Obtenção de isolado proteico de tilápia (Oreochromis niliticus) e sua aplicação como cobertura em melões minimamente processados

Abstract

Since ancient times, fish has been an important source of food and fishing is an economic activity that promotes social benefits for human populations around the world. In relation to the nutritional value, the fillet of Nile Tilapia has on average 75% of water, between 3.4 to 8.5% of lipids, 20% of protein and 2% of minerals, and the nutritional composition can vary in Function of diet composition, food management, age and fish size. The acid and basic protein isolates were developed by the chemical solubility method and isoelectric precipitation of the protein, through pH variation. After extracting the isolates, they were characterized functionally and centesimamente, and carried out the application in the form of covering in melons. The melon Cucumis melo L is a polymorphic species. Minimally processed products provide practicality and higher added value, but this processing causes injuries and decreases the useful life. Edible coatings have been used to reduce these effects. The objective of this work was to evaluate the effects of acidic isolates and basic protein isolates as edible coatings on the physical, chemical and microbiological characteristics of minimally processed melons. Melons were used, they were peeled and cut into cubes, then submerged in the solutions with the respective coatings for 1 minute. Four treatments were used: (T1) control (melon without coating); (T2) 1.5% IPA (m / v), 1.5% OEC (v / v); (T3) 1.5% IPC (m / v), 1.5% OEC (v / v). The minimally processed melons were packed in PET containers and refrigerated at 4 ± 1 ° C for 12 days. Physical and physicochemical analyzes were performed, such as mass loss, firmness , color, pH, soluble solids, and microbiological evaluations of microorganisms Psychrotrophs, fungi and yeasts, Escherichia coli and Salmonella spp. The analyzes were performed in triplicate and analyzed by ANOVA. Having the acid isolate highest percentage protein 93.05%, when compared to the basic isolate that obtained 92.77%. The T2 and T3 coverages based on protein isolate from Tilapia showed lower growth of psychrotrophs, molds and yeasts, with those evaluated being treated with a protein isolate (T3) at 1.5% and OEC 1.5% presented the best results , Especially when compared to the control treatment. All treatments showed absence of salmonella in 25 g and thermotolerant coliforms. It was concluded that the T3 treatment showed lower mass loss 7.54%, lower microbial growth, lower firmness decrease, greater acceptability in the sensorial analysis presented the best results on minimally processed melon cover.