Effects of Edible Coatings Based on Ultrasound-treated Fish Proteins Hydrolysate in Quality Attributes of Chilled Bonito Fillets

Fish by-products which occur during the processing steps in seafood industry, have a potential utilization in production of value-added products such as protein hydrolysates. Innovative edible coatings were prepared from fish protein hydrolysates (FPH) produced from trout by-products, by conventionally enzymatically (CH) and ultrasound-assisted enzymatically (UH) to extend the quality and shelf life of bonito (Sarda sarda) fillets stored at 4 +/- 1 degrees C. For this purpose, FPH with 86.40 g/100 g (CH) and 86.75 g/100 g (UH) protein contents were used as the coating forming material with glycerol in a ratio of 2:1 as plasticizer. Bonito fillets were protected by means of the functionalized coatings stored for 15 days at 4 +/- 1 degrees C. Coated bonito fillets exhibited higher antimicrobial efficiency against mesophilic, psychrophilic, and coliform bacteria and yeast and mold. Lower total volatile basic nitrogen (TVB-N) and thiobarbituric acid (TBA) and trimethylamine (TMA) production were observed in coated fillets during the storage. All sensory criteria of control group fell below 4.00 point on the 9th day but CHCG and UHCG were acceptable up to the 12th day of storage.