Lactoferrin is an important multifunctional protein that has a variety of biological activities, such as anti-bacterial, anti-tumor, anti-allergy, immunoregulatory and so on. The related basic research and application development of lactoferrin have attracted wide attention. Therefore, the detection methods for lactoferrin have drawn increasing attention. Especially the advantages, sensitivity, accuracy and stability of different methods vary to different extents, which directly affects their applicable scope. The present paper has described the detection methods which have been reported to be suitable for different types of biological samples, mainly including spectrophotometry, high performance liquid chromatography (HPLC), enzyme-linked immunosorbent assay (ELISA), high affinity chromatography (HPAC), efficient capillary electrophoresis (HPCE) and surface plasmon resonance (SPR). The advantages and disadvantages of these different detection technologies also have been analyzed and compared. This review is expected to provide reference for selection of the suitable detection method for lactoferrin in research and development practices.

The solubility of milk protein concentrate (MPC), which has a direct impact on its application value, may be reduced during storage. The effect of ultrasonic treatment with different powers for different durations on the solubility of fresh and stored MPC was studied. The results showed when stored MPC85, a commercial product, was treated with ultrasonic (at 50, 300 or 600 W for 5 min, or at 300 W for 3, 5 or 10 min), its solubility decreased sharply. As for fresh MPC70 stored for 30 d after treated with ultrasonic (at 300 or 600 W for 3, 5 and 10 min, respectively), its solubility decreased slowly and the smallest decrease was observed upon ultrasonic treatment for 300 W, 10 min. Ultrasonic treatment is useful to retard the decrease in the solubility during storage of MPC.

In the present study, a preliminary purification was carried out to obtain heat-resistant lipase secreted by Pseudomonas fluorescens separated from fresh milk. Moreover, the effects of temperature, pH, and Ca2+ concentration on the activity of this lipase were determined. Results showed that the lipase from Pseudomonas fluorescens had a molecular weight 55 kD and a purity of 91.5% after the purification, and its relative activity was 75.02%, 86.21%, 73.25%, 17.62% and 13.63% after heat treatment at 50 ℃ for 30 min, 63 ℃ for 30 min, 72 ℃ for 20 s, 90 ℃ for 10 min, and 121℃, 0.1 MPa for 20 min, respectively. The optimum reaction pH and temperature for this enzyme were 8.0 and 63 ℃, respectively. The lipase activity was not significantly affected by Ca2+ concentration.