Lungten Wangmo, Atitaya Suratsawadee, Thanchanok Ratvijitvech, and Atitaya Siripinyanond*
A colorimetric pH sensor was developed for freshness monitoring of shrimp. The sensor was fabricated by using commercially available tapioca pearl as a detection platform and anthocyanin from purple sweet potato as a sensing element. Five tapioca pearls were stacked in a pipette tip to observe the color change of the pearls by bead counting approach. The color of the tapioca pearl changed from purple to greenish-blue upon the detection of volatile nitrogen compounds and then to green on prolonged exposure to volatile nitrogen compounds. This color change was observed from the first bead and gradually observed on the next beads according to the concept of distance-based colorimetric measurement. Upon storage of shrimp samples, this sensor was used to observe the color change of the tapioca pearls and the total volatile basic-nitrogen (TVB-N) content was analyzed. With time, the TVB-N value increased and the number of tapioca pearl beads that changed the color was also increased.
Thanks are due to the Thailand Research Fund (TRF) and Mahidol University under grant number BRG 6180006. The support from Center of Excellence for Innovation in Chemistry (PERCH-CIC) and National Research Council of Thailand (IRN/502/2563) are gratefully acknowledged. We are thankful for Thailand International Cooperation Agency (TICA) for the scholarship given to LW. This work is related to the SDGs 4 (Quality Education).
Reference: Wangmo, L., Suratsawadee, A., Ratvijitvech, T., Siripinyanond, A. A novel sensor based on bead-counting of purple sweet potato tapioca pearl for freshness monitoring of shrimp (2021) Food Chemistry, 368, art. no. 130863, . DOI: 10.1016/j.foodchem.2021.130863