The study of bovine lactoferrin hydrolysate and EDTA on antioxidative and antimicrobial activities of fresh meat and meat product

Autor: Li-Hui Jiang, 蔣力惠
Rok vydání: 2007
Druh dokumentu: 學位論文 ; thesis
Popis: 95
In this study, lactoferrin hydrolysate (bLFH) was prepared by pepsin cleavage of bovine lactoferrin (bLF) at 37°C and pH 2.5, and the purposes of this study are to investigate the anti-microbial and anti-oxidative properties of bLFH and EDTA. The study was divided into three parts. The first part is to investigate the antimicrobial activities of bLF and bLFH solution. Preparing bLFH solution with different hydrolyzing time (0, 10, 20, 30, 40, 50 min and 1, 2, 3, 4, 5, 6 h) to investigate their degree of hydrolysis (DH). Results indicted that the DH of bLFH solution would be increased while hydrolyzing time increasing. After 4 h (DH was 6.88%), the DH was not changed significantly. The SDS-PAGE of bLFH showed that increased in hydrolyzing time, 2.55 kD polypeptides within bLFH solution would be increased. bLFH solution hydrolyzed for 4 hours contained more polypeptides with low molecular weight. The minimal inhibitory concentrations (MICs) of bLF and bLFH solution hydrolyzed for 4 hours toward Staphylococcus aureus ATCC 9144 were 0.4 mg bLF/mL and 0.2 mg bLFH/mL, respectively. bLF showed no antibacterial activity to Pseudomonas aeruginosa ATCC 14207, but the MIC of bLFH solution to this strain is 1.6 mg bLFH/mL. The antibacterial activity of bLFH solution over 4 h-reaction would be increased slightly but there was no significant difference with bLFH solution hydrolyzed for 4 hours. The second part is to investigate the microbial and chemical properties of non-vacuum-package ground hams added 250 ppm EDTA and/or 4 mg bLFH/g meat and all of them named EDTA treatment, bLFH treatment and bLFH+EDTA treatment were stored at 4°C for 0, 2, 4 and 6 days. Results indicted that bLFH had pro-oxidative action. And perhaps owing to EDTA the TBARS value of bLFH+EDTA treatment was the lowest. The nonheme iron of bLFH treatment was more than control, but bLFH+EDTA treatment and control were not significantly different. The nonheme iron of EDTA treatment was the least. The total plate counts, lactic acid bacterial counts and coliforms in all treatments were lower than control which indicted that adding bLFH and/or EDTA could inhibit the growth of microbe. The third part is to investigate the microbial properties of non-vacuum-package Chinese meat balls added 250 ppm EDTA and/or 4 mg bLFH/g meat and all of them named EDTA treatment, bLFH treatment and bLFH+EDTA treatment were stored at 7°C for 0, 2, 4, 6 and 8 days. The results showed that bLFH did not have any antioxidative activity. And perhaps owing to EDTA the TBARS value of bLFH+EDTA treatment was the lowest The total plate counts and the lactic acid bacterial counts in all treatments were lower than control which indicted that adding bLFH and/or EDTA into cooked meat products could also inhibit the growth of microbe.
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