Purple sweet potato (Ipomoea batatas L.) extract as a pH-sensitive natural dye for the development of packaged food freshness indicator. Journal of Tropical Agriculture and Food Science (JTAFS), 53 (1). pp. 59-64. (2025)
Abstract
Natural pigments from tubers are applied for the development of pH indicator for food freshness label. In this study, the extract from purple sweet potato was used for pH sensitive dye characterisation. The colour changes of the sample extract were measured using UV-Vis spectrophotometer at the absorbance range between 400 nm to 800 nm and also a chroma meter. The results showed that the dye from purple sweet potato exhibited pH sensitivity. The colour was red in acidic pH, purple in neutral and green to yellow in alkaline pH. The maximum absorbance peak was found at 475 nm for the pH below than 3. In pH range of 4 to 6, the absorbance peaks were found at 500 nm and 525 nm for neutral pH. An alkaline pH buffers show the absorbance peaks around 550 nm. There are significant (p <0.05) differences in value of a*, b*, C* and ΔE* with pH variation. The ΔE* value also shows a linear and quantitative relationship to a specific pH range. Due to the sensitivity characteristic of the dye at different buffer pHs, this dye has the potential to be used as an indicator for food freshness especially for the products that undergo pH changes during deterioration.
| Item Type: | Article |
|---|---|
| Keywords: | Purple sweet potato, anthocyanin, pH, natural dye, freshness indicator |
| Taxonomy: | By Niche > Food Technology > Food Packaging > Biodegradable & Eco-Friendly Packaging By Niche > Food Technology > Research & Food Product Development (R&D) > Food Chemistry |
| Local Content Hub: | Niche > Food Technology |
| Depositing User: | Muhammad Shafiq Amirullah |
| Date Deposited: | 10 Dec 2025 08:22 |
| Last Modified: | 10 Dec 2025 08:22 |
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