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.     

Bioactivities of peptide fractions derived from proteolytic enzyme-injected Hanwoo longissimus muscle in a model system

In this study, crude peptide fractions from Hanwoo loins were released by injecting with proteolytic enzymes [no enzymes (control); protease type XIII (E1); thermolysin (E2); and combination of E1 and E2 (E3)] and their bioactivities were determined. The peptides derived from E2-injected Hanwoo loin exhibited the highest angiotensin I–converting enzyme (ACE) inhibitory activity and vitamin C equivalents antioxidant capacity among the treatments. The released peptide by treatment of E2 and E3 had similar (P > 0.05) inhibitory activity in HT29 cancer cell viability compared with luteolin as a positive control and non-cytotoxic effect on normal cell (3T3-L1). Therefore, the released peptide fraction from thermolysin (E2)-injected Hanwoo beef might contain potent bioactive peptides with ACE inhibitory and antioxidative activity and inhibition effect on certain cancer cell viability.     

橄榄抑菌活性部位研究

目的:测试橄榄提取物对食品生产、加工和贮藏中常见的腐败菌的抑制作用,寻找橄榄抑菌作用的活性部位。方法:采用抑菌圈法测试橄榄提取物对大肠杆菌、金黄色葡萄球菌、枯草杆菌、啤酒酵母、黑曲霉、黑根霉、青霉等细菌,酵母菌,霉菌的抑制作用,橄榄三个提取部位对金黄色葡萄球菌、枯草杆菌、大肠杆菌的抑制作用。结果:橄榄提取物对测试菌种中的细菌和酵母菌有一定的抑制作用,但对霉菌几乎没有抑制作用。橄榄乙酸乙酯部位对金黄色葡萄球菌、枯草杆菌、大肠杆菌有较强抑制作用。结论:橄榄提取物对细菌和酵母菌有一定的抑制作用,乙酸乙酯部位为橄榄抑菌活性部位。      

Assessment of multifunctional activity of bioactive peptides derived from fermented milk by specific Lactobacillus plantarum strains

Milk-derived bioactive peptides with a single activity (e.g., antioxidant, immunomodulatory, or antimicrobial) have been previously well documented; however, few studies describe multifunctional bioactive peptides, which may be preferred over single-activity peptides, as they can simultaneously trigger, modulate, or inhibit multiple physiological pathways. Hence, the aim of this study was to assess the anti-inflammatory, antihemolytic, antioxidant, antimutagenic, and antimicrobial activities of crude extracts (CE) and peptide fractions (<3 and 3–10 kDa) obtained from fermented milks with specific Lactobacillus plantarum strains. Overall, CE showed higher activity than both peptide fractions (<3 and 3–10 kDa) in most of the activities assessed. Furthermore, activity of <3 kDa was generally higher, or at least equal, to the 3 to 10 kDa peptide fractions. In particular, L. plantarum 55 crude extract or their fractions showed the higher anti-inflammatory (723.68–1,759.43 μg/mL of diclofenac sodium equivalents), antihemolytic (36.65–74.45% of inhibition), and antioxidant activity [282.8–362.3 µmol of Trolox (Sigma-Aldrich, St. Louis, MO) equivalents]. These results provide valuable evidence of multifunctional role of peptides derived of fermented milk by the action of specific L. plantarum strains. Thus, they may be considered for the development of biotechnological products to be used to reduce the risk of disease or to enhance a certain physiological function.     

Antioxidant and antibacterial activities of peptide fractions from flaxseed protein hydrolysed by protease from Bacillus altitudinis HK02

Flaxseed protein (FP) hydrolysates by crude protease of strain Bacillus altitudinis HK02 were further separated into five fractions by ultrafiltration membranes with a molecular weight cut‐off of 10, 5, 3 and 1 kDa for the analysis of antioxidant activities and antibacterial ability. The results demonstrated that the fraction of 1‐ to 3‐kDa peptides exhibited higher antioxidant activities on the free radical‐scavenging ability and the reducing power than those of Vit C, Vit E, BHA and other fractions. The fraction with a low molecular weight (<1 kDa) of peptides demonstrated the highest ferrous ion‐chelating ability and a higher inhibition of lipid peroxidation than BHA and other fractions. Moreover, it also exhibited the best growth inhibition of Pseudomonas aeruginosa and Escherichia coli. The results, including the concentration‐dependent effect of peptides fractions, demonstrated that it is feasible to derive functional ingredients of natural antioxidants along with antimicrobial activity from FPs hydrolysed by protease from B. altitudinis HK02.     

乙醇萃取3种酶解产物鲜味肽的研究

以牡蛎、鸡肉和南极磷虾为原料,利用胰蛋白酶和风味蛋白酶组成复合酶对其进行酶解,以感官评分、肽分子量分布和氨基酸组成为指标,考察乙醇萃取3种酶解产物鲜味肽过程中感官评分、肽分子量分布和氨基酸组成的变化。研究结果表明:90%乙醇萃取牡蛎、鸡肉和南极磷虾3种酶解产物的上清液均具有较强的鲜味,分子量在5ku以下的肽比例分别为93.00%,86.82%,87.86%。3种酶解产物中分子量10ku和5~10ku的肽,经过90%乙醇萃取后明显减少。90%乙醇萃取3种酶解产物的上清液小分子肽中含有较高比例的甜味和鲜味氨基酸。90%乙醇萃取方法可用于牡蛎、鸡肉和南极磷虾酶解产物中鲜味肽的快速萃取。     

Fermentation characteristics of polysaccharide fractions extracted from the cell walls of maize endosperm

Cell walls were extracted from maize endosperm and separated into different polysaccharide fractions by sequential extraction with solutions of saturated Ba(OH)₂, demineralised water and 1 and 4 M KOH. Solubilised polysaccharides were collected after each extraction. Residues were collected following the extractions with demineralised water and 1 and 4 M KOH. The original cell wall (CW) material, extracts and residues were analysed for their fermentation characteristics using an in vitro cumulative gas production technique. The rate of fermentation of the alkali‐treated residues was faster than that of the original CW material, except for the 4 M KOH residue, which had a similar rate of degradation to the original CW material. The polysaccharides solubilised from the cell wall (extracts) were all rapidly fermented, more rapidly than both CW and residues. A division of the gas production profile into two phases using curve fitting was in good agreement with a division of the cell wall fermentation into the fermentation of arabinoxylans and cellulose. Therefore the likelihood of preferential degradation of arabinoxylans from the maize cell wall was discussed. The volatile fatty acid production pattern was fairly well explained by the fermentation rate and composition of the substrates. It was concluded that breaking the interactions of polysaccharides in the maize cell wall by mild alkali extraction increases the fermentability of maize cell walls in the gastrointestinal tract of farm animals. Contrarily, more severe alkali extractions will reduce the fermentability of maize cell walls. © 2002 Society of Chemical Industry     

Determination of antioxidant activity of bioactive peptide fractions obtained from yogurt

In this study, physicochemical and microbiological properties of traditional and commercial yogurt samples were determined during 4 wk of storage. Proteolytic activity, which occurs during the storage period of yogurt samples, was also determined. Peptide fractions obtained from yogurts were investigated and the effect of proteolysis on peptide release during storage was determined. The antioxidant activities of peptides released from yogurt water-soluble extracts (WSE) and from HPLC fractions were determined by 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. The antioxidant activity of WSE from traditional yogurt was greater than that of WSE from commercial yogurts. In analysis by the ABTS method, mean values increased from 7.697 to 8.739 mM Trolox/g in commercial yogurts, and from 10.115 to 13.182 mM Trolox/g in traditional yogurts during storage. Antioxidant activities of peptides released from HPLC fractions of selected yogurt samples increased 10 to 200 times. In all yogurt samples, the greatest antioxidant activity was shown in the F2 fraction. After further fractionation of yogurt samples, the fractions coded as F2.2, F2.3, F4.3, and F4.4 had the highest antioxidant activity values. Total antioxidant activity of yogurts was low but after purification of peptides by fractionation in HPLC, peptide fractions with high antioxidant activity were obtained.     

Fermentation characteristics of polysaccharide fractions extracted from the cell walls of soya bean cotyledons

Full‐fat soya beans were separated into hulls and cotyledons. After separation the cell wall fraction was extracted from the cotyledons. These purified cell walls were sequentially extracted with 0.05 M cyclohexane‐trans‐1,2‐diamine‐N,N,N ′,N ′‐tetraacetate (CDTA) + 0.05 M NH₄ oxalate (extract 1), 0.05 M NaOH (extract 2), 1 M KOH (extract 3) and 4 M KOH (extract 4) to fractionate the cell wall into its polysaccharide fractions. The extraction procedure was designed to first extract the pectic fraction (extracts 1 and 2), after which more hemicellulose was extracted in subsequent steps (extracts 3 and 4). In addition to the polysaccharides solubilised during extraction, the residues after each extraction step were collected. Extracts and residues were analysed for their fermentation characteristics using an in vitro gas production procedure. Fermentability of the sequential extracts increased for each subsequent extraction step, as witnessed by an increasing rate of fermentation (from 2.2 to 10.0% h⁻¹) and decreasing half‐time of gas production (from 56.0 to 18.7 h). Fermentability of the residues increased after pectins had been removed in the first two extraction steps, as witnessed by a shorter half‐time of gas production (from 47.0 to 29.7 h). Fermentability was similar for residues 2 and 3, but decreased again for residue 4, which was deemed to consist mainly of cellulose. The different cell wall sugars were degraded at different rates, with a rapid rate of degradation for galactose and arabinose, an intermediate rate for xylose and uronic acids and a slow rate for glucose. The sugar degradation rates for extract 1 had a similar ranking. These results are discussed in light of the concept that pectins determine the pore size of the cell wall matrix (Carpita NC and Gibeant DM, Planta J 3 : 1–30 (1993) and the model of the cell wall architecture of legumes of Hatfield (Hatfield RD, in Forage Cell Wall Structure and Digestibility, Ed by Jung HG, Buxton DR, Hatfield RD and Ralph J. American Society of Agronomy/Crop Science Society of America/Soil Science Society of America, Madison, WI, pp 285–313 (1993)). © 2000 Society of Chemical Industry     

乳酸菌发酵法制备茶渣可溶性膳食纤维的工艺研究

以茶渣为原料,采用保加利亚乳杆菌和嗜热链球菌(1∶1)混合菌为发酵菌种,研究以微生物发酵法制备茶渣可溶性膳食纤维(SDF)的最佳工艺参数。通过单因素实验,探讨了接种量、发酵温度、发酵时间和料液比等因素对发酵工艺的影响,利用L9(34)正交实验对茶渣SDF的制备工艺进行优化。结果表明:发酵法制备茶渣SDF的最佳工艺条件为:接种量为3%,发酵温度40℃,发酵时间25h,料液比1∶10(g/mL),在此条件下得到的茶渣SDF的平均得率可达10.99%。      

Antioxidant activity of peptide fractions derived from cottonseed protein hydrolysate

BACKGROUND: Cottonseed protein is widely regarded as a potential source of nutrients for humans and animals, but it is mainly used as forage in China. In the present study, Neutrase was employed to hydrolyse cottonseed protein to produce a hydrolysate with antioxidant activity suitable for conversion to high‐value products. The antioxidant potential of the cottonseed protein hydrolysate (CPH) and its fractions was investigated using different in vitro methods. Furthermore, the amino acid composition of the CPH fractions was determined to evaluate the relationship between antioxidant activity and amino acid composition. RESULTS: The CPH prepared using Neutrase was separated into four fractions (I, II, III and IV) by gel filtration on Sephadex G‐25. All fractions were effective antioxidants, with fraction III (0.8–1.2 kDa) showing the strongest activity. The amino acid analysis showed that fraction III also had the highest total amino acid content (616.8 g kg^?1 protein) and was rich in Phe, His, Pro, Met, Ile and Cys compared with the other fractions. CONCLUSION: The results showed that the hydrolysate derived from cottonseed protein, particularly fraction III, could be a natural antioxidant source suitable for use as a food additive. Copyright © 2010 Society of Chemical Industry     

Purification and characterisation of a novel antioxidant peptide from porcine haemoglobin hydrolysate

Porcine haemoglobin, which is normally discarded as a by‐product of meat industry, was hydrolysed using pepsin, AS1398 neutrase, trypsin, flavorzyme, papain and alcalase respectively. The peptic hydrolysate exhibited the highest antioxidant activities than those of other hydrolysates, which was separated using ultrafiltration membranes, and consecutively using chromatographic methods including ion‐exchange chromatography on SP Sephadex C‐25 column, gel filtration chromatography on Sephadex G‐25 column and reversed‐phase high performance liquid chromatography. Finally, a novel antioxidant peptide from porcine haemoglobin (APPH) was purified, and its sequence was identified to be ARRLGHDFNPDVQAA (1666 Da) using mass spectrometry. APPH exhibited significant higher lipid peroxidation inhibitory ability than that of α‐tocopherol as positive control (P < 0.05), and efficiently quenched hydroxyl radical (IC₅₀ = 26.9 μm ). APPH agrees with the 115–129 residues of the β‐chain from porcine haemoglobin. These results indicate that APPH would be a beneficial ingredient for functional food and pharmaceuticals.     

Interaction of MDpep9, a novel antimicrobial peptide from Chinese traditional edible larvae of housefly,with Escherichia coli genomic DNA

Antimicrobial peptides from edible insects may serve as a potentially significant group of food preservatives. In the present work, the mode of action of a novel antimicrobial peptide MDpep9 from Chinese traditional edible housefly larvae was investigated. MDpep9 was shown to bind to bacterial DNA from the results of gel retardation and fluorescence quenching experiments. Further investigations confirmed that MDpep9 could bind with the phosphate group of DNA and intercalate into the base pairs in a helix of DNA or locate in hydrophobic environment of DNA. The previous and present results demonstrated that MDpep9 has dual mechanisms of bactericidal activity: disrupting bacterial cell membranes and binding to bacterial genomic DNA to inhibit cellular functions, ultimately leading to cell death. The results of DNA-binding mode may be contributive in designing new and promising antimicrobial peptides for food preservatives.     

Angiotensin‐I converting enzyme inhibitory and antioxidant activities of peptide fractions extracted by ultrafiltration of cowpea Vigna unguiculata hydrolysates

BACKGROUND: Enzymatic proteolysis of food proteins is used to produce peptide fractions with the potential to act as physiological modulators. Fractionation of these proteins by ultrafiltration results in fractions rich in small peptides with the potential to act as functional food ingredients. The present study investigated the angiotensin‐I converting enzyme (ACE‐I) inhibitory and antioxidant activities for hydrolysates produced by hydrolyzing Vigna unguiculata protein extract as well as ultrafiltered peptide fractions from these hydrolysates. RESULTS: Alcalase^®, Flavourzyme^® and pepsin–pancreatin were used to produce extensively hydrolyzed V. unguiculata protein extract. Degree of hydrolysis (DH) differed between the enzymatic systems and ranged from 35.7% to 58.8%. Fractionation increased in vitro biological activities in the peptide fractions, with IC₅₀ (hydrolysate concentration in µg protein mL^?1 required to produce 50% ACE inhibition) value ranges of 24.3–123 (Alcalase hydrolysate, AH), 0.04–170.6 (Flavourzyme hydrolysate; FH) and 44.7–112 (pepsin–pancreatin hydrolysate, PPH) µg mL^?1, and TEAC (Trolox equivalent antioxidant coefficient) value ranges of 303.2–1457 (AH), 357.4–10 211 (FH) and 267.1–2830.4 (PPH) mmol L^?1 mg^?1 protein. CONCLUSION: The results indicate the possibility of obtaining bioactive peptides from V. unguiculata proteins by means of a controlled protein hydrolysis using Alcalase^®, Flavourzyme^® and pepsin–pancreatin. The V. unguiculata protein hydrolysates and their corresponding ultrafiltered peptide fractions might be utilized for physiologically functional foods with antihypertensive and antioxidant activities. Copyright © 2010 Society of Chemical Industry     

鱼类抗菌肽研究的最新进展

鱼类抗菌肽作为天然免疫系统的主要组成部分,有着非常显著的碱性、热稳定性和广谱抗菌性。研究发现,抗菌肽对一些真菌、原虫、病毒及癌细胞等均具有很强的杀伤作用。因此,鱼类抗菌肽具有重要的研究意义。该文根据近年来国内外的有关研究报道,介绍了鱼类抗菌肽的种类,简述了抗菌肽的抗菌机制,同时回顾了已发现的鱼类抗菌肽的基因结构,并对其应用前景方面做了简要的分析。     

黄鲫蛋白抗菌肽—葡萄糖美拉德反应物的抑菌性实验研究

利用响应面分析法优化黄鲫蛋白抗菌肽-葡萄糖美拉德反应条件,提高产物的抑菌活性。以大肠杆菌为指示菌,在黄鲫蛋白抗菌肽初始反应pH为5.58条件下,进行葡萄糖添加量、加热温度和加热时间三因素三水平Box-Benhnken响应面分析实验,得出黄鲫蛋白抗菌肽-葡萄糖美拉德反应最优条件为葡萄糖添加量0.25%(w/v)、加热温度100℃、加热时间60 min。在最优反应条件下,黄鲫蛋白抗菌肽-葡萄糖美拉德反应物对大肠杆菌的抑菌圈直径为28.9 mm,与理论值28.4 mm接近。     

Amino acid composition and anti‐polyphenol oxidase of peptide fractions from sericin hydrolysate

Sericin hydrolysate (SH), prepared from enzymatic hydrolysis of sericin, was investigated for its antipolyphenol oxidase (PPO) properties. SH decreased PPO activity from both purified mushroom PPO and extracts from apple and eggplant, and retarded browning in fresh‐cut apple and eggplant. SH was a competitive inhibitor using catechol as a substrate. SH exhibited copper ion‐chelating power and reducing power abilities. Fractionation of SH using size exclusion chromatography resulted in four fractions, designated as F1, F2, F3 and F4, with PPO inhibition of 35.75%, 3.89%, 24.52% and 14.75%, respectively. Ser and Asp were major amino acids found in F1. Amino acid sequences in F1, as investigated by LC‐MS/MS using de novo sequencing, contained a high ratio of amino acids with chelating ability. Moreover, amino acids with reducing power ability and with antityrosinase ability were also identified in the sequences.     

发酵豆粕制备大豆肽饮料发酵条件的研究

文中对米曲霉液态发酵豆粕制备大豆肽发酵液进行了研究.以发酵液中大豆肽转化率为指标,研究豆粕浓度、碳氮比(C/N)、发酵温度和发酵时间对其影响.正交试验确定最佳的发酵条件,即豆粕浓度为3％、C/N为14、发酵温度为30℃、发酵时间为46h,得到的大豆肽发酵液大豆肽转化率达到55.6％.所得的大豆肽分子量分布在204u～1335u之间的百分比为43.28％.