Formulation of Iranian white cheese enriched with rainbow trout (oncorhynchus mykiss) protein extracted by acid and alkaline hydrolysis: investigation of physicochemical, microbial, textural and sensory characteristics.

Rainbow salmon is one of the species with commercial value and is one of the farmed fish belonging to cold and clear waters, and it is of great importance in terms of having optimal nutritional compounds. For this purpose, to extract protein from fish by pH-shift method, (pH = 3.5) acid treatment and (pH =10.5) alkaline treatment were used, and two groups of acid and alkaline treatments were at the levels of 0.5%, 1% and 1.5%. It was added to cow's milk and then physicochemical characteristics such as moisture percentage, pH, acidity, protein content, fat content, microbial count, textural properties (hardness, cohesiveness, stickiness, chewability and gumminess), color and sensory indicators ( (such as smell, taste, texture, consistency and overall acceptance) of the cheese samples were evaluated. The results showed that by adding different percentages of acid and alkaline treatment protein, moisture content and acidity, fat, redness index (a*) and lightness (L*) of the samples decreased and protein and pH of the cheese samples enriched significantly increased (P≤0.05). Also, the count of coliforms was less than the defined limit, and the total amount of forms in samples enriched with acid treatment was lower than alkaline treatment. In the samples of cheese enriched with acid and alkaline treatment protein, the degree of hardness, stickiness, cohesiveness, gumminess and chewability of the samples increased significantly. Iranian white cheese is one of the most important and widely consumed milk dairy products, and in order to enrich and improve its physicochemical, sensory and textural characteristics, various methods are used. Among the proteins of rainbow salmon, it is more interesting due to its favorable nutritional characteristics.