乳鐵蛋白水解物耐熱性及對冷藏絞碎豬肉微生物之探討乳鐵蛋白水解物耐熱性及對冷藏絞碎豬肉微生物之

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Title:	乳鐵蛋白水解物耐熱性及對冷藏絞碎豬肉微生物之探討乳鐵蛋白水解物耐熱性及對冷藏絞碎豬肉微生物之
Other Titles:	Studies on thermal properties of lactoferrin hydrolysate and effect on microbial properties of chilled ground pork
Authors:	張建銘 Chang, Chien-Ming
Contributors:	郭俊欽 Kuo, Chun-Chin 東海大學食品科學系
Keywords:	乳鐵蛋白水解物、抗菌胜?區分 lactoferrin hydrolysate, antibacterial peptide fractions
Date:	2007
Issue Date:	2011-03-30T06:14:19Z (UTC)
Abstract:	本實驗利用胃蛋白?（pepsin）於pH 2.5、37℃下水解5％乳鐵蛋白（Lactoferrin）水溶液4小時，來製備乳鐵蛋白水解物（Lactoferrin hydrolysate），經陽離子樹脂分離後，利用高效液相層析儀分析（High Performance Liquid Chromato -graphy, HPLC）收集水解液中所含抗菌胜?區分（Antibacterial peptide fractions）並探討其抑菌效果，結果發現水解率為7.4％之乳鐵蛋白水解液，其為濃度8.1 mg/ml之多胜?水溶液，具抗菌活性之胜?區分1及胜?區分2含量分別為591.3 μg/ml及491.8 μg/ml，且胜?區分1及胜?區分2對L. monocytogenes之最小抑菌濃度分別為25 μg/ml及50 μg/ml。將乳鐵蛋白水解液之稀釋液，濃度為125、250、500及1000 μg/ml，在100℃下加熱0、5、10、15、20、25、30及60分鐘，冷卻後分別測試對於兩株病原菌：革蘭氏陽性菌（Listeria monocytogenes）及革蘭氏陰性菌（Salmonella typhimurium）（菌體濃度約104 CFU/ml之對數生長期之菌體）之抑菌效果，結果發現不論是否加熱或加熱時間長短，乳鐵蛋白水解液之濃度為125 μg/ml時，其無抑菌效果，而濃度為500 μg/ml或以上時，其對兩株病源菌有顯著抑制效果。當濃度為250 μg/ml時，未加熱之水解液對於兩株病原菌也具抑制效果，但經加熱10分鐘後，其對S. typhimurium的抑菌效果會顯著降低（P < 0.05）；經加熱30分鐘後，對L. monocytogenes的抑菌效果會顯著的下降（P < 0.05）。而本實驗進一步把乳鐵蛋白水解液（500 μg/ml）加熱（100℃）0、5及10分鐘後離心並分析上澄液之乳鐵蛋白素含量；發現未加熱但經離心之上澄液所含胜?區分1及胜?區分2的濃度分別為571.6 μg/ml與487.3 μg/ml，為未離心之乳鐵蛋白水解液中抗菌胜?含量的百分之97與99，可知抗菌胜?大部分存在於乳鐵蛋白水解液之上澄液中；但加熱5分鐘的乳鐵蛋白水解液之上澄液中所含的胜?區分1與胜?區分2減少為原始濃度之62.8％（371.1 μg/ml）及49.9％（245.6 μg/ml），加熱10分鐘更減少為原始濃度之36.3％（214.8 μg/ml）與42.8％（210.4 μg/ml）；證明加熱時間越長，乳鐵蛋白水解液之上澄液所含抗菌胜?濃度越低。將乳鐵蛋白水解液進行冷凍乾燥，得到之冷凍乾燥乳鐵蛋白水解物（freeze drying lactoferrin hydrolysate, FD-LfH），本實驗添加冷凍乾燥乳鐵蛋白水解物2.03 g （FD-LfH 6.78 mg/g）及4.08 g （FD-LfH 13.56 mg/g）於300 g 絞碎豬肉中，分別為3倍（75 μg/g）與6倍（150 μg/g）胜?區分2之最小抑菌濃度，結果發現控制組與FD-LfH 6.78 mg/g及FD-LfH 13.56 mg/g的水分含量有顯著差異（P<0.05），但FD-LfH 6.78 mg/g與FD-LfH 13.56 mg/g組之間並無顯著差異。在儲藏實驗中之總生菌結果方面，FD-LfH 13.56 mg/g對於絞碎豬肉中之總生菌數，在儲藏時間中皆與控制組及FD-LfH 6.78 mg/g有顯著之差異（P<0.05），而FD-LfH 6.78 mg/g亦在儲藏後的第2、4、6及8天，與控制組之總生菌數有顯著之差異（P<0.05）。 In this experiment, lactoferrin was hydrolysis four hours by pepsin at 37℃and pH2.5 to manufacture lactoferrin hydrolysate (LfH), then separated by cation-exchanged resin and analyzed by high performance liquid chromatography to collect the peptide fractions for investigating its antibacterial activity. The hydrolysis ratio of LfH is 7.4%, and the concentration of polypeptide is 8.1 mg/ml including the antibacterial peptides-peptide1 (591.3 μg/ml) and peptide 2 (491.8 μg/ml). The minimal inhibition concentrations of peptide fraction 1 (PF 1) and peptide fraction 2 (PF 2) toward Listeria monocytogenes was 50 μg/ml and 25 μg/ml. The experiment to investigate that antibacterial activity of two pathogenic bacteria: Listeria monocytogenes (gram positive bacteria) and Salmonella typhimurium (gram negative bacteria) from LfH was diluted to 125, 250, 500 and 1000 μg/ml, and heated for 0, 5, 10, 15, 20, 25, 30 and 60 minutes at 100℃. The results were non-antibacterial activity in 125μg/ml LfH without heated or not, inversely, LfH had significantly antibacterial activity at 500 μg/ml. LfH at 250 μg/ml still have antibacterial activity, but the antibacterial activity of S. typhimurium from LfH heated for 10 minutes was significantly degraded (P < 0.05). And the antibacterial activity of L. monocytogenes from LfH heated for 30 minutes was significantly degraded (P < 0.05).LFH was heated at 100℃ for 0, 5 and 10 minutes, than collected the suspending liquid of centrifuged LfH to analyse the concentration of antibacterial peptide fractions. The concentration of PF 1 and PF 2 in unheated and centrifuged LfH is 571.6 μg/ml and 487.3 μg/ml, and that was 97% and 99% of original consistence respectively. The result was meant that the most of antibacterial peptides existed in the suspending liquid of LfH. The concentration of PF 1 and PF 2 in LfH heated for 5 minutes is 62.8% (371.1 μg/ml) and 49.9% (245.6 μg/ml) of original consistence, and the concentration of PF 1 and PF 2 in LfH heated for 10 minutes is 36.3% (214.8 μg/ml) and 42.8% (210.4 μg/ml) of original consistence. So these were proved that the longer heating time and the lower concentration of antibacterial peptides in suspending liquid of LfH.The final purposes of this study were to investigate the microbial and composition properties of non-vacuum-package ground pork loin added freeze drying lactoferrin hydrolysate (FD-LfH) to 6.78 mg/g (FD-LfH 6.78 mg/g) or 13.56 mg/g (FD-LfH 13.56 mg/ml), then stored at 2℃ for 0, 2, 4, 6 and 8 days. The moisture of control is significantly higher than FD-LfH 6.78 mg/g and FD-LfH 13.56 mg/g (P < 0.05), but the moisture of FD-LfH 6.78 mg/g and FD-LfH 13.56 mg/g were non-significantly different. The total plate counts were lower in FD-LfH 13.56 mg/g than other treatments during storage (P < 0.05), and the total plate counts in FD-LfH 6.78 mg/g also lower than control in the 2nd, 4th, 6th and 8th day (P < 0.05).
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