The Antibacterial Function Of Lactoferrin And Its Preservative And Antioxidant Effect On The Chilled Meat

Chilled meat, because of it's delicate flavor, higher nourishment value, safety , hygiene, is a current extensively applied sales form of fresh meat abroad. But it is difficulty to control the growth of the microorganism completely at 4℃. Deterioration and discolouration of chilled meat are usually happened during the course of storage and sale.The color of surface of meat often turns into gray and brown, which influences appearance and acceptability seriously. Thus the development of chilled meat was restricted. Lactoferrin(LF), an iron-binding glycoprotein, Mr=77000+2000Da, pI = 8.0 ±0.2, has many biological activities , antibacterial, antioxidant and absorbing iron ion etc. In this study ,chilled pork was used as experimental materials, the Minimal Inhibition Concentrtion(MIC) of Lactoferrin the antibacterium , preservative and antioxidate effect were researched, and the effect of combination the lactoferrin and natural preservatives to extend the shelf life of the chilled pork were studied. The experiment of keeping color of chilled pork was studied with combination Lactoferrin with containing oxygen modified atmosphere packaging(MAP). The main studies are as below:1. It has been shown that lactoferrin is bacteriostatic against a wide range of microorganisms. Lactoferrin exerts its antibacterial activity in two ways. The first mechanism is by depriving the microorganisms from iron needed for growth; the second mechanism is by direct binding to the microbial membrane. The results showed that lactoferrin has significant effect on Micrococcus and Staphylococcus aureus, but it has slight effect on Pseudomonas Fluorescens and E.Coli, This maybe their cell wall sturcture is different. The influence of pH on LF was studied, it has better effect when pH value is 7.5 . An orthogonal experiment design was used to research the optimum proportion of antioxidants. This optimum proportion was as following: 5mg/ml Lactoferrin + 1.5mg/ml Lysozyme + 0.2mg/ml Nisin.2. The effect of Lactoferrin on the chilled meat was studied . LF has a little preservative function at 3mg/ml, increasing its effect with increasing concention. Firstly, three factors three levels orthogonal experiments were applied to find the optimum proportion of preservatives, three optimum proportion were: 6mg/ml LF+1.0mg/ml Lysozyme+0.1 mg/ml Nisin. Secondly, the optimum proportion of preservatives combinated with MAP of different gas proportion, researched the effect of them on the chilled meat. The result is: 50%CO₂+40%O₂+10%N₂ and 2mg/ml LF+0.5mg/ml Lysozyme+0.1 mg/ml Nisin; 30°/oCO₂+60%O₂+10%N₂ and 6mg/ml LF+1.0mg/ml Lysozyme+0.1 mg/ml Nisin.3. It is effective of containing oxygen MAP in stabilizing the color of meat. But the increasing of oxygen concention can promote lipid oxidation, discoloration and lipid oxidation are interlated in meat, and lipid oxidation can be restricted by antioxidants. In order to improve the colour of chilled pork, the combination of containing oxygen MAP and antioxidants were studied. The influence of the Lactoferrin and containing oxygen MAP to the chilled pork was studied . The optimum concention of Lactoferrin appeared on accepTab appearance at the 21^th day. An orthogonal experiment design was used to research the optimum proportion of LF,...