Colorimetric ammonia (NH3) sensor based on an alginate-methylcellulose blend hydrogel and the potential opportunity for the development of a minced pork spoilage indicator

Multicolor PEGDA/LCNF Hydrogel in the Presence of Red Cabbage Anthocyanin Extract

“…As common knowledge, the hydroxyl could interact with water through hydrogen bonding. With this swelling ratio value, PEGDA/LCNF could have a good ability as the matrix to entrap the anthocyanin extract, and the sensitivity of the anthocyanin extract in this matrix could be enhanced, as mentioned in a previous study [34].…”

“…As common knowledge, the hydroxyl could interact with water through hydrogen bonding. With this swelling ratio value, PEGDA/LCNF could have a good ability as the matrix to entrap the anthocyanin extract, and the sensitivity of the anthocyanin extract in this matrix could be enhanced, as mentioned in a previous study [34]. Meanwhile, the effect of LCNF content was determined by preparing hydrogel with the following composition: 7.5 v/v.% of PEGDA and 0.5-2.0 w/v.% of LCNF, as well as a curing time of 60 s. Figure 5b shows that PEGDA/LCNF has a higher value than PEGDA, and the value increased as the amount of LCNF increased.…”

“…A correlation between Figures 7 and 8 can be utilized to explain the absorbance shift phenomenon from the lower (525 nm) to higher (600 nm) wavelength, because each color of the solution has a specific spectrum pattern. The absorbance peak shifted to the higher wavelength as the pH increased [34,37,38]. This phenomenon is called bathochromic shift, and normally occurs when a structure of flavonoid group-in this case, anthocyanin-changes as a result of pH change or even chemical reaction [37,38].…”

“…This statement has been mentioned in a related study, not only acting as a matrix to entrap the anthocyanins, and the PEGDA/LCNF materials can also absorb moisture to act as the solid support to prevent false indication. With the moisture-holding ability, the PEGDA/LCNF matrix can enhance the pH indicator sensitivity, owing to the proton transfer phenomenon between the entrapped anthocyanin and pH solution [34].…”

“…This statement has be tioned in a related study, not only acting as a matrix to entrap the anthocyanins PEGDA/LCNF materials can also absorb moisture to act as the solid support to false indication. With the moisture-holding ability, the PEGDA/LCNF matrix can the pH indicator sensitivity, owing to the proton transfer phenomenon between trapped anthocyanin and pH solution [34]. The L, a, and b values of each color were determined using ImageJ 1.52i (ht agej.net/software/fiji/index, 29 August 2021), and white paper was used as the c normalize any factor that influences the L, a, and b values when taking a picture a*, and b* values of each produced color at different pH can be seen in Table 1.…”