Cinnamil- and Quinoxaline-Derivative Indicator Dyes for Detecting Volatile Amines in Fish Spoilage

Abstract

Colorimetric indicators are versatile for applications such as intelligent packaging. By interacting with food, package headspace, and/or the ambient environment, color change in these indicators can be useful for reflecting the actual quality and/or monitoring distribution history (e.g., time and temperature) of food products. In this study, indicator dyes based on cinnamil and quinoxaline derivatives were synthesized using aroma compounds commonly present in food: diacetyl, benzaldehyde, p-tolualdehyde and p-anisaldehyde. The identities of cinnamil and quinoxaline derivatives were confirmed by Fourier transform infrared (FT–IR) spectroscopy, mass spectrometry (MS), 1H nuclear magnetic resonance (NMR) and 13C NMR analyses. Photophysical evaluation showed that the orange-colored cinnamil derivatives in dimethylsulfoxide (DMSO) turned to dark brownish coloration when exposed to strong alkalis. The cinnamil and acid-doped quinoxaline derivatives were sensitive to volatile amines commonly present during the spoilage in seafood. Quinoxaline derivatives doped by strong organic acid were effective as pH indicators for volatile amine detection, with lower detection limits than cinnamil. However, cinnamil exhibited more diverse color profiles than the quinoxaline indicators when exposed to ammonia, trimethylamine, triethylamine, dimethylamine, piperidine and hydrazine. Preliminary tests of acid-doped quinoxaline derivatives on fresh fish demonstrated their potential as freshness indicators in intelligent packaging applications.

Synthesis of cinnamils and quinoxalines and their biological evaluation as anticancer agents

“…Cinnamils (1,6‐diarylhexa‐1,5‐diene‐3,4‐diones) (Figure 1a) are curcumin‐like, colored compounds, which are useful precursors having many applications. They have been used for the synthesis of dye‐sensitized solar cells (DSSCs), [ 1–6 ] metal ligands, [ 2,3,7–12 ] and photoluminescence materials, [ 13,14 ] and were first used in the study of Alzheimer's disease. [ 15 ] The first synthesis of cinnamil was reported by Sorenson in 1947, wherein they condensed 2,3‐butanedione with the corresponding aldehydes using the Claisen‐Schmidt method.…”

“…[ 49 ] Interestingly, both cinnamils and quinoxalines were used as dyes for the detection of volatile amines in food packages. [ 1 ] The applications of quinoxalines have been extensively reviewed. [ 50 ]…”

“…cells (DSSCs), [1][2][3][4][5][6] metal ligands, [2,3,[7][8][9][10][11][12] and photoluminescence materials, [13,14] and were first used in the study of Alzheimer's disease. [15] The first synthesis of cinnamil was reported by Sorenson in 1947, wherein they condensed 2,3-butanedione with the corresponding aldehydes using the Claisen-Schmidt method.…”

Smart and Safe packaging

“…For a direct transmission of the information, several colorimetric indicators were also prepared mainly based on pH sensitive materials like sulphonephtalein dyes, purple sweet potato anthocyacin, cinamil and quinoxaline, curcumin and other classic colorimetric dyes such as bromophenol blue, bromocresol green, etc. [339][340][341][342][343][344][345][346] .…”

“…Figure I-25: NH3 and volatile amine indicators for fish and seafood spoilage detection with a) pH sensitive film made of curcumin/tara gum/PVA and colour change before (left) and after spoilage (right), b) pH sensitive label with an array of 16 different colorimetric dyes and colour change after exposure to fresh (left) and spoiled salmon (right), c) fluorescent label based on pyrylium salts and colour change under UV light for unspoiled (left) and spoiled (right) specimen, d) pH sensitive label made by drop-casting quinoxaline on cellulose paper and colour at 0, 4 and 12 hours (from left to right) of storage at room temperature for control, cod, haddock, perch, tilipia (from top to bottom) and e) pH sensitive film using bromophenol blue extruded with LDPE and respective change of colour after storage at room temperature (from left to right: 0, 24 and 48 hours). Respectively reproduced and adapted from Ma et al (2017) with permission from Elsevier (Copyright 2017) for a)345 , from with permission from Elsevier (Copyright 2015) for b)346 , from with permission from the American Chemical Society (Copyright 2020) for c)339 , from 343 for d) and from with permission from Elsevier (Copyright 2018) for e)342 …”