No abstract

The main of this work was to evaluate the influence of the temperature, pH and enzyme concentration in the hydrolysis of mechanically separated chicken meat (MSCM) with and without previous heat treatment. The influence of pH (8.08 to 8.92), temperature (50.75ºC to 59.25ºC), enzyme concentration (0.38 to 4.62%) and reaction time (0.17 to 5.83 h) on the degree of hydrolysis and protein concentration were evaluated. The conditions that promoted the best degree of hydrolysis where 58°C, pH 8.5, enzyme concentration of 4.62 and reaction time of 3 h without previous heat treatment. The hydrolysed presented IC50 of 4 mg/mL. The MSCM hydrolyzed in these conditions is alternative of product with antioxidant properties with potential of application in foods.

The hydrolysate from mechanically separated chicken meat (MSCM) was separated by an ultrafiltration (UF) membrane and the total protein and antioxidant activity of the resulting fractions were evaluated. The enzymatic hydrolysis was carried out at 58°C, pH 8.5, and 4.62% enzyme (w/w), with 3 h reaction time. For the separation, a flat membrane (4 kDa) of polyvinylidene fluoride (PVDF) was used, operating tangentially, at pressures of 1.5 and 2.5 bar at 45°C. The retentate and permeate from the UF were analyzed in relation to total protein and antioxidant activity. The permeate flux was evaluated and experimental data fitted by Ho and Zydney's mathematical model to study the fouling phenomenon. The pressure of 2.5 bar resulted in high total protein content and low inhibitory concentration (IC50) value when compared with 1.5 bar. The UF pressures showed different permeate and fouling flux behavior. At 1.5 bar there was a flux reduction by simultaneous cake formation and pore blocking, while at 2.0 bar, there was pore blocking followed by cake formation during the process. The Ho and Zydney model showed the best fit at 1.5 bar with R2 of .9876. According to the results obtained, the hydrolysate showed antioxidant properties with potential for application in foods. Practical applications The poultry industry has stood out in recent decades mainly due to technological advances, making poultry price very competitive, leading to a high consumption of this meat by the population. However, the preference for more noble cuts of chicken meat, such as breast, and thigh, means that in the processing carried out by the industries there is a large production of mechanically separated meat (MSM). MSM is usually used in the production of mortadella, sausages, and others. In addition, it is possible to use MSM to produce protein hydrolysates in order to obtain bioactive peptides, which have functional properties such as antioxidants. Bioactive peptides may have different characteristics due to their molecular size. Thus, the use of membranes can be interesting since they make it possible to separate hydrolysates from MSM to obtain peptides of different sizes which may have different properties, thus being able to add value to this by‐product.