大孔吸附树脂对麦胚肽的吸附特性研究

从大孔吸附树脂对麦胚肽的静态吸附率与解吸率考察了9种树脂的吸附性能，DA201—C大孔吸附树脂吸附特性优于其它8种树脂；吸附流速、麦胚肽的浓度及不同离子强度的样品溶液等对大孔吸附树脂动态吸附性能有影响；DA201-C大孔吸附树脂对麦胚肽的脱盐率为92．13％，麦胚肽的回收率为78．55％：利用不同浓度乙醇可将麦胚肽段按疏水性大小进行初步分离纯化，具有最大疏水性值的75％乙醇洗脱组分清除超氧阴离子自由基（听）的能力最强，其IC50为490．49μg/mL。     

DA201-C大孔吸附树脂对腐乳多肽脱盐作用的研究

为去除腐乳中的盐分,利于其中活性肽的分离纯化,以腐乳多肽的回收率为指标,采用DA201-C大孔吸附树脂对超滤的水溶性低聚肽的脱盐工艺进行了研究。结果表明:DA201-C大孔吸附树脂对腐乳多肽较佳的脱盐工艺条件为上样浓度45 mg/mL、洗脱流速120 mL/h、解吸剂为70%乙醇。腐乳多肽经DA201-C大孔吸附树脂处理后脱盐率达到98.19%,肽回收率大于90%,抗氧化活性得到提高。利用DA201-C大孔吸附树脂是进行腐乳多肽脱盐处理的一种简便有效方法。     

大豆分离蛋白ACE活性抑制肽的研究

研究了预处理条件对大豆分离蛋白水解效果的影响,热处理与微波辅助处理相结合能显著提高蛋白酶的水解效率.比较了6种酶解大豆蛋白产物的ACE抑制活性,选择碱性蛋白酶为最佳水解用酶,并优化了酶解条件.研究了8种大孔树脂对水解产物精制效果,结果表明:经D3520型大孔吸附树脂精制后,水解产物脱盐率89.4%,肽回收率90.6%,ACE抑制活性达84.1%.经HPLC法测定,大豆分离蛋白ACE活性抑制肽混合物分子质量主要分布在200～800 ku之间.     

大孔吸附树脂对玉米蛋白水解液脱盐效果的研究

采用大孔吸附树脂DA201-C对玉米蛋白水解液进行脱盐处理,静态吸附和解吸试验表明,大孔吸附树脂DA201-C对玉米多肽吸附性能良好,75%乙醇为较佳解吸剂;动态试验表明,最佳工艺条件:pH=8、样品浓度为30mg/mL玉米蛋白水解液以2BV/h流速上样。该条件下,大孔吸附树脂DA201-C对玉米肽的回收率为79.67%,脱盐率达90.10%。结果表明,用大孔吸附树脂DA201-C对玉米蛋白水解液进行脱盐处理是一种简便有效的方法。     

大孔吸附树脂对酪蛋白非磷肽脱盐效果的研究

采用DA201-C型大孔吸附树脂对酪蛋白非磷肽(CNPPs)进行脱盐处理。采用脱盐率,回收率和血管紧张素转化酶(ACE)抑制活性为指标考察脱盐效果。结果表明:CNPPs的脱盐率达到95.40%,回收率达到85%以上,ACE抑制活性得到提高,半抑制浓度(IC_(50))由0.35mg/mL下降到0.21mg/mL。本研究表明,采用大孔吸附树脂进行CNPPs的脱盐处理是一种简便有效的方法。     

利用大孔吸附树脂DA201-C Ⅱ对燕麦蛋白水解液脱盐的研究

采用大孔吸附树脂DA201-C Ⅱ对燕麦蛋白水解液进行脱盐处理是行之有效的方法。静态吸附和解吸实验表明,大孔吸附树脂DA201-C Ⅱ对燕麦肽的吸附性能优于其他七种树脂,其最佳工艺条件为：pH4.0、多肽浓度39mg/ml 的酶解液以1BV/h 的流速上样、1BV/h 的流速水洗、1.5ml/min 的75% 乙醇解吸。在此条件下,大孔吸附树脂DA201-C Ⅱ对水解液的脱盐率为93.4%,燕麦肽的回收率可达72.3%。     

苋籽ACE抑制肽的大孔树脂分离纯化

比较6种大孔树脂对苋籽ACE抑制肽的吸附-解吸效果,从中筛选出合适该活性肽分离纯化的树脂,并对其吸附-解吸工艺进行优化.结果表明,DA201-C树脂最适合苋籽ACE抑制肽的纯化,在样品质量浓度10mg/mL,pH为5,上样量1BV,流速6mL/min时,树脂的吸附效果最佳,吸附率达83.69％,再用5BV体积分数75％乙醇,以5mL/min的流速进行洗脱,此时几乎把吸附的多肽全部洗脱下来,解吸率为98.69％.经树脂纯化,样品的蛋白纯度为89.47％,脱盐率为88.86％,短肽含量提高了20.96％,ACE抑制活性提高了27.91％.     

大孔树脂分离纯化麦胚黄酮研究

在前期研究麦胚黄酮最佳浸提工艺基础上,为探讨麦胚黄酮纯化工艺,本实验选择大孔树脂对其进行分离纯化。以吸附能力、吸附率及解吸率为考察指标,从7种型号大孔树脂中筛选出分离纯化麦胚黄酮效果优的树脂,并确定该树脂的最佳工艺条件。结果表明,H103大孔树脂的吸附率、吸附能力都较高,为麦胚黄酮最佳分离树脂,其最佳工艺条件为上样浓度约0.65 mg/m L、上样速度2.0 BV/h、解吸乙醇浓度70%、解吸速度2.0 BV/h。经H103树脂分离后的麦胚黄酮纯度大大提高,为11.77%,比浸提液中麦胚黄酮纯度0.96%提高了12.26倍。     

麦胚降血糖肽的分离纯化及鉴定

建立麦胚降血糖肽的分离纯化方法及鉴定活性多肽的结构组成。采用胰蛋白酶酶解麦胚蛋白,得到降血糖多肽,并进行降血糖动物实验。超滤获得高活性组分,离子交换吸附实验选择最佳的树脂,并对麦胚降血糖肽进行离子交换吸附分离,SephadexG-25和SephadexG-15分离,再经过反相高效液相色谱（reverse phase-high performance liquid chromatography,RP-HPLC）分离高活性成分。最后采用高效液相色谱-电喷雾-质谱（HPLC-electrospray ionization-mass spectrometry,HPLC-ESI-MS）鉴定活性多肽的结构组成。结果显示酶解麦胚蛋白对α-葡萄糖苷酶的抑制性IC50为10.98?mg/mL,能够缓解糖尿病小鼠的症状。超滤获得分子质量小于5?kDa的高活性组分,IC50为1.60?mg/mL。732型阳离子交换树脂的分离效果最好,2.5%氨水的洗脱率为98.13%,通过动态离子交换吸附分离后,活性显著提高,IC50为0.30?mg/mL。通过SephadexG-25和SephadexG-15分离得到高活性组分,经RP-HPLC分离得到8?个组分（峰）,其中1号峰的活性和含量都最高,IC50为0.098?mg/mL。HPLC-ESI-MS结果显示m/z?274.45的丰度比较高,经离子碎片拼接,共有7?种多肽,其中二肽有1?种,三肽有6?种。本研究对于开发具有降血糖功效的新型功能性食品有一定的作用。     

麦胚蛋白双酶酶解物的制备及其体外醒酒活性的研究

为充分利用麦胚资源,制备具有醒酒作用的麦胚肽,本研究以Na_2CO_3预处理过的麦胚为原料,以肽得率(TCA-PSI)、水解度(DH)及乙醇脱氢酶(ADH)激活率为指标,研究了碱性蛋白酶(Alcalase)、中性蛋白酶(Neutral)双酶分步酶解工艺及酶解物的醒酒活性。结果表明,双酶分步酶解的最优工艺条件为麦胚蛋白质量分数为3.5%,Alcalase添加量4 000 U/g,Neutral添加量1000 U/g,所得酶解物的TCA-PSI、DH、ADH激活率分别为:75.49%、65.18%、68.37%。表明麦胚蛋白双酶酶解物可以显著提高ADH的活力,具有较好的体外醒酒活性。     

食品蛋白质降血压肽的研究进展

在阐述血管紧张纛转化酶抑制剂降压机理的基础上，综述了食品蛋白质降血肽的研究进展，对结构与活性之间的关系及其在降低高血压患者血压中的重要性进行了讨论，并展望了其广阔的发展前景。     

Angiotensin-converting enzyme inhibitory activity of Lactobacillus helveticus strains from traditional fermented dairy foods and antihypertensive effect of fermented milk of strain H9

Hypertension is a major global health issue which elevates the risk of a large world population to chronic life-threatening diseases. The inhibition of angiotensin-converting enzyme (ACE) is an effective target to manage essential hypertension. In this study, the fermentation properties (titratable acidity, free amino nitrogen, and fermentation time) and ACE-inhibitory (ACEI) activity of fermented milks produced by 259 Lactobacillus helveticus strains previously isolated from traditional Chinese and Mongolian fermented foods were determined. Among them, 37 strains had an ACEI activity of over 50%. The concentrations of the antihypertensive peptides, Ile-Pro-Pro and Val-Pro-Pro, were further determined by ultra performance liquid chromatography with quadrupole-time-of-flight mass spectrometry. The change of ACEI activity of the fermented milks of 3 strains exhibiting the highest ACEI activity upon gastrointestinal protease treatment was assayed. Fermented milks produced by strain H9 (IMAU60208) had the highest in vitro ACEI activity (86.4 ± 1.5%), relatively short fermentation time (7.5 h), and detectable Val-Pro-Pro (2.409 ± 0.229 µM) and Ile-Pro-Pro (1.612 ± 0.114 µM) concentrations. Compared with the control, a single oral dose of H9-fermented milk significantly attenuated the systolic, diastolic, and mean blood pressure of spontaneously hypertensive rats (SHR) by 15 to 18 mmHg during the 6 to 12 h after treatment. The long-term daily H9-fermented milk intake over 7 wk exerted significant antihypertensive effect to SHR, but not normotensive rats, and the systolic and diastolic blood pressure were significantly lower, by 12 and 10 mmHg, respectively, compared with the control receiving saline. The feeding of H9-fermented milk to SHR resulted in a significantly higher weight gain at wk 7 compared with groups receiving saline, commercial yogurt, and captopril. Our study identified a novel probiotic L. helveticus strain originated from kurut sampled from Tibet (China), which is a valuable resource for future development of functional foods for hypertension management.     

大孔树脂对罗非鱼皮胶原蛋白抗氧化肽脱盐作用的研究

为了探索罗非鱼皮胶原蛋白抗氧化肽的最佳脱盐工艺,本文采用DA201-C大孔吸附树脂对抗氧化肽进行脱盐试验。结果表明:DA201-C大孔吸附树脂对抗氧化肽的静态吸附率和吸附量分别为82.56%和54 mg/g;动态吸附和解吸最佳的上样浓度为60mg/mL,最佳上样流速为1 mL/min,解吸剂为75%乙醇。抗氧化肽经过DA201-C大孔吸附树脂处理后脱盐率为97.13%,回收率为81.16%,质量浓度为0.245 mg/mL时对ABTS自由基的清除率提高至39.58%。采用DA201-C大孔吸附树脂对罗非鱼皮胶原蛋白抗氧化肽进行脱盐处理是一种简便有效的方法。     

大豆多肽的降压活性及其相对分子质量分布研究

采用以FAPGG为底物的酶活力检测法对由不同蛋白酶（碱性蛋白酶、胰蛋白酶、风味蛋白酶、木瓜蛋白酶和菠萝蛋白酶）水解制备的大豆多肽的降压活性进行了测定。结果表明,碱性蛋白酶、胰蛋白酶和风味蛋白酶三酶联合水解制备的大豆多肽具有较好的降压活性,其ACE抑制率达62.78%。经超滤发现,5kDa膜滤过液中多肽含量最多,占总量的73.44%,降压活性最强,其ACE抑制率达84.44%。最后,采用SephadexG-25凝胶色谱进一步分离纯化,得到5个峰,其相对分子质量在1 200以下的组分约占75%,其中相对分子质量在250—600左右的组分占47.6%,降压活性最强,ACE抑制率达92.15%。     

Antihypertensive effect and antioxidant activity of peptide fractions extracted from Spanish dry-cured ham

This study examined the antihypertensive and antioxidant activities of water soluble fractions of a Spanish dry-cured ham extract. Antihypertensive activity of a fractionated peptide extract, by size-exclusion chromatography was determined by measuring changes in systolic blood pressure of spontaneously hypertensive rats after oral administration. Every sample exhibited antihypertensive activity, pooled fractions corresponding to 1700 Da or lower were the most antihypertensive with a decrease of 38.38 mm Hg in systolic blood pressure. In vitro experiments revealed marked in vitro angiotensin I-converting enzyme inhibitory activity in fractions corresponding to these elution volumes. Some of the fractions exhibited great 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity, ranging from 39% to 92% as well as superoxide ion extinguishing ability with values ranging from 41.67% to 50.27% of the antioxidant activity, suggesting the presence of peptides with antioxidant activity. These findings suggest that Spanish dry-cured ham contains peptides with antioxidant and antihypertensive activities.     

Antihypertensive activity of milk fermented by Enterococcus faecalis strains isolated from raw milk

A total of 231 microorganisms were isolated from raw cow milk samples and the angiotensin-converting enzyme-inhibitory (ACEI) activity of the resultant fermented milk produced with the isolated microorganisms was assayed. Forty-six of these microorganisms were selected on the basis of high ACEI activity. Four Enterococcus faecalis strains stood out as producers of fermented milk with potent ACEI activity (IC₅₀ (the protein concentration that inhibits 50% of ACE activity): 34–59 μg mL⁻¹). Single doses (5 mL kg⁻¹) of the whey fraction obtained from these fermented milk samples were administered to spontaneously hypertensive rats (SHR) and to normotensive Wistar-Kyoto (WKY) rats in order to investigate their possible antihypertensive activity. Highly significant decreases in the systolic blood pressure (SBP) and in the diastolic blood pressure (DBP) were observed when the fermented milk was administered to SHR. Nevertheless, the fermented milk did not modify the SBP and the DBP of the WKY rats. Raw cow milk is an excellent source of wild lactic acid bacteria able to produce fermented milk with antihypertensive activity and antihypertensive activity of milk fermented by Enterococcus faecalis strains was associated with peptides different from Ile-Pro-Pro and Val-Pro-Pro.     

重量法结合氨基酸分析法测定婴幼儿配方乳粉中小分子蛋白肽含量

目的:建立婴幼儿配方乳粉中小分子肽含量的定量分析方法。方法:分别采用凯氏定氮法、重量法、离子交换色谱等方法测定婴幼儿配方乳粉中总蛋白、高分子蛋白和游离氨基酸含量,通过计算求得小分子蛋白肽含量。结果:高分子蛋白检测精密度RSD (n=6)为0.74%;17种氨基酸回收率为91.0%～103.2%,检测结果的相对偏差为0.6%～2.5%;小分子蛋白肽添加回收率为95.2%～98.2%。结论:所建方法精密度和回收率良好,可用于婴幼儿配方乳粉中小分子肽含量的测定。