Development of a novel colorimetric sensor based on alginate beads for monitoring rainbow trout spoilage

Abstract

Alginate is a non-toxic, renewable, and linear copolymer obtained from the brown algae that can be easily shaped into beads. Its good gel forming properties have made it useful for entrapping food and pharmaceutical ingredients. In this study, alginate beads were used in a novel application as a colorimetric sensor in food intelligent packaging. Colorimetric sensor was developed through entrapping red cabbage extract as a pH indicator in alginate beads. The pH indicator beads were used in rainbow trout packaging for monitoring fillets spoilage. Color change of beads during fish storage was measured using the CIELab method. The alginate bead colorimetric sensor is validated by measuring total volatile basic nitrogen (TVB-N) levels and microbial populations in fish samples. Moreover, peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) were evaluated during storage. Results indicated that increasing the bacterial population during storage and production of proteolytic enzymes resulted in protein degradation, accumulation of volatile amine compounds, increase in the pH and finally color change of alginate beads. The values of TVB-N, pH, PV and TBARS increased with time of storage. The results of TVB-N and microbial growth were in accordance with color change of beads and CIELab data. Therefore, the proposed system enjoys a high sensitivity to pH variations and is capable of monitoring the spoilage of fish or other protein-rich products through its wide range of color changes. The alginate beads containing the red cabbage extract can, thus, be used as a low-cost colorimetric sensor for intelligent packaging applications.

Chlorogenic acid osmosis of snakehead fish: a novel approach to maintain quality and suppress deterioration during storage

“…Because of irreversible spoilage and decline of quality, more attention has been provided regarding evaluation and detection of fish quality as well as revealing the mechanism of fish degradation. [7][8][9] Earlier studies confirmed that quality decline related to oxidation-reduction, enzymatic hydrolysis, microbial action. [10,11] Osmosis plays a significant role in preserving meat quality.…”

“…Modified sensory evaluation was carried out for odor, flavor, and texture by the sensory panel of 25 panelists. [7,9,30] Panelists provided scores on a 5-point scale: 5, excellent; 4, good; 3, acceptable; 2, fair; and 1, unacceptable. The sensory evaluation was performed in a sensory assessing room at 25°C.…”

“…The change in TVB-N and pH of the samples ( Figure 2) was similar: the increasing TVB-N was related to the increasing pH level during storage time, which is supported by the previous study. [9,30,34] AV changes during storage AV trend of snakehead fish fillets during storage is presented in Figure 3a. The controlled sample showed an early rise in AV and later slight decline while treated samples showed increase in AV during storage.…”

Bio-Based Smart Materials for Food Packaging and Sensors – A Review

“…Many fruits, berries, vegetables and flowers with colors covering practically the entire visible spectrum are dyed by natural compounds such as anthocyanins and curcumin known as natural pH indicators (Yoshida et al, 2009;Silva-Pereira et al, 2015;Choi et al, 2017;Dudnyk et al, 2018;Majdinasab et al, 2018;Saliu and Pergola, 2018;Zhai et al, 2018;Kurek et al, 2019). Upon protonation/deprotonation of these molecules, their delocalized electronic structure rearranges and the change of the total number of resonant electrons as well as their confinement result in a change of their color (Figure 4).…”

“…Although colorimetric pH-sensitive sensors are typically not convenient for selective analysis, it is often sufficient to evaluate the food quality based on the change of the pH, as deteriorating proteins produce alkaline volatile nitrogen compounds (cadaverine, putrescine, histamine, and ammonia) (Bulushi et al, 2009;Prester, 2011). Exploiting this indirect sensing mechanism, curcumin based indicator films, e.g., in gelatin (Musso et al, 2017) and bacterial cellulose membranes (Kuswandi et al, 2012), blueberry and red grape skin pomace in chitosan and carboxymethyl cellulose matrix (Kurek et al, 2019), chitosan-corn starch film with red cabbage extract (Silva-Pereira et al, 2015), alginate beads with red cabbage extract (Majdinasab et al, 2018) as well as red cabbage extract in pectin films (Dudnyk et al, 2018) have been shown as feasible indicators of meat, shrimp and fish spoilage by detecting amines and cyclic N-containing compounds. In a similar way, acidic CO 2 evolves during the metabolism of pathogens in the food thus lowering pH, which may be detected, e.g., by anthocyanin/polylysine in cellulose matrix in a reversible manner as demonstrated by Saliu and Pergola (2018).…”