基于高效液相色谱法分析烘焙程度对咖啡中绿原酸含量的影响（网络首发、推荐阅读）

探究烘焙程度对10支不同产地（产地一：云南，产地二：非洲，产地三：美洲）卡蒂姆咖啡豆中7种绿原酸化合物含量影响。采用高效液相色谱法测定生豆和烘焙豆中绿原酸、新绿原酸、隐绿原酸、异绿原酸A、异绿原酸B、异绿原酸C和5-阿魏酰奎宁酸含量。经响应面法优化7种绿原酸化合物的最佳提取条件为100 mL 0.1%磷酸溶液沸水浴提取30 min，7种绿原酸化合物在2~150 mg/L质量浓度范围内，线性相关系数良好，相关系数均大于0.999 4，方法检出限0.005~0.500 mg/g，定量限0.02~2.00 mg/g，咖啡生豆中绿原酸的含量最高，其次是5-阿魏酰奎宁酸。随着烘焙程度增加，绿原酸和5-阿魏酰奎宁酸含量显著降低（P<0.05），新绿原酸和隐绿原酸含量先升高再降低，异绿原酸A的降解速度明显高于异绿原酸B和异绿原酸C，绿原酸、5-阿魏酰奎宁酸的降解速度与其余5种绿原酸相比，较为稳定。通过对不同烘焙程度下7种绿原酸化合物含量变化的研究，可以进一步针对咖啡绿原酸功效成分进行评价，为咖啡烘焙和品质控制提供参考依据。     

不同加工年份诺邓火腿理化特性研究

分别以不同加工年份（一年、两年及三年）的诺邓火腿为对象,分析其理化特性变化及内在联系。结果表明,肉香、腌制味和油脂香是诺邓火腿的特征香气,两年诺邓火腿肉香得分最高,腌制味逐年上升,不同加工年份诺邓火腿油脂香差异不显著。随着加工时间延长,盐分含量、pH值、过氧化值（peroxide value,POV）、硫代巴比妥酸值（thiobarbituric acid value,TBA值）、亚硝酸盐含量、硬度、咀嚼性、剪切力呈升高趋势（P＜0.05）,而水分含量、水分活度、弹性、内聚性和回复性呈下降趋势（P＜0.05）。L*值和b*值随加工时间的延长呈先升高后下降的趋势（P＜0.05）,而a*值逐渐升高（P＜0.05）。水分含量与pH值、盐分含量、亚硝酸盐含量、a*值、硬度、咀嚼性、剪切力呈极显著负相关（P＜0.01）,而与水分活度、弹性、回复性和内聚性呈极显著正相关（P＜0.01）。     

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。     

咖啡精油超临界CO2萃取工艺优化及理化特性分析

以云南保山小粒咖啡豆为对象,根据国家标准,测定生、熟咖啡豆的营养成分,在单因素实验的基础上,以响应面优化超临界CO₂萃取咖啡精油的工艺参数;测定生、熟咖啡精油理化指标,并通过气相色谱-氢火焰离子化检测器（GC-FID）分析生、熟咖啡精油的脂肪酸组成。结果表明:经烘焙处理后,熟咖啡豆中水分、水浸出物、咖啡因、总糖、粗纤维和粗脂肪含量与生咖啡豆中的存在显著差异（P<0.05）;超临界CO₂萃取生咖啡精油的最佳工艺条件为萃取压力25 MPa,萃取温度54 ℃,萃取时间150 min,在此条件下咖啡精油萃取得率为13.98%。烘焙处理前后,咖啡精油各常规理化指标无显著差异,且均符合国家标准要求。通过GC-FID分别检测到15和16种脂肪酸,其中亚油酸、棕榈酸、硬脂酸和油酸等为主要脂肪酸,烘焙对咖啡豆脂肪酸组成影响不明显,但各脂肪酸的含量存在一定差异。烘焙对咖啡豆及咖啡精油的各项指标均有一定程度的影响,为云南地区咖啡产业发展提供科学依据。     

温度动态变化对不同水分含量稻谷主要品质变化的影响

目的：研究低温（10 ℃左右波动）、中温（20 ℃左右波动）和高温（30 ℃左右波动）动态储运条件下稻谷的糊化特性、表面颜色以及直链淀粉含量的变化情况,为稻谷动态储运提供数据支持和理论依据。方法：将稻谷水分含量调节为14%、16%、18%、20%、22%,分别在低温（0 ℃左右波动）、中温（20 ℃左右波动）和高温（30 ℃左右波动）3 个温度条件下动态储运2 个月,每15 d进行一次品质测量。结果：稻谷的峰值黏度、热浆黏度、最终黏度、崩解值、色度a*值和b*值随着储运时间的延长呈上升趋势;色度L*值随着储运时间的延长则呈下降趋势;回生值随着储运时间的延长先增加后降低或平缓;直链淀粉含量随储运时间的延长基本不发生明显变化,仅在高温后期有所降低。初始水分含量对峰值黏度、热浆黏度、色度a*值和b*值影响显著（P＜0.05）;对最终黏度和色度L*值影响显著（P＜0.01,P＜0.05）;对崩解值和回生值影响不显著。温度对峰值黏度、最终黏度、崩解值、回生值和色度a*值影响显著（P＜0.01,P＜0.05）;对热浆黏度影响显著（P＜0.05）;对色度L*值和a*值影响不显著。峰值黏度与稻谷回生值呈显著正相关（r = 0.571,P＜0.01）,回生现象越明显,稻谷的食用品质越差,直链淀粉含量与糊化特性各指标都呈极显著负相关（P＜0.01）。结论：低温可以降低高水分稻谷品质的变化;温度动态变化的长时间运输过程中（30 d以内）稻谷初始水分含量应严格控制在16%以下。     

暂养环境因子对斑点叉尾鮰肌肉理化性质与质构特性的影响

以斑点叉尾鮰（Ictalurus punctatus）为研究对象，通过控制暂养温度（12、16、20、24 ℃）、氨氮质量浓度（0、5、10、20 mg/L）和暂养密度（1∶2、1∶3、1∶4、1∶5，m/V），考察不同环境因子对斑点叉尾鮰肌肉理化特性（水分含量、pH值和持水力）与质构特性的影响。结果表明：暂养温度24 ℃组鱼肉的水分含量与持水力显著低于其他温度组（P＜0.05）；12 ℃组鱼肉的水分含量、pH值和持水力较稳定，且肌肉弹性和咀嚼性显著高于其他温度组（P＜0.05）；水体氨氮质量浓度为0 mg/L时，鱼肉pH值稳定在7.12～7.15，持水力稳定在65%左右，随着暂养时间的延长，该组鱼肉硬度显著下降（P＜0.05），弹性和咀嚼性有所上升，回复性与凝聚性维持在稳定水平；暂养密度不低于1∶4（m/V）时，鮰鱼肌肉水分含量和持水力均随暂养密度的下降而显著上升（P＜0.05）；在整个暂养期间，1∶4（m/V）组鱼肉弹性大部分显著高于其他密度组（P＜0.05），且其鱼肉弹性和咀嚼性随着暂养时间的延长呈上升趋势，回复性和凝聚性随着暂养时间的延长呈下降趋势，而肌肉硬度与黏性无显著变化。综上，温度12 ℃、氨氮质量浓度0 mg/L、暂养密度1∶4（m/V）的暂养环境较有利于维持和提高斑点叉尾鮰肌肉品质。     

温度、时间和水分对配合饲料脂质酸败的影响

采用三因素二次回归正交组合设计,研究了温度（6－42℃）、时间（3－57d）和水分（9％－18％）与配合饲料（10－20kg仔猪）脂质酸败的关系。试验结果表明：脂质水解酸败随着温度升高,时间延长和水分含量升高,呈极显著线性增强（P＜0.01）。水分范围16％－18％配合饲料脂质氧化酸败最慢,随着饲料水分含量的降低（低于16％）,温度的升高（6－42℃）和时间的延长（3－57d）,脂质氧化酸败显著地增强（P＜0.05）。水分含量16％,贮藏温度低于20.6℃,贮藏时间在24d内,饲料未产生酸败味。     

橄榄二酯油烘焙苏打饼干中3-氯丙醇酯、缩水甘油酯产生规律及其质构分析

以橄榄甘油二酯油为原料,制作苏打饼干,考察甘油二酯（diglycerides,DAG）含量、烘焙温度、盐添加量、烘焙时间对饼干中3-氯丙醇酯（3-monochloropropane-1,2-diol esters,3-MCPDE）和缩水甘油酯（glycidyl esters,GE）及饼干硬度和黏度的影响。结果表明,苏打饼干中3-MCPDE和GE的最高含量分别为1.05 mg/kg和0.37 mg/kg,且烘焙过程中3-MCPDE含量与烘焙温度和盐添加量呈正相关,在170 ℃以上时GE含量随烘焙温度升高而增加。但烘焙时间和DAG质量分数对3-MCPDE和GE的产生无显著影响（P＞0.05）。综上,橄榄甘油二酯油应用于烘焙苏打饼干具有良好的安全性和改善产品质构的效果,同时控制烘焙温度和盐添加量能在一定程度降低苏打饼干中3-MCPDE和GE的含量。     

发酵对山黑猪肉干品质特性的影响

为探究发酵条件对山黑猪肉干发酵过程中理化性质和感官品质的影响,以山黑猪后臀肉为原料,考察发酵温度、接种量和菌种配比3?个因素对山黑猪肉发酵过程中pH值、水分活度（aw）、总游离氨基酸、组胺、亚硝酸盐残留量、蛋白质分子质量、色泽、质构和感官评分的影响。结果表明,不同菌种配比组中,随着木糖葡萄球菌占比增大,游离氨基酸含量、L*、a*逐渐升高（P＜0.05）;随着清酒乳杆菌清酒亚种占比增大,pH值、aw降低,硬度和咀嚼性增大（P＜0.05）;发酵32?h,随接种量增大,组胺含量上升趋势减缓,亚硝酸盐残留量、弹性降低（P＜0.05）,硬度、咀嚼性、a*逐渐增大（P＜0.05）,107?CFU/g组感官评价最佳;发酵32?h,随发酵温度升高,pH值、aw、亚硝酸残留量呈先降低后升高的趋势,游离氨基酸、硬度、咀嚼性、L*和a*显示先增大后减小的趋势。因此,选择合适的发酵条件可以改善发酵山黑猪肉干色泽和质构,提高游离氨基酸含量,降低亚硝酸盐残留量,提高产品安全性。     

食盐添加量对哈尔滨风干肠理化特性的影响

以哈尔滨风干肠为研究对象,通过对其发酵过程中水分含量及分布、食盐含量、pH值、色差、剪切力、硫代巴比妥酸（thiobarbituric acid reactive substances,TBARS）值及菌落总数等指标的测定,研究降低食盐添加量（2.5%、2.0%、1.5%、1.0%）对风干肠理化特性的影响,以期减少风干肠中食盐含量。结果表明,发酵前期（0～6?d）,降低食盐添加量会导致风干肠水分含量、水分活度（water activity,Aw）、L*值、TBARS值和菌落总数较高（P＜0.05）,而a*值、pH值及剪切力较低（P＜0.05）;发酵后期（6～12?d）,降低食盐添加量会导致风干肠水分含量、Aw、pH值和L*值的降低（P＜0.05）,而TBARS值、剪切力和菌落总数升高（P＜0.05）,各组风干肠a*值没有显著差异（P＞0.05）。此外,低场核磁分析结果表明,随着发酵时间的延长,各组风干肠中的不易流动水对应的弛豫时间（T21）变快,并且食盐添加量越少,弛豫时间越快（P＜0.05）。感官评价结果表明,食盐添加量为2.0%时,风干肠总体可接受性最好,咸味适中。综上所述,确定哈尔滨风干肠中食盐的最佳添加量为2.0%。     

Effect of the roasting method on the content of 5-hydroxytryptamides of carboxylic acids in roasted coffee beans

Coffee beans of Coffea liberica (robusta) variety were roasted using convection and microwave heating. For roasting we used green coffee beans of 7.5% moisture content, and beans wetted to 10% moisture content and dried to 5% moisture content. The content of 5-hydroxytryptamides of carboxylic acids C-5-HT (determined by TLC) as the index of substances irritating alimentary canal was investigated in the roasted beans, depending on the bean treatment before roasting and applied roasting method. Analytical results show that predrying of the coffee beans caused 15-30% loss of C-5-HT, depending on the applied drying conditions. The content of C-5-HT in the roasted beans depended on the roasting method and preliminary treatment of the beans prior to roasting. A higher C-5-HT loss occurred in the case of beans subjected to two-stage processing, predrying and roasting. Convection roasting caused higher degradation of C-5-HT than microwave roasting.     

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.     

Effect of the roasting method on the content of 5‐hydroxytryptamides of carboxylic acids in roasted coffee beans

Coffee beans of Coffea liberica (robusta) variety were roasted using convection and microwave heating. For roasting we used green coffee beans of 7.5% moisture content, and beans wetted to 10% moisture content and dried to 5% moisture content. The content of 5‐hydroxytryptamides of carboxylic acids C‐5‐HT (determined by TLC) as the index of substances irritating alimentary canal was investigated in the roasted beans, depending on the bean treatment before roasting and applied roasting method. Analytical results show that predrying of the coffee beans caused 15–30% loss of C‐5‐HT, depending on the applied drying conditions. The content of C‐5‐HT in the roasted beans depended on the roasting method and preliminary treatment of the beans prior to roasting. A higher C‐5‐HT loss occurred in the case of beans subjected to two‐stage processing, predrying and roasting. Convection roasting caused higher degradation of C‐5‐HT than microwave roasting.     

Antioxidant activity,polyphenols, caffeine and melanoidins in soluble coffee: The influence of processing conditions and raw material

The production of soluble coffee starts with the selection of beans and is followed by roasting, grinding, extraction and drying. Lyophilised soluble coffees extracted by various methods from light, medium and dark-roasted arabica and robusta beans were evaluated for antioxidant activity (AA) using ABTS, Folin, DPPH and FRAP techniques. Caffeine, chlorogenic acid (5-CQA) and melanoidin content was also quantified. The data were analysed by principal component analysis. The AA values derived from the various methods used were correlated. Roasting resulted in the degradation of 5-CQA and formation of melanoidins, while AA was largely unaffected by roasting. The extraction of soluble coffee more prominently affected the AA of light-roasted coffee, mainly because it favoured the extraction of 5-CQA. The larger caffeine content in robusta coffee resulted in greater AA. All of soluble coffee products studied possessed antioxidant potential, which was conferred by their concentrations of phenolic compounds, caffeine and melanoidins.     

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。     

Tocopherols in cocoa butter obtained from cocoa bean roasted in different forms and under various process parameters

Obtaining good quality chocolate strongly depends on raw material, i.e. cocoa beans. The processing of cocoa beans consists of some important steps, including fermentation, drying fermented beans and roasting. Traditionally roasting is performed on whole beans but currently, roasting crushed cocoa beans or cocoa liquor becomes more and more popular. Many biologically active compounds may be found in the cocoa beans, including tocopherols. This work investigates the influence of the constant or variable roasting process parameters (temperature, velocity and relative humidity of roasting air) on the tocopherol concentration in cocoa butter (CB) extracted from cocoa beans originating from Togo and roasted in two different forms, namely as whole and crushed beans. Whole cocoa beans were roasted to a 2% moisture content and crushed cocoa beans were firstly partially dried which further enables easier dehusking, then ground, dehusked and roasted until their humidity decreased to around 2%. Roasting resulted in lowering the content of individual tocopherols in analyzed material. The degree of degradation of tocopherols in CBs was different, depending on the form of roasted beans from which these CBs were extracted. Higher concentrations were determined in CBs extracted from beans roasted in the form of crushed samples comparing to CBs obtained from beans roasted as a whole. The study investigates different roasting parameters of crushed beans, none of which drastically lowered the concentration of tocopherols in extracted CBs. Their concentration in CBs extracted from whole beans was, on the other hand, influenced by roasting air parameters. In case of whole beans roasted under constant parameters, application of 150 °C proved to be more favorable than roasting at 135 °C, as well as application of “dry” air and 1 m/s roasting air velocity. Discussing the variable roasting process parameters, in case of applied roasting temperature it is more favorable to change it from 150 °C to 135 °C, than the other way round. Changing the relative humidity of roasting air from 5 to 0.3%, lower degradation of tocopherols in CB occurs when the process is conducted at 150 °C. It may be further concluded that a direct dependence between the velocity of roasting air varied during the process and the concentration of tocopherols in extracted CB may not be indicated. In conclusion, it is stated that the temperature of the air applied during the roasting process has the decisive influence on the tocopherol content in CBs extracted from cocoa beans subjected to the process.     

Identification of Chemical Clusters Discriminators of Arabica and Robusta Green Coffee

The chemical parameters pH, soluble solids, caffeine, trigonelline, total chlorogenic acids, total caffeoylquinic acids, 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, 5-O-caffeoylquinic acid, total dicaffeoylquinic acids, 3,4-O-dicaffeoylquinic acid, 3,5-O-dicaffeoylquinic acid, 4,5-O-dicaffeoylquinic acid, total feruloylquinic acids, 3-O-feruloylquinic acid, and 5-O-feruloylquinic acid were measured in Arabica (C. arabica) and Robusta (C. canephora) green coffees in order to determine discrimination parameters. In general, Robusta green coffee showed higher values for pH, soluble solids, caffeine, total caffeoylquinic acids, total dicaffeoylquinic acid, and total feruloylquinic acid, but the content of soluble solids was not significantly different in both species of green coffee. Through application of a multivariate analysis, it was concluded that these chemicals form three clusters, being the group of caffeine, trigonelline, 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, 3-O-feruloylquinic acid, 5-O-feruloylquinic acid, 3,4-O-dicaffeoylquinic acid, 3,5-O-dicaffeoylquinic acid, and 4,5-O-dicaffeoylquinic acid highly discriminating for Arabica and Robusta green coffees.     

Effect of packaging materials and storage time on changes of colour,phenolic content,chlorogenic acid and antioxidant activity in arabica green coffee beans (Coffea arabica L. cv. Catimor)

The conditions and storage time of green coffee beans are very important for the commercial quality of coffee. This includes factors such as light, humidity and temperature in the warehouse and also the packaging material used. The aim of this study was to evaluate the effects of type of packaging materials namely high density polyethylene (HDPE) bag and jute sack on moisture content, colour, phenolic contents, chlorogenic acids content and antioxidant activity of Arabica green coffee bean during 15 months of storage. The results show that HDPE bag can preserve the moisture content, colour and chlorogenic acid in green coffee beans (GCB) better than a jute sack during storage. No significant difference of phenolics content in green coffee beans was observed during 4 months of storage in both types of packaging. During initial 10 months of storage the antioxidant activity of GCB stored in HDPE showed higher values than that of GCB stored in jute sack. However, after 1 year of storage, the phenolics content and antioxidant activity in GCB in a jute sack were higher than in HDPE bag. The fluctuation of moisture content could lead to stress condition of green coffee bean and contributing to forming of bioactive compounds. This finding was observed and need further investigation.