News on the Maillard reaction of oligomeric carbohydrates: a survey

The reaction behaviour of monosaccharides in the Maillard reaction is well investigated. Amadori compounds, for instance, form deoxyhexosuloses which are responsible for the formation of volatile flavour substances and melanoidins. These intermediates can be quantified by a trapping reaction with o‐phenylendiamine as stable quinoxalines. However the reaction behaviour of oligo and polymeric carbohydrates in non‐enzymatic browning reactions are hardly known. Therefore maltooligosaccharides and in some cases starch were used together with glycine as model substances to investigate the Maillard reaction mechanism of oligo and polysaccharides. In quasi waterfree reaction systems oligosaccharides form α‐dicarbonyl compounds via a “peeling off” mechanism. The Maillardreaction with the amino compound starts at the reducing end of an α‐glucane residue and results in the formation of 1,4‐dideoxyhexosulose. This is the main α‐dicarbonyl compound found by trapping reaction with o‐phenylendiamine during thermally induced degradation of maltooligosaccharides. The thermal reaction of maltooligosaccharides is accompanied by transglycosylations leading to formation of branched carbohydrate structures and by dehydrations forming anhydrosugars. The reaction mechanism which is responsible for degradation of oligomeric carbohydrates in aqueous model systems differs significantly from pathways mentioned above for water free reaction conditions. As the main α‐dicarbonyl compound 3‐deoxypentosulose is formed which can be proved also by trapping reactions. Under aqueous reaction conditions the formation of other α‐dicarbonyls plays only a marginal role in the Maillard reaction of oligomeric carbohydrates. In an aqueous system transglycosylation and dehydration of maltooligosaccharides are not important.     

Kinetic aspects of the Maillard reaction: a critical review.

The literature concerning the kinetics of the Maillard reaction was critically discussed according to the initial, intermediate and advanced stages, as this is the way the Maillard reaction is traditionally analysed. For each stage, a division is made between simple kinetics and complex kinetics. Simple kinetics means that the general rate law is used and results are reported as zero-, first- or second-order reactions (sometimes a fractional order). It is emphasized that this approach for a complex reaction as the Maillard reaction only results in a mathematical fit procedure, not in mechanistic insight. The rate constants and activation energies derived are in fact composed of several elementary rate constants. With complex kinetics, i.e. trying to establish the kinetics for individual reaction steps, more mechanistic information can be extracted. However, there are conflicting results in literature and the interpretation is not always correct, as is shown in several examples. A summary of activation energies reported for the various stages in the Maillard reaction reveals large discrepancies, probably reflecting strong effects of experimental conditions on results that are obtained. Careful control of experimental conditions and proper kinetic analysis of the various stages in the Maillard reaction should lead to more consistent results in the future.     

简述美拉德(Maillard)反应

简述了美拉德反应的机理及影响因素,总结了MRPs的抗氧化性、与突变的关系及其在食品上的作用,最后说明了美拉德反应进度的判断依据。     

Kinetic aspects of the Maillard reaction: a critical review

The literature concerning the kinetics of the Maillard reaction was critically discussed according to the initial, intermediate and advanced stages, as this is the way the Maillard reaction is traditionally analysed. For each stage, a division is made between simple kinetics and complex kinetics. Simple kinetics means that the general rate law is used and results are reported as zero‐, first‐ or second‐order reactions (sometimes a fractional order). It is emphasized that this approach for a complex reaction as the Maillard reaction only results in a mathematical fit procedure, not in mechanistic insight. The rate constants and activation energies derived are in fact composed of several elementary rate constants. With complex kinetics, i.e. trying to establish the kinetics for individual reaction steps, more mechanistic information can be extracted. However, there are conflicting results in literature and the interpretation is not always correct, as is shown in several examples. A summary of activation energies reported for the various stages in the Maillard reaction reveals large discrepancies, probably reflecting strong effects of experimental conditions on results that are obtained. Careful control of experimental conditions and proper kinetic analysis of the various stages in the Maillard reaction should lead to more consistent results in the future.     

美拉德反应研究进展

美拉德反应(Maillard Reaction)是指氨基化合物和羰基化合物之间的一类化学反应,此类反应常存在于食品加工、烟草研制、中药炮制、疾病生理以及饲料制备和酒业酿造等过程中。近年来,Maillard反应的研究主要集中在中药现代化和疾病生理等方面,尤其关注抗氧化产物以及甲基糠醛和丙烯酰胺等与人类健康密切相关方面的研究。拟对Maillard反应研究进展做一简要综述,并在此基础上对Maillard反应在各领域中的前景作一展望,为Maillard反应各类研究及应用提供一定的参考。     

Kinetic study on the Maillard reaction. Consideration of sugar reactivity

The aim of the present study was to compare five reducing sugars (ribose, xylose, arabinose, glucose and fructose) with respect to their relative reactivity in the Maillard reaction (MR) (55 °C, pH 6.5) with a shrimp hydrolysate. For each system, the extent of the MR was assessed for a 24-h period by monitoring browning intensity, free amino group disappearance and sugar consumption. Results revealed the prevailing propensity of pentoses over hexoses to react in the MR, with a distinguishable behaviour for the ribose-hydrolysate system. Interestingly, pentoses were shown to mainly differ in terms of reaction rate. Complementary data on the chemical composition of the MR products (MRPs) were provided by size-exclusion chromatography, thus demonstrating the occurrence of some molecular rearrangements detected at 294 nm. The modification of protein substrates through the MR could represent a key step in the formation of new molecules and constitute a promising means to produce high value-added ingredients with biological and techno-functional properties.     

抗氧化剂对美拉德反应的影响

采用葡萄糖分别与天冬酰胺和甘氨酸在160℃下反应建立美拉德反应的模拟体系,通过HPLC分析和褐变程度的测定,探讨了4种抗氧化剂BHA、BHT、TBHQ、Vc对美拉德反应的影响。结果表明,添加抗氧化剂对其HPLC色谱峰的出峰数、峰面积都有较大影响。相同条件下,添加抗氧化剂对甘氨酸-葡萄糖体系影响较大。     

脂类对反应型香精风味形成影响的研究

根据3种不同原料所含主要脂肪酸及不饱和度的不同,通过反应所生成主要风味物质差异来进一步探讨反应型香精风味形成机理。     

Maillard反应对卵白蛋白稳定性的影响

为了确定Maillard反应对卵白蛋白稳定性的影响,本文研究了Maillard反应卵白蛋白处于酶解、酸性环境、加热、变性剂、反复冻融等不利条件下的理化特点。结果表明Maillard反应抑制了蛋白酶对卵白蛋白的酶解效果。Maillard反应卵白蛋白在p H2⁷的范围内,空间结构伸展程度较小。Maillard反应将卵白蛋白的变性温度从71.3℃提高到76.9℃,明显改善了卵白蛋白的热稳定性。6mol·L-1的尿素能够使热处理卵白蛋白和天然态卵白蛋白完全变性,而只能使Maillard反应卵白蛋白部分变性。Maillard反应能够提高卵白蛋白的溶解度,其溶解度经过反复冻融后仍处于较高水平。Maillard反应可以有效提高卵白蛋白稳定性,从而保证卵白蛋白功能性的发挥。      

Maillard反应对卵白蛋白稳定性的影响

为了确定Maillard反应对卵白蛋白稳定性的影响,本文研究了Maillard反应卵白蛋白处于酶解、酸性环境、加热、变性剂、反复冻融等不利条件下的理化特点。结果表明Maillard反应抑制了蛋白酶对卵白蛋白的酶解效果。Maillard反应卵白蛋白在p H2~7的范围内,空间结构伸展程度较小。Maillard反应将卵白蛋白的变性温度从71.3℃提高到76.9℃,明显改善了卵白蛋白的热稳定性。6mol·L-1的尿素能够使热处理卵白蛋白和天然态卵白蛋白完全变性,而只能使Maillard反应卵白蛋白部分变性。Maillard反应能够提高卵白蛋白的溶解度,其溶解度经过反复冻融后仍处于较高水平。Maillard反应可以有效提高卵白蛋白稳定性,从而保证卵白蛋白功能性的发挥。     

Creating proteins with novel functionality via the Maillard reaction: a review

Proteins are widely utilized to add functional properties, such as gelling and emulsification to foods. These attributes depend on a number of factors such as molecular structure of the protein, the pH, and the composition of its chemical environment. There is substantial evidence to suggest that the functional properties of food proteins can be further improved by derivatization. Covalent bonding of proteins to polysaccharides and smaller reducing sugars via the Maillard reaction has been shown to alter the functionality of proteins without requiring the addition of chemical reagents. Establishment of a technologically feasible method for preparing the conjugates and optimization of the processing conditions, however, is needed to promote their development as functional food ingredients. This paper provides a state-of-the-art contribution to the impact of the Maillard reaction on protein functionality. It presents a deeper understanding of the influence of processing conditions and reactant formulation on improving desirable properties of proteins. In particular attention is given to how potential improvements could be achieved in the emulsifying, textural, and solubility properties of proteins to add value to commodity food ingredients. Elements that are considered to be critical to the design of functional Maillard conjugates are highlighted and suggestions proposed to facilitate progress in this area.     

影响蒜氨酸美拉德反应速度的因素

为了解蒜氨酸美拉德(Maillard)反应对大蒜加工品质量和风味的影响,使合成蒜氨酸、果糖、葡萄糖在80～120℃,pH5～10条件下反应1～1.5h,通过感观评价和测定反应物的吸光度,评价Maillard反应效果。结果表明:在80～120℃、pH5～10、含水量10%条件下反应2.5h时,Maillard反应达到最大值,反应产物具有明显的大蒜辛辣味,反应物颜色为红棕色(与果糖反应)或桔红色(与葡萄糖反应)。这些结果对于控制大蒜加工品的质量与风味有参考价值。     

不同反应条件下的Maillard反应产物对卷烟燃吸品质的影响研究

制备了在不同反应条件下混合氨基酸和葡萄糖的Maillard反应产物,并把它们加入空白烟丝中进行详细的感观评价,在该反应体系中,反应温度为105℃左右,pH为10左右,反应时间5 h左右条件下的MaiⅡard反应产物对卷烟加香效果较好.     

不同因素对牡蛎酶解液美拉德反应产物的影响

该文研究不同反应因素对牡蛎酶解液美拉德反应产物(Maillard reaction produncts,MRPs)的影响,制备具有肉香味的天然牡蛎调味液。通过以牡蛎酶解液与葡萄糖建立美拉德反应体系,以感官评分、褐变程度和中间产物为指标,通过单因素试验和正交试验研究L-半胱氨酸盐(L-Cystine,L-Cys)质量分数、硫胺素(Vitamin B_1,V_(B_1))质量分数、体系初始p H及反应时间4个因素对MRPs的影响,优化得到美拉德反应的最佳工艺条件。结果表明,美拉德反应的最佳工艺条件为:L-Cys质量分数0. 15%、V_(B_1)质量分数0. 50%、体系初始pH 8. 0、反应时间130 min。在此最优组合条件下,MRPs的感官评分为4. 67,A_(420)为0. 672,A_(294)为0. 853,具有良好的肉香味。美拉德反应可以有效改善牡蛎酶解产物的风味,在新型牡蛎调味品的开发中具有良好的应用前景。     

Effects of drying processing on the Maillard reaction in pasta

The effect of low, high and very high drying temperatures on the development of the Maillard reaction in pasta was studied. In particular, an investigation was carried out into the influence of the different temperatures used on the development of colour, the formation of furosine and the changes in the chain breaking activity of pasta samples having different moisture contents as well as on the adsorption and desorption isotherms. Results showed that, depending on temperature, time and moisture conditions, pasta had antioxidant or pro-oxidant properties. The increase in the antioxidant potential was always associated with an increase in brown colour, while the pro-oxidant properties were observed in the early stages of the Maillard reaction.     

Mailard反应制备鱼味香精生产工艺的研究

本文以鳙鱼为原料,利用Mailard反应制备鱼味香精,文章较系统地研究了Mailard反应过程中温度、pH值、时间以及酶解液浓度对鱼味香精感官品质的影响。通过试验可知:反应温度、pH值、反应时间以及酶解液浓度均显著地影响鱼味香精感官品质(P≤0.05),其最佳反应条件为:温度115℃,反应pH值7.5,时间40 min,酶解液浓度为40%。     

食品中的美拉德反应及其影响

探讨了食品中发生的美拉德反应途径、底物、温度、水分活度、pH和金属离子等影响因素,同时讨论了抗茵性、抗氧化性和乳化性等食品功能性以及蛋白质的糖基化、溶解性和风味特性的修饰改进,并介绍了其时生物活性体的影响性以及丙烯酰胺等有害物质的生成与消除,丰富了食品化学理论并对食品加工生产应用有很好的指导意义.     

Control of the Maillard reaction by ferulic acid

This study investigated how ferulic acid (FA) affects the formation of certain Maillard reaction products (MRPs), i.e., early MRPs, fluorescent and non-fluorescent advanced glycation end products (AGEs), and melanoidins in model systems. Glycation mixtures were prepared containing soy glycinin or bovine serum albumin (final concentration 10 mg/ml) and fructose (222 mM) in 0.2% KOH in the presence or absence of FA (12.95 mM) and incubated at 60 °C for 60 min. The extent of the MR was estimated by analysis of free amino groups, the incorporation of sugar into the protein backbone as well as the formation of N^?-(carboxymethyl)lysine (CML), fluorescent AGEs (λ_exc = 337 nm, λ_em = 350–550 nm) and melanoidins (absorbance at 420 nm). Formation of CML and fluorescent AGEs was reduced by nearly 90% by the addition of FA while early MRPs and melanoidins were inhibited to a lesser extent (∼10% and 28%, respectively) compared to AGE formation. A controlled formation of early MRPs was achieved by use of FA, and it is a new finding. To the best of our knowledge, for the first time the use of FA as a reliable means of obtaining novel glycoprotein preparations containing low amounts of AGEs, with the potential to be used as functional food ingredients, is proposed.     

美拉德反应法制备鸡肉味香精

实验是利用鸡骨架酶解液为原料,通过美拉德反应制备鸡肉味香精。探讨了还原糖的添加量,反应温度,反应时间,pH值等因素对鸡肉香精热反应体系的影响,并得到制备鸡肉味香精的各因素最佳水平组合,即当木糖添加量为2.5%,反应pH为8,反应温度为120℃,反应时间为25 min时的美拉德反应产物具有优良的鸡肉香精风味。     

Characterization of the Maillard reaction in bread crisps

Maillard reaction (MR) is one of the main chemical event occurring during baking. To study the reaction in bakery products, a dry model system is more useful than an aqueous one. In this work, the effects of formulation and processing conditions in a crisp bread system were investigated to test the effects of different additives on both the overall reaction and the formation of MR products such as 5-hydroxymethyl-2-furaldehyde (HMF) and acrylamide. Cylindrical dough made up of flour, water and yeast was baked at 180 °C for 35 min and the slices were toasted at different times/temperatures combinations. Browning and water content were monitored along with the kinetic of formation of chemical indicators such as HMF and acrylamide also calculating rate constants and activation energy. These parameters were also monitored in systems added with glycine and asparaginase. During toasting water content follows an exponential trend, being the rate of water loss faster in the initial stage of toasting and at higher temperature. Browning was more intense when toasting at higher temperature and a linear correlations between browning (ΔL*, ΔE*), HMF and acrylamide concentration were observed when toasting at 180 °C. HMF and acrylamide content increased with the toasting time and temperature. Their concentrations were strongly dependent on the water content of the final product, and both the addition of glycine and asparaginase are effective in reducing acrylamide content. The addition of glycine enhanced the browning of toasted bread, and slightly increased HMF content at any toasting temperature. The system characterized in this work represents a suitable tool to study the development of the MR in dry systems.