Effect of chitosan-based solutions applied as edible coatings and water glazing on frozen salmon preservation - A pilot-scale study

The aim of this research was to compare the effect of chitosan solutions on frozen salmon preservation with that of water glazing. For this purpose, three chitosan solutions (0.25%, 0.50% and 0.75% w/v) and water were applied in different amounts (6%, 8% and 11% of coated fillet weight) directly on the surface of frozen salmon. In order to accelerate the deterioration processes, salmon was stored during 14 weeks at −5 °C. Microbial and chemical indices were used to assess deterioration during storage and the coating stability was evaluated through weight loss measurements. The results obtained showed that chitosan coatings can be a good barrier to protect frozen fish from deterioration. Microbial growth, assessed by total viable counts (TVC), and total volatile basic nitrogen (TVB-N) were maintained below the maximum limits recommended which are 5 × 105 CFU/g and 35 mg nitrogen/100 g fish, respectively. The use of 0.50% and 0.75% chitosan solutions generally demonstrated to be more efficient in preventing salmon weight loss.