BIOCHEPHY: Journal of Science Education
Vol. 6 No. 1 (2026)

Effectiveness of Purple Cabbage Flower (Brassica oleracea var. capitata f. rubra) Extract as a Natural Indicator for Borax Identification in Food Products

Fauziah Indira Siregar (Universitas Negeri Medan)
Rahel Nainggolan (Universitas Negeri Medan)
Nayla Azizah (Universitas Negeri Medan)
Teresia Vredemika Sidauruk (Universitas Negeri Medan)
Miquel Kaban (Universitas Negeri Medan)
Larasati Arum Utami (Universitas Negeri Medan)
Nurbaity Situmorang (Universitas Negeri Medan)



Article Info

Publish Date
01 Jun 2026

Abstract

The misuse of borax as a preservative in school snacks poses a serious threat to food safety, necessitating practical and accessible solutions for the general public. This study aimed to evaluate the effectiveness of purple cabbage (Brassica oleracea var. capitata f. rubra) extract as a natural indicator for the qualitative detection of borax. Laboratory experiments were conducted at the Biology Laboratory of Universitas Negeri Medan using the maceration method with water as the solvent to extract anthocyanin pigments. Food samples tested included meatballs, tofu, yellow noodles, and crackers. The results showed that purple cabbage extract successfully detected borax in yellow noodle samples through a colour change from purple to bluish-green, caused by the deprotonation of anthocyanins under alkaline conditions. These findings demonstrate that purple cabbage extract is a valid, economical, practical, and environmentally friendly screening tool to support public food safety monitoring.

Copyrights © 2026






Journal Info

Abbrev

biochephy

Publisher

Subject

Education

Description

BIOCHEPHY: Journal of Science Education is an open-access journal published by the MO.RI Publishing. This journal aims to provide a forum for researchers, educators, teachers, trainer, and other practitioners to present their latest research papers on the results of the study and review of the ...