the effect of adding sturgeon-isolated protein on the microbial characteristics of fish nuggets

Fish and aquatic processing usually produce significant by-products, including heads, guts and viscera, skin and fins, and bones. therefore, the non-use of fish by-products not only leads to environmental problems and increases the cost of disposal of these products, but also leads to the loss of potential income sources. fish by-products are rich in high-quality proteins that can be recovered and purified by different methods. one of the methods of fish protein extraction is ph shift, which is named fish protein isolated (fpi). fpi has high digestibility. they can also be used in many foods due to functional nutritional properties such as water-holding capacity, oil absorption, gelling activity, and emulsification properties. today, these products are the main source of low-cost proteins, especially for athletes, vegetarians, dairy, and baby food. isolated proteins with the ability to absorb water and fat are widely used in processed meat products such as cutlets, nuggets, bread, and sausages. in the present study, fpi was extracted by alkaline ph shifts from the head and fin of siberian sturgeon (acipenser baerii) and then replaced in fish nuggets in 10, 20, 30, and 40%. the results showed that the fpi has about 92% protein and the tvb-n amount was within the standard range. the stability of fpi foam was shown about 50%. the results of particle size and zeta potential showed that the fpi particles were micron size and have negative charge. after preparing fish nuggets (88% fish meat) and initial cooking, total viable count (tvc) and psychrophilic bacteria were evaluated. there was no significant difference between the control group and the experimental treatments (p < 0.05). in general, considering the large volume of sturgeon by-products in processing, and considering the amount of protein, functional properties, and nutritional value of fpi, and considering the possibility of producing quality fish nuggets from it, using it in the human food and feed industry, and sports supplements are recommended.