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.     

Reduction of Acrylamide Formation in Sweet Bread with l-Asparaginase Treatment

Acrylamide, 2-propenamide, has the chemical formula $ \mathrm{CH}2=\mathrm{CH}-\mathrm{CO}-\mathrm{NH}2 $ . It is produced at elevated levels in high temperature fried and baked foods. It has adverse effects on human health and is proven to be neurotoxic, genotoxic, carcinogenic, and toxic to reproductive system. The aim of this paper was to reduce acrylamide formation in bakery products such as sweet bread by enzyme treatment. l-Asparaginase produced from Cladosporium sp. was treated to wheat-based dough at different concentrations (50–300 U). There was no change in the rheological properties of wheat flour and physico-sensory characteristics of bread with l-asparaginase treatment. Moisture, sugars, l-asparagine, acrylamide, and some indicators of Millard reaction (hydroxymethylfurfural (HMF), color, browning) were estimated. With increase in l-asparaginase level the acrylamide formation was reduced. At 300 U, there was 97 % and 73 % reduction of acrylamide formation in the crust and crumb regions of bread, respectively. HMF, a common intermediate product in the Maillard reaction and a genotoxic compound via 5-sulfoxymethylfurfural, also decreased in l-asparaginase-treated bread samples. These results indicated the potential of l-asparaginase enzyme for industrial and domestic applications in reducing harmful Maillard reaction compounds.     

EFFECT OF SODIUM METABISULFITE ADDITION AND BAKING TEMPERATURE ON MAILLARD REACTION IN BREAD

ABSTRACT

In this study, the effect of sodium metabisulfite (SMBS) doses (0, 25, 50, 100 mg/kg dough) and baking temperatures (200, 230 and 250C) on the physical, chemical and sensory properties of bread were researched to reduce 5‐hydroxymethyl‐2‐furfural (HMF) and acrylamide contents. HMF and acrylamide contents of bread crust were decreased significantly by increasing SMBS dose and decreasing baking temperature. The HMF (137.29 mg/kg) and acrylamide (671.44 µg/kg) contents of bread crust were decreased by 33 and 67%, respectively by addition of 100 mg/kg SMBS. The maltol content of bread crusts were significantly affected by baking temperature, and were 7.19, 10.23 and 22.69 mg/kg in breads baked at 200, 230 and 250C, respectively. No HMF, acrylamide and maltol were detected in the bread crumb. The sulfur dioxide content of the crust and crumb of control bread was 6.99 and 10.69 mg/kg, and increased by 49 and 59%, respectively at 100 mg/kg SMBS dose. All breads were evaluated as acceptable by a sensory panel.

PRACTICAL APPLICATIONS

Since Maillard reaction products such as acrylamide and 5‐hydroxymethyl‐2‐furfural (HMF) are known as toxic compounds, mitigation of these compounds is important subject for health and nutrition. There is not an efficient method to prevent the formation of acrylamide and HMF in bread crusts comparison with potato crisps. The purpose of this research is to slow down Maillard reaction by addition of sodium metabisulfite in bread‐making process. As a result of this research, acrylamide and HMF content of bread crusts decreased by 33 and 67%, respectively with acceptable sensory evaluation.     

Acrylamide and 5-hydroxymethylfurfural (HMF): A review on metabolism, toxicity, occurrence in food and mitigation strategies

Neo-formed contaminants (NFCs) are compounds forming during heating or preservation processes and exhibiting possible harmful effects to humans. Among the several NFCs described in literature, Acrylamide and 5-hydroxymethylfurfural (HMF) have attracted the attention of the scientific community in recent years. Both acrylamide and HMF are considered as probably or potentially carcinogenic to humans or might be metabolized by humans to potentially carcinogenic compounds. Acrylamide and HMF are mainly formed through Maillard Reaction and can be regarded as the most important heat-induced contaminants occurring in bread and bakery products. Acrylamide is carcinogen in rodent and some recent epidemiological studies have highlighted the association between dietary acrylamide and an increased risk of some types of cancer. HMF has been recently shown to be converted in vivo to 5-sulfoxymethylfurfural (SMF) which is a genotoxic compound. Dietary intake of HMF is in the order of mg/kg far above that of other food toxicants. In this paper, the latest available data on acrylamide and HMF have been reviewed focusing on available mitigation strategies, metabolism, dietary exposure, and toxicity. The results from the epidemiological studies about acrylamide and cancer risk and their relevance have been discussed, the major gaps of knowledge have been identified and the perspective of ongoing and future research was established.     

Effect of amino acids on Maillard reaction product formation and total antioxidant capacity in white pan bread

Maillard reaction products (MRPs) can be an important dietary antioxidant source. Bread is the most popular bakery product; however, limited information is available on the antioxidant activities of MRPs generated during bread-baking. This paper reports the effect of different amino acids on bread properties, melanoidin formation and antioxidant activities. Totally six amino acids at four different levels were evaluated. Increasing the amount of amino acid led to darker bread crust, higher melanoidin content and stronger antioxidant activity. Among the six amino acids, bread with glycine had the highest melanoidin content and ABTS radical scavenging activity up to 1079.77 ± 8.43 μmol TE mg⁻¹. Bread with lysine had the highest DPPH radical scavenging activity up to 281.97 ± 10.52 μmol TE mg⁻¹. Bread with alanine had the highest crust metal chelating activity compared with others. Adding certain dietary amino acids is a potential approach to enhance the antioxidant capacity of bread products.     

美拉德反应过程中7种豆粉对丙烯酰胺和羟甲基糠醛形成的影响

丙烯酰胺和羟甲基糠醛是高温加工食品中产生的两种内源污染物。本文研究了7种豆类（黑豆、鹰嘴豆、绿豌豆、小扁豆、绿豆、黄豌豆和黄豆）的豆粉对天冬酰胺/葡萄糖反应体系中丙烯酰胺和羟甲基糠醛（HMF）形成的影响,以其为两者的控制提供参考。结果表明：采用全豆粉试验时,有5个品种的豆粉抑制丙烯酰胺（抑制率10.3~55%）形成,但都促进HMF的产生;去皮脱脂后的豆粉更能抑制丙烯酰胺形成。有趣的是,其中4个品种的豆皮也能抑制丙烯酰胺的产生。进一步研究发现,有5个品种的脱脂豆粉能消除已形成的丙烯酰胺,消除率为5.9%（绿豆粉）至28.5%（大豆粉）。通过统计本研究的39种处理发现,丙烯酰胺与HMF的形成量呈现负相关。     

Browning development in bakery products – A review

This paper presents a review regarding several aspects of the development of browning during baking of bakery products, mainly from an engineering point of view. During baking, the formation of colour is due to the Maillard reaction, and caramelization of sugars. Besides the major influence of this phenomenon on the initial acceptance of products by consumers, it is the responsible for other relevant changes occurring in food during baking, i.e. production of flavour and aroma compounds, formation of toxic products (e.g. acrylamide), and decrease of nutritional value of proteins. As well as baking, the development of browning in bakery products is a simultaneous heat and mass transfer process that occurs mostly in a non-ideal system under non-ideal conditions. In addition, the mechanisms of chemical reactions involved are still not elucidated completely, so the process is difficult to control and represents a major challenge for food engineers. Effects of browning on properties of products and experimental, modelling and technological aspects of colour formation during baking are reviewed.     

Investigating 5-hydroxymethylfurfural formation kinetic and antioxidant activity in heat treated honey from different floral sources

The quality and biochemical properties of honey are affected by heating or during storage period. The most important biochemical reaction that occurs in this process is the Maillard reaction. HMF (5-hydroxymethylfurfural) is one of the major intermediate products in the Maillard reaction that can lead to quality reduction in heated honey. In this study, the effect of heating on the antioxidant activity, and colour values as Maillard reaction indicators of three different botanical honeys were investigated; the HMF formation was also determined. Temperatures of 50, 70 and 80 °C were applied on the honeys between 0 and 48 h. Total phenolic content, ferric reducing/antioxidant power and scavenging of 2,2-diphenyl-1-picrylhydrazyl free radical assays are used to determine the antioxidant capacity. Results showed that the formation of HMF and the antioxidant properties of honeys were significantly increased during the heating process. Pure HMF compound also showed lower antioxidant activity. The formation of HMF has higher degree of linearity in the fit of the zero order reaction and also it was the highest in the chestnut honey. Furthermore, it was found that as the biochemical value of the honeys increased, the HMF formation decelerated.     

The Inhibition of Maillard Browning by Different Concentrations of Rosmarinic Acid and Epigallocatechin‐3‐Gallate in Model,Bakery, and Fruit Systems

Rosmarinic acid and Epigallocatechin gallate concentrations were studied as natural inhibitors of Maillard browning in glucose/glycine model systems, and in bakery rolls and applesauce. The concentrations of the inhibitors were varied to determine the highest level of inhibition without a pro‐oxidant/browning effect. UV absorbance and gas chromatography/mass spec (GC/MS) with solid phase microextraction (SPME) sampling was used to study browning in the model systems. Hunter L*, a*, b* was used to analyze the color change results of the inhibitors on applesauce and bakery rolls. It was determined that a 1.0% solution of either antioxidant in the glucose/glycine system produced the greatest inhibition and a synergistic effect was not apparent when the two were combined. Inhibition of browning and a lack of synergy between the antioxidants were also determined in food systems consisting of applesauce and bakery rolls. GC/MS analysis of the model system revealed a high level of pyrazine formation in no‐inhibitor control samples and the absence of pyrazines in inhibitor‐containing samples.     

超声促进美拉德反应对金带细鲹鱼肉蛋白酶解物的修饰及潜在危害物形成的影响

本文采用超声波法促进金带细鲹鱼肉蛋白酶解物与葡萄糖间的美拉德修饰反应,研究美拉德反应对酶解物功能特性、抗氧化性及潜在危害物形成的影响。结果表明:超声功率或反应时间越高,修饰产物中游离氨基含量越低,接枝度越大,超声处理能加快美拉德反应的速率,且减少丙烯酰胺等美拉德反应潜在危害物的形成。功能特性分析表明,超声处理能显著提高酶解物的溶解性和乳化性(p0.05),同时,体外模拟消化分析表明,超声处理降低了酶解物的消化性。修饰产物的DPPH自由基清除力、羟自由基清除力、还原力和Fe~(2+)螯合力显著提高(p0.05),而且超声修饰的能力和修饰物的特性均优于水浴法处理组。超声波促进美拉德修饰反应可提高金带细鲹鱼肉蛋白酶解物的功能特性和抗氧化活性,并减少丙烯酰胺等美拉德反应潜在危害物的形成。     

甘氨酸和淀粉膜对面包中丙烯酰胺的协同控制作用

研究面包配料中添加甘氨酸和在面团表面涂刷淀粉膜对面包表皮中丙烯酰胺的协同控制作用。甘氨酸对丙烯酰胺的抑制效果非常显著,当甘氨酸的添加量为面粉的0.1%时,对丙烯酰胺的抑制率达到80.5%;当甘氨酸添加量为面粉的3%时,能将丙烯酰胺含量减少到检测限（＜1?μg/kg）以下。在对面团进行焙烤前,将面团表面涂刷不同的淀粉膜,能够抑制面包中的丙烯酰胺20%以上;抑制效果由高到低分别为：混合淀粉膜＞马铃薯淀粉膜＞玉米淀粉膜。将两种方法结合,甘氨酸在低添加量（0.1%）时结合玉米淀粉膜,对丙烯酰胺的抑制率增加到85.1%,同时还能较好地保持面包的外观颜色。甘氨酸与天冬酰胺竞争底物和淀粉膜中限制性前体物质天冬酰胺的大量减少,是面包中丙烯酰胺的生成量显著降低的主要原因。     

加工方式对外施天然抗氧化剂面制品抗氧化能力的影响

本文研究了发酵+焙烤、发酵+蒸制、直接焙烤3种烘焙方式对添加天然抗氧化剂面制品的抗氧化能力的影响。通过在面食中添加5种天然抗氧化剂(大豆异黄酮、茶多酚、花青素、植酸、V_C/V_E),测定面食制品在加工前后的丙酮提取液对各种自由基的清除率,通过变异系数法全面评价面制品的抗氧化能力。结果表明:加工方式和添加的抗氧化剂种类是影响小麦面制品抗氧化能力的重要原因。添加大豆异黄酮的面制品用于直接焙烤能提高抗氧化性能的3.85%,添加茶多酚的面制品用于直接焙烤时抗氧化损失率最低为-3.39%,添加花青素的面制品应用于发酵+焙烤可以更好地保留其抗氧化活性,损失率为-1.77%,添加植酸和V_C/V_E的面制品应用于发酵+蒸制可以更好地保留其抗氧化能力,损失率分别为-4.66%、-5.14%。在天然抗氧化剂作为面制品添加剂时,针对不同的抗氧化剂选择最适的加工方式,能够在一定程度上改善面制品的抗氧化能力。     

Acrylamide formation in a cookie system as influenced by the oil phenol profile and degree of oxidation

The purpose of this study was to investigate the effect of the olive oil phenolic compounds as well as of thermoxidised oil on the formation of acrylamide in a cookies system. Three virgin olive oils having different phenolic profile and a thermoxidised sunflower oil were selected. Cookies were baked at 190 °C for different times (8–16 min) following a basic recipe where type of oil was the variable. Additionally to acrylamide (AA), other parameters such as colour, moisture, antioxidant activity (AOA), and hydroxymethylfurfural (HMF) were measured. Results showed that concentration and composition of phenolic moiety of virgin olive oil significantly affect the acrylamide formation, particularly at prolonged baking time. Virgin olive oil with a higher dihydroxy/monohydroxy ratio was more efficient in the AA mitigation and AA was reduced up to 20%. Colour and AOA were not significantly different among the three types of oils. However, AA is dramatically increased when thermoxidised oil is used with a parallel increase of browning and HMF. It was concluded that lipid oxidation products should be considered as an important factor in acrylamide formation during baking of fat-rich products.     

Nonenzymatic browning reactions of retro-aldol degradation products of carbohydrates

 Methylglyoxal and glyceraldehyde were used to demonstrate the involvement of retro-aldol degradation products of carbohydrates in browning (A ₄₂₀), the formation of hydroxymethylfurfural (HMF), and the extent to which the mechanism of browning proceeds by homolytic or heterolytic pathways in the caramelization and Maillard reactions of mono- and disaccharides. The amino component of Maillard systems is required for the retro-aldol cleavage of D-glucose. The short-chain α-dicarbonyl compounds so formed appear to dominate not only the formation of brown products but also the mechanism of the browning of D-glucose under these conditions, even if only small amounts are formed. Evidence is presented to link the formation of free radicals in the browning of glucose to reactions of the retro-aldol products. A novel reaction pathway is suggested for the formation of HMF from glyceraldehyde. Received: 9 October 1998 / Revised version: 15 December 1998     

不同模式体系美拉德反应程度及抗氧化活性比较

以葡萄糖、果糖、蛋氨酸、甘氨酸、精氨酸和大豆分离蛋白为美拉德反应原料,研究加热时间和混合比例对褐变程度的影响,并对褐变程度最强的产物进行抗氧化活性检测。结果表明：葡萄糖、果糖分别与甘氨酸按物质的量之比2:1混合(pH9.0),并于100℃恒温水浴锅中加热180min时褐变程度最强。葡萄糖-甘氨酸与果糖-甘氨酸模式体系的美拉德反应物都具有一定的抗氧化能力。在相同体积分数条件下,果糖-甘氨酸模式体系的美拉德反应物的还原能力和抗氧化值均要强于葡萄糖-甘氨酸模式体系的美拉德反应物。葡萄糖-甘氨酸模式体系的美拉德反应物对 ·OH和O2 ·的抑制率最高分别达50.65%和45.42%,而果糖-甘氨酸模式体系的美拉德反应物对 ·OH和O2 ·的抑制率最高则分别达57.55%和28.54%。     

EFFECT OF SUGARS AND MAILLARD REACTION PRODUCTS ON POLYPHENOL OXIDASE AND PEROXIDASE ACTIVITY IN FOOD

The effect of glucose, fructose and sucrose aqueous solutions on polyphenol oxidase (PPO) and peroxidase (POD) activity was studied. Solutions with high concentrations of sugars showed a slight inhibiting effect on PPO while an activation was observed for POD. Glucose solutions, tested after sufficient heat treatments, showed an inhibiting action only on PPO activity. Maillard reaction products, obtained by heating a glucose/glycine solution, caused an unexpectedly strong inhibiting effect on both enzymes. The inhibition became more evident with increasing heating times of the glucose/glycine solution, reducing the activity of PPO and POD nearly to zero. Thus, the Maillard reaction products, already known for their antioxidant properties, were also shown to have a strong inhibiting effect on enzymatic browning.     

低分子添加剂法抑制焙烤食品中丙烯酰胺的研究现状

丙烯酰胺属于对人可能致癌物质,其主要产生于食品加工过程中的Maillard反应。目前,关于丙烯酰胺的研究主要集中于油炸食品,但关于焙烤食品如面包、饼干、蛋糕等方面的研究较少,而且由于工艺的不同,油炸食品中可行的方法并不能直接应用于焙烤食品。使用低分子添加剂是目前较为新兴的抑制丙烯酰胺的方法,其在油炸食品及焙烤食品中均具有良好的效果,且对产品风味的影响较小。本文总结了近些年学者们通过使用低分子添加剂降低焙烤食品中丙烯酰胺含量的实践及研究。     

Effect of Flour Extraction Rate and Baking on Thiamine and Riboflavin Content and Antioxidant Capacity of Traditional Rye Bread

ABSTRACT:  The effect of rye flour extraction rates and baking on thiamine and riboflavin content, and antioxidant capacity of traditional rye bread were studied and compared with white wheat flour. The content of thiamine was higher (10.9%) in rye dough formulated with dark rye flour (F-100%; extraction rate of 100%) than in rye dough formulated with brown rye flour (F-92%; extraction rate of 92%) that was similar to dough made with wheat flour. The riboflavin content in rye dough made from flour F-100% was also higher (16%) than in dough formulated with flour F-92%, and both provided larger riboflavin content than wheat dough. Baking led to reductions in thiamine of 56% for wheat bread and of 20% for both rye breads; however, this process caused only a 10% decrease in riboflavin for wheat bread and a 30% decrease for rye breads. Trolox equivalent antioxidant capacity, peroxyl radical scavenging capacity, DPPH radical scavenging activity, and Folin–Ciocalteu reducing capacity were higher in rye than in wheat dough and bread. Baking process produced slight changes in antioxidant activity, except for Superoxide Dismutase-like activity where a sharp decrease was observed. Our findings showed that rye breads are an important source of B vitamins and rye breads formulated with dark and brown flours showed better antioxidant properties than wheat bread. Therefore, rye breads should be more widely recommended in human nutrition.     

焙烤食品中生成丙烯酰胺的影响因素

人类可能致癌物丙烯酰胺在富含碳水化合物的热加工食品中含量较高。本文结合近年来的研究结果.综合分析了影响焙烤食品中丙烯酰胺形成的因素(前体物质、水分、酸碱环境、油脂氧化、阳离子、抗氧化剂和加工工艺)。并探索将糠氨酸和羟甲基糠醛作为预洲焙烤食品中丙烯酰胺含量的指示物。     

Fiber from fruit pomace: A review of applications in cereal-based products

Fruit pomace is a by-product of the fruit processing industry composed of cell wall compounds, stems, and seeds of the fruit; after washing, drying, and milling, a material high in fiber and bioactive compounds is obtained. In bakery products, dried fruit pomace can be added to replace flour, sugar, or fat and thus reduce energy load while enhancing fiber and antioxidant contents. The high fiber content of fruit pomace, however, results in techno-functional interactions that affect physicochemical and sensory properties. In this article, different sources of fruit pomace are discussed along with their application in bread, brittle and soft bakery products, and extrudates.