Antioxidant activity of Maillard reaction products derived from aqueous glucose/glycine,diglycine, and triglycine model systems as a function of heating time

The purpose of this study was to evaluate the antioxidant activity of Maillard reaction products (MRPs) derived from aqueous glucose/glycine, diglycine, and triglycine model systems as a function of heating time. The pH of MRPs derived from the Glu-G model system decreased markedly as the heating time increased, while MRPs derived from the Glu-Di model system showed the highest increase in absorbance at 420 nm. MRPs derived from the Glu-G model system showed the highest cupric ion chelating ability, while MRPs derived from the Glu-Di model system had the highest ferrous ion chelating activity. MRPs derived from the Glu-Di model system were found to be effective antioxidants in different in vitro assays with regard to the 2,2′-azinobis(3-ethylbenothiazoline-6-sulphonic acid) diammonium salt (ABTS) and 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging activities and ferric reducing/antioxidant power (FRAP).     

Characterization of antioxidant activity and volatile compounds of Maillard reaction products derived from different peptide fractions of peanut hydrolysate

Five peptide fractions isolated from peanut hydrolysate were purified by ultrafiltration and gel filtration chromatography. Their reaction degrees with glucose or lecithin in Maillard reaction were compared. Glucose consumption, oxygen radical absorbance capacity (ORAC) values and volatile compounds composition of peanut hydrolysate (PH) and its peptide fractions after thermal treatment and Maillard reaction were evaluated. Results revealed that the peptide fraction of 1-3 kDa showed the highest antioxidant activity. The peptides with smaller molecular weight showed a higher reaction degree to increase antioxidant activity and to produce more volatile compounds through Maillard reaction. Analysis of molecular weight distribution showed that peptide degradation and cross-linking simultaneously occurred during the Maillard reaction. In addition, lecithin addition to peptide-glucose system caused a significant increase of antioxidant activity possibly due to more nitrogen-containing compounds formed.     

酪蛋白-木糖体系美拉德反应产物的抗氧化活性

研究评价了由酪蛋白-木糖模拟体系产生的美拉德反应产物的抗氧化活性,考察了反应过程中体系的pH、褐变和中间产物的变化,并测定了美拉德反应产物对金属离子(Cu2+和Fe2+)的螯合能力、自由基清除能力(.OH、DPPH.和ABTS.)以及其还原能力。结果表明,模拟体系的酸度和褐变均随反映的进行而逐渐增加,中间产物在反应初期大量形成;美拉德反应产物对Fe2+的螯合能力要明显强于对Cu2+的螯合能力;美拉德反应产物对DPPH.和ABTS.具有较强的清除作用,而对.OH的清除作用较弱;美拉德反应产物的还原能力随反应时间的延长而逐渐增大。     

Effect of Maillard reaction products prepared from glucose–glycine model systems on starch digestibility

The Maillard reaction is one of the most important phenomena occurring spontaneously during food processing and storage. However, research on the effects of Maillard reaction products (MRPs) on starch hydrolysis remains insufficient. To investigate the effects of MRPs on in vitro starch digestibility, the characteristics of glucose–glycine model system containing MRPs and digestive enzyme activities by MRPs were measured. MRPs were prepared by heating of glucose–glycine mixture solution at 90°C for different times (0, 1, 3, 9, 18, 24, and 48 h). As the Maillard reaction proceeded, browning intensity, and furosine and hydroxymethylfurfural content increased, whereas pH value decreased. The reducing power of MRPs was increased as the Maillard reaction progressed, and MRPs produced in 18 and 24 h showed the highest values (both 1.2). In MRPs heated for 48 h, the reducing sugar content and hydrolysis index were lowest values (88.6 and 87.0%) among the samples. The activity of digestive enzymes significantly decreased by adding of MRPs, as the browning of added MRPs increased. Therefore, MRPs seem to be contributed to decrease in starch digestibility, as shown by an enzymatic digestion result.     

乳及乳制品加工中的美拉德反应

针对乳及乳制品在加工和储藏过程中由于发生美拉德反应不仅使乳制品的营养物质受到破坏，还产生对人体有害的物质，在很大程度上影响的乳制品的质量，对乳制品中美拉德反应的历程，产生的标志物及其测定方法等进行了的综述。     

不同分子量分布的美拉德产物的呈味特性及抗氧化抗菌活性研究

通过超滤及葡聚糖凝胶色谱技术结合将美拉德产物按分子量大小分级成三个组分,即小于1000u、1000～5000u和大于5000u,并评价其在清汤中的风味特性、清除DPPH自由基的能力及对金黄色葡萄球菌、李斯特菌、大肠杆菌和沙门氏菌的抑制活性。结果显示,1000～5000u的美拉德产物增强风味的效果最显著,其次是小于1000u的产物,这两种产物对DPPH自由基清除率分别达80%和72%,对四种菌的最低抑制浓度达25～75mg/mL。大于5000u的美拉德产物在较低浓度下清除率达90%,对四种菌的最低抑制浓度为6.25～25mg/mL,且对金黄色葡萄球菌的抑制效果最强,最低抑制浓度达6.25mg/mL。     

葡萄糖-甘氨酸美拉德反应产物对脂肪氧合酶的抑制作用研究

以葡萄糖和甘氨酸为原料制备美拉德反应产物（Glu/Gly-MRPs）,研究其对大豆脂肪氧合酶（LOX）的抑制作用以及机理。结果表明:随着反应中甘氨酸浓度、反应初始pH、反应温度和反应时间的增大,Glu/Gly-MRPs的褐变程度加深,pH下降,对LOX的抑制作用增强;当甘氨酸浓度大于0.6mol/L、反应体系初始pH高于8.0、反应温度高于110℃、反应时间长于3h时,MRPs对LOX的抑制率均趋于稳定值（80%¹00%）。Glu/Gly-MRPs对LOX酶促反应的迟滞时间具有延长作用,通过Lineweaver-Burk双倒数法确定Glu/Gly-MRPs对LOX的抑制类型为混合型抑制。      

Effect of Maillard reaction products on oxidation products in ground chicken breast

Three amino acid-sugar solutions were adjusted to pH 8.0, heated and lyophilized prior to addition to ground chicken breast (GCB). GCB with no additives, GCB with 0.01% BHT, GCB with 0.1 or 0.2 mg/g glucose heated with arginine, valine, or histidine were prepared. Thiobarbituric acid reactive substances (TBARS), volatiles determined by gas chromatography, and Hunter L*, a* and b* values were monitored over nine days. Multiple linear regression models were used to determine the effects of the studied factors on the corresponding outcome variables. a* values of GCB ranged from 1.60 to 4.90 over nine days of storage. While Maillard reaction products (MRP) lowered oxidation compared to control, no significant difference in TBARS between MRP solutions heated for 8 or 24 h was found. Further, 0.1 mg/g heated glucose-valine mixture decreased aldehydes up to 72.87%. Therefore, shelf-life of GCB could be extended using 0.1 or 0.2 mg/g MRP.     

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.     

Inhibition of enzymatic browning in actual food systems by the Maillard reaction products

BACKGROUND: The Maillard reaction occurring between amino acids and sugars produces neo‐formed compounds having certain levels of antioxidant activity depending on the reaction conditions and the type of reactants. The objective of this study was to investigate enzymatic browning inhibition capacity of Maillard reaction products (MRPs) formed from different amino acids including arginine (Arg), histidine (His), lysine (Lys) and proline (Pro). RESULTS: The inhibitory effects of the MRPs on polyphenol oxidase (PPO) were determined. The total antioxidant capacity (TAC) of MRPs derived from different amino acids were in the order Arg > His > Lys > Pro. The TAC and PPO inhibition of MRPs were evaluated as a function of temperature (80–120 °C), time (1–6 h) and pH (2–12). Arg‐Glc and His‐Glc MRPs exhibited strong TAC and PPO inhibition. Increasing temperature (up to 100 °C) and time also increased TAC and PPO inhibition. Kinetics analysis indicated a mixed type inhibition of PPO by MRPs. CONCLUSION: The results indicate that the MRPs derived from Arg and His under certain reaction conditions significantly prevent enzymatic browning in actual food systems. The intermediate compounds capable of preventing enzymatic browning are reductones and dehydroreductones, as confirmed by liquid chromatographic–mass spectrometric analyses. Copyright © 2010 Society of Chemical Industry     

Disappearance of Maillard reaction products during ensilage and rumen fermentation in vitro

The disappearance of Maillard reaction products (MRPs) during ensilage and rumen fermentation was studied. MRPs were prepared by heating mixtures of D ‐glucose and glycine (GG) or D ‐xylose and glycine (XG); lyophilised powder (MW > 1000) was subjected to anaerobic incubation for 24 h with lucerne juice or buffered rumen fluid. Changes in MRPs were assessed by comparing gel filtration profiles before and after incubation, and the proportion of disappeared MRPs was calculated based on the area under the curve. A portion of MRPs, particularly high‐MW fractions, disappeared when incubated with lucerne juice, and the extent was greater (P < 0.01) in XG than in GG. The disappearance of GG was increased (P < 0.01) when ensilage was fortified with added glucose, while that of XG was unaffected with or without the fermentable substrate. Rumen fermentation had little impact on GG and XG, whereas a portion of MRPs disappeared when microbial activity was enhanced by adding lucerne hay to the media. Volatile fatty acid production was unaffected by MRPs in either ensilage or rumen fermentation. These results suggest that the effect on MRPs of anaerobic fermentation may be different between ensilage and rumen digestion. Significant amounts of MRPs would enter the intestine when ruminants are fed hay‐based diets rather than silage‐based diets. © 2000 Society of Chemical Industry     

乳制品中的Maillard反应标示物及其应用

乳制品中的Maillard反应标示物既可作为乳制品热处理程度的指标，还可用于不同热处理乳制品的鉴别。介绍了在评价乳制品热处理程度以及区分不同乳制品中常用的几种Maillard反应标示物。这些标示物包括糠氨酸、乳果糖、糠醛类化合物、荧光化合物等。此外，还介绍了可溶性乳清蛋白、碱性磷酸酶和乳过氧化物酶等热处理标示物，这些标示物与Maillard反应之间具有较好的相关性，也是评价乳制品热处理程度以及区分不同乳制品时常用的指标，可与Maillard反应标示物联合应用。     

美拉德反应产物的抗突变作用

美拉德反应是食品制备、加工和贮存过程中发生的非酶褐变反应，褐变的发生对产品质量有很大影响，从食品卫生学的角度来看，有些产物对人体健康有极大的危害。本文讨论的是美拉德反应产物有益的一面，即其抗突变的效果。     

2种氨基酸与葡萄糖美拉德反应产物的抗氧化活性研究

以对DPPH自由基（DPPH·）的清除能力为抗氧化指标,研究脯氨酸、L-精氨酸分别与葡萄糖在不同反应条件下微波加热美拉德反应产物的抗氧化活性。探究了加热时间、微波功率、pH、氨基与羰基比4个因素对美拉德反应产物抗氧化性的影响,并通过正交实验得到最佳工艺条件。脯氨酸为:加热时间5min,微波功率800W,pH5,氨基与羰基比1∶2.5,对DPPH·清除率为98.94%。L-精氨酸为:加热时间5min,微波功率800W,pH8,氨基与羰基比为2∶1,对DPPH·清除率为96.81%。4个因素对美拉德反应产物的DPPH·清除率的影响均极显著。      

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。