食品中丙烯酰胺与5-羟甲基糠醛的研究进展

食品热加工过程生成的丙烯酰胺与5-羟甲基糠醛严重影响人们的身体健康。研究这两种物质的毒性、形成机理以及抑制方法,有助于合理控制热加工工艺,改善热加工食品的安全性,开发新的抑制方法。本文评述了丙烯酰胺与5-羟甲基糠醛的毒性、形成机理、检测及抑制方法,总结了目前抑制方法存在的问题,提出未来将朝着能同时抑制多种潜在毒性的美拉德反应产物的可能途径发展。     

食品中5-羟甲基糠醛的形成与控制

5-羟甲基糠醛(5-hydroxymethylfurfural,HMF)是食品热加工和贮藏过程中产生的内源性污染物,主要通过美拉德反应和己糖在酸性条件下脱水产生,其形成过程受反应底物种类、加热温度、反应体系p H、水分活度及金属离子等影响。HMF具有一定神经毒性、遗传毒性;摄入后在磺基转移酶作用下可转化为具有致癌毒性的羟甲基糠醛次硫酸,因而近年来HMF受到了国内外的广泛关注。本文综述了HMF形成的途径、影响因素和控制措施。     

美拉德反应中间体2,3-二氢-3,5-二羟基-6-甲基-4(H)吡喃-4-酮的研究进展

2,3-二氢-3,5-二羟基-6-甲基-4(H)吡喃-4-酮(2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, DDMP),是美拉德反应关键中间体之一,在美拉德反应产物调控中起到重要作用。DDMP属于烯醇酮类化合物,广泛存在于天然尤其是热加工食品,具有抗氧化、抗菌、心脏保护等作用。当前,随着对食品安全、风味和活性功能关注度的不断提升,学者对DDMP进行了广泛而深入的研究。该文基于近年来相关文献,对DDMP的存在、形成及降解、生物活性及感官特性等方面的研究进展进行全面系统的总结,旨在为DDMP在食品、医药、香料领域的基础和应用研究提供参考。     

食品中糠醛和5-羟甲基糠醛的产生机理、含量检测及安全性评价研究进展

含糖丰富的食品在热加工过程中会产生大量的糠醛和5-羟甲基糠醛(HMF),不同食品加工后所产生的糠醛及HMF的含量有所差异,但当含量超过标准时就会对人体产生危害。因此,本文对食品中糠醛和HMF的产生机理、含量检测分析及安全性评价进行综述。     

5-羟甲基糠醛在食品中的变化及其安全性研究进展

5-羟甲基糠醛(5-hydroxymethylfurfural, 5-HMF)又称5-羟甲基-2-糠醛, 是一种呋喃类化合物, 与焦糖化反应、美拉德反应密切相关, 化学性质较为活泼。5-HMF广泛存在于乳制品、焦糖化食品中, 对食品的颜色和风味有一定的影响, 可作为反映食品新鲜及褐变程度的指示物。5-HMF在体外和体内通过磺基转移酶(sulfotransferase, SULT)会转化为5-SMF, 对皮肤黏膜、眼睛等产生刺激, 还会损伤人体的骨骼肌、肾脏等器官。但随着深入研究, 5-HMF的抗氧化性、抗菌性等生物活性也逐渐被人们所发现。根据5-HMF目前在食品中的研究现状, 其通用脱除和检测手段较少, 本文综述了5-HMF的产生过程及理化性质, 阐述了5-HMF的生物活性以及在食品中的应用, 以期为改善含5-HMF食品的品质、探索5-HMF的通用检测及弱化方法奠定理论基础。     

对-香豆酸和绿原酸对美拉德反应体系中5-羟甲基糠醛形成的影响

以谷氨酸、赖氨酸、甘氨酸、半胱氨酸分别与葡萄糖反应构建美拉德反应体系,研究5-羟甲基糠醛(5-HMF)的形成量随时间的变化规律及对-香豆酸和绿原酸对5-HMF形成量的影响。结果表明:在相同反应时间内,模拟体系中5-HMF形成量由高到低排列依次是:谷氨酸-葡萄糖模拟体系>赖氨酸-葡萄糖模拟体系>甘氨酸-葡萄糖模拟体系>半胱氨酸-葡萄糖模拟体系;对-香豆酸、绿原酸对美拉德反应中5-HMF形成均表现出抑制和促进的"双重作用";不同质量浓度的对-香豆酸、绿原酸对5-HMF的影响趋势不同,相同质量浓度的同种酚酸对不同模拟反应体系中5-HMF的影响也有差异。     

白杨素对蒜氨酸美拉德反应的影响

以化学合成的蒜氨酸为原料,研究白杨素对蒜氨酸美拉德反应的影响。结果表明,在一定反应条件下,白杨素可能轻微促进蒜氨酸与果糖美拉德反应体系中羟甲基糠醛物质的生成;在反应初期,白杨素可以部分抑制蒜氨酸的分解,其分解率仅有10.1%,而空白对照体系的分解率接近25.0%,分解产物主要为二烯丙基硫醚,但到反应后期,白杨素对蒜氨酸分解的影响较弱,蒜氨酸的最终分解率达到68.2%,分解产物为二烯丙基硫醚、二烯丙基二硫醚、二烯丙基三硫醚等混合物;羟甲基糠醛对蒜氨酸的分解具有显著的促进作用,反应5 h后,蒜氨酸的分解率接近100%,推测羟甲基糠醛在蒜氨酸的分解中可能扮演了催化剂的角色。     

抗氧化剂在工业级干酪素色泽改善中的应用研究

针对用曲拉生产的干酪素颜色青灰、无光泽,不能满足市场需要的问题,通过实验研究找到了干酪素颜色青灰、无光泽的原因,指出了在干酪素生产过程中加碱、加热及混入其它杂质都会促进酪蛋白中赖氨酸与还原糖发生美拉德反应,影响干酪素的质量,用美拉德反应中间产物羟甲基糠醛(HMF)值作为美拉德反应程度的标准来衡量提出了使用抗氧化剂来达到色泽改善的目的,并对抗氧化剂的用量及使用条件进行了研究。     

反应条件对葡萄糖-甘氨酸美拉德反应体系中糠醛类化合物形成的影响

为了分析美拉德反应体系中糠醛类化合物的形成规律，本研究构建了葡萄糖-甘氨酸反应体系，探究了反应物配比、体系初始pH、加热时间和温度对5-羟甲基糠醛（5-Hydroxymethylfurfural,HMF）、2-糠醛（2-Furfural,F）和5-甲基糠醛（5-Methyl-2-furfural,MF）形成的影响，并分析了它们的形成动力学，预测了它们的表观活化能。结果显示：葡萄糖与甘氨酸的摩尔浓度比对糠醛类化合物的生成量有较大影响。HMF生成量随着摩尔浓度比的增大而持续增加，而F与MF的生成量在摩尔浓度比为1:1时达到最高值；酸性pH条件有利于HMF的形成，中性和碱性pH条件有利于F的形成，糠醛类化合物生成总量随着pH的增加而迅速减少；随着加热温度升高、加热时间延长，HMF、F和MF的生成量均逐渐增加；HMF和F的形成在温度较低时符合一级动力学模型（HMF:70～110℃；F:70℃），在温度较高时符合零级动力学模型（HMF:130℃；F:90～130℃）；MF的形成符合零级动力学模型（90～130℃）。本研究可对食品热加工过程中HMF、F和MF的生成和控制提供理论指导。     

HPLC法检测分析温度对中药口服液品质的影响

运用高效液相色谱法（HPLC）比较分析了正常、异常中药（TCM）口服液中美拉德反应产物组成及其对中药口服液质量的影响。结果表明,异常样品的还原糖、蛋白质含量、美拉德反应中间产物糠氨酸、糠醛、5-羟甲基糠醛和丙烯酰胺以及氨基酸含量如赖氨酸、甘氨酸、亮氨酸等均比正常样品偏高。采用不同温度处理提取的类黑素的黑化程度随加热温度的升高而增强。美拉德反应程度随样品烘干温度的升高而增加,高温处理不利于中药口服液样品的安全性。     

A study on the mechanism of browning in mei liqueur using model solutions

Browning mechanisms of mei liqueur were studied using model solutions containing 28% ethanol in 0.1 M citrate solution (pH 3.0). Catechin alone was stable in the model solution but degraded rapidly to form hydroxymethyl furfural (HMF) in incubation with fructose at 70 °C. The rate of increase in the absorbance at 420 nm also suggested that fructose was more potent than glucose in enhancing browning in acidic ethanolic environment. We propose that the major browning mechanisms in mei liqueur are the oxidation and condensation of tannins and the interactions between tannins and HMF derived from fructose, rather than Maillard reaction, ascorbic acid degradation, or caramelization.     

Development of the Maillard reaction in foods cooked by different techniques. Intake of Maillard-derived compounds

Specific and non-specific Maillard reaction (MR) indices such as CIELab colour, browning measurement, furosine, hydroxymethylfurfural (HMF) and furfural, as well as the nutrient content, were analysed for commonly consumed dishes, to test the effects of different culinary treatment on dishes composed of the same ingredients. In addition, the consumption of early MR products (MRP), Amadori compounds, HMF and furfural from a normal serving of these dishes was calculated. As expected, recipes including frying, apart from their particular composition, led to significantly higher values of furosine and HMF, ranging from 4.40 to 175 and from 0.30 to 22.7 mg/kg, respectively; consequently they provided the highest levels of Amadori compounds and HMF intake (0.42–26.8 and 0.02–2.38 mg/serving, respectively). Even so, MRP intake/serving was not very high in comparison with levels reported in the bibliography on some individual foods typically studied in terms of MR development, suggesting that the culinary treatments used do not make a great contribution to the daily MRP consumption.     

Identification of bitter compounds in whole wheat bread

Bitterness in whole wheat bread can negatively influence product acceptability and consumption. The overall goal of this project was to identify the main bitter compounds in a commercial whole wheat bread product. Sensory-guided fractionation of the crust (most bitter portion of the bread sample) utilising liquid–liquid extraction, solid-phase extraction, ultra-filtration and 2-D offline RPLC revealed multiple bitter compounds existed. The compounds with the highest bitterness intensities were selected and structurally elucidated based on accurate mass-TOF, MS/MS, 1D and 2D NMR spectroscopy. Eight bitter compounds were identified: Acortatarins A, Acortatarins C, 5-(hydroxymethyl)furfural(HMF), 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one (DDMP), N-(1-deoxy-d-fructos-1-yl)-l-tryptophan (ARP), Tryptophol (TRO), 2-(2-formyl-5-(hydroxymethyl-1H-pyrrole-1-yl)butanoic acid (PBA) and Tryptophan (TRP). Based on the structures of these compounds, two main mechanisms of bitterness generation in wheat bread were supported, fermentation and Maillard pathways.     

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。     

“Assessing the Maillard reaction development during the toasting process of common flours employed by the cereal products industry”

The present paper aimed to study the development of the Maillard reaction during the drying–toasting step of different flours usually employed for the formulation of cereal-based products. The results state the idea that a great part of hydroxymethylfurfural (HMF) and furfural found in cereal-based products are supplied by the rest of the ingredients composing these foods and not from the toasting of the flours employed. Moreover, a high furfural generation was associated to the fibre-enrichment of whole wheat flour. Glucosylisomaltol (GIM) measurement could be established as a useful indicator for controlling the manufacture conditions of cereal-based products, if significant amounts of maltose are present. Furosine determination is suitable for flours with either low or high reactivity due to its inherent sensibility to thermal treatment but, in extremely reactive flours like soybean, HMF shows better application. Finally, the ΔE parameter resulted in a reliable measurement of the visible colour production for the toasting step of the flours studied.     

Study on fluorescence of Maillard reaction compounds in breakfast cereals

During the advanced stage of the Maillard reaction (MR) in food processing and cooking, Amadori rearrangement products undergo dehydration and fission and fluorescent substances are formed. Free and total (free + linked to the protein backbone) fluorescence (FIC) due to Maillard compounds in 60 commercial breakfast cereals was evaluated. Pronase was used for efficient release of linked fluorescent Maillard compounds from the protein backbone. Results were correlated with some heat-induced markers of the extent of the MR or sugar caramelisation during cereal processing, such as hydroxymethylfurfural, furfural, glucosilisomaltol and furosine. The effect of sample composition (dietary-fibre added, protein, etc.) on levels of FIC, expressed as fluorescence intensity (FI) per milligram of sample, is discussed. FIC is significantly correlated to the protein content of the sample and fluorescent Maillard compounds are mainly linked to the protein backbone. The ratio of total-FIC to free-FIC was 10.4-fold for corn-based, wheat-based and multicereal-based breakfast cereals but significantly higher in rice-based samples. Addition of dietary fibre or honey increased the FIC values. Data support the usefulness of FIC measurement as an unspecific heat-induced marker in breakfast cereals.     

热加工食物中糠醛类化合物的剂量安全与减控研究进展

糠醛类化合物作为美拉德反应的中间过程产物之一,在各类热加工食品中广泛存在,其中羟甲基糠醛和糠醛是最常见的2种化合物,而反应物种类、加工方式、贮藏条件、水分活度、pH等因素都会影响其产生与积累。目前关于糠醛类化合物相关的安全性报道并不多见且并未得出一致的结论,少量报道指出了低浓度糠醛类化合物的有益作用和高浓度的不良影响。基于糠醛类化合物在食物中分布的广泛性、多样性,及潜在的安全风险,考虑到食物中糠醛类化合物的过量暴露可能会给人体带来健康风险,因此有必要对其含量加以减控。本文旨在归纳包括乳制品在内的各种热加工食物中糠醛类化合物的分布情况,围绕国内外糠醛类化合物的安全性研究现状、减控技术展开综述,以期为食品质量安全控制提供理论参考。     

Comparative study of antioxidant and flavour characteristics of Maillard reaction products from five types of protein hydrolysates

Antioxidant, structural, and flavour characteristics of Maillard reaction products (MRPs) prepared from different hydrolysates of sweet potato protein (SPPH), potato protein (PPH), soy protein isolate (SPIH), egg white protein (EWPH), and whey protein isolate (WPIH) were compared. WPIH-MRPs exhibited the highest Maillard reaction (MR) progress followed by SPPH-MRPs as indicated by the lowest pH (4.95 and 5.10, respectively) and the highest fluorescence intensity (P < 0.05). The results of Fourier transform infrared (FTIR) explained the significant changes in functional groups of peptides after MR, especially in WPIH-MRPs and SPPH-MRPs. The highest oxygen radical absorbance capacity (ORAC) of 125.24 µg TE (Trolox equivalents)/mL was observed for WPIH-MRPs, followed by SPPH-MRPs with an ORAC value of 104.07 µg TE/mL (P < 0.05). MR conferred an increase of sweetness, sourness, and umami attributes and reduction of bitterness for all MRPs, and WPIH-MRPs presented the highest umami taste score of 7.4, followed by SPPH-MRPs with a taste score of 7.1. Stronger umami taste was correlated with MW 200–500 and <200 Da peptides. No acrylamide was detected in SPPH-MRPs, which also presented less 5-hydroxymethyl furfural (HMF) and Nε-(1-Carboxymethyl)-L-lysine (CML) compared to WPIH-MRPs. Thus, MRPs derived from SPPH could be an alternative way for natural flavours’ production with improved antioxidant activity and less harmful compounds.     

Conventional and emergent technologies for honey processing: A perspective on microbiological safety,bioactivity, and quality

Honey is a natural food of worldwide economic importance. Over the last decades, its potential for food, medical, cosmetical, and biotechnological applications has been widely explored. One of the major safety issues regarding such applications is its susceptibility to being contaminated with bacterial and fungi spores, including pathogenic ones, which may impose a hurdle to its consumption in a raw state. Another factor that makes this product particularly challenging relies on its high sugar content, which will lead to the formation of hydroxymethylfurfural (HMF) when heated (due to Maillard reactions). Moreover, honey's bioactivity is known to be affected when it goes through thermal processing due to its unstable and thermolabile components. Therefore, proper food processing methodologies are of utmost importance not only to ensure honey safety but also to provide a high-quality product with low content of HMF and preserved biological properties. As so, emerging food processing technologies have been employed to improve the safety and quality of raw honey, allowing, for example, to reduce/avoid the exposure time to high processing temperatures, with consequent impact on the formation of HMF. This review aims to gather the literature available regarding the use of conventional and emergent food processing technologies (both thermal and nonthermal food processing technologies) for honey decontamination, preservation/enhancement of honey biological activity, as well as the sensorial attributes.