Nuclear chemistry

Color difference

Biology

Fabrication

Statistics

Materials science

Chromatography

Cellulose

Chitosan

Computer science

Correlation coefficient

Food science

Filter (signal processing)

pH indicator

Alternative medicine

Genetics

Nanotechnology

Organic chemistry

Mathematics

Characterization (materials science)

Staining

Medicine

Chemistry

ALIZARIN RED

Alizarin

Computer vision

Pathology

Sensors and Actuators B Chemical

This study was aimed to develop a colorimetric indicator for real-time freshness monitoring of minced beef. The indicator fabricated by incorporation of alizarin (1% w/v) in cellulose-chitosan film developed by sol-gel method and then characterized. Addition of alizarin did not change the swelling index, while water solubility decreased. Fourier-transform infra-red analysis showed successful binding between alizarin and film, and scanning electron microscopic images presented the compact structure of the indicator. The indicator showed a clear color response from yellow to brown and purple at pH 2–11 and had more color stability at 4 °C as compared with 25 °C during storage for 2 months. Importantly, the indicator revealed color variation from brown to purple when total volatile basic nitrogen (TVB-N) reached the critical amount of 20.53 mg N/100 g. Pearson correlation coefficient represented a strong correlation between total color difference and TVB-N. Therefore, the alizarin based cellulose-chitosan pH-sensitive indicator has the ability to track the freshness of minced beef during the storage through perceptible color changes.

Fabrication and characterization of alizarin colorimetric indicator based on cellulose-chitosan to monitor the freshness of minced beef