The microbiology of instant coffee

The microbiology of a coffee production line, as well as of the final products was investigated. Lactic acid bacteria were found to be the predominant microflora with lactobacilli as the major group and L. plantarum as the dominant species. Growth kinetics of this species were examined in the presence of pure caffeine solutions and at different concentrations of total solids of instant coffee. Total inhibition of growth was obtained at 15 mg ml^?1 of a pure caffeine solution and at 60% total solids of non-decaffeinated coffee.The growth kinetics of some pathogenic bacterial strains were examined in both decaffeinated and non-decaffeinated coffee; coffee liquor was not a suitable medium for growth of these strains. The spoilage micro-organism, Saccharomyces cerevisiae, was not inactivated in coffee liquor.     

Norharman and harman in instant coffee and coffee substitutes

Norharman and harman are two neuroactive β-carbolines present in several plants and thermally processed foods, including roasted coffee. The objective of this study was to evaluate their amounts in commercial instant coffee-based and coffee substitute beverages (n = 48), with variable amounts of coffee, chicory, barley, malt, and rye. All samples contained variable amounts of both β-carbolines, always with a higher proportion of norharman than harman. The highest levels (p < 0.01) were found in 100% instant coffees, with mean amounts of 3.8 μg/g and 1.5 μg/g for NH and H, respectively, followed by plain chicory. The lowest amounts were found in 100% barley, with 1.1 μg/g for NH and 0.3 μg/g for H. The NH and H content was statistically higher (p < 0.01) in all mixtures with coffee when compared to those without it. Nevertheless, and except for 100% barley, the amounts provided by beverages based on coffee substitutes are within those reported for standard coffee brews.     

荞麦“咖啡”生产工艺研究报告

采用养麦发芽、浸泡、烘炒的方法,生产出的荞麦“咖啡”色浓、味香,且芦丁保留量较高。正交试验结果表明,荞麦“咖啡”生产的最优工艺条件为：将荞麦进行发芽处理,荞米浸泡吸水时间为９０ｍｉｎ,烘炒温度及烘炒时间分别为２２０℃、３５－４０ｍｉｎ。     

果味速溶咖啡的研制

为了丰富速溶咖啡的产品线,满足更多消费者的口味需要,进行了果味速溶咖啡的研制。通过单因素和正交试验,对影响果味咖啡口感的主要因素咖啡粉、白砂糖、果味粉、植脂末的添加量进行了分析。结果表明,果味咖啡的最佳配方为:咖啡粉13.1%、白砂糖47.7%、果味粉7.7%、植脂末32.3%。     

Recent developments in the manufacture of instant coffee and coffee substitutes

This paper describes modern production methods resulting from the developments that have been taking place recently in the field of instant coffee and coffee substitutes. Such developments involve new processing techniques to achieve higher extraction yields and improve extract concentration, and more efficient spray drying. A tabulated comparison of operating conditions when spray drying chicory, pure coffee and chicory/coffee mixtures is given.     

海南产即溶咖啡粉中丙烯酰胺的膳食暴露风险评估

目的 开展海南即溶咖啡粉中丙烯酰胺的膳食暴露风险评估, 为咖啡粉质量安全的监管提供技术支撑。方法 采用食品安全风险评估的一般步骤: 危害识别、危害特征描述、膳食暴露评估、风险特征描述, 对海南即溶咖啡粉中的丙烯酰胺进行膳食暴露风险评估。结果 各年龄段居民的理论暴露量均低于其理论每日允许摄入量。结论 海南产即溶咖啡粉中的丙烯酰胺不会对消费者身体健康产生危害, 不必进入风险管理程序。     

Relating consumer preferences to sensory attributes of instant coffee

The sensory profiles of 11 instant coffees including pure coffees (PC), coffee blends (CB) and a chicory instant drink (CID), commercially available in South Africa, were described and quantified. These were then related to consumer preferences (n=199) for the instant coffees using preference mapping. Based on consumer preferences, four consumer groups were identified, “pure coffee lovers” (23%), “coffee blend drinkers” (30%), “general coffee drinkers” (37%) and “not serious coffee drinkers” (10%). The “pure coffee lovers” prefer the more astringent, bitter, roasted, nutty and full-bodied flavour of the pure coffee samples. The less intense coffee flavour character, but higher sweetness and root flavour, typical of chicory blended instant coffee, were attributes that were preferred by the “coffee blend lovers”. The “general coffee drinkers” seem to consume coffee out of habit and are less concerned about the specific sensory properties of the coffee.     

速溶咖啡生产控制和质量改善的研究

简述了速溶咖啡的生产工艺及质量控制关键因素的调控方法以及品质改善的方法。     

Minimal clean-up and rapid determination of polycyclic aromatic hydrocarbons in instant coffee

The essential aim of this work is the development of a simple, fast, quantitative and economic method for polycyclic aromatic hydrocarbons (PAHs) potentially generated by roasting coffee beans, which is the most important process in the coffee industry for the development of the characteristic flavour of the bean mix. The PAHs were chosen because they differed in the number of aromatic rings, had different polarity, have low residual limits, are commonly widespread in the environment and are generated by roasting. The key issue is whether or not the most polar PAHs, those with lower molecular weight or less rings, appear in the water extracts of ground roasted coffee beans, taking into account that those PAHs with lower molecular weight are those with higher volatality. The proposed analytical method is also broadly applicable to other roasted foods or their aqueous extracts. The method was evaluated by constructing calibration curves, measurement of recovery and precision, and the limits of detection. The method involves extraction with hexane, clean-up with a silica cartridge, concentration to dryness and injection of the acetonitrile solution of the residue for HPLC analysis with fluorescence detection. The method allowed to confirm or not the presence of the selected PAHs in instant coffees.     

Mitigation of acrylamide and hydroxymethyl furfural in instant coffee by yeast fermentation

Acrylamide being known as carcinogenic and hydroxymethyl furfural (HMF) being known as cytotoxic compounds are heat induced process contaminants found in instant coffee. Today's instant coffee production method involves roasting of coffee beans, grinding, flavor and aroma separation, extraction, concentration, and drying steps. During roasting, acrylamide and HMF are formed in varying amounts depending upon the degree of heat treatment as a result of the Maillard reaction. This study was conducted in order to reduce the concentrations of acrylamide and HMF in instant coffee. Instant coffee (20%, w/v) was mixed with sucrose (0–10, w/v) and baker's yeast (Saccharomyces cerevisiae, 1–2%, w/v) in a tightly closed glass vessel. The mixture was fermented at 30 °C for 48 h. The kinetics of acrylamide and HMF degradation was investigated. HMF and acrylamide contents were reduced exponentially at varying rates, depending upon fermentation medium and time. After 24 h, HMF concentration was decreased by 61.2%, 75.7%, 93.6% and 99.2% in the fermentation media containing none, 1%, 5%, and 10% of sucrose, respectively. After 48 h, acrylamide concentration was decreased by about 70%. These results revealed that yeast fermentation is promising for the mitigation of HMF and acrylamide in instant coffee.     

焙焦油莎豆粕速溶咖啡的开发及其品质分析

目的 开发焙焦油莎豆粕速溶咖啡并对其品质进行研究。方法 将制备的焙焦油莎豆粕速溶粉与咖啡速溶粉、白砂糖、脱脂奶粉进行复配,通过单因素和正交试验设计,以感官评分为指标,优化产品配方。再利用气相色谱-质谱法对咖啡品质和理化性质进行分析。最后利用微流变分析冲释稳定性,确定食用条件。结果 确定焙焦油莎豆粕速溶咖啡最佳配比为焙焦油莎豆粕速溶粉添加量35%,咖啡速溶粉添加量5%,白砂糖添加量35%,奶粉添加量30%。咖啡成品脂肪含量为0.99%,蛋白质含量为10.01%,溶解度为94.58%,酸度为22.52%,固形物含量为7.75%。咖啡中含有34种香气成分,冲释后2h内具有较好的流变学品质。结论 油莎豆粕中含有丰富的功能活性因子,本产品的成功研发强化了咖啡的功能特性,拓宽了油莎豆副产物的应用范围,提高了油莎豆副产物的应用价值。     

D-最优混料设计优化肉苁蓉速溶咖啡加工工艺

目的 结合工厂实际优化肉苁蓉速溶咖啡配方加工工艺。方法 运用模糊综合评价法结合D-最优混料设计对肉苁蓉速溶咖啡配方进行优化, 考察总粉量、加糖量、总浸粉的占比及肉苁蓉和咖啡浓缩液的质量比对感官评分的影响。建立组成成分与肉苁蓉速溶咖啡感官评价之间的回归模型, 通过JMP软件优化得到最佳的加工工艺条件。结果 肉苁蓉速溶咖啡的最佳工艺配方: 总粉量20%、加糖量25%、总浸粉55%、肉咖比1:2、2种混合浓缩液与麦芽糊精之比1:0.6; 最佳的冲调比例: 粉水比1:8。在此条件下的感官评分为96.80分, 与预测感官评分的偏差为0.23%, 不存在显著性差异(P>0.05)。结论 本研究建立的方法及模型真实有效, 可为实际生产提供参考依据。     

Comparison of antioxidant and pro-oxidant activity in coffee beverages prepared with conventional and “Torrefacto” coffee

Antioxidant and pro-oxidant properties of coffee can be affected by several factors such as coffee variety, roasting process, storage, etc. The aim of this study was to compare the antioxidant and pro-oxidant properties of coffee beverages obtained with conventional and torrefacto roasted coffee.Coffee variety influences on the antioxidant capacity of ground coffee. A100 roasted samples presented lower antioxidant capacity than Robusta varieties. This could be due to the higher percentage of chlorogenic acids in Robusta ground coffee than in Arabica. Beside, A100 samples presented the highest value of pro-oxidant activity because these samples presented less efficient antioxidants.In Torrefacto roast, the antioxidant capacity increased and redox potential decreased due to the formation of MRPs, which have reducing properties.     

Evaluation of test conditions during the measurement of coffee stability of instant whole milk powder

Coffee provides a harsh environment for the reconstitution of milk powder with undissolved powder being manifested as undesirable 'floaters' or 'sinkers'. A coffee test method was adapted to explore the behaviour of a range of industrial samples of coffee stable and coffee unstable instant whole milk powders, under varying pH, temperature and water hardness. The development and application of a simulation test suggests evidence of some stabilizing contribution by the coffee itself. High surface fat coverage, as determined by electron spectroscopy for chemical analysis, and high ionic calcium levels were associated with instances of poor coffee stability. The effects of the physicochemical characteristics of the powders on coffee stability appear to predominate when various measures were implemented, such as prior reconstitution of the powder before addition to coffee, increased agitation and use of surface active agents, which succeeded in reducing coffee sediment.     

Caffeinated and decaffeinated instant coffee consumption partially reverses high-fat diet-induced metabolic alterations in mice

Epidemiological data has associated coffee consumption with a lower prevalence of type 2 diabetes, metabolic syndrome and chronic liver disease. However, the mechanisms and coffee substances responsible for these effects remain unclear. In the present study, mice received caffeinated or decaffeinated instant coffee ad libitum during a two week period after inducing obesity by introducing a high-fat diet over a 10 week period. Body weight, glucose homeostasis, and liver and visceral adipose tissue inflammation were assessed. In addition, AKT signaling, the fatty acid profile and liver histopathological analyses were performed. Ingestion of caffeinated or decaffeinated coffee for 2 weeks resulted in reductions in glucose and insulin blood levels, and insulin tolerance was improved without reductions in final body weight or adiposity. Only caffeinated coffee modified the adipokine profile in visceral adipose tissue, resulting in a restoration of adiponectin levels. However, deleterious liver alterations, which manifested as reductions in steatosis, inhibition of iNOS expression and restoration of insulin inducing-AKT phosphorylation, were reversed by the ingestion of both caffeinated and decaffeinated coffee. Serum AST and ALT levels were also improved in mice after coffee ingestion, while the fatty acid profile in the liver and the cytokine profiles in adipose and liver tissues were not altered by coffee ingestion. Thus, instant coffee consumption reverses obesity-induced alterations in mice, and our results corroborate those of epidemiological studies that associated coffee consumption with a lower prevalence of obesity-related pathologies.     

Evaluation of sensory attributes of coffee brews from robusta coffee roasted under different conditions

Robusta coffee beans with a different initial moisture of 5, 7.5 and 10% were convectively roasted at 230 °C, microwaved at 700 W, and roasted by the coupled convective-microwave method. Sensory attributes of brews prepared from these coffee samples were evaluated. Final temperature of microwaved coffee beans was lower than that of the beans processed by the two other methods, which resulted in a higher content of volatile aroma compounds and a lesser degree of charring of their surface. Lower initial humidity of coffee beans shortened the time of roasting. However, the aroma developed upon roasting of the moistest beans was the most intense and pleasant. Modification of roasting conditions increased shifting of the overall acceptability of coffee infusions by 2 points in a 10-point hedonic scale, which implies that, if roasting conditions are adequate to the type of coffee, its sensory characteristics can be improved. Thus, optimization of roasting parameters can increase the share of robusta in well-accepted commercial coffee blends, a convenient fact because of the significant difference in price between the latter and arabica coffee.     

方便米饭品质特性与原料适应性的研究

精选37个品种稻米制作方便米饭,分析原料大米的成分、蒸煮品质、质构性质以及方便米饭的感官品质之间的关系。结果表明,质构仪指标中弹性与感官指标中的弹性显著正相关,咀嚼性与软硬度呈显著正相关,大米成分中的直链淀粉含量和蛋白质含量与方便米饭的软硬度有显著负相关性,与方便米饭颜色呈正相关,利用TPA实验和食味计可以快速辅助感官评价实验对方便米饭感官品质进行评价。选用直链淀粉含量低,蛋白质含量低,吸水率和体积膨胀率小的大米品种制作的方便米饭感官品质较好。