Çaça (Sprattus sprattus, L., 1758) Protein Hidrolizatının Fizikokimyasal Özellikleri ve Alabalık (Oncorhynchus mykiss, Walbaum, 1792) Filetolarında Kaplama Malzemesi Olarak Kullanımı

Abstract

Trout is the most widely cultivated and traded fish species in Turkey and many European countries, and a total of 471686 tons of production was realized in Turkey’s seas and inland waters in 2021. In addition to its nutritive value, this fish takes a crucial position in the aquaculture sector due to its continuous and intensive production. In this study, innovative bioactive protein hydrolysates (PH) produced from sprat were used as a coating to increase the quality and shelf life of trout fillets stored at +4 ˚C. The yields of traditional hydrolysate (TH) and ultrasound-assisted hydrolysate (UH) were 8.66% and 12.63%, respectively. Protein values of TH and UH were 75.88 and 74.45%, respectively. Three fillet groups were prepared from trout: uncoated control group (C), traditional enzymatic protein hydrolysate coated group (THC), and ultrasound-assisted enzymatic protein hydrolysate coated group (UHC). TVB-N value, which was 12.96 mg/100g in fresh trout, exceeded the consumable limit with 38.52 mg/100g on the 9th day of storage in the C. This value reached 32.92 mg/100g and 33.62 mg/100g on the 12th day for THC and UHC, respectively. At the beginning of storage, 0.21 mg MA/kg TBA reached the consumable limit with 7.72 mg MA/kg in the C on the 9th day, while THC and UHC remained within the limit with 6.67 mg MA/kg and 6.79 mg MA/kg, respectively. Total aerobic mesophilic bacteria (TAMB) and total aerobic psychrophilic bacteria (TAPB) counts on day 0 of storage were 2.13 log cfu/g and 1.66 log cfu/g, respectively. These values were calculated as 6.90, 5.20, 5.04, 6.95, 3.48, and 3.22 log cfu/g for C, THC, and UHC on the 12th day of storage, respectively. The application of ultrasound during the production of protein hydrolysate significantly increased the yield and hydrolysis degree of UH compared to TH. The lipid ratio of UH was also found to be significantly lower than TH. In these respects, the application of ultrasound has provided an advantage. Although both coatings have provided significant protection compared to the C, generally similar results were obtained between the THC and UHC. PH coatings delayed the chemical, physical, and microbial spoilage of trout fillets and extended the storage period. The results showed that PH can be used as a coating on fish fillets stored in cold conditions.