EnzymesIs a protein compound that speed up or cartelize the reaction rate of a substance. They are made of protein, amino acids and their functions are determined on their shape. They are characterized as a living thing and therefore having life span. Some have long lifespan while others have short life span. Every enzyme has a specific function. The nature of lactoperoxidaseLactoperoxide is a natural enzyme that is characterized in damaging of cell membrane. It is a glycoprotein that has a high haem group of isoelectric point. The enzyme is found in mammals such as pigs, humans and cows which are associated with milk production, tears and saliva.
Lactoperoxide kills bacteria and causes inhibition in the presence of thiocyanate, pseudo halogen and hydrogen peroxide. It is naturally found in antimicrobial peptide which is used in food processing industries. Different studies of raw milk preservation through activating natural lactoperoxide system were advanced. Lactoperoxide (LP) is a non-immunoglobulin glycoprotein enzyme with haeme structure that contains one molecular iron per mole. It has 1% content of protein. LP is described by its stability of heat, since it retains normal in milk pasteurization, this is to say; temperature is retained at 72ºc every 15 seconds or 63ºc for every 30 minutes and destruction done at 80ºc.
Cow’s milk is actively associated with LP, though it varies in its content range from 13 mg/L to 30 mg/L. However, there are various factors that affects the concentration of LP, these factors include; the age of the cow, breed, cows nutrition, its location state and the health status of the cow as well as daily variations. Lactoperoxidase enzyme does not have activity of antibacterial.
Natural component of antibacterial system is formed through combining hydrogen peroxide and thiocyanate that gives rise to lactoperoxidase. It has been proven that LP (lactoperoxidase) has both bactericidal and bacteriostatic micro-organisms since it is activated by hydrogen peroxide and thiocyanate reaction, and LP acting as catalysis (Arthur P & Riley Pp 9). LPs effectiveness in maintaining quality hygienic raw milk storage at a limited time has been established. Its effectiveness depends on the initial amount that microbiological contaminants contain. The temperature of milk during storage is also considered.
Preliminary bacteriotic effects are exerted to milk by lactoperoxidase system. Its activation delays psychotropic bacteria growth in milk thus the spoilage of milk is also delayed compared to refrigeration. The purpose of LP system is to preserve milk in its original content. However, LP is not primarily responsible for providing safer milk for human consumption. Long lasting bacterial effects of milk from cows is activated by LPs due to higher level of antimicrobial components. In mastitic milk LPs is not that effective unlike in milk that comes out from healthy cows since they have higher reductive agent concentration.
catalase enzyme is highly active in mastitic. Lactococci and non-pathogenic streptococci effects of lactoprotoxidase are less. The sensitivity of strains varies in different ways by different inhibitors and cell structures. Catalytic enzyme has a defiance of Bacteria lactic acid. On production of yoghurt, LP was sensitive to starter culture when the hydrogen peroxide concentration is higher. The lesser the amount of hydrogen peroxide used its effects yields a positive result as the yoghurt produced has a smooth texture.
Lactoperoxidase system was not completely able to destroy monocytogenes growth but it has the ability to delay its growth in milk. However, lactoperoxidase occurs in exocrine milk secretion gland. It is a prominent enzyme and a protective agent of non-immunoglobulin protein which prevents mammary gland from microbial invasion. Oxidative mechanisms are used by peroxidase enzyme to kill bacteria. (Bøgh-Sørensen, pg 57).