Use of chitosan coating in increasing the shelf life of liquid smoked Nile tilapia (Oreochromis niloticus) fillet

Repurposing chitin-rich seafood waste for warm-water fish farming

The pisciculture industry has grown multi-fold over the past few decades. However, a surge in development and nutrient demand has led to the establishment of numerous challenges. Being a potential solution, chitosan has gained attention as a bio nanocomposite for its well-acclaimed properties including biodegradability, non-toxicity, immunomodulatory effects, antimicrobial activity, and biocompatibility. This biopolymer and its derivatives can be transformed into various structures, like micro and nanoparticles, for various purposes. Consequently, with regards to these properties chitin and its derivatives extend their application into drug delivery, food supplementation, vaccination, and preservation. This review focuses on the clinical advancements made in fish biotechnology via chitosan and its derivatives and highlights its prospective expansion into the pisciculture industry-in particular, warm-water species.

Astaxanthin improves the shelf-life of tilapia fillets stored under refrigeration

BACKGROUND

Astaxanthin, classified as a xanthophyll, has antioxidant properties about 500 times greater than α-tocopherols and ten times greater than β-carotenes. Based on the antioxidant activity of this carotenoid, this study aimed to evaluate the shelf-life of tilapia fillets (Oreochromis niloticus) fed with astaxanthin, by determining the microbiological quality (colimetry, counts of mesophilic and psychrotrophic microorganisms), physicochemical analyses (colorimetry, pH, thiobarbituric acid reactive substances (TBARS)) and sensory analysis.

RESULTS

Tilapia supplemented with astaxanthin presented a reduction in the counts of microorganisms (mesophiles and psychrotrophics) and lower lipid oxidation index (TBARS), when compared to fillets of control fish. Colorimetric changes of fillet degradation were observed, associated with increased pH during storage, as well as loss of brightness and texture in addition to worsening of appearance and odor. These deteriorating changes were minimized using astaxanthin.

CONCLUSION

Our results demonstrate the beneficial performance of astaxanthin in the shelf-life of tilapia fillets stored under refrigeration. Therefore, dietary supplementation with astaxanthin (100 and 200 mg kg^-1 of feed) improves the microbiological and physicochemical quality of tilapia fillets during 50 days of shelf-life. © 2022 Society of Chemical Industry.

Bioactive Protecting Coating of Guar Gum with Thyme Oil to Extend Shelf Life of Tilapia (Oreoschromis niloticus) Fillets

Edible coatings are safe, legal, and sensory acceptable for food applications and they can be incorporated as natural additives due to their antimicrobial activity, thickening capacity, nutrient content, and bioactive agents for protecting seafood from physical, chemical, and microbiological damage that affects its shelf-life. This study aimed to evaluate the effect of the guar gum bioactive coating with thyme oil on the quality of tilapia fish fillets for 15 days of storage at 4 °C, as a means to extend shelf-life. pH, moisture, ash, fat, color, thiobarbituric acid reactive substances (TBARS), total volatile basic nitrogen (TVB-N), microbiological, and sensory examinations were investigated, and the results were analyzed by analysis of variance. The treatments were control (uncoated, UC), GGC (coated with guar gum, GGC), and guar gum combined with thyme oil (GGCTH). Tilapia fillets were stored at 4 °C, the safe temperature for refrigerated storage for 15 days. GGCTH had a slower increase of pH after 15 days of storage in comparison with GGC and UC (p < 0.05). GGC and GGCTH resulted in lower and lowest lightness (L*; p < 0.05) values, lower and lowest redness (a*; p < 0.01) values, and greater and greatest yellowness (b*; p < 0.05) values compared to UC, respectively. UC reduced shear force at 5 (0.37 kgf), 10 (0.32 kgf), and 15 (0.30 kgf) days post-storage in comparison with GGC (0.43, 0.43, and 0.43 kgf) and GGCTH (0.43, 0.44, and 0.44 kgf), respectively. There was less (p < 0.05) deterioration, as well as differences in textural and sensorial variables between uncoated and coated fish fillets. The microbiological analyses demonstrated that there was greater microbial growth in the uncoated fillets than in the coated ones. It was concluded that this bioactive coating with thyme oil retards microbial colonization of fish and reduces degradability of quality variables, therefore, it is a reliable and effective alternative to extend the shelf-life of tilapia fillets.

Preservation of meatballs with edible coating of chitosan dissolved in rice hull-based liquid smoke

The purpose of this study was to determine the effectiveness of edible coatings of chitosan dissolved with liquid smoke in preserving meatballs. The liquid smoke was derived from rice hulls pyrolyzed at 340 °C. The edible coating was made by dissolving 0.5%, 1%, and 1.5% chitosan in 100 ml of liquid smoke at concentrations of 3% and 5%. Preservation was carried out by soaking the meatballs in the edible coating solution for 15 min and storing them at room temperature with observations every 6 h. Food resistance was examined using the Antibacterial Activity Test, Total Plate Count (TPC), and Total Volatile Base Nitrogen (TVB-N).

The results of the antibacterial activity test showed that chitosan-dissolved liquid smoke had inhibition zones ranging from 6.49–7.07 mm against E. coli and 6.52–7.26 mm against Salmonella bacteria. The use of 5% concentrated liquid smoke reduced the number of bacterial colonies, with TPC values not below the SNI threshold after 48-hour storage. This indicates that liquid smoke has potential as an antibacterial. The TVB-N value doubled after 24 h, but the meatballs still had good freshness. After 54 h of storage time, the TVB-N value in all treatments exceeded the SNI threshold of 0.254 mgN/100 g, and the meatballs were no longer suitable for consumption.

A simple, efficient and economic method for obtaining iodate-rich chili pepper based chitosan edible thin film

The present study was aimed at designing an iodine supplement in form of edible film made of iodate-coated chitosan (CS-IO₃). Inclusion of so obtained films in diet can help in preventing thyroid cancer, leading to improved public health. Chili pepper was coated with iodate thin film (1.5 µm). The iodate-rich film is ready-to-eat serving valuable nutrients. Stability studies of CS-IO₃ film using water dipping revealed that there was no leaching of iodate ion, due to the strong interactions between cationic amino group of chitosan and iodate ion. The film showed no change in its antioxidant activity. Iodate concentration in the film was determined at 620 nm selectively, based on the decolorization of malachite green economic method. Iodate content in fruits coated with 1.5% (w/v) CS-IO₃ was 11.5 mg g^-1 of dry film sample. The iodate-rich samples could be stored without much effect on its freshness, indicating a good shelf life.

The investigation of the shelf life at 2 ± 1 °C of Luciobarbus esocinus fillets packaged with films prepared with the addition of different essential oils and chitosan

In this study, the chemical, microbiological and sensory changes during storage at 2 ± 1 °C of Luciobarbus esocinus fillets coated with edible films prepared with chitosan incorporation of thyme, clove, rosemary essential oils were examined. To create the experimental samples, a total of six groups of L. esocinus fillets coated with different edible films (normal, vacuum-packed, chitosan, chitosan with added thyme oil, chitosan with added clove oil, and chitosan with added rosemary) were used. The food composition of the fillets and experimental samples were determined after they had been coated with edible films. The results of analysis showed that, the preservation period of fresh fillets ended on day 12th, that of vacuum-packed fillets on day 15th, that of fillets coated with chitosan incorporation of rosemary on day 27th, that of fillets coated with chitosan incorporation of thyme and chitosan incorporation of cloves on day 30th. In comparison with the control group, fish spoilage was significantly delayed in samples coated with chitosan incorporation of thyme and chitosan incorporation of cloves (p < 0.05). The lowest bacterial growth, values of PV, TBA and TVB-N were obtained in fish samples coated with thyme + chitosan and cloves + chitosan. In terms of the general acceptability of the fish, as determined by qualified panelists, it was determined that the highest score was given to the experimental group to which essential oil of clove had been applied.