.6 h, when initial inoculation level decreased from ∼103 to ∼101 cfu/mL.