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Selected ion flow tube-mass spectrometry (SIFT-MS) was used to measure the real-time concentrations of cocoa volatiles in the headspace during roasting. Alkalized and unalkalized Don Homero and Arriba cocoa beans were roasted at 120, 150, and 170 °C in a rotary roaster. The concentrations of total alcohols, acids, aldehydes, esters, ketones, and alkylpyrazines increased, peaked, and decreased within the timeframe used for typical roasting. The concentrations of alkylpyrazines and Strecker aldehydes increased as the roasting temperature increased from 120 to 170 °C. For most of the volatile compounds, there was no significant difference between Arriba and Don Homero beans, but Arriba beans showed higher concentrations of 2-heptanone, acetone, ethyl acetate, methylbutanal, phenylacetaldehyde, and trimethylpyrazine. For unalkalized Don Homero beans (pH 5.7), the time to peak concentration decreased from 13.5 to 7.4 min for pyrazines, and from 12.7 to 7.4 min for aldehydes as the roasting temperature increased from 120 to 170 °C. Also, at 150 °C roasting, the time to peak concentration was shortened from 9 to 5.1 min for pyrazines, and from 9.1 to 5 min for aldehydes as the pH increased from 5.7 to 8.7. PRACTICAL APPLICATION: SIFT-MS allows for real-time monitoring of the key volatile compounds contributing to chocolate flavor, with minimal sample preparation, thus can be used to facilitate adjusting the roasting conditions, such as temperature and time, to optimize chocolate flavor during roasting. Real-time monitoring during roasting can also be used to evaluate the flavor quality of different types of beans by comparing the concentrations of key flavor compounds. 相似文献
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Pablo Rodríguez Elevina Pérez Romel Guzmán 《Journal of the science of food and agriculture》2009,89(7):1186-1194
BACKGROUND: The alkalization process is extensively used in the cocoa industry, but information is scarce and not easy to acquire. The goal of the study was to evaluate the effect of different types and concentrations of alkali on the color of cocoa liquor. Dried beans from Chuao (state Aragua, Venezuela) were used to produce cocoa liquors. Samples of liquors were alkalized with solutions of NaHCO3, Na2CO3 and NaOH at concentrations of 10, 20 and 30 g kg?1. RESULTS: The data showed that values of the coordinates L*, a* and b* decrease when liquors were treated with the three different types and concentrations of alkalis. Almost all samples had ΔE* values above 1. The ratios b*/a* and a*/b* and the proximate composition were also modified. Crude protein, crude fat and polyphenol concentrations were decreased and the ash content augmented as concentrations of the alkalis were increased. The fatty acid and sugar profiles were also affected. These ratios were most pronounced when NaOH was used. CONCLUSION: The selection of the type or concentration of alkali is a function of the type of product to be elaborated. Copyright © 2009 Society of Chemical Industry 相似文献
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The objective of this study was to evaluate the effectiveness of using enzymatic hydrolysis and microbial fermentation coupled with thermal treatment methods in valorising a type of industrially generated meat by-product: pork trimmings, so as to produce a value-added meat-based flavouring. The pork trimmings were first hydrolysed using a protease (Flavourzyme) under optimised conditions and then fermented into liquid hydrolysates with mixed Lactobacillus fermentum and Pichia kluyveri; afterwards, xylose and cysteine were added to the fermented hydrolysates for heat treatment. A characteristic “savoury and roasted-meat” aroma was produced due to the formation of potent sulphur-containing volatile compounds such as 2-furfurylthiol and methionol, though the browning intensity was inhibited due to the presence of cysteine. The thermal treatment did not significantly affect the fruity and sweet-smelling ester volatiles such as isoamyl acetate and hexyl acetate that resulted from microbial fermentation. The decreases of amino acids and xylose might be due to their active participation in the Maillard reaction. The produced pork hydrolysates that imparted a unique aroma could be applied as a flavour enhancer or seasoning in the food industry. 相似文献
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为探讨不同反应温度和糖种类对牦牛肉肌原纤维蛋白与糖产生美拉德反应时挥发性物质的影响。将牦牛肉肌原纤维蛋白与葡萄糖或果糖于50、70、90、110、130℃下加热,在顶空瓶中直接反应或坩埚中间接反应,并采用气相色谱-质谱联用仪(GC-MS)对挥发性物质进行测定。结果表明:在顶空瓶中直接反应并检测相比在坩埚中反应再转至顶空瓶中检测的制样方式检测出的挥发性物质的种类多、相对含量高;反应温度越高,美拉德反应产物中挥发性风味物质的种类越多、相对含量也越高;当反应温度为130℃时,葡萄糖或果糖与肌原纤维蛋白反应产生的挥发性风味物质的种类分别为40种和44种,相对含量分别为93.59%和98.72%;在130℃时,于顶空瓶中直接反应,两种糖的美拉德反应都可以产生的重要肉味挥发性化合物:壬醛、己醛、辛醛、十六醛、十八醛、2,3戊二酮和2-乙酰基呋喃。 相似文献
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木糖母液是玉米芯或蔗渣酸水解的副产物,含大量的糖类,但由于分离困难,限制了其在工业中的大规模使用。以废弃的木糖母液为研究对象,将其与L-谷氨酸进行美拉德反应,采取正交试验确定最佳反应条件,并对其反应产物的挥发性成分采用气相色谱-质谱（GC-MS）法进行分析测定。试验结果表明：当反应温度为105 ℃、反应时间为3.0 h、pH值为12时,吸光度值为1.910,在此条件下,木糖母液美拉德反应褐变程度最强;通过对产物进行气相色谱-质谱联用仪分析,共鉴定出91种木糖母液美拉德反应产物挥发性成分,主要有醇、酮、酸、酯及醚五大类。 相似文献
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采用动态顶空-气相色谱-质谱联用和电子鼻分析亚油酸对美拉德体系的作用以及复热对亚油酸-木糖-半胱氨酸的影响。结果显示：共测定出53 种挥发性物质,其中共有物质13 种,3 个组中挥发性物质总量分别为1 598.61、2 330.71 μg/kg和1 675.09 μg/kg。添加亚油酸后美拉德反应产物含量降低,说明亚油酸对于美拉德反应具有抑制作用。复热处理后模拟体系中除酸、醇类物质外,其他类物质含量均呈降低趋势,气味活度值分析显示1-辛烯-3-醇含量的增加以及肉香、脂香类物质含量的降低可能是导致热异味产生的原因。电子鼻分析显示无机硫化物也可能是复热导致异味来源。 相似文献
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亚麻籽油中Maillard源挥发性香气形成机理的初步研究 总被引：1，自引：0，他引：1
对亚麻籽油中Maillard源挥发性香气形成机理进行了初步研究。采用HS-SPME-GC-MS分析亚麻籽油挥发性化合物。结果表明:从6个不同炒籽时间(200℃)的亚麻籽油样品中鉴定出69种挥发性化合物;炒籽30~40 min时亚麻籽油会形成较多有利的挥发性香气物质,其中醛类、酮类及杂环类挥发性化合物随着炒籽时间的延长明显增多;亚麻籽油挥发性香气前体物质主要与天冬氨酸、组氨酸、精氨酸、甲硫氨酸、亮氨酸、赖氨酸、葡萄糖和果糖有关;模式美拉德反应验证发现亚麻籽油挥发性香气成分主要来自炒籽过程中上述物质间的美拉德反应,模式美拉德反应产物不仅给亚麻籽油提供特征香气物质,还具有延长亚麻籽油保质期的作用,其中\"葡萄糖+天冬氨酸\"体系抗氧化效果最为显著。 相似文献
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Edy S de Brito Narendra Narain Nelson H Pezoa García Antonio L
P Valente Glucia F Pini 《Journal of the science of food and agriculture》2002,82(5):534-537
Cocoa mass was treated with glucose and/or glycine before roasting. For glucose‐treated samples the reductions in reducing sugars and free amino acids were 41.1 and 56.9% respectively, whereas for glycine‐treated samples the respective reductions were 16.2 and 37.4%. The combination of glucose plus glycine treatment led to 39.0 and 48.9% reductions in reducing sugars and free amino acids respectively. For free amino acids the reductions in control and glucose‐treated samples were similar, 56.2 and 56.9% respectively, indicating that the added glucose did not significantly (P < 0.05) influence the free amino acid uptake. When glycine was added, the consumption of free amino acids (37.4%) was lower than for the control and glucose treatments. When glucose and glycine were added, the reduction in free amino acids (48.9%) was lower than for the control and glucose treatments but higher than for the glycine treatment. Apparently, glycine addition inhibited the reducing sugar and free amino acid consumption, whereas glucose addition enhanced the reducing sugar and free amino acid consumption. The glucose plus glycine treatment was similar to the glycine treatment in the contents of 2,5‐dimethyl‐ and trimethylpyrazines. For 2‐methylpyrazine the value for glucose‐treated samples was lower than for control and glycine‐treated samples but almost equal to the value for the glucose plus glycine treatment. It is concluded that the addition of glucose and/or glycine does not affect pyrazine production. © 2002 Society of Chemical Industry 相似文献
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为了探究不同碱化条件对成品可可碱化粉颜色的影响,采用CIELAB颜色参数系统比较了可可粉/仁碱化粉的颜色值。结果表明：提高温度和压力均可以提高碱化粉的色差值（ΔE）,加深碱化程度。相同温度条件（120 ℃）下,施加0.1 MPa压力时,可可仁碱化粉比可可粉碱化粉的ΔE提高得多;碱化时间越长,碱化粉ΔE越大;随着碱液质量浓度的增加,碱化粉ΔE呈现增加的趋势,且高质量浓度碱液有助于碱化粉形成红色色调;K2CO3有助于增加可可仁碱化粉的ΔE,NaOH、NaHCO3对增加可可粉碱化粉的ΔE有利;随着碱液质量浓度增加,可可粉/仁碱化粉的pH均增加。 相似文献
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Vanja Todorovic Marina Milenkovic Bojana Vidovic Zoran Todorovic Sladjana Sobajic 《Journal of food science》2017,82(4):1020-1027
Many factors can influence antioxidative and antimicrobial characteristics of plant materials. The quality of cocoa as functional food ingredient is influenced through its processing. The main aim of this study was to test if there is difference in polyphenol content, antioxidant capacity, and antimicrobial activity between nonalkalized and alkalized cocoa powders. To estimate polyphenol and flavonoid content in cocoa samples the spectrophotometric microassays were used. Flavan‐3ols were determined with reversed‐phase high‐performance liquid chromatography (RP‐HPLC). Antimicrobial activity against 3 Gram positive bacteria, 4 Gram negative bacteria and 1 strain of yeast was determined using broth microdilution method. Total polyphenol content was 1.8 times lower in alkalized cocoa samples than in natural ones. Epicatechin/catechin ratio was changed due to the process of alkalization in favor of catechin (2.21 in natural and 1.45 in alkalized cocoa powders). Combined results of 3 antioxidative tests (DPPH, FRAP, ABTS) were used for calculation of RACI (Relative Antioxidant Capacity Index) and GAS (Global Antioxidant Score) values that were consistently higher in natural than in alkalized cocoa extracts. Obtained results have shown significant correlations between these values and phenolic content (0.929 ≤ r ≤ 0.957, P < 0.01). Antimicrobial activity varied from 5.0 to 25.0 mg/ml (MICs), while Candida albicans was the most sensitive tested microorganism. Cocoa powders subjected to alkalization had significantly reduced content of total and specific phenolic compounds and reduced antioxidant capacity (P < 0.05), but their antimicrobial activity was equal for Gram‐positive bacteria or even significantly enhanced for Gram‐negative bacteria. 相似文献
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以花蟹酶解液为原料,通过均匀设计实验法,结合感官评价方法,优化美拉德反应型蟹味香精的最佳配方及制备条件,并采用固相微萃取气质联用技术（SPME-GC-MS）研究反应前后的挥发性风味物质组成。研究结果表明,美拉德反应最佳参数为:以花蟹酶解液为基准,分别添加葡萄糖6.7%,木糖2.0%,甘氨酸0.6%,精氨酸2.2%,牛磺酸0.1%,硫胺素1.4%;反应温度101℃,时间33 min,p H7.5。所得反应产物呈均一的红褐色,且香气浓郁,特征风味明显,鲜味醇厚。从花蟹酶解液和反应产物中分别检测出24种和43种风味成分,反应产物中含有酮类8.82%、醛类30.87%、呋喃类18.83%、吡嗪类20.04%、醇类6.35%及一些其他的挥发性风味物质。2,3-丁二酮、3-甲硫基丙醛、2-甲基吡嗪、1-辛烯-3-醇等化合物风味阈值较低,对整体香气具有重要的贡献作用。 相似文献
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以肉味香精为研究对象,从感官品质、挥发性风味物质组成和电子鼻分析角度研究不同反应温度对其风味品质的影响。结果表明,不同温度条件下肉味香精在感官评价、挥发性风味物质等方面都有较大的差异性。105 ℃条件下的肉味香精产品风味和口感相对较好;经气相色谱-质谱联用仪分析,该条件得到的肉味香精中挥发性物质相对含量较高,达到93.62%,其中具有特征风味的吡嗪类化合物高达8.19%,醛、酮类化合物的相对含量较高;在此条件下得到的肉味香精,色泽呈现深褐色,香味浓郁,回味悠长。运用电子鼻技术分析发现,不同温度条件下样品存在显著性差异,风味有所改变。 相似文献
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The effect of pH on the formation of volatile compounds was investigated using minced beef in which the pH was adjusted within the range 4.0–5.6, by the addition of hydrochloric acid before cooking. The strong buffering capacity of the meat ensured that the pH did not vary during heating. Volatiles were analysed using headspace concentration and gas chromatography-mass spectrometry. The total quantity of volatile compounds increased as the pH decreased. A number of furanthiols and their oxidation products were preferentially formed at acid pH; some of these compounds had strong meaty aromas. The formation of other heterocyclic compounds such as thiazoles and pyrazines were favoured by higher pH. 相似文献
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考察了复杂美拉德3组分反应体系“L-抗坏血酸-L-半胱氨酸-甘氨酸(ASA-Cys-Gly)”,在不同pH值(4.5,5.8,7.0,8.0,9.5)溶液中挥发性物质的生成情况。采用顶空固相微萃取-气相色谱-质谱(HS-SPME-GC-MS)联用技术及内标和标准物质对比分析、鉴定各反应体系中挥发性的物质。在各物质自降解及2组分体系反应挥发性物质生成与分布研究的基础上,探讨pH值对L-抗坏血酸-L-半胱氨酸-甘氨酸3组分体系挥发性化合物形成的影响。结果表明,3组分体系生成的挥发性化合物主要为噻吩、噻唑、吡嗪及硫醇等化合物。在不同pH值条件下,3组分反应中各挥发性物质生成的种类及含量有显著差异:噻吩类化合物在酸、碱性条件下均可生成,且种类多,含量高,是复杂美拉德反应体系的优势生成物;而噻唑和吡嗪类化合物主要在中、碱性条件下生成;硫醇类化合物主要在酸性条件下生成。根据各体系中挥发性物质的生成情况,提出不同pH值下各体系挥发性物质可能的形成机制。 相似文献
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L-抗坏血酸对大豆肽美拉德反应体系色香味的影响 总被引：1，自引：1，他引：1
通过颜色测定、感官评定分子量分布及GC-MS分析,研究了L-抗坏血酸(Vc)的添加对大豆肽-木糖-半胱氨酸美拉德反应体系色泽香气滋味的影响。结果表明,Vc的添加量为0.20%(w/w)时,对体系色泽的形成具有一定的抑制作用,同时提升了焦甜香味,而醇厚味无显著变化。Vc的添加对产物分子量分布没有明显的影响,但明显抑制2-呋喃甲硫醇的形成,Vc添加前其含量为10.187 2μg/g,添加后未检出。Vc的添加有助于吡嗪类化合物的产生,Vc添加前后其含量分别为1.371 5μg/g和7.856 0μg/g。表明添加Vc的美拉德产物适合于开发色泽较浅且焦香味突出的风味增强肽调味产品。 相似文献
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以牛肉酶解物、L 半胱氨酸盐酸盐、DL 丙氨酸、D 木糖、盐酸硫胺素等为模式体系反应制备热加工肉类风味料 ,采用固相微萃取 (SPME) GC MS对反应产物进行分析 ,共分离鉴定出 71种挥发性化合物 ,尤其是分离鉴定出 2 ,5 二甲基 4 羟基 3 (2H) 呋喃酮、2 乙基 4 羟基 5 甲基 3(2H)呋喃酮、甲基吡嗪、2 ,5 二甲基吡嗪、2 ,6 二甲基吡嗪、4,5 二甲基噻唑、2 乙酰基 3 氨基噻吩、3 甲基 2 噻吩羰基醛、甲基 (2 甲基 -3 呋喃基 )二硫醚、反式茴香醚、5 乙烯基 4 甲基噻唑、四氢 3 甲基 1 ,3 二硫醇 (4 ,5 b)呋喃、十六醛等肉香或特征性牛肉风味化合物。 相似文献