陈窖豆豉粑传统工艺剖析及优势菌群鉴定

工艺独特的贵州黔西、大方两地陈窖豆豉粑微生物区系分离鉴定结果表明,黔西陈窖豆豉粑以泛酸芽胞杆菌(B.pantothenticus)、蜂房芽胞杆菌(B.alvei)、坚强芽胞杆菌(B.firmus)等芽胞杆菌为优势菌群,为细菌发酵型产品,而大方陈窖豆豉粑则是爪哇毛霉(M.javanicusWehmer)、鲁氏毛霉(M.rouxians(Calmette)Wehmer)、总状毛霉(M.racemosusFres.)、坚强芽胞杆菌、革兰氏阳性无芽胞杆菌等霉菌和细菌共存发酵的复合发酵型产品,同时两地产品的后期陈窖阶段,均有球菌(Stophylococcus或Pediococcus)和酵母菌(HansenulaanomalaH.etp.sydowvar.amomala)富集,可能对产品的风味和营养起着一定作用。     

陈窖豆豉粑益酵菌株筛选

从贵州黔西和大方两地传统陈窖豆豉粑不同工艺阶段分离到的40株菌株,经胞外蛋白质和脂肪水解酶活力、耐盐性能、抗紫外光照射和抗生素敏感性等综合性能评价,筛选到12株芽胞杆菌可作为陈窖豆豉粑纯菌发酵的选择菌株。     

陈窖豆豉粑类黑精组分体外抗氧化活性研究

药食资源中天然存在的抗氧化活性物质对人体健康的保护作用被日益关注。发酵期18个月的陈窖豆豉粑类黑精的不同组分,经体外抗氧化活性实验表明,粗提物(DCBM)及其S-8树脂粗分组分(DCBM-W和DCBM-E)均显示出一定的抗亚油酸氧化能力,样品浓度为100μg/mL时,活性强于VC,低于BHT,其中DCBM-E可达BHT的1/2,并且DCBM-E经ODS-AQ反相C18柱分离后,其还原力[、DPPH]和[.OH]自由基清除能力虽不及BHT或VC,但组分间差异较大,进一步分离纯化可望筛选到抗氧化活性极强的化合物。     

传统发酵豆豉粑特征风味物质研究

为探究豆豉粑的风味特征,以大方产豆豉粑为试材（S1～S7）,对其滋味和挥发性物质进行分析,并采用多元统计分析方法筛选特征风味物质。结果表明：7种豆豉粑中富含17种游离氨基酸,以苦味和甜味氨基酸含量较高。通过顶空固相微萃取结合气质联用技术鉴定出71种挥发性化合物,以羧酸类、吡嗪类和酯类为主。基于正交偏最小二乘判别分析,共筛选出25个特征风味物质,主要涵盖甜味和鲜味氨基酸、酸类和吡嗪类化合物。聚类热图显示,样品S1、S5和S7中四甲基吡嗪含量较高,甘氨酸、乙酸甲酯、棕榈酸甲酯和4-甲基戊酸在样品S6中含量较高,样品S3中异戊酸、异丁酸和谷氨酸含量显著较高,S2中苯乙酸含量较显著,S4中吡嗪类含量较高。这些特征风味物质以协同、增效作用赋予了豆豉粑浓郁且独特的滋香味。本研究可为豆豉粑特征风味物质的定向调控提供科学依据。     

大孔树脂对曲霉型豆豉类黑精的精制研究

研究了大孔树脂吸附和解吸曲霉型豆豉类黑精的特性。实验结果表明,采用大孔树脂精制曲霉型豆豉类黑精的最佳条件为:X-5树脂对曲霉型豆豉类黑精的吸附效果最好;X-5树脂在类黑精溶液pH为6,浓度为30．12mg/ml,吸附流速为1．5ml/min时吸附能力较强;在室温(20℃)解吸流速为1．5ml/min的条件下,以60%乙醇作为解吸剂时洗脱效果最好。     

曲霉型豆豉类黑精的提取与精制

本文研究了用水浸提和树脂精制曲霉型豆豉类黑精。实验结果表明：水浸提法粗提曲霉型豆豉类黑精的最佳工艺参数为：料液比为1：15，提取时间为8h，提取级数为二级；大孔树脂精制曲霉型豆豉类黑精的最佳工艺条件为：吸附流速为1．5mL／min；在室温和解吸流速为1．5mL／min的条件下，以60％乙醇作为解吸剂时洗脱效果最好。     

黑蒜加工中类黑精相关成分变化及其组成分析

以黑蒜为原料,采用DNS法、苯酚-硫酸法、全自动氨基酸分析仪及高效液相色谱法,对黑蒜加工不同时间点还原糖、总糖、氨基酸、5-羟甲基糠醛(5-HMF)等类黑精形成相关成分的含量进行分析。同时提取黑蒜类黑精,采用热裂解-气相色谱-质谱(pyrolysis-gas chromatography-mass spectrometry,Py-GC-MS)联用技术分析黑蒜类黑精的化学组成:结果表明:加工过程中总糖呈下降趋势,还原糖含量逐渐升高;共检出13种氨基酸,除组氨酸外,其他氨基酸均有不同程度的降低,其中降幅最为明显的有精氨酸、赖氨酸、天冬氨酸和苯丙氨酸;5-HMF有一个先升后降的过程;Py-GC-MS结果表明:黑蒜类黑精中相对含量最高的为呋喃类,其次为吡咯类、噻吩类、烷烃、糠醛类、酚类等。     

陈窖豆豉粑黄豆原料理化特征及浸泡蒸煮特性的表征关联

源于东北和贵州两地10个不同黄豆品种的理化特征、浸泡蒸煮特性以及Pearson相关分析结果表明,贵州黄豆区别于东北大豆的高蛋白和小粒特征是其作为陈窖豆豉粑首选原料的两大优势,以物性仪测试的应力-应变（时间）曲线最大峰值（g）尤宜作为浸泡黄豆蒸煮硬度的量化表征,化学组成中蛋白含量是影响黄豆浸泡吸水率和蒸煮硬度的关键因素.     

黑菊芋类黑精制备条件优化及组成成分分析

通过单因素及正交试验L_9(3~4)对黑菊芋类黑精的最佳制备条件进行了优化。结果表明:黑菊芋类黑精最佳提取条件为提取温度40℃、料液比1∶5、提取时间6 h、乙醇浓度0%(蒸馏水);醇沉条件为3倍无水乙醇反应6 h。同时,采用热裂解气质(Py-GC-MS)和氨基酸分析仪对类黑精组成成分进行分析,结果表明:黑菊芋类黑精中相对含量最高的是呋喃类,其次为吡咯类和酚类等。总氨基酸组成中含量最高的为精氨酸,其次为丙氨酸、苏氨酸和天冬氨酸。     

不同发酵豆酱鲜味及鲜味物质对比分析

此研究对比了12种发酵豆酱的鲜味、丰度和鲜味物质组成(包括氨基酸态氮、全氮、氨基酸和多肽氮含量)。结果表明鲜味与氨基酸态氮、谷氨酸和天冬氨酸相关,而丰度与1～3 kDa的肽段含量相关。根据样品的鲜味物质进行主成分和聚类分析,可将样品分为3大类,其中:黑豆酱醪、豆粕酱醪、黄豆酱醪、面酱醪、韩式大酱和东北大酱的氨基酸态氮、谷氨酸和天冬氨酸含量最为突出,其鲜味表现也较强;阳江豆豉和永川豆豉的全氮和1～3 kDa肽氮含量较高,其丰度感官最突出;味噌和腐乳较为相似。该研究为调控发酵豆酱的鲜味感官提供了数据支撑和理论依据,对于提高传统发酵豆酱的风味品质具有重要意义。     

Functional properties of melanoidins: In vitro antioxidant,antimicrobial and antihypertensive activities

Melanoidins formed at the last stage of the Maillard reaction have been pointed out to possess certain functional properties such as antioxidant, antimicrobial and antihypertensive activities. In order to gain more insights on these functional properties different soluble melanoidins and melanoidin fractions isolated from several amino acid–glucose model systems has been analysed In the case of antioxidant and antimicrobial properties, low molecular weight compounds bounded to melanoidins (BMC fraction) exerts antioxidant and antimicrobial activities usually higher than those of the pure melanoidins to whom they are linked. Contrary, in the case of antihypertensive activity it has been found that the main activity is related to the melanoidin core, not to BMC fraction. In addition it has been found no correlation, except for ABTS assay, among colour and antioxidant, antimicrobial or antihypertensive activity, supporting the idea that melanoidin chromophores are not responsible for these actions.     

Isolation and characterisation of a coffee melanoidin fraction

BACKGROUND: Melanoidins contribute to the colour and flavour of coffee brews and are also reported to be physiologically active components. However, structural information about coffee melanoidins is rare and current models are supported by few data. RESULTS: Using hydrophobic interaction chromatography (HIC), melanoidin fractions were isolated from different high‐molecular‐weight fractions of coffee brews obtained by ultrafiltration. Generally, melanoidin fractions isolated by HIC showed three‐ to fourfold higher antioxidant activities than the remaining high‐molecular‐weight material in the ultrafiltration fractions. Melanoidin fractions showed an intense brown colour: aqueous solutions with a concentration as low as 40 µg mL^?1 were distinguishable from pure water. The melanoidin fractions contained less than 6% each of releasable carbohydrates and amino acids. The molecular masses of the melanoidins were estimated to be between 3 and 22 kDa, irrespective of the ultrafiltration fraction from which they were obtained. Two‐dimensional nuclear magnetic resonance studies revealed an enrichment of phenolic/aromatic/olefinic structural units and did not support the idea of intact ferulate or caffeate moieties integrated into the melanoidin polymer. CONCLUSION: These studies support melanoidin models describing them as high‐molecular‐weight compounds themselves as opposed to models describing them as low‐molecular‐weight chromophores bound to polysaccharides or proteins. Phenolic constituents are more likely integrated into melanoidins as condensed phenolics than as intact hydroxycinnamates from chlorogenic acids. Copyright © 2008 Society of Chemical Industry     

Investigation on the extractability of melanoidins in portioned espresso coffee

Coffee melanoidins have attracted interest as a result of its potential health benefits. This investigation aims to elucidate the extraction behavior of melanoidins and their populations during the preparation of portioned espresso coffee and its relationship with the antioxidant activity of the coffee brew. Filter-paper pods, FAP capsule, and clone capsule containing light roasted coffee have been investigated. An accumulative fractionation approach has applied to model the extraction kinetics of melanoidins, melanoidin populations, browning, chlorogenic acids (CGA), and antioxidant activity. Melanoidins were very efficiently extracted in clone capsules since less than 9 s was necessary to extract the 50% of the melanoidin content as compared with pods and FAP capsules, and the kinetic of extraction is slower than CGA. The extraction profile of melanoidins and browning fitted better with the antioxidant capacity than CGA and total solids profile. Melanoidin populations were obtained according to ethanol solubility. Total melanoidin content and the ratio between melanoidin populations did not change during extraction volume for espresso coffee. Melanoidin populations soluble at 75% ethanol showed the highest antioxidant activity. However, melanoidins with higher antioxidant activity are extracted at higher volumes. This investigation could make possible the adjustment of the technological requirements of espresso coffeemakers to produce an espresso coffee with high levels of beneficial compounds.     

Formation of N-Substituted Pyrrole-2-Aldehydes in the Browning Reaction Between D-Xylose and Amino Compounds

SUMMARY– The formation of N -substituted pyrrole-2-aldehydes in the browning reaction between D-xylose and selected amino acids was investigated.
In order to facilitate the separation of the reaction products, the carbonyl compounds formed in the browning solution were converted into 2,4-dinitrophenylhydrazones (2,4-DNPs) and then esterified with diazomethane. Isolation of the esterified 2,4-DNP was accomplished by column chromatography with alumina. Chemical structures of the isolated 2,4-DNPs were confirmed by elementary analyses, ultraviolet and visible absorption spectra, and nuclear magnetic resonance spectra.
The following N -substituted pyrrole-2-aldehydes were isolated as methyl ester of 2,4-DNP, respectively: (2-formylpyrrol-I-ybacetic acid from the reaction mixture of D-xylose and glycine, 3-(2-formylpyrrol-1-y1)propionic acid from β-alanine, and 2-(2-formylpyrrol-1-y1)-4-methyl-valeric acid from L-leucine.
The extent of pyrrolealdehyde formation from D-xylose and selected alkylamine or amino acid was in the following order which corresponded to the extent of melanoidin formation: n-butylamine > methylamine, β-alanine > glycine > DL-alanine. N-substituted pyrrole-2-aldehyde was rather stable and was not considered to be an important intermediate of melanoidins. However, some correlationships between the formation of pyrrolealdehyde and that of melanoidins were demonstrated and discussed.     

Melanoidins produced by the Maillard reaction: Structure and biological activity

Melanoidins are compounds generated in the late stages of the Maillard reaction from reducing sugars and proteins or amino acids during food processing and preservation. Recently the effects of melanoidins on human health and the chemical characterisation of the beneficial components have gained a lot of attention. Food melanoidins have been reported to be anionic, coloured compounds and some of their key chromophores have been elucidated. The antioxidant activity and other biological effects of melanoidins from real foods and model systems have been widely studied. Despite this, very few different melanoidin structures have actually been described, and specific health effects have yet to be linked to chemically distinct melanoidins. The variety of different Maillard reaction products formed during the reaction, in conjunction with the difficulty in purifying and identifying them, makes a thorough analysis of melanoidins challenging. This review provides a comprehensive look at what is known to date about melanoidin structure, the formation mechanism for these compounds, and the biological properties related to the beneficial health effects of melanoidins.     

云南不同地区烘焙咖啡豆主要成分分析及类黑精组成成分

以云南3个咖啡主产区(普洱、怒江、德宏)的生咖啡豆为原料,通过不同程度(轻度、中度、重度)烘焙,对其主要成分进行分析,并提取类黑精,采用热裂解-气相色谱-质谱(pyrolysis-gas chromatography-mass spectrometry,Py-GC-MS)联用技术分析咖啡类黑精的化学组成。结果显示:随着烘焙程度加深,咖啡豆的蛋白质和粗脂肪含量增加,总氨基酸含量降低,其中蛋白质含量最高为重度烘焙后的普洱咖啡豆(16.3 g/100 g),氨基酸含量最高为普洱生咖啡豆(9.41%),粗脂肪含量最高为中度烘焙后的德宏咖啡豆(13.85 g/100 g),矿物质元素中含量较高的为K、Mg、P、Ca,普洱咖啡豆经重度烘焙后K含量最高(2.2 g/100 g)。Py-GC-MS分析结果表明:不同产地、不同烘焙程度咖啡豆的类黑精组成差异明显,但也存在共性特征,咖啡因和酸类相对含量最高,其次是胺类、酯类、酚类、吡咯类、呋喃类、吡啶类、醛类、醇类、酮类等。     

山西老陈醋类黑精的分离及其抑菌活性

为探究老陈醋类黑精的抑菌作用,采用超滤和尺寸排阻色谱法将山西老陈醋冻干粉（Shanxi aged vinegarextract,SAVE）分离成不同分子质量的水提物和类黑精部分,采用NaCl解离法将醋类黑精解离为类黑精骨架和小分子复合物两部分,用比浊法测定各组分对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌的抑菌活性。结果表明：SAVE中的类黑精具有显著的抑菌活力（P＜0.05）,类黑精对SAVE的抑菌性发挥了主要作用;类黑精中分子质量在3～5 kD的组分抑菌活力最强,其对3 种受试菌的最低抑菌浓度（minimal inhibitory concentration,MIC）均为5 mg/mL;类黑精组成中的小分子复合物比类黑精骨架部分具有更强的抑菌活性。     

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.     

云南小粒咖啡类黑精的抗氧化及减肥功能

目的：探讨云南小粒咖啡类黑精的抗氧化能力和减肥功能。方法：用热水提取法提取中烘焙度云南小粒咖啡中的类黑精（M总）,再将提取的类黑精产物按分子质量大小分成＞100 kDa（M1）、10～100 kDa（M2）、＜10 kDa（M3）3 个部分。用羟自由基、1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除率和总还原力评价M总、M1、M2、M3的抗氧化能力;通过饲喂高脂饲料建立大鼠肥胖模型,检测不同质量浓度咖啡类黑精对肥胖大鼠体质量、体脂质量、血脂水平、脂体比、脂肪组织形态、肝脏组织形态等指标的影响。结果：相同质量浓度下,云南小粒咖啡类黑精不同分子质量产物自由基清除能力和总还原力不同;不同剂量处理组咖啡类黑精均能降低大鼠体质量、体脂质量;肝组织切片显示,中、高剂量处理组大鼠肝脏组织结构完整、肝细胞大小一致、胞浆均匀、细胞核清晰;脂肪组织切片显示,高剂量处理组大鼠脂肪细胞较模型组减小,且排列均匀、结构完整。结论：云南小粒咖啡类黑精及不同分子质量产物均具有不同程度抗氧化能力;高质量浓度（72 g/100 mL）云南小粒咖啡类黑精具有一定的减肥作用,能抑制大鼠体质量的增加,减少肝脏内脂肪堆积,对肝脏具有一定的保护作用。     

Five years of research on health risks and benefits of Maillard reaction products: an update

When the COST Action 919 started to investigate the role of melanoidins in food and health in 1999, the chemical structures of dietary melanoidins were poorly defined and hardly anything was known about structure-specific health effects of this chemical class. In addition, the degradation of melanoidins in the gut and their absorption and function or that of any of their degradation products had not yet been reported. In the past five years, results from in vitro studies demonstrated that at least some of the dietary melanoidins are degraded by intestinal microorganisms, possibly influencing their growth rate. The absorption and excretion rates of individual Maillard reaction compounds and melanoidin structures have been investigated in animal studies. These studies show that at least 30% of the ingested dose of low-molecular-weight compounds are absorbed. Structure-specific health-promoting effects of newly identified compounds have been described by means of their antioxidant and chemopreventive activity in cell culture investigations as well as in animal feeding studies and human trials. Harmful effects of dietary melanoidins have been investigated in the context of their ability to promote glycation reactions in vivo, which are involved in the progression of several diseases, such as diabetes mellitus, cardiovascular complications, and Alzheimer's disease. Toxicological studies were performed showing that melanoidin structures can not be classified as potent dietary mutagens or genotoxins. Thus, substantial knowledge on the health effects of melanoidins has been gained within COST Action 919. But still, further studies are needed to distinguish between chemically identified harmful and health-beneficial melanoidins.