中低pH下Maillard反应产物抗氧化性研究

以脯氨酸与葡萄糖的Maillard反应为模型,研究了两种加热方式下,三种配比反应混合物在两种pH环境下,反应温度和时间对反应产物的抗氧化性影响。实验通过比色法来检测Maillard反应产物对DPPH自由基的清除率,用以表征其抗氧化性。结果显示:pH=5和7时,反应产物中都有抗氧化物质形成,较高的pH和葡萄糖配比更有利于反应产物中抗氧化物质的形成;微波加热时间对抗氧化物质形成影响不大,而常规油浴加热时间越长抗氧化物质形成越多;微波加热比常规油浴加热更能促进反应产物中抗氧化物质的快速形成。     

乳清蛋白半乳糖Maillard反应产物的体内抗氧化性研究

探讨乳清分离蛋白(WPI)半乳糖Maillard(美拉德)反应产物在动物体内是否具有抗氧化性。建立了两种小鼠损伤模型:四氯化碳(CCl4)肝损伤模型和四氧嘧啶氧化损伤模型,通过检测对照组和各剂量组血清及肝脏中谷草转氨酶(AST)、谷丙转氨酶(ALT)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)含量的变化来研究WPI-半乳糖Maillard反应产物在体内的抗氧化活性。结果表明:WPI-半乳糖Maillard反应产物在两种损伤模型中能够显著抑制血清及肝脏中ALT、AST、MDA含量的升高,增加血清及肝脏中SOD、GSH-Px的含量,尤其是高剂量组(500 mg/(kg·d))抗氧化效果明显,抗氧化活性随剂量加大而增强。证明乳清蛋白半乳糖Maillard反应产物在动物体内具有良好的抗氧化活性,这种活性可能与清除自由基有关。     

基于烟草水提物的Maillard反应产物影响因素

为充分利用烟叶资源,提高其使用价值,以亚临界萃取后的烟叶残渣为原料制备了烟草水提物,利用GC-MS法对Maillard反应产物进行定量分析,系统探讨了氨基酸种类及用量、反应时间对Maillard反应产物化学组成及卷烟感官质量的影响;并探讨了Maillard反应产物中的18种成分与卷烟感官指标的相关关系。结果表明:①谷氨酸和天冬氨酸的Maillard反应产物与水提物自身的Maillard反应相似,以5-羟甲基糠醛为主,其次为羟基丙酮、2-乙酰基吡咯;脯氨酸参与的反应产物则以羟基丙酮、糠醇和5-羟甲基糠醛为主。②以感官作用为依据,基于烟草水提物Maillard反应的最佳条件为还原糖（以葡萄糖计）与谷氨酸的摩尔比n_还原糖:n_谷氨酸=1:0.5、反应温度110 ℃、反应时间2 h。③18种成分中,2-甲基四氢呋喃-3-酮与烟气浓度相关关系密切,糠醛、5-甲基糠醛、2-呋喃基羟基甲基酮和5-羟甲基糠醛与透发性关系密切,羟基丙酮和3-甲基-1, 2-环戊二酮与烘焙香关系密切。      

37℃下金属离子对模式体系Maillard反应的影响

为研究低温下金属离子对模式Maillard反应体系的影响,测试了D-葡萄糖与L-谷氨酸、L-苯丙氨酸、L-脯氨酸、L-赖氨酸、L-天门冬氨酸、L-丙氨酸在37℃,pH 6.5和/或添加Fe2+,Cu2+,zn2+,Mg2+,K+的条件下反应1～35 d的Maillard反应产物在420 nm处的吸光度.结果表明,在相同条件下,赖氨酸的反应活性是其他5种氨基酸的3-6倍;在金属离子作用下,除K+对脯氨酸与葡萄糖体系呈抑制作用外,其他各Maillard反应体系的棕色化程度均被催化增强.其中.Fe2+,Cu2+催化效果最好.     

Maillard反应产物的分级分离及卷烟加香评价

为揭示Maillard反应产物各组分的加香特征和找出具有良好加香效果的组分,以葡萄糖-脯氨酸的Maillard反应产物为研究对象,采用凝胶渗透色谱对产物进行分级分离,分级组分分别进行热裂解(Py)-GC/MS分析和卷烟加香评价。结果表明:1通过凝胶柱层析,可有效地将产物按分子量大小分级,实现产物的分级分离。2各组分间化合物种类有较大的差别,H1和H2组分主要为分子量较大的含氮杂环化合物,H3和H4组分主要为分子量相对较小的含氧杂环化合物。3分级后组分的卷烟加香效果优于未分级产物,且以分子量较大的组分效果最佳。     

核桃粕固态发酵酱油的制备及抗氧化性分析

目的：以米曲霉为菌种制备核桃酱油,开发功能性酱油。方法：制备酱油基础上,利用高效液相色谱仪、全自动氨基酸分析仪和气相色谱仪测定酱油营养成分,使用超滤对10 kDa以下组分进行分离,然后测定核桃酱油组分中多肽含量、ABTS自由基清除能力、羟自由基清除能力及DPPH自由基清除能力。结果：核桃酱油中16种氨基酸总含量为4.86 g/100 g,不饱和脂肪酸含量占脂肪酸总量的82.84%。核桃酱油组分中多肽含量为6.804 g/100 mL,当多肽质量浓度为3.6 mg/mL时,核桃酱油组分ABTS自由基清除能力达到95.13%、羟自由基清除能力达到28.20%、DPPH自由基清除能力达到20.08%。结论：核桃酱油组分具有较高的抗氧化性,且其抗氧化能力与多肽含量有关。     

Maillard反应合成咸味香精研究进展

阐明了国内外Maillard反应合成咸味香精的研究进展,并对其目前存在的问题及发展趋势作了进一步的说明。      

Maillard反应合成咸味香精研究进展

阐明了国内外Maillard反应合成咸味香精的研究进展,并对其目前存在的问题及发展趋势作了进一步的说明。     

乳清蛋白-麦芽糖糊精的Maillard反应复合物制备β-胡萝卜素纳米乳液

系统考察乳液制备参数对乳液粒径分布及稳定性的影响,同时以干热法制备乳清分离蛋白（Whey Protein Isolate,WPI）-麦芽糖糊精（Maltodextrin,MD）的Maillard反应复合物（Maillard Reaction Products,MRPs）。以此为基础,制备WPI-MD MRPs稳定的β-胡萝卜素纳米乳液,并进一步考察乳液的物理稳定性及β-胡萝卜素的化学稳定性。结果表明,WPI-MD的MRPs能够显著降低纳米乳液的粒径,并提高纳米乳液的物理稳定性。同时,WPI-MD的MRPs可加速油相中β-胡萝卜素的降解,其机理有待进一步研究。      

反应条件对葡萄糖/苯丙氨酸和葡萄糖/丙氨酸Maillard模型体系挥发性产物的影响

为研究反应条件对葡萄糖/苯丙氨酸和葡萄糖/丙氨酸Maillard反应体系中挥发性化合物形成的影响,采用气相色谱-质谱（gas chromatography-mass spectrometer,GC-MS）法对不同反应物比例和反应时间下Maillard反应产物中挥发性化合物进行了分析。结果表明：1）反应时间对葡萄糖/苯丙氨酸和葡萄糖/丙氨酸体系挥发性产物的影响趋势相似,随着反应时间延长挥发性香味成分总量及脂肪族、芳香族、呋喃类、有机酸、吡啶、吡咯、呋喃酮和碳环类化合物的生成量增加,吡喃酮类化合物生成量先增加后减少。2）反应物比例对葡萄糖/苯丙氨酸和葡萄糖/丙氨酸体系挥发性香味成分生成量的影响不同,随着体系中氨基酸含量增加,葡萄糖/苯丙氨酸体系芳香族化合物生成量增加,脂肪族化合物生成量降低,而在葡萄糖/丙氨酸体系中呈相反的趋势。两个体系中吡嗪类、有机酸、吡喃酮类、吡啶、吡咯、碳环类和呋喃酮类化合物生成量均随体系中氨基酸含量的增加而增加。     

猪骨粉酶解液的美拉德反应产物清除DPPH·的研究

以猪骨粉酶解液为原料,与还原糖（葡萄糖或木糖）反应制备美拉德反应产物（MRPs）,研究其对DPPH·清除率的影响。结果表明:当起始pH为6.5,时间为4h,温度为120℃,葡萄糖添加量为1.5%时,获得的葡萄糖-MRPs的DPPH·清除率为82.53%;当起始pH为7.5,时间3h,温度为120℃,木糖添加量为1.5%时,木糖-MRPs的DPPH·清除率为88.58%;木糖-MRPs的清除DPPH·的能力较葡萄糖-MRPs的高。      

Characteristics and antioxidant activity of Maillard reaction products from psicose-lysine and fructose-lysine model systems

D-Psicose, an epimer of D-fructose isomerized at C-3 position, is a rare ketohexose that is thought to be beneficial for obese people and diabetic patients as a noncaloric sweetener. In the present study, model Maillard reaction products were obtained from D-psicose (or D-fructose) and L-lysine heating at 120 °C up to 8 h with the initial pH 9.0. The changes in pH, UV-vis absorbance, and free amino groups during the reaction were detected. Moreover, the antioxidant potential of the Maillard reaction products at different intervals was investigated. Although there was almost no difference in the oxygen radical absorbance capacity, the Maillard reaction products from psicose performed better than that from fructose in the radical-scavenging activity of 2, 2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt and 1, 1,-diphenyl-2-picryl-hydrazyl. The reducing power of the Maillard reaction products from psicose was also stronger than that from fructose. These results indicated that psicose played an effective role in the Maillard reaction and its Maillard reaction products could act as potential antioxidants in food industry.     

双孢蘑菇源抗氧化肽的美拉德反应修饰研究

以还原力为指标对双孢蘑菇源抗氧化肽进行美拉德反应修饰研究。通过单因素实验研究了糖种类、体积比、pH、时间对双孢蘑菇源抗氧化肽美拉德反应修饰的影响,在此基础上采用正交实验优化了双孢蘑菇源抗氧化肽的美拉德反应修饰工艺。实验结果表明双孢蘑菇源抗氧化肽的最佳美拉德反应修饰工艺为:以果糖作为修饰反应物,果糖、双孢蘑菇源抗氧化肽二者的体积比为4:1,pH11.0,时间150min;该条件下制备的美拉德反应产物的还原力大约是修饰前的5倍,提示美拉德反应是提高抗氧化肽抗氧化活性的有效方法。      

美拉德反应产物的褐变、荧光吸收及抗氧化性的研究

采用以还原糖-氨基酸(木糖/葡萄糖分别与甘氨酸、赖氨酸、谷氨酰胺、半胱氨酸)模式美拉德反应(Maillard Reaction,MR)制备得到美拉德反应产物(MRPs),研究反应条件对MRPs的褐变程度、荧光吸收强度以及其抗氧化活性的影响,并分析MRPs的光学特征与抗氧化活性之间的联系。结果表明,还原糖和氨基酸的种类对MR的褐变强度有很大影响,其影响程度由强到弱分别为:Xly>Glc,Lys>Gly>Glu>Cys。随着反应时间的延长,各体系MRPs的褐变程度逐渐变强;而荧光吸收强度随着加热时间的延长而增强,然后在出现最大值后趋于平缓或者表现出下降的趋势。MRPs的抗氧化能力也随反应时间的延长而增强,抗氧化活性与褐变强度呈正相关,与荧光吸收特性没有表现出明显的关联。     

美拉德反应对芝麻多肽抗氧化活性的影响

在制备芝麻多肽的基础上,研究美拉德反应对芝麻多肽抗氧化活性的影响。结果表明,芝麻多肽美拉德反应的适宜肽糖比为1:2(质量比);美拉德反应能够显著提高芝麻多肽的抗氧化活性,其还原力、ABTS+自由基清除率、DPPH自由基清除率和羟自由基清除率分别提高了121. 4%,304. 5%,81. 2%,103. 2%。美拉德反应降低了芝麻多肽中赖氨酸、甲硫氨酸和酪氨酸含量,增加了丙氨酸、缬氨酸含量,且生成了天冬氨酸、谷氨酸、半胱氨酸和甘氨酸。褐变程度和接枝度均随美拉德反应时间的延长而增加,在反应4 h时,其褐变程度和接枝度分别为1. 42%,26. 4%。美拉德反应产物在210,260 nm处具有吸收峰,且吸收峰强度随着反应时间的延长逐渐增强,这与反应产物中肽键发生了改变和类黑精含量增加有关。可见,美拉德反应对芝麻多肽的抗氧化活性具有一定的影响。     

The effects of Maillard reaction products on apple and potato polyphenoloxidase and their antioxidant activity

The effects of Maillard reaction products (MRPs) on apple and potato polyphenol oxidase (PPO) were estimated spectrophotometrically. Model systems of glucose and amino acids [lysine (lys), tyrosine (tyr), proline (pro), cysteine (cys), glumatic acid (glu), aspartic acid (asp), and histidine (his)] were heated at 90 °C for 3 h. The MRPs showed inhibitory effects on PPO extracted from apple and potato. These effects depend on the type of MRP and origin of PPO. The antioxidant activity of MRPs was evaluated. It was found that MRPs exhibit different free radical scavenging activity and these effects were significant. The colour intensity of MRPs was estimated. Browning was not directly related to the antioxidant activity.     

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.     

山茱萸美拉德反应产物的超滤分离及其体外抗氧化活性

目的:通过超滤分离中药山茱萸美拉德反应产物的最佳有效部位,并比较各截留产物的理化性质和体外抗氧化作用。方法:以山茱萸为美拉德反应底物,经高温反应后获得反应产物。采用中空纤维膜对反应产物进行分级过滤,过膜级数为0.45、0.22μm、100、50、10、4 ku,对各分级截留产物分别进行冷冻干燥并测定它们的理化特性(紫外吸收和褐变程度);同时观察它们对DPPH自由基的清除能力和对铁氰化钾的还原能力。结果:不同截留产物的紫外吸收曲线基本类同,且在284 nm处均有最大吸收。相比之下,0.45~0.22μm截留产物的褐变程度最大,同时其自由基清除率和还原能力也最高。结论:提示山茱萸美拉德反应产物中抗氧化的最佳活性部位为0.45~0.22μm的超大分子类物质。      

Characteristics and antioxidative activity of Maillard reaction products from a porcine plasma protein–glucose model system as influenced by pH

Maillard reaction products (MRPs) were prepared by heating the solution containing 2% porcine plasma protein (PPP) and 2% glucose adjusted to various pHs (8, 9, 10, 11 and 12) at 100 °C for different times (0, 2, 4, 6 and 8 h). The pH of all MRPs markedly decreased within 2 h of heating time. Browning and intermediate products, as monitored by absorbance at 420 nm and absorbance at 294 nm, sharply increased within 2 h (P < 0.05). Thereafter, slight increases were observed up to 8 h. Fluorescence intensity (Ex 347 and Em 415 nm) sharply increased within the first 2 h with a subsequent decrease when heating time increased (P < 0.05). Increases in browning and formation of intermediate products were concomitant with the decreases in free amino group and reducing sugar contents. Among all MRPs tested, those derived from the PPP–glucose system at pH 12 rendered the highest browning and intermediate products. However, no differences in reducing power or DPPH radical-scavenging activity of MRPs with initial pH ranges of 10–12 were noticeable. Electrophoretic study revealed that cross-linked proteins with high molecular weight were formed in the PPP–glucose model system to a greater extent at pHs 8 and 9, than at pHs 10–12. Nevertheless, heating times had no pronounced effect on protein pattern of glycated proteins.