Physiological alterations involved in inactivation of autochthonous spoilage bacteria in orange juice caused by Citrus essential oils and mild heat

Geany Targino de Souza Pedrosa, Evandro Leite de Souza, Adma Nadja Ferreira de Melo, Erika Tayse da Cruz Almeida, Jossana Pereira de Sousa Guedes, Rayssa Julliane de Carvalho, Rafael Pagán, Marciane Magnani

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11 Citations (Scopus)

Abstract

This study investigated physiological alterations involved in the inactivation of Levilactobacillus (L.) brevis and Leuconostoc (Lc.) mesenteroides in orange juice caused by Citrus lemon essential oil (CLEO) and C. reticulata essential oil (CREO) alone and combined with mild heat treatment (MHT). Damage in DNA, membrane integrity, membrane potential, metabolic and efflux activity of bacterial cells were measured after exposure (6 and 12 min) to CLEO or CREO (0.5 μL/mL) and/or MHT (54 °C) using flow cytometry. Limonene was the major constituent in CLEO (66.4%) and CREO (89.4%). The size of the damaged cell subpopulations increased (p < 0.05) after longer exposure time and varied with the tested essential oil and/or bacterial isolate. After exposure to CLEO and CREO alone, the cell subpopulations with damage in measured physiological functions were in a range of 19.6–66.8% and 23.8–75.9%, respectively. Exposure to CREO resulted in larger Lc. mesenteroides cell subpopulations (35.4–68.7%) with damaged DNA, permeabilized and depolarized membrane and compromised metabolic or efflux activity compared to L. brevis (23.8–58.0%). In contrast, exposure to CLEO led to higher damaged L. brevis cell subpopulations (35.1–77%) compared to Lc. mesenteroides (25.3–36.6%). Exposure to combined treatments (CLEO or CREO and MHT) affected the measured physiological functions in almost the entire L. brevis and Lc. mesenteroides cell population (up to 99%), although the damage extension on each isolate varied with tested essential oil. Results show that inactivation of L. brevis and Lc. mesenteroides cells caused by CLEO and CREO alone and combined with MHT in orange juice involves a multi-target action, which causes DNA damage, altered permeability and depolarization of membrane and compromised metabolic and efflux activities.

Original languageEnglish
Article number108837
JournalInternational Journal of Food Microbiology
Volume334
DOIs
Publication statusPublished - 2 Dec 2020
Externally publishedYes

Keywords

  • Cell damage
  • Combined processes
  • Flow cytometry
  • Lactic acid bacteria
  • Lemon essential oil
  • Mandarin essential oil

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