UV-Vis spectroscopic investigation on color change kinetics of lac dye as influenced by some food spoilage metabolites: validation for milk quality monitoring
ISSN: 0369-9420
Article publication date: 28 July 2022
Issue publication date: 2 January 2024
Abstract
Purpose
This paper aims to study the color change kinetics of lac dye in response to pH and food spoilage metabolites (ammonia, lactic acid and tyramine) for its potential application in intelligent food packaging.
Design/methodology/approach
UV-Vis spectroscopy was used to study the color change of dye solution. Ratio of absorbance of dye solution at 528 nm (peak of ionized form) to absorbance at 488 nm (peak of unionized form) was used to study the color change. Color change kinetics was studied in terms of change in absorbance ratio (A528/A488) with time using zero- and first-order reaction kinetics. An indicator was prepared by incorporating lac dye in agarose membrane to validate the result of study for monitoring quality of raw milk.
Findings
Dye was orange-red in acidic medium (pH: 2 to 5) and exhibited absorbance peak at 488 nm. It turned purple in alkaline medium (pH: 7 to10) and exhibited absorbance peak at 528 nm. The change in absorbance ratio with pH followed zero-order model. Acid dissociation constant (pKa) of dye was found to be 6.3. Color change of dye in response to ammonia and tyramine followed zero-order reaction kinetics, whereas for lactic acid, the first-order model was found best. In the validation part, the color of the indicator label changed from purple to orange-red when the milk gets spoiled.
Originality/value
The study opens a new application area for lac dye. The results suggest that lac dye has potential to be used as an indicator in intelligent food packaging for detection of spoilage in seafood, meat, poultry and milk.
Keywords
Acknowledgements
Funding: The author(s) received no financial support for the research, authorship and/or publication of this article.
Conflicts of interest: All authors have no conflict of interest to report.
Data availability: The data used to support the findings of the study are included within the article.
Citation
Sakare, P., Giri, S.K., Mohapatra, D. and Tripathi, M.K. (2024), "UV-Vis spectroscopic investigation on color change kinetics of lac dye as influenced by some food spoilage metabolites: validation for milk quality monitoring", Pigment & Resin Technology, Vol. 53 No. 1, pp. 103-113. https://doi.org/10.1108/PRT-03-2022-0033
Publisher
:Emerald Publishing Limited
Copyright © 2022, Emerald Publishing Limited