@article{XIAO2025, 
author = {Xinglong XIAO and Ziqiang ZHANG and Juntai CHEN and Jialin XIE and Yifang CAO},
title = {Synergistic Effect and Mechanism of Phloretin and Lauraldehyde on the Killing of Alicyclobacillus acidoterrestris Spores},
year = {2025},
journal = {Journal of South China University of Technology (Natural Science Edition)},
volume = {53},
number = {10},
pages = {145-154},
keywords = {Alicyclobacillus acidoterrestris, spores, juice, phloretin, lauraldehyde, food control technology},
url = {https://www.sciopen.com/article/10.12141/j.issn.1000-565X.240526},
doi = {10.12141/j.issn.1000-565X.240526},
abstract = {To address the challenge of Alicyclobacillus acidoterrestris spore contamination of fruit juice, this study aimed to screen and evaluate the bactericidal effect of a synergistic combination of plant-derived actives and their mechanism of action. The study determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of plant-derived active compounds. By calculating the fractional inhibitory concentration index (FICI), a synergistic combination against Alicyclobacillus acidoterrestris spores was identified: phloretin (Ph) and lauric aldehyde (La). The results show that the MIC of phloretin is 0.1 mg/mL, and MBC is more than 6.4 mg/mL; the MIC of lauraldehyde is 0.4 mg/mL, and MBC is more than 6.4 mg/mL; the FICI of the combined effect of the two substances is 0.5. The 8PL (2 MICPh + 2 MICLa) synergistic combination shows the best spore-killing effect in the synergistic combinations, and in the culture medium, the number of spores decreases by 106.1 CFU/mL after 2 days of treatment in the 8PL synergistic combination; inoculating 104 CFU/mL of Alicyclobacillus acidoterrestris spores in apple juice, the 8PL synergistic combination treatment can reduce the spores to 0 after 1 day and maintain the effect for at least 14 days. For apple juice samples with an inoculation amount of 106 CFU/mL, the 8PL synergistic combination treatment requires more than 3 days to reduce spores to 0 CFU/mL, but after 14 days, 102.2 CFU/mL spores are detected again. As the concentration of synergistic combination increases, the spore absorbance significantly decreases and the fluorescence spectrum increases. By scanning electron microscopy, irregular wrinkles on the surface of the spores disappear, and the surface gradually becomes smooth with an increase in the degree of depression and fragmentation. Transmission electron microscopy (TEM) observations revealed spore membrane disruption, accompanied by progressively increasing leakage of nucleic acids and proteins. The above results indicate that the synergistic combination will cause certain damage to structures such as spore membranes. In addition, the release of pyridine dicarboxylic acid (DPA) also significantly increases, greatly reducing the stress resistance of spores. In summary, the synergistic combination of phloretin and lauraldehyde has a good killing effect on Alicyclobacillus acidoterrestris spores, and it is an effective strategy for fruit juice antibacterial and preservative properties.}
}