Kinetic Modelling of Biopreservation of Mango Fruit Juice Using Murraya koenigii Sprengel

ABSTRACT

Biopreservative was extracted from the leaves of Murraya koenigii (L.) Sprengel (MKS) and characterized. It was used to preserve mango fruit juice and the microbial growth inhibition in mango fruit juice was studied at different concentrations of the preservative. The effect of concentration, time, initial substrate concentration on microbial growth was examined. The study showed that increase in the concentration of biopreservative from 10 mg/ml to 30 mg/ml increased the lag phase thereby inhibiting microbial growth. Also, microbial growth increased with increase in time and then decreased after the optimum time was reached for all the samples. Likewise, the specific growth rate of the samples increased as the initial substrate concentration increased form (1 g/l to 4 g/l) and subsequently decreased at substrate concentration above 4 g/l. This shows that initial substrate concentration above 4 g/l was inhibitory to the growth of the microorganisms. The kinetic parameters: Maximum Specific Growth Rate (μ_m), Monod’s Constant (k_s), Death Rate Constant (k_d) and Inhibition Constant (K_I) were determined as 0.1309 hr^-1, 1.3083 g/l, -0.3750 hr^-1 and 37.28 respectively for Murraya Koenigii Spreng biopreservative. The μ_m and K_s for the Control broth were 0.1546hr^-1 and 0.648g/l respectively. The study showed that biopreservatives from Murraya koenigii Sprengel is a good biopreservatives for mango fruit juice.