A chitosan–gelatin blend as a coating for fish patties

Abstract

A coating made in cold from a blend of a chitosan and a gelatin solution was applied to patties made of chilled cod, and its preservative effect was assessed by colour measurements, rheological measurements (hardness, elasticity, cohesiveness, chewiness, gumminess, and adhesiveness), biochemical determinations (total volatile bases and thiobarbituric acid as measures of rancidity) and microbiological assays (total bacterial counts, luminiscent bacteria, enterobacteria, pseudomonas, lactic acid bacteria, and Staphylococcus aureus). The effect of dry powdered chitosan mixed into the patties was tested as well. The use of chitosan either as a coating or as a powdered ingredient did not affect lightness at the end of the storage period considered but did result in an increase in the value of yellowness. The coating increased patty elasticity, whereas adding powdered chitosan to the patty mixture increased the other rheological parameter values. The findings on the effect of the chitosan on rancidity were not conclusive due to the low values recorded in the cod. However, the coating did prevent spoilage of the cod patties as reflected by a decrease in total volatile basic nitrogen and in the microorganism counts, in particular counts of gram-negative bacteria. In contrast, none of these effects on spoilage were observed when the chitosan was added to the patty mixture in powdered form. Coatings prepared in cold from a blend of gelatin and chitosan offer a promising alternative for preserving fish patties.

Use of Natural Preservatives in Seafood: Plant Extracts, Edible Film and Coating

“…The antimicrobial properties of chitosan coating have been reported in the literature López-Caballero et al, 2005). Jeon et al (2002) described how bacterial growth (total counts on plate count agar at 20ºC) reached the stationary phase in all chitosan-coated cod and herring samples after 6 days, and also how there was a reduction of up to three log cycles between coated samples and controls after 12 days of chilled storage.…”

“…Jeon et al (2002) described how bacterial growth (total counts on plate count agar at 20ºC) reached the stationary phase in all chitosan-coated cod and herring samples after 6 days, and also how there was a reduction of up to three log cycles between coated samples and controls after 12 days of chilled storage. López-Caballero et al (2005) reported that a coating consisting of a blend of chitosan dissolved in acetic acid and gelatine exerted an inhibitory effect on the gram-negative flora of fish patties. Various factors affect the antimicrobial action of chitosan and its mechanism of action appears to be related to interactions between the positively charged chitosan molecules and the negatively charged microbial cell membrane (Shahidi et al, 1999) as well as to its function as a barrier against oxygen transfer .…”

Factors influencing antibacterial activity of chitosan against Aeromonas hydrophila and Staphylococcus aureus

“…The use of chitosan as an antimicrobial material for food has been widely reported, for example, in bread , seafood (Tsai et al, 2002;López-Caballero et al, 2005), fruit and vegetables (Chien et al, 2007;Badawy and Rabea, 2009), meat (Sagoo et al, 2002;Rao et al, 2005), sausage (Lin and Chao, 2001;Soultos et al, 2008) and dairy products (Suman et al, 2010).…”

Effect of tuna skin gelatin-based coating enriched with seaweed extracts on the quality of tuna fillets during storage at 4 °C

“…Nowzari et al (2013) found that rainbow trout coated with gelatin based films and stored refrigerated for 16 days has lower TBARS values than controls. However, Lopez-Caballero, Gomez-Guillen, Perez-Mateos, and Montero (2005) observed that gelatin coatings have no influence on lipid oxidation of cod fillets stored at 2°C for 15 days. Besides this, in the present work, for coated samples with FGF it seemed that the increase was generally smaller (results not showed), however, there were no statistically significant differences (ANOVA, LSD test; p > 0.05) supporting that conclusion.…”