Intelligent pH indicator film composed of agar/potato starch and anthocyanin extracts from purple sweet potato

Inyoung Choi, Jun Young Lee, Monique Lacroix, Jaejoon Han

Research output: Contribution to journalArticlepeer-review

448 Citations (Scopus)


A new colorimetric pH indicator film was developed using agar, potato starch, and natural dyes extracted from purple sweet potato, Ipomoea batatas. Both agar and potato starch are solid matrices used to immobilize natural dyes, anthocyanins. The ultraviolet-visible (UV-vis) spectrum of anthocyanin extract solutions and agar/potato starch films with anthocyanins showed color variations to different pH values (pH 2.0–10.0). Fourier transform infrared (FT-IR) and UV-vis region spectra showed compatibility between agar, starch, and anthocyanin extracts. Color variations of pH indicator films were measured by a colorimeter after immersion in different pH buffers. An application test was conducted for potential use as a meat spoilage sensor. The pH indicator films showed pH changes and spoilage point of pork samples, changing from red to green. Therefore, the developed pH indicator films could be used as a diagnostic tool for the detection of food spoilage.

Original languageEnglish
Pages (from-to)122-128
Number of pages7
JournalFood Chemistry
Publication statusPublished - 2017 Mar 1

Bibliographical note

Funding Information:
This research was supported by the High Value-added Food Technology Development Program of the Korea Institute of Planning and Evaluation for Technology of Agriculture, Forestry, Fisheries and Food , Republic of Korea (No. 314074-3 ).

Publisher Copyright:
© 2016 Elsevier Ltd


  • Agar
  • Anthocyanin
  • Intelligent packaging
  • Potato starch
  • Purple sweet potato
  • pH indicator

ASJC Scopus subject areas

  • Analytical Chemistry
  • Food Science


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