兴隆咖啡烘焙过程中香气物质的变化规律

本文利用顶空固相微萃取-气相色谱-质谱(HS-SPME/GC-MS)结合电子鼻对海南兴隆地区咖啡豆不同烘焙度分别为极浅度(JQ)、浅度(Q)、浅中度(QZ)、中度(Z)、中深度(ZS)、深度(S)、极深度(JS)和法式重度(FZ)的挥发性成分进行分析。结果表明:JQ到FZ分别检出61、68、72、72、72、68、70、70种,在JQ、Q和QZ时,挥发性物质主要为吡嗪类和酸类,呈现坚果味和酸味;在Z及ZS时,呋喃类、吡咯类和酮类等起主要作用,为焦糖味和烧焦味;而S、JS和FZ时,主要是酚类和吡啶类贡献烟熏味和愉悦的丁香味。电子鼻可分析不同烘焙度咖啡的香气差异,除LY2/g CT和LY2/AA外,其他4个传感器对8种不同烘焙度咖啡样品的响应值均有明显差异性。本研究明晰了海南兴隆地区咖啡豆烘焙过程中香气成分的变化规律,为兴隆咖啡的烘焙工艺改进提供理论支撑。     

基于HS-SPME/GC-MS和电子感官技术的热泵干燥对烘焙咖啡豆风味品质影响研究

为了探讨热泵干燥对烘焙咖啡豆风味品质的影响,本研究以日晒干燥为对照,采用顶空固相微萃取-气相色谱质谱联用(HS-SPME/GC-MS)、电子鼻和电子舌检测技术,研究了热泵干燥不同温度下焙炒咖啡豆的挥发性风味成分、气味及滋味特性。HS-SPME/GC-MS结果表明:共检测到挥发性风味成分131种,包括10大类物质;干燥温度为40℃时检测数目最多,为124种,随着温度升高,挥发性风味成分数目呈下降趋势,其中呋喃类化合物和吡嗪类化合物所占百分含量最高,均达到了20%以上,酮类化合物数目最多为31种。电子鼻及电子舌数据经主成分分析(PCA)降维处理,结果表明:电子鼻和电子舌的前两个主成分累积方差贡献率分别为99.66%和84.59%,均大于80%,能够较好的提取样品中多维数据信息,并且均能够有效的区分日晒干燥及不同热泵干燥温度处理所得烘焙咖啡豆。     

兴隆咖啡烘焙过程中香气物质的变化规律研究

本文利用顶空固相微萃取-气相色谱-质谱（HS-SPME/GC-MS）结合电子鼻对海南兴隆地区咖啡豆不同烘焙度分别为极浅度（JQ）、浅度（Q）、浅中度（QZ）、中度（Z）、中深度（ZS）、深度（S）、极深度（JS）和法式重度（FZ）的挥发性成分进行分析。结果表明：JQ 到 FZ 分别检出 61,68,72,72,72,68,70,70 种,在 JQ、Q 和 QZ 时,挥发性物质主要为吡嗪类和酸类,呈现坚果味和酸味;在 Z 及 ZS 时,呋喃类、吡咯类和酮类等起主要作用,为焦糖味和烧焦味;而 S、JS 和 FZ 时,主要是酚类和吡啶类贡献烟熏味和愉悦的丁香味。电子鼻可分析不同烘焙度咖啡的香气差异,除 LY2/g CT 和 LY2/AA 外,其他 4 个传感器对 8 种不同烘焙度咖啡样品的响应值均有明显差异性。本研究明晰了海南兴隆地区咖啡豆烘焙过程中香气成分的变化规律,为兴隆咖啡的烘焙工艺改进提供理论支撑。     

基于HS-SPME/GC-MS和电子感官技术的热泵干燥对烘焙咖啡豆风味品质影响研究

为了探讨热泵干燥对烘焙咖啡豆风味品质的影响,本研究以日晒干燥为对照,采用顶空固相微萃取-气相色谱质谱联用（HS-SPME/GC-MS）、电子鼻和电子舌检测技术,研究了热泵干燥不同温度下焙炒咖啡豆的挥发性风味成分、气味及滋味特性。HS-SPME/GC-MS结果表明：共检测到挥发性风味成分131种,包括10大类物质;干燥温度为40 ℃时检测数目最多,为124种,随着温度升高,挥发性风味成分数目呈下降趋势,其中呋喃类化合物和吡嗪类化合物所占百分含量最高,均达到了20%以上,酮类化合物数目最多为31种。电子鼻及电子舌数据经主成分分析（PCA）降维处理,结果表明：电子鼻和电子舌的前两个主成分累积方差贡献率分别为99.66%和84.59%,均大于80%,能够较好的提取样品中多维数据信息,并且均能够有效的区分日晒干燥及不同热泵干燥温度处理所得烘焙咖啡豆。     

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。     

基于电子舌与电子鼻评价烘培时间对黄秋葵籽风味品质的影响

分析不同烘焙时间对黄秋葵籽滋味、气味的影响,采用电子舌法、电子鼻法结合感官评定比较分析黄秋葵籽风味品质的变化。结果表明:电子舌与电子鼻对不同烘焙时间下的黄秋葵籽风味特征呈现不同的响应值,电子舌中涩味的特征向量值最高为0.88,电子鼻对硫化物响应最强;黄秋葵籽烘焙25 min的感官评定总体风味较佳。电子舌PCA分析能较好地区分不同烘焙时间下的黄秋葵籽测试液,而电子鼻的PCA和LDA分析对测试液的区分均存在重叠区,区分性不好。感官评定与电子舌检测的结果对于烘焙时间引起黄秋葵籽的滋味的变化均得到了较好的区分。感官评定与电子鼻检测的结果对于烘焙时间引起黄秋葵籽的气味的变化区分效果均不好。不同烘焙时间下黄秋葵籽感官评定的结果具有差异性,电子舌和电子鼻分析结果与感官评定结果相比较风味品质的检测结果相近。     

高压结合热处理对猪肉滋味的影响

为研究高压结合热处理对猪肉滋味物质的影响,以猪背最长肌为原料,用不同压力(200~600 MPa)结合热(20~60℃)处理10 min,然后测定各样品氨基酸组成、核苷酸组成、还原糖含量、硫胺素含量、脂肪酸组成,并用电子舌对样品的整体滋味进行评价。高压结合热处理极显著(p0.01)影响猪肉中游离氨基酸总含量和组成;核苷酸及降解产物总含量极显著(p0.01)增加,特别是次黄嘌呤核苷酸(IMP);还原糖和硫胺素含量都显著降低(p0.05);但高压结合热处理对猪肉总脂肪酸组成影响不明显(p0.05)。偏最小二乘回归(APLSR)分析表明压力和温度对各样品滋味的影响程度相当;电子舌分析表明处理条件越剧烈样品的整体滋味和对照样的差异越大,在200和400 MPa下温度对整体滋味的影响较大,而在600 MPa下温度的作用很小。在实际应用中为了更好地保留新鲜肉的滋味应避免采用600 MPa或60℃的条件对猪肉进行处理。     

不同焙炒程度下哥伦比亚咖啡豆香气成分分析

哥伦比亚咖啡豆经过浅度焙炒、中度焙炒、深度焙炒3种方式处理,用热脱附法提取香气成分,进行GCMSD分析,并采用峰面积对比含量变化,研究不同焙炒程度对哥伦比亚咖啡豆香气成分的影响。经过分析后得到,浅度焙炒有89个化合物,中度焙炒有90个化合物,深度焙炒有92个化合物,主要成分有吡嗪类化合物、呋喃类化合物、吡咯类化合物、吡啶类化合物、嘧啶类化合物,还有大量的醛酮类、酚类、酯类、醇类化合物。三种焙炒程度下的咖啡豆,香气种类不同,含量不同。深度香气含量最多,整体香气浓郁焦苦,而中度次之,整体香气浓郁香醇,浅焙最少,整体香气淡薄。     

咖啡生豆及其烘焙程度对生物胺含量的影响

为了探明烘焙工艺参数对咖啡豆品质的影响,研究了烘焙程度对越南罗巴斯达咖啡豆中生物胺种类和生物胺含量的影响。采用高效液相色谱法测定不同烘焙条件下6种生物活性胺的含量。试验结果表明:在咖啡生豆中存在4种生物活性胺,生物胺总含量为5.253 mg/100 g。烘焙处理使咖啡豆生物活性胺含量先减少后增加,其中以维也纳式烘焙生物胺总含量最低,0.6 mg/100 g;到西班牙式烘焙,生物胺含量增加到1.33 mg/100 g。到法式烘焙时出现组胺,并且随烘焙程度的加深,组胺含量逐渐增高。到西班牙式烘焙时组胺含量达0.29 mg/100 g。     

云南不同地区生咖啡豆的风味前体物质研究

本文通过测定云南德宏、保山、临沧和普洱四个地区生咖啡豆中风味前体物质组成和含量,结合一元方差分析(ANOVA)和主成分分析(PCA)进行统计学分析,探索了不同地区生咖啡豆中风味前体物质的差异性。实验结果表明:氨基酸总量最高为德宏咖啡(10.31%),最低为保山咖啡(9.07%);蛋白质测定结果与氨基酸相类似;而德宏和临沧咖啡中脂肪和脂肪酸含量均小于普洱和保山咖啡;单糖总量最高为普洱咖啡(17.21%),最低为保山咖啡(15.95%)。PCA分析和方差分析表明,普洱咖啡中脂肪酸和其他地区均呈显著性差异(P0.05);保山咖啡中氨基酸同其他地区均呈显著性差异;而临沧咖啡中单糖、蛋白质、脂肪和保山咖啡均呈显著性差异;除少数样品外,大部分样品在PCA的二维得分投影图上按特性各自聚为一类。本研究可为云南咖啡的烘焙加工提供理论参考。     

A comparative study of chemical attributes and levels of amines in defective green and roasted coffee beans

Differences in chemical attributes (proximate composition, water activity, sucrose, acidity and pH levels) and amine levels between defective and healthy coffee beans were studied. Before roasting, significant differences (p < 0.05) were observed for the ash contents of the coffee samples, with the highest values found for black beans. Moisture content was higher for non-defective beans in comparison to defective beans. Non-defective coffee beans had higher lipids contents than both sour and black beans. There were no significant differences (p > 0.05) for protein levels between defective and non-defective beans. After roasting, protein levels remained constant, there was a small decrease in ash contents and a slight increase in oil contents of black and sour beans. Both black and sour beans had higher acidity levels than immature and non-defective beans. Acidity levels decreased after roasting. Water activity levels also decreased with roasting, with slightly higher levels for defective beans in comparison to non-defective ones. Sucrose levels were much higher in non-defective beans, and the lowest values were in black beans, prior to roasting. After roasting, only traces of sucrose were found. Total amine levels were much lower for black beans, in comparison to the other coffee samples. Putrescine was the prevailing amine in all samples. Histamine was only detected in the defective coffee samples. Small amounts of serotonin, cadaverine and tryptamine were found in some of the samples. After roasting to a light degree, only traces of serotonin were detected and no amines were detected after roasting to medium and dark degrees.     

Physicochemical characteristics of Ethiopian Coffea arabica cv. Heirloom coffee extracts with various roasting conditions

This study aimed to investigate the physicochemical characteristics of Ethiopian Coffea arabica cv. Heirloom coffee extracts with various roasting conditions. Green coffee beans were roasted at four different conditions (Light-medium, Medium, Moderately dark, and Very dark) and used to extract espresso and drip coffee. Moisture content in coffee beans was decreased as the roasting degree increased. The contents of crude fat and ash were lower in the Light-medium roasted coffee beans than in green coffee beans but increased as the roasting degree increased. The values of lightness (L^*), redness (a^*), yellowness (b^*), and browning index of coffee extracts were decreased as the roasting degree increased. Total dissolved solids in espresso coffee were increased with increasing roasting degree but decreased in drip coffee. In both the extracts, the contents of reducing sugar, titratable acidity, organic acids, and chlorogenic acid were decreased, but that of caffeine was increased with the roasting degree increased.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10068-020-00865-w.     

烘焙度对冷萃咖啡理化指标与风味成分的影响

以亚洲咖啡豆为研究对象,分别选取浅、中、深3 种烘焙度的中国云南和印度尼西亚苏门答腊产的卡蒂姆种咖啡豆,比较分析冷萃与热萃方式对萃取浓度、萃取率、可滴定酸、总酚、总糖、咖啡因、葫芦巴碱、绿原酸、抗氧化活性与挥发性成分的差异,并进行主成分分析,从而探究烘焙度对冷萃咖啡理化指标与风味成分的影响规律。结果表明,随着烘焙度增加,冷萃咖啡的萃取浓度、萃取率均显著上升,可滴定酸、总酚、葫芦巴碱、绿原酸、抗氧化活性均显著下降（P＜0.05）。冷萃咖啡较热萃咖啡拥有更高的萃取浓度、萃取率与总糖含量（P＜0.05）,而可滴定酸、总酚含量、抗氧化活性较热萃显著偏低（P＜0.05）。经顶空固相微萃取-气相色谱-质谱检测分析发现,浅烘咖啡豆萃取液中的挥发性成分含量显著低于烘焙度高的咖啡萃取液,深烘咖啡豆萃取液中挥发性成分种类与总含量最多。进一步通过主成分分析能较好区分冷萃和热萃咖啡,两者挥发性成分贡献率具有较大差异。2-丁酮、2-丁烯醛等花香类物质对浅烘冷萃咖啡贡献率更高,而2-甲基吡嗪、糠醇等呈现烘焙坚果类香气物质对浅烘热萃咖啡贡献率更高;2,6-二乙基吡嗪、川芎嗪等烘焙坚果类香气物质对中烘冷萃和热萃咖啡具有较高的贡献率;2-乙烯基呋喃、甲基糠硫醇、2,5-二乙基吡嗪、糠基甲基硫醚等物质对深烘冷萃咖啡有较高贡献率,二甲基二硫、对甲酚、1-甲基吡咯等物质对深烘热萃咖啡贡献率更高。相对于热萃咖啡,烘焙度对冷萃咖啡抗氧化能力与挥发性成分的影响更大。     

Sensory profile of Italian Espresso brewed Arabica Specialty Coffee under three roasting profiles with chemical and safety insight on roasted beans

Specialty coffee (SC) has been showing an increasing interest from the consumers which appreciate its traceability and the peculiar flavours from each single origin. Additionally, the processes to which coffee fruits underwent to get green coffee characterise the beans in terms of macromolecules acting as substrates during the roasting. This work evaluates via sensory analysed eight SC, roasted at light, medium, and dark level, submitted to Italian espresso extraction, to assess how different roasting levels exalt the expected cup profile obtained by the suppliers via cupping in origin countries. Finally, roasted beans were characterised for physico-chemical features (pH, titratable acidity, caffeine, melanoidins, polyphenols and acrylamide). Sensory analysis demonstrated that the intermediate roasting level and espresso extraction match better attributes from in-origin cupping. Melanoidins (mmol g⁻¹ coffee d.b.) was able to discriminate among roasting levels (light 0.12 ± 0.01; medium 0.13 ± 0.003; dark 0.14 ± 0.01; α = 0.05). Acrylamide analyses ensured compliance with the food safety standards (light 301.9 ± 37.2 ppb; medium 126.1±19ppb; dark 107.9 ± 22.5ppb). Physico-chemical features were able to cluster samples from different origins within the same roasting level (α = 0.05). Results showed correlations (α = 0.01) between sensory analysis and physico-chemical values: direct for caffeine and astringency, reverse for perceived acidity in relation to astringency, roasted, dried fruits and nutty notes.     

Peroxyl radical-scavenging activity of coffee brews

The ORAC_FL assay was used in non-automated mode to evaluate the specific peroxyl radical scavenging properties of the aqueous soluble components of green and roasted Arabica and Robusta coffee samples. A relationship between ORAC_FL and the concentration of CQAs (caffeoyl quinic acids) was found for the extracts from green coffee beans. Aqueous extracts from roasted coffee beans possessed equal or stronger scavenging power than that obtained for the green coffee beans extracts and the scavenging activity depended on the variety of coffee and the roasting conditions. Brews from Robusta coffee beans showed the highest ORAC_FL. The best scavenging properties for the brews from Arabica coffee beans were detected in samples prepared from coffee beans roasted under light conditions. The data indicate that, during roasting, a complex network of reactions takes place leading to the formation of a wide number of compounds possessing specific scavenging properties. Under mild roasting conditions, caffeoyl quinic acids appear to be the main components responsible for the free radical scavenging power of coffee brews. In contrast, Maillard reaction products may be the principal components with free radical scavenging activity in more severely (medium and dark) roasted coffees.     

基于UPLC-MS/MS探究烘焙程度对咖啡豆中有机酸含量影响

为探究烘焙工艺对咖啡豆口感的影响,本文研究了烘焙程度对咖啡豆中有机酸含量的影响。采用新建立超高效液质联用法（UPLC-MS/MS）测定不同烘焙条件下7种有机酸的含量。结果表明:7种有机酸化合物在0.5～20.0 mg/kg范围内线性关系良好,决定系数均大于0.990。7种有机酸的加标回收率在81.9%～104.7%,RSD为0.53%～6.64%。洪都拉斯咖啡豆样品检测结果显示随烘焙程度增加,苹果酸和柠檬酸含量下降,富马酸含量先升后降,琥珀酸、酒石酸、莽草酸和奎尼酸含量上升。轻度烘焙下苹果酸与柠檬酸总量最高,达到1201.5 mg/kg,酸度最佳;奎尼酸含量最少,为1363.7 mg/kg,涩度最低。肯尼亚、印尼、巴西、萨尔瓦多咖啡豆中有机酸在相同烘焙条件下表现相似。     

Discrimination between defective and non-defective roasted coffees by diffuse reflectance infrared Fourier transform spectroscopy

The objective of this work was to evaluate the feasibility of employing Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) for discrimination between defective and non-defective coffees after roasting and grinding. Defective (black, immature and sour) and non-defective Arabica coffee beans were submitted to light, medium and dark roasts at 220, 235 and 250 °C. Principal Components Analysis of the DRIFTS spectra (normalized or not) and of the first derivatives of the spectra provided separation of the samples into four groups: non-defective, black, dark sour and light sour, with immature beans scattered among the sour samples. Classification models were developed based on Linear Discriminant Analysis and recognition and prediction abilities of these models ranged from 95 to 100%. Such results indicate that DRIFTS presents potential for the development of a fast and reliable analytical methodology for discrimination between defective and non-defective coffee after roasting and grinding.     

A DAIRY-BASED ESPRESSO BEVERAGE MANUFACTURED USING THREE DIFFERENT COFFEE BEAN ROASTS

The objective of this study was to evaluate the effects of coffee bean roast on the acceptability of a dairy‐based espresso drink. Espresso coffee was made from freshly ground coffee beans with light‐medium roast, between roast (between medium and dark) and dark French roast in order to show the influence of roasting on flavor. Samples were prepared by blending skim milk, soft‐serve ice cream mix, ice and fresh espresso extracts. No significant differences (P < 0.05) were detected in total solids and fat content among treatments. Viscosity for the light‐medium roasted beverage was significantly (P < 0.05) higher than the others. The beverage pH increased with increased darkening of roast. The beverage made with the light‐medium roasted coffee had significantly (P < 0.05) higher preference scores for coffee flavor and overall flavor than beverages made with the between and French roasts. The between and French roasted treatments were shown to have a more intense coffee flavor by trained sensory panelists. Consumers in this study preferred a less intense coffee flavor.     

ABTS radical scavenging capacity in green and roasted coffee extracts

The impact of two parameters (temperature and duration) on the radical scavenging capacity of individual compounds, and total extracts found in coffee was investigated. Phenolic coffee extracts of light (200 °C), medium (225 °C) and dark (235 °C) roasted coffees in a range of 0–30 min were analyzed by an on-line RP-HLPC-ABTS^•+ decolourization assay. This study revealed a general decrease of radical scavenging capacity related to native phenolic compounds. Processing coffee beans leads to generation of up to 10 new radical scavengers. The roasting process influences not only color and taste in coffees, but also the radical scavenging capacity of coffee as well. Phenolic content in roasted coffee and green coffee is very different. Six compounds identified as caffeoylquinic acids and dicaffeoylquinic acids, endowed with radical scavenging capacity were found in green coffee, whereas depending on the roasting process, roasted coffees can present up to 16 different radical scavengers. The compounds formed during the roast are most likely chlorogenic acids derivatives, of which 4 could be clearly identified as two feruloylquinic acids and two caffeoylquinides. In longer roasting durations, these molecules are subjected to auto-degradation, thus total radical scavenging capacity in coffee decline along with roasting (duration and temperature).