不同干燥方法对乳源血管紧张素转化酶抑制肽活性的影响

Effect of Different Drying Methods on Angiotensin Converting Enzyme Inhibitory Activity of Peptides from Bovine Casein Hydrolysate

用不同的干燥方法干燥富含血管紧张素转化酶(angiotensin converting enzyme,ACE)抑制肽的酪蛋白水解物,研究对ACE活性抑制的影响。在研究过程中,采用喷雾干燥法、流化床干燥法和真空冷冻干燥法干燥富含ACE抑制肽的酪蛋白水解产物,以干燥产物的水分含量低于5%为指标,确定干燥条件,以干燥产物的ACE活性半数抑制浓度(half inhibitory concentration,IC50)值,优化干燥条件。并通过动物实验,评价不同干燥方法所得产物的降血压效果。结果显示,采用喷雾干燥法干燥水解产物优化条件为:进风温度190℃、出风温度75℃、进料量44 m L/min,其干燥产物的ACE活性抑制的IC50值为0.442 mg/m L;流化床干燥水解物的条件为:进风温度65℃、进料量180 m L、悬浮介质添加量30 g,其干燥产物ACE活性抑制的IC50值为0.294 mg/m L;真空冷冻干燥产物的ACE活性抑制的IC50值为0.275 mg/m L。动物实验结果显示,采用真空冷冻干燥方法所得干燥产物,最有利于ACE抑制肽活性的保留,其次是流化床干燥,而喷雾干燥产物的活性损失最大。因此,在富含ACE抑制肽水解产物干燥时,采用冷冻干燥方法较好。

The objective of this paper was to explore the effect of different drying methods i.e., spray drying, fluid beddrying and vacuum freeze drying on the angiotensin converting enzyme （ACE） inhibitory activity of peptides from bovinecasein hydrolysate. The operating parameters were optimized to obtain both a moisture content lower than 5% and reducedhalf inhibitory concentration （IC50） for ACE inhibition of dried product. The antihypertensive efficiency of the dried productsobtained by different drying methods was evaluated by animal tests. The results showed that the spray drying conditionswere optimized as 190 ℃, 75 ℃ and 44 mL/min for air inlet and air outlet temperatures and feeding rate, respectively. TheIC50 for ACE inhibition of the dried product obtained under these conditions was 0.442 mg/mL. The optimal fluid bed dryingconditions were established as 65 ℃, 180 mL and 30 g for air inlet temperature, loading amount and suspending mediumamount, respectively, which gave a dried product with an IC50 of 0.294 mg/mL for ACE inhibition. The IC50 for ACEinhibition of the dried product obtained by vacuum freeze drying was 0.275 mg/mL. The results of animal tests showed thatupon oral administration of the three different dried products at the same dose, the anti-hypertension activity of dried productwas best maintained by by vacuum freeze drying, followed by fluid bed drying, and spray drying caused the maximum lossof anti-hypertension activity. Therefore, vacuum freeze drying is a better drying method for casein hydrolysate rich in ACEinhibitory peptides.