National Food Institute, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
Mar Drugs. 2024 Sep 10;22(9):413. doi: 10.3390/md22090413.
This study employed a diverse approach to extract antioxidant peptides from red seaweed , recognized for its comparatively high protein content. Initially, an aqueous extraction of the entire seaweed was performed, followed by enzymatic hydrolysis of the solid residues prepared from the first step. The effects of three different pH levels (3, 6, and 9) during the aqueous extraction were also examined. Results indicated that the solid fraction from the sequential extraction process contained significantly higher levels of proteins and amino acids than other fractions ( < 0.05). Furthermore, the solid fractions (IC ranging from 2.29 to 8.15 mg.mL) demonstrated significantly greater free radical scavengers than the liquid fractions (IC ranging from 9.03 to 10.41 mg.mL or not obtained at the highest concentration tested) at both stages of extraction ( < 0.05). Among the solid fractions, those produced fractions under alkaline conditions were less effective in radical scavenging than the produced fractions under acidic or neutral conditions. The fractions with most effective metal ion chelating activity were the solid fractions from the enzymatic stage, particularly at pH 3 (IC = 0.63 ± 0.04 mg.mL) and pH 6 (IC = 0.89 ± 0.07 mg.mL), which were significantly more effective than those from the initial extraction stage ( < 0.05). Despite no significant difference in the total phenolic content between these solid fractions and their corresponding liquid fractions (3.79 ± 0.05 vs. 3.48 ± 0.02 mg.mL at pH 3 and 2.43 ± 0.22 vs. 2.51 ± 0.00 mg.mL at pH 6) ( > 0.05), the observed antioxidant properties may be attributed to bioactive amino acids such as histidine, glutamic acid, aspartic acid, tyrosine, and methionine, either as free amino acids or within proteins and peptides.
本研究采用多种方法从红海藻中提取抗氧化肽，红海藻因其相对较高的蛋白质含量而备受关注。首先，对整个海藻进行水提取，然后对第一步得到的固体残渣进行酶水解。还考察了水提取过程中三种不同 pH 值（3、6 和 9）的影响。结果表明，顺序提取过程中的固体部分比其他部分含有更高水平的蛋白质和氨基酸（<0.05）。此外，固体部分（IC 范围为 2.29 至 8.15 mg.mL）在两个提取阶段均表现出比液体部分（IC 范围为 9.03 至 10.41 mg.mL 或在最高测试浓度下未获得）更高的自由基清除剂（<0.05）。在固体部分中，在碱性条件下产生的部分比在酸性或中性条件下产生的部分在清除自由基方面效果较差。具有最强金属离子螯合活性的部分是酶解阶段产生的固体部分，特别是在 pH 3（IC = 0.63 ± 0.04 mg.mL）和 pH 6（IC = 0.89 ± 0.07 mg.mL）时，显著优于初始提取阶段产生的部分（<0.05）。尽管这些固体部分与其相应的液体部分之间的总酚含量没有显著差异（在 pH 3 时为 3.79 ± 0.05 与 3.48 ± 0.02 mg.mL，在 pH 6 时为 2.43 ± 0.22 与 2.51 ± 0.00 mg.mL）（>0.05），但观察到的抗氧化特性可能归因于生物活性氨基酸，如组氨酸、谷氨酸、天冬氨酸、酪氨酸和蛋氨酸，无论是以游离氨基酸还是蛋白质和肽的形式存在。
