Evaluation of the potential of purple eggplant peel extract (Solanum melongena L.) as a pH indicator for Escherichia coli

Authors

  • Wenni Oktraiani Purba Medical Technology Laboratory, Poltekkes Kemenkes Medan
  • Yuli Yantika Syahputri The integrated Laboratory, Poltekkes Kemenkes Medan
  • Nita Andriani Lubis Politeknik Kesehatan Kementerian Kesehatan Medan
  • Gabriella Septiani Nasution Politeknik Kesehatan Kementerian Kesehatan Medan
  • Dewi Setiawati Politeknik Kesehatan Kementerian Kesehatan Medan
  • Febri Sembiring Politeknik Kesehatan Kementerian Kesehatan Medan

DOI:

https://doi.org/10.24843/JBIOUNUD.2025.v29.i01.p01

Keywords:

anthocyanin, E. coli, pH Indicator, purple eggplant peel, Solanum melongena

Abstract

Anthocyanins are natural pigments found in various plants and fruits, known for their ability to change color according to the pH of their environment. This property can be utilized as a pH indicator in observing carbohydrate fermentation reactions by bacteria. This study aims to evaluate the potential of purple eggplant peel extract (Solanum melongena L.) as an alternative pH indicator to monitor bacterial growth. Purple eggplant peel was extracted using 80% ethanol containing 1% HCl, stored for 24 hours at 4 °C, centrifuged, and concentrated using a rotary evaporator at 35 °C. The extract obtained was used as a pH indicator in Tryptic Soy Broth (TSB) media for Escherichia coli growth. This test used two treatments; namely purple eggplant peel extract added into TSB media before bacterial inoculation and purple eggplant peel extract added after bacteria grew on TSB media. The results showed that purple eggplant peel extract effectively showed a clear color change according to different pH levels. However, when applied to bacterial growth media, the addition of purple eggplant peel extract showed no significant color change on TSB media, neither before nor after bacteria growth. Thus, to effectively utilize this extract as an indicator in bacterial growth media, further research is needed to explore methods to maintain the stability of the pigments contained in purple eggplant peel extract when added to bacterial growth media.

Downloads

Published

30-08-2025

Issue

Vol. 29 No. 1 (2025): Jurnal Biologi Udayana

Section

Articles

License

Copyright (c) 2025 Wenni Oktraiani Purba, Yuli Yantika Syahputri, Nita Andriani Lubis, Gabriella Septiani Nasution, Dewi Setiawati, Febri Sembiring

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

License Term

All articles published in Jurnal Biologi Udayana  are open access and licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0). This means that anyone is free to:

  • Share — copy and redistribute the material in any medium or format.

  • Adapt — remix, transform, and build upon the material for any purpose, even commercially.

However, this is granted under the following conditions:

  • Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.

  • No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

By submitting an article to Jurnal Biologi Udayana, authors agree to the publication of their work under this open access license. The authors retain the copyright of their work, but grant Jurnal Biologi Udayana  the right of first publication.

For more information about the CC BY 4.0 license, please visit the official website: https://creativecommons.org/licenses/by/4.0/