Lyophilized bromelain enzyme was obtained from the Department of Food Sciences, College of Agricultural Engineering Sciences, University of Baghdad. Some properties of the enzyme were determined, the optimum temperature and pH for activity and stability, as it used a range of graduated temperatures from 25 °C to 85 °C, as well as a range of pH degrees from 4 to 9. The results showed that the best pH for activity was 7, as it reached the enzymatic activity was 42.3 units/ml, and the best pH range for stability was 7-5. The best temperature for the activity was 45°C, as the enzymatic activity reached 59.3 units/ml, and the enzyme retained its full activity after being incubated at a temperature of 25 - 45 °C. The anti-browning enzyme activity was tested by using apple juice by adding graded concentrations of the enzyme of 15, 30, 45, and 60 mg/ml of bromelain enzyme. It was found that bromelain has the ability to reduce the amount of enzymatic browning, as the absorbance reached 0.987, 0.973, 0.891, 0.831, and 0.817 at zero time, and after 30 minutes the absorbance reached 1.315, 1.243, 1.132, 1.124, and 1.113, but after 60 minutes, the absorbance reached 1.412 And 1.312, 1.192, 1.133, and 1.124, and after 90 minutes it reached 1.623, 1.378, 1.211, 1.157, and 1.135, to reach after 120 minutes to 1.858, 1.416, 1.243, 1.182, 1.182, and 1.14 for the control treatment, the first treatment (15 mg enzyme/ml), the second treatment (30 mg enzyme/ml), the third treatment (45 mg enzyme/ml) and the fourth treatment (60 mg enzyme/ml), respectively. The ability of the bromelain enzyme to inhibit the growth of some types of Gram-negative and Gram-positive bacteria was studied, with an antibacterial effect, as the diameters of the inhibition zones were 4.91, 6.55, 12.85, and 2.8 mm for Staphylococcus aureus, B. cereus, E. coli, and Salmonella, respectively, when using the concentration of 15 mg/ml of bromelain enzyme, but when using 30 mg/ml, the diameters of the inhibition zones were 7.05, 8.5, 13.85, and 6.85 mm, respectively.
