“Investigating the Effect of Lactoperoxidase system on Keeping Quality of Raw Goat milk: Case study on Goat milk from Bishoftu, Ethiopia

Abstract

Milk is an important source of nutrients for humans and animals. But it is a perishable food that can be spoiled easily and also becomes an important vehicle for transmission of pathogenic microorganisms to human beings. The main goal of this study was to preserve raw goat milk by keeping its quality using the lactoperoxidase system without using the refrigeration system which in effect to deliver safe milk to consumers and to maximize the income by minimizing loss of milk due to spoilage. The composition analysis of raw goat milk and the effects of process parameters on the activation of lactoperoxidase system were also investigated. The lactoperoxidase system was activated by increasing the concentration of sodium thiocyanate and hydrogen peroxide reacting with each other to yield antibacterial compound. The experiment was designed by design expert software 11.00 using central composite design to evaluate the effect of process variables on the growth of total coliform count. The minimum growth of total coliform count 2.658 log CFU/ml were found at the optimal condition of 25 oC temperature, 4hr time, 29.98 PPM of sodium thiocyanate and 16.6 PPM of hydrogen peroxide. The process variables, had a significant (p < 0.05) effects on the growth of total coliform count. The physiochemical characterization (protein content, fat content, lactose content, total solids, moisture content and ash content) of the preserved milk under optimal state were found to be 3.84%, 5.61%, 4.68%, 14.98%, 85.02% and 0.85% respectively. Microbiological analysis and physicochemical characterization of the raw and preserved goat milk was analyzed using Minitab 17 version. Therefore the lactoperoxidase system does not induce any significant adverse effects on the physicochemical characteristics of raw goat milk. Activation of the lactoperoxidase system can keep goats’ milk fresh for up to 10 hr when stored at 250C.