Characteristics and antioxidant activity of ultrafiltrated Maillard reaction products from a casein–glucose model system

Maillard reaction products (MRPs) were prepared from casein–glucose by refluxing for 130 min at 102 °C and initial pH 12.0 without pH control to investigate the characteristics of casein–glucose Maillard reaction and the antioxidant activity difference among different fractions of MRPs. Browning and intermediate products increased, however, the pH of the system decreased with increase in the heating time. Free amino group content decreased 78% during first 10 min and did not change nearly thereafter. Amino acid analysis indicated that lysine and arginine decreased significantly, and casein was partially hydrolysed to peptides or free amino acid. High molecular weight compounds were dominant in the MRPs, determined by high performance gel-filtration chromatography. After ultrafiltration, antioxidant activity of each MRPs fraction was investigated by DPPH radical-scavenging activity, reducing power, Fe²⁺ chelating activity and lecithin oxidation assay. MRPs of different molecular weight exhibited distinctly different antioxidant activities.     

膜分离鸡骨素酶解液美拉德反应产物的初步研究

本研究对鸡骨素酶解液美拉德反应产物(MRPs)膜分离后的不同组分进行了初步分析。首先鸡骨素酶解液经美拉德反应制得鸡骨素酶解液MRPs,再利用膜分离技术将鸡骨素酶解液MRPs进行微滤、超滤、纳滤和反渗透,从而得到不同分子量范围的鸡骨素酶解液MRPs组分;然后通过吸光度和感官仪器分析,检测了鸡骨素酶解液MRPs各组分的褐变程度、风味色泽变化;通过对还原力、ABTS+自由基清除力、AEC抑制率、氧自由基吸收能力(ORAC)及对环状质粒DNA的保护能力的检测,研究了鸡骨素酶解液MRPs各组分的抗氧化特性,并最终对各组分进行了综合评价。结果表明:鸡骨素酶解液美拉德反应中引起褐变的物质分子量大于3 kDa,反应中间产物的分子量集中在0.3~1 kDa;鸡骨素酶解液经美拉德反应后风味得到改善,抗氧化活性显著提高(p < 0.05),其中呈味物质主要集中在微滤和纳滤组分,鸡骨素酶解液MRPs中各组分与未分离原液相比抗氧化活性有所降低,但都显著高于鸡骨素酶解液(p < 0.05);综合评价显示,鸡骨素酶解液美拉德反应原液的综合得分最高,鸡骨素酶解液MRPs各组分得分也高于鸡骨素和鸡骨素酶解液。     

美拉德反应对金枪鱼红肉酶解液挥发性物质和游离氨基酸的影响

为了高值化利用金枪鱼红肉这一蛋白质资源,利用气相色谱-质谱联用(GC-MS)和高效液相色谱(HPLC),研究美拉德反应对金枪鱼红肉酶解液挥发性物质和游离氨基酸的影响。GC-MS结果表明,金枪鱼红肉酶解液中共检测出19种挥发性化合物,其中未加热的酶解液中有10种,而经过不同时间(30、60和90 min)加热的酶解液中,分别检测出12种、15种和15种,其中呋喃类物质的含量随反应时间延长显著增加。HPLC分析表明,随着加热时间的增加,酶解液中呈味氨基酸总量均上升,但是鲜味和甜味氨基酸的比例呈下降趋势,苦味氨基酸则呈上升趋势。表明,美拉德反应赋予酶解液更加丰富的风味的同时,却使其呈现更多的苦味。     

超滤技术分离花生抗氧化肽及其性能研究

采用超滤技术分离花生抗氧化肽,研究超滤操作压力、温度、pH 值和滤液浓度对膜通量的影响,结果表明,滤液浓度2%,压力0.08MPa,温度25℃和时间20min 条件下,膜通量相对较高为45.18ml/m2·min,分子量3kD 以下的花生肽抗氧化活性较高。利用大豆油研究花生抗氧化肽的活性,当添加0.10% 3kD 花生抗氧化活性肽到大豆油中,存放7d 其POV 值为9.15meq/kg,抗氧化活性较好。     

Effect of xylose on the molecular and particle size distribution of peanut hydrolysate in Maillard reaction system

BACKGROUND: The Maillard reaction is a complex series of reactions between reducing sugars and amino groups. Changing any of reaction parameters would alter the reaction pathway. This study investigated the effect of xylose concentration on the molecular and particle size distribution of Maillard reaction products (MRPs) derived from peanut hydrolysate and xylose to discuss their formation mechanism. RESULTS: Molecular weight and particle size distribution analyses indicated that both peptide degradation and peptide cross‐linking occurred during the Maillard reaction. Heat treatment would make the high‐molecular‐weight peptides degrade into low‐molecular‐weight peptides and free amino acids. Maillard reaction increased the molecular weight and particle sizes of products as the xylose concentration increased from 1% to 4%. CONCLUSION: The study shows that both peptide degradation and peptide cross‐linking occurred during the Maillard reaction. The thermal degradation product (TDP) and MRPs had significantly different molecular size distribution, and the particle size distribution of TDPs and MRPs had similar change tendency to that of the molecular size distribution. These would provide an insight into the formation mechanism of MRPs. Copyright © 2011 Society of Chemical Industry     

Effects of Galactose Concentration on Characteristics of Angiotensin-I-Converting Enzyme Inhibitory Peptides Derived from Bovine Casein in Maillard Reaction

Bovine casein peptide had a strong angiotensin-I-converting enzyme inhibitory activity. The objective of this study was to evaluate the effects of the galactose concentration on angiotensin-I-converting enzyme inhibitory activity, antioxidant activity, and physicochemical properties of Maillard reaction products derived from bovine casein peptide and galactose in aqueous model system. The browning intensities of galactose-bovine casein peptide Maillard reaction products increased remarkably with the galactose concentration increased during heat treatment, while its pH and amino groups decreased significantly. The fluorescence compounds of galactose-bovine casein peptide Maillard reaction products reached the maximum when the galactose concentration was 45 g/L. Compounds with molecular weight between 2941 and 8864 Da were dominant while compounds smaller than 250 Da were also produced during the reactions, as characterized by size exclusion chromatography. Galactose-bovine casein peptide Maillard reaction products lost 14.6% of the original angiotensin-I-converting enzyme inhibitory activity of bovine casein peptide after the addition of galactose concentration ranged from 0 to 12%, but its strong antioxidant activities were obtained. A high galactose concentration could decrease angiotensin-I-converting enzyme inhibitory activity of bovine casein peptide and enhance its antioxidant activities.     

Antioxidant activity, browning and volatile Maillard compounds in Pedro Ximénez sweet wines under accelerated oxidative aging

Pedro Ximénez wine, aged by thermal treatment during 10, 20 and 30 days in the presence or absence of oak chips, was studied in terms of antioxidant activity, browning and volatile Maillard compounds. The phenolic fractions obtained by the SepPack tC-18 column revealed that the antioxidant activity after 10 days of thermal treatment was due to the presence of phenols and polar compounds possibly formed by the Maillard reaction. After 30 days, however, the antioxidant activity was also due to high-molecular weight procyanidins. Volatile Maillard compounds increased throughout the thermal treatment. It should be noted that there was an increase in the 5-ethoxymethylfurfural content and the presence of 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-2-one, which was recently shown to inhibit growth of colon tumor cells. The presence of oak chips had a substantial effect on the contents in volatile Maillard compounds after the thermal treatment with the exception of corylon. The wine obtained after 10 days of thermal treatment was judged to be the best in terms of sensory properties. In fact, it exhibited the optimum balance between varietal and aging aromas due to Maillard compounds.     

Sensory Characteristics and Antioxidant Activities of Maillard Reaction Products from Soy Protein Hydrolysates with Different Molecular Weight Distribution

Soy protein was hydrolyzed using two enzymes to obtain soy protein hydrolysate (SPH), the SPH was fractionated with ultrafiltration membranes to obtain peptide fractions below 1,000 Da (SP1) and 1,000–5,000 Da (SP2), and for the meantime, SPH was further completely hydrolyzed to get compound amino acids (CAA). Maillard reaction products (MRPs) were prepared from aqueous xylose–SPH/SP1/SP2/CAA model systems by heating at 120°C for 2.0 h. Compared with the original hydrolysates and other MRPs, the MRPs from SP2 exhibited a distinctly enhanced effect on flavor, including the caramel-like, soy sauce-like odors, umami and mouthful tastes and a greatly reduced bitterness in consomme′ soup. Antioxidant activities of SPH, SP1, SP2, CAA, and their MRPs were investigated through reducing power, DPPH radical-scavenging activity, and Fe²⁺ chelating activity. Before Maillard reaction, the antioxidant activities of peptide fractions with different molecular weights were quite different, and SP2 showed the highest activity; however, CAA exhibited very poor antioxidant activity. The antioxidant activities of SPH, SP1, SP2, and CAA were greatly enhanced by Maillard reaction, and the MRPs prepared from xylose–CAA model system exhibited a higher antioxidant activity than those from other model systems. Pyrazines, pyrroles, furans, and thiazoles were significantly correlated with reducing power and Fe²⁺ chelating activity by principal component analysis.     

鲢鱼肽美拉德反应产物超滤组分的抗氧化活性研究

鲢鱼肽美拉德反应产物(MRPs)经5 k Da、1 k Da超滤膜分离、然后再经溶剂分级后,获得了不同组分,分析其抗氧化活性与理化特性。通过对不同组分的DPPH自由基清除活性、金属离子螯合活性和总抗氧化能力的测定可以看出,水溶性组分中的高分子量化合物比低分子量化合物具有较高抗氧化活性,而醇溶性组分中高分子量的抗氧化活性比低分子量的低。MRPs中水溶性组分F-3(5 k Da)对DPPH自由基清除活性、对金属离子的螯合活性和总抗氧化力最高;水溶性组分中F-3和F-2(1 k Da~5 k Da)的褐变程度较高,F-3的荧光强度最高;FI-IR分析发现,F-2和F-3在860.01 cm-1和948.61 cm-1处有强烈的吸收峰,这表明肽因美拉德反应发生了结构的变化。因此,鲢鱼肽MRPs中起主要抗氧化作用的为水溶性物质,且其中相对高分子量的有色水溶性产物抗氧化活性较强。     

咸味香精中美拉德反应产物的抗氧化性研究

利用膜分离手段从肉味香基中分离得到不同分子量范围的美拉德反应产物(MRPs),考察咸味香精中的肉味香基以及不同分子量的MRPs对卵磷脂脂质体的抗氧化效果。结果表明,肉味香基对脂质体过氧化有抑制能力,其抗氧化能力随反应物浓度的增加而增强。高分子量MRPs的抗氧化能力最强,其次为中分子量MRPs,小分子量MRPs抗氧化能力最弱,并且MRPs的抗氧化能力与其褐色程度成正比。     

Contribution of sulfur-containing compounds to the colour-inhibiting effect and improved antioxidant activity of Maillard reaction products of soybean protein hydrolysates

BACKGROUND: Light‐coloured and savoury‐tasting flavour enhancers are attractive to both consumers and food producers. The aim of this study was to investigate the colour‐inhibiting effect of L ‐cysteine and thiamine during the Maillard reaction of soybean peptide and D ‐xylose. The correlation between volatile compounds and antioxidant activity of the corresponding products was also studied. RESULTS: Colour formation was markedly suppressed by cysteine. Compared with peptide/xylose (PX), the taste profile of Maillard reaction products (MRPs) derived from peptide/xylose/cysteine (PXC) and peptide/xylose/cysteine/thiamine (PXCT) was stronger, including umami, mouthfulness, continuity, meaty and overall acceptance. PXC and PXCT also exihibited distinctly higher antioxidant activity. Principal component analysis was applied to investigate the correlation between antioxidant activity and volatile compounds. Of 88 volatile compounds identified, 55 were significantly correlated with antioxidant activity by two principal components (accounting for 85.05% of the total variance). CONCLUSION: Effective colour control of the Maillard reaction by L ‐cysteine may allow the production of healthier (higher antioxidant activity) and tastier foods to satisfy consumers' and food producers' demands. Light‐coloured products might be used as functional flavour enhancers in various food systems. Copyright © 2010 Society of Chemical Industry     

Antioxidant capacity of Maillard reaction products’ fractions with different molecular weight distribution from chicken bone hydrolysate – galactose system

Maillard reaction products (MRP) were prepared from an aqueous chicken bone hydrolysate (CBPH) – galactose systems by heating at 100 °C for up to 7.5 h without pH control, and then separated into the <3‐, 3‐ to 10‐ and >10‐kDa fractions using ultrafiltration. Antioxidant capacity and spectral properties of these MRP fractions were studied. The scavenging activity towards DPPH and hydroxyl radicals as well as reducing power of each MRP fraction increased with the heating time, in accordance with the increase in UV absorbance, browning and fluorescence intensity. For the same MRP, the fraction with high molecular weight (MW) demonstrated the stronger radical scavenging activity and reducing power than that with low MW. Radical scavenging activities of MRP fractions largely depended on their MW, while their reducing powers were more related to the reaction progress. These results suggested that antioxidant capacity of MRP fractions should be positively related to its molecular size.     

海参酶解产物的分离及其体外抗氧化作用的研究

从海参酶解产物中分离制备海参肽.并研究其体外抗氧化作用。采用超滤、冷冻干燥方法分离不同分子质量范围的海参肽;采用二苯代苦味酰基自由基(DPPH),研究海参肽的抗氧化活性;经Sephadex G-25和反相高效液相色谱对抗氧化海参肽进行进一步分离。结果表明,分子质量在1000～3000u的海参肽表现出很强的抗氧化作用,对DPPH自由基的清除能力强于V_E,其再经Sephadex G-25分离得到海参肽Ⅰ的抗氧化活性最强,对DPPH自由基的清除率达56.3%(1mg/mL),海参肽Ⅰ经反相高效液相色谱将分离得到2个海参多肽组分.     

草鱼抗氧化肽的美拉德反应特性研究

本研究通过单独加热草鱼肽和添加木糖加热反应制备热降解产物（TDPs）和美拉德反应产物（MRPs),运用DPPH?抑制率、肽分子量分析及氨基酸分析等方法评价不同反应时间草鱼肽热降解产物及美拉德反应产物的抗氧化性能、分子量分布以及氨基酸组成的变化规律,深入探讨了反应时间对草鱼肽的美拉德反应产物特性的影响。研究发现,单独加热草鱼肽对各时间段热降解产物的总氨基酸含量无显著影响,游离氨基酸含量显著增加,而3000 Da以下肽段含量增多。美拉德反应体系样品随着反应时间的增加,产物中总氨基酸及游离氨基酸含量下降,其中精氨酸及赖氨酸减少尤其显著,分子量大于3000 Da的肽段明显增多,3000 Da以下的肽段含量降低,此外,美拉德反应产物中抗氧化活性显著增强。     

贵州三穗鸭鸭骨酶解液美拉德反应条件优化及挥发性风味物质分析

为提高鸭骨利用率以及深加工研制新型肉味香料,以贵州三穗鸭鸭骨酶解液为原料,通过正交试验结合改良的模糊数学感官评价方法确定最佳反应条件,同时采用固相微萃取-气质联用（SPME-GC-MS）仪分析其挥发性风味物质。结果表明：贵州三穗鸭骨酶解液美拉德反应最佳条件为反应pH值7.0、反应温度105 ℃、反应时间30 min。在此优化条件下,低分子香味中间体形成程度高,A280 nm值为0.214±0.019,制得的肉味香料综合评分最高,为3.92分。SPME-GC-MS分析结果表明,从鸭骨酶解液及美拉德反应产物中分别检测出26、49种挥发性成分,主要是醛、酯、烃、呋喃、酸类。经美拉德反应制成的肉味调味料,挥发性风味成分种类明显增加,且生成了噻唑类、呋喃类、芳香族及含硫化合物等肉类产品的特征风味物质。     

Isolation and identification of two novel umami and umami-enhancing peptides from peanut hydrolysate by consecutive chromatography and MALDI-TOF/TOF MS

Peanut hydrolysate produced by crude protease extract from Aspergillus oryzae HN 3.042 was found to elicit intense umami and umami-enhancing effect. Taste profiles, amino acid and organic acid composition of peanut hydrolysate and its separation fractions by ultrafiltration were evaluated. The results revealed that peanut hydrolysate was mainly low molecular weight compounds. Fractions of 1-3 kDa and below 1 kDa prominently contributed to the umami taste and umami-enhancing effect of the peanut hydrolysate. The two fractions were further purified, using gel filtration chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC), in combination with sensory evaluation, to obtain a umami peptide and umami-enhancing peptide. The active peptides were identified as Ser-Ser-Arg-Asn-Glu-Gln-Ser-Arg (SSRNEQSR, 963.9 Da) and Glu-Gly-Ser-Glu-Ala-Pro-Asp-Gly-Ser-Ser-Arg (EGSEAPDGSSR, 1091.1 Da), by MALDI-TOF/TOF MS, respectively.     

大豆肽的制备及其美拉德反应产物特性研究

本文以高温大豆粕为原材料,模拟酱油制曲工艺,通过发酵和酶解技术制备大豆肽,研究大豆肽及其美拉德反应产物的特性。通过比较其蛋白质回收率、DPPH自由基清除率等抗氧化指标、褐变程度及其肽分子量分布情况,深入研究了发酵酶解工艺和酶解时间对大豆肽及其美拉德产物抗氧化特性的影响。研究发现,发酵和酶解处理均可显著提升高温大豆粕的蛋白质回收率和抗氧化活性,在酶解时间为24 h时大豆粕的回收率达到最大值77.21%,此时大豆粕酶解产物的DPPH自由基IC50值和还原力(A700)分别为0.77 mg/m L和0.16。而美拉德反应则可以进一步提升大豆粕酶解产物的抗氧化活性。另外美拉德反应过程中分子质量较大的组分热降解反应比较剧烈,而小分子寡肽则比大分子多肽具有更高的美拉德反应活性。     

酶法及美拉德反应改进鸡肉蛋白功能性质的研究

利用不同单酶酶解鸡胸肉,制得的酶解液和木糖进行美拉德反应,考察不同酶解方式制得的底物对美拉德反应产物的各检测指标(肽、氨基酸、糖等反应底物含量和美拉德产物含量及其抗氧化性能力)影响,并分析各检测指标间的相关性。实验表明:酶解程度对美拉德反应产物特性有显着性影响,酶解作用所得的肽具有更强的美拉德反应活性,酶解程度越大的酶解液,消耗糖量越多,生成的MRPs越多,其MRPs抗氧化活性越强,同一反应起始浓度,8 h与2 h酶解液的MRPs抗氧化能力相比,FRAP还原能力与DPPH·清除能力增强倍数高达2倍和7倍;美拉德反应能明显改善了酶解液的性质,可溶解性肽的含量最高增加了2倍,可溶性氨基酸最高增加了1倍,抗氧化能力最高增强了40倍;从检测指标的相关性可知,糖的消耗量变化一定程度上能反应美拉德反应的程度,美拉德反应能促进肽的分解生成氨基酸。     

鸡肉酶解物中不同氨基前体对肉香味形成的贡献

通过超滤分离鸡肉酶解物,制备分子质量小于1 ku、1~5 ku、大于5 ku的3个肽组分样品。采用盐酸水解鸡肉酶解物,制备氨基酸组分样品。以3个肽组分和氨基酸组分及葡萄糖为原料,设计加或不加氧化鸡脂两类共8个模型反应体系,研究鸡肉酶解物中不同氨基组分对肉香味形成的贡献。通过分析比较反应产物在波长420 nm处紫外-可见光吸收值和pH变化值,以及固相微萃取/气-质联机分析挥发性风味物质组成,发现对于加与不加氧化鸡脂的两类反应体系,均为随氨基组分的分子质量增大,420 nm处紫外-可见光吸收值降低,产生的挥发性化合物总量减少,这可能因分子质量大反应活性差导致。无论加或不加氧化鸡脂,均为氨基酸组分对含硫化合物贡献最大,小于1 ku和1~5 ku肽组分对吡嗪类化合物贡献最大。但氧化鸡脂中含有羰基类脂质氧化产物可对美拉德反应有影响,与不加氧化鸡脂相比,加入氧化鸡脂后420 nm处紫外-可见光吸收值稍增加,产生的风味化合物总量大幅度下降,并有带烷基链的化合物(如2-甲基-5-丙基-噻吩)含量增加及新杂环化合物2-丁基吡啶出现。     

Free amino acids and peptides as related to antioxidant properties in protein hydrolysates of mackerel (Scomber austriasicus)

Mackerel (Scomber austriasicus) hydrolysates were prepared by an autolytic process and accelerated hydrolysis with a commercial enzyme, Protease N. Changes in the levels and compositions of free amino acids and small peptides during hydrolysis were investigated to find out their relationships with antioxidant activities. Increased levels of free amino acids, anserine, carnosine and other peptides of the hydrolysates obtained with protease were much higher than those by autolysis. Different antioxidant measurements including the inhibition of linoleic acid autoxidation, the scavenging effect on ,-diphenyl-β-picrylhydrazyl free radical, and the reducing power showed that mackerel hydrolysates possessed noticeable antioxidant activities. A good correlation existed between the amount of peptides and antioxidant activity. Three peptide fractions were separated from the hydrolysate by size exclusion chromatography. Results revealed that the peptide with molecular weight of approximately 1400 Da possessed a stronger in vitro antioxidant activity than that of the 900 and 200 Da peptides.