The measurement of feruloylquinic acids and caffeoylquinic acids in coffee beans. Development of the technique and its preliminary application to green coffee beans.

This paper describes the development of a quantitative, colorimetric technique for the determination of feruloylquinic acids, caffeoylquinic acids and total chlorogenic acids in synthetic mixtures and green coffee beans. The results are analysed statistically and discussed with reference to previously published data.     

咖啡生豆多糖提取及抗氧化活性

目的:为咖啡中多糖成分的研究和天然活性多糖的开发提供基础数据。方法:研究了云南小粒咖啡生豆多糖(GBP)的水提工艺和抗氧化活性。应用响应面法对咖啡生豆多糖提取工艺进行优化;运用傅里叶变换红外光谱(FT-IR)和扫描电镜(SEM)共同鉴定和表征咖啡生豆多糖的结构特点。采用DPPH自由基、ABTS自由基清除试验和FRAP法评估咖啡生豆多糖体外抗氧化能力。结果:咖啡生豆多糖水提法的最佳工艺条件：提取温度59℃、提取时间45 min、液料比(V_水∶m_咖啡生豆)21∶1 (mL/g)、浓缩体积1/8及乙醇体积分数75%,该条件下咖啡生豆多糖得率达9.56%。多糖样品经红外光谱和电镜扫描显示咖啡生豆是表面呈不规则的孔状结构的多糖。咖啡生豆多糖对DPPH自由基、ABTS自由基清除能力分别为2.32 mg/mL(IC₅₀)、0.011 mmol Trolox/g GBP,铁还原能力为0.95 mmol Fe²⁺/g GBP。结论:咖啡生豆多糖是具有抗氧化活性的不规则孔状结构多糖,具有进一步研究和开发的价值。     

Strontium and oxygen isotope fingerprinting of green coffee beans and its potential to proof authenticity of coffee

Multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) and Isotope Ratio Mass Spectrometry (IRMS) were applied to combine strontium and oxygen isotope abundance ratios of green coffees from 20 geographical origins in order to evaluate the suitability of these parameters as indicators of geographical origin, which is an important parameter of coffee quality. Results show that both isotopic systems of green coffee beans show a relation to environmental factors that influence processes occurring during the growth of the coffee bean. The final results allowed discrimination of local provenances investigated in this study by principal component analysis (PCA) and exhibit the potential to proof authenticity of world coffees. A good discrimination was obtained especially for coffee of South America region and coffees originating from islands.     

黑豆花生复合饮料的研制

以黑豆、花生为主要原料,经烘烤、磨浆、调配等工序研制黑豆花生复合饮料。通过正交试验,以感官鉴定评分为考察指标,研究了黑豆花生复合饮料的配方及稳定剂添加比例。试验结果表明：采用50%黑豆浆、40%花生浆、加糖量5%的饮料配方时,感官品质最佳;添加0.1%蔗糖酯、0.05%羧甲基纤维素钠、0.05%海藻酸钠制成的饮料稳定性较好。     

Overview on the mechanisms of coffee germination and fermentation and their significance for coffee and coffee beverage quality

Quality of coffee is a complex trait and is influenced by physical and sensory parameters. A complex succession of transformations during the processing of seeds to roasted coffee will inevitably influence the in-cup attributes of coffee. Germination and fermentation of the beans are two bioprocesses that take place during post-harvest treatment, and may lead to significant modifications of coffee attributes. The aim of this review is to address the current knowledge of dynamics of these two processes and their significance for bean modifications and coffee quality. The first part of this review gives an overview of coffee germination and its influence on coffee chemistry and quality. The germination process initiates while these non-orthodox seeds are still inside the cherry. This process is asynchronous and the evolution of germination depends on how the beans are processed. A range of metabolic reactions takes place during germination and can influence the carbohydrate, protein, and lipid composition of the beans. The second part of this review focuses on the microbiota associated with the beans during post-harvesting, exploring its effects on coffee quality and safety. The microbiota associated with the coffee cherries and beans comprise several bacterial, yeast, and fungal species and affects the processing from cherries to coffee beans. Indigenous bacteria and yeasts play a role in the degradation of pulp/mucilage, and their metabolism can affect the sensory attributes of coffee. On the other hand, the fungal population occurring during post-harvest and storage negatively affects coffee quality, especially regarding spoilage, off-tastes, and mycotoxin production.     

Effect of zinc and its form of supply on production and quality of coffee beans

BACKGROUND: In Brazil, the usual forms of zinc (Zn) supply to coffee plants have limitations that compromise the element availability to the plant. This study proposes to test an alternative approach to supplying the nutrient to Coffea arabica L. using trunk implanted zinc tablets. Additionally, the effect of Zn on the production and quality of coffee beans was also evaluated. RESULTS: The highest total coffee bean production was recorded in plants implanted with Zn tablets (TA), while the lowest was recorded in the control treatment, without zinc supply (WZn), reaching a bianual production of 188.2 and 130.1 60‐kg bags of processed beans per hectare, respectively. In the treatments where Zn were applied as tablet implantation or as foliage spraying (SZn); the bean size was larger, while the grain electrical conductivity and potassium leaching were lower compared with WZn. CONCLUSION: Zn supply via tablet implantation into tree trunks provides yield and quality similar to those obtained by foliage spraying. Independent of the form of supply, Zn positively influences the production and quality of coffee beans. Copyright © 2011 Society of Chemical Industry     

Diffusion phenomena during the decaffeination of coffee beans

The coffee bean behaves with respect to the diffusion of caffeine almost as perfectly as a spherical model system. This behaviour is a consequence of at least two opposite effects—the taking up of solvent and the water loss. The overall change of the diffusion coefficient caused by these factors remains, however, small compared with the shifts brought about by the parameters investigated: water content and temperature. It is therefore reasonable to express the effects of these variables by using a single quantity, namely, the average apparent diffusion coefficient which, for Columbia and Robusta coffee and at optimal experimental conditions, lies in the range 0·5–1·3.10^?6 cm² sec^?1.     

Impact of gamma irradiation on the monsooning of coffee beans

Monsooned coffee is a special coffee produced only in India. As the process is carried out during the monsoon period, the time taken for monsooning is dependent on rainfall and atmospheric humidity. Traditional methods employed in the monsooning process favour growth of microorganisms, which may affect the quality of the produce. The present study aimed to understand the role of microorganisms in the monsooning process. Coffee beans (both Arabica and Robusta variety) were subjected to irradiation treatments of 5 kGy (kilo Gray) and 10 kGy doses in order to achieve the above objective. Irradiation led to reduction of natural mycoflora with the 10 kGy dose being more efficient than the 5 kGy dose. Aspergillus niger was found to be the dominant fungus colonising the beans prior to monsooning, whereas A. ochraceus was found dominant during the course of monsooning. The other commonly encountered fungi were species of Aspergillus, Penicillium, Absidia, Syncephalastrum, Mucor and Rhizopus occuring at low numbers. At the start of the monsooning process, irradiated samples showed negligible numbers of microorganisms and also lesser number of fungal species during monsooning compared with the non-irradiated samples. Non-irradiated samples took five weeks for the completion of monsooning compared with two weeks for irradiated samples and hence it may be inferred that microorganisms may be playing a minimal role in monsooning.     

黑豆纳豆饮料发酵条件的研究

以黑豆作为原料,采用纳豆芽孢杆菌进行发酵,比较黑豆汁初始pH值、接种量、发酵温度、发酵时间对纳豆激酶活性和饮料感官评分的影响.并通过L9(3 4)正交试验,确定最佳发酵条件为:接种量4％,发酵温度33℃,发酵时间24 h、黑豆汁初始pH值7.5.在此条件下可以获得酶活性达到627.5 U/ml、口感较好、兼具黑豆营养成分和纳豆营养产物的新型发酵饮料.     

仿咖啡乳饮料的研究

研究了用决明子、脱脂奶粉、大豆芽、小麦等加工咖啡味乳饮料的最佳组合及加工的最适工艺条件。试验结果表明：决明子、大豆芽烘烤,小麦炒炭,粉碎,分别以决明子2g、大豆芽1.5g、小麦0.6g的比例加入水中,在95℃下恒温浸提1h,过滤,再溶入脱脂奶粉3g,可得到色泽纯厚、苦味适中、易消化吸收、具有咖啡的口感和风味但不含咖啡因的饮料。     

乳化剂对咖啡乳饮料脂肪稳定性的影响

随着西方文化的渗透,咖啡成为越来越多的消费者喜闻乐见的饮料产品,国内即饮咖啡市场也随之愈发壮大,咖啡加牛奶是中国消费者最为接受的咖啡产品形式,但货架期内产品的稳定性仍是困扰各食品饮料企业的技术难题,其中脂肪上浮是含乳饮料常见的现象,通过控制脂肪上浮,改善体系稳定性成为咖啡乳饮料研制中的关键问题。本文针对以乳粉、咖啡为主要原料而研制出的咖啡乳饮料进行了稳定性研究,选取单甘脂、蔗糖酯、三聚甘油酯、SSL、DATEM、酪蛋白酸钠进行单因素试验,并进行L_8(2~7)正交试验,以脂肪上浮情况作为评价指标,确定最优的乳化配方为:单甘酯0.15%,SSL0.04%。     

黑豆醒酒饮料的研制

采用甲醛滴定法,对中性蛋白酶、碱性蛋白酶和木瓜蛋白酶进行筛选,确定最佳酶解黑豆蛋白的酶.结果发现碱性蛋白酶酶解较果最好,且确定了碱性蛋白酶的最适宜酶解条件:时间为5h,温度为50℃,酶的添加量为1200U/g,pH值为9.后采用正交试验的方法,确定了黑豆醒酒饮料调配的最适宜比例:黑豆蛋白肽混合液70％,蜂蜜4g/150mL,白砂糖11g/150mL.最后,根据瓦勒-霍赫法对黑豆醒酒饮料进行体外试验,得出酶解后的黑豆蛋白肽能够激活乙醇脱氢酶(ADH),而ADH能够增强乙醇的代谢,从而降低人体中乙醇的浓度,测得本实验产品对ADH的激活率达到了31.98％.     

Investigations of peptides and proteases in green coffee beans

Cof. canephora var. robusta. The coffee types were not significantly different in peptide content, but were significantly different in peptide composition. Peptides with weakly acid pI values were mainly found in the Cof. robusta samples. In comparison, peptides from Cof. arabica samples ranged evenly from the weakly acidic up to the weakly basic pH range. The apparent molecular masses of the peptides in the two groups of samples lie between 4 kDa and 10 kDa. The cysteine content of the peptides was relatively high. Model roastings permitted the assumption that peptides make a contribution to coffee flavour. Peptides are already available in freshly harvested coffee. Model tests have suggested that processing after the coffee harvest has an influence on peptide composition but not on the amounts of peptide. All coffee samples contained some extractable proteases. The electrophoretically obtained enzyme patterns of Cof. arabica and Cof. robusta were different. Received: 6 September 1999     

基于YOLOv5的咖啡瑕疵豆检测方法

目的:实现咖啡豆瑕疵检测。方法:提出一种基于改进YOLOv5s网络,以YOLOv5s为基线网络嵌入并优选不同的注意力机制模块与激活函数。结果:使用CBAM模块与激活函数Hardswish的平均精度均值相比基线网络分别提高了5.3%和2.9%。经过200次迭代训练,模型准确率为99.5%,平均精度均值为97.6%,召回率为0.98,识别速率为64幅/s,模型大小为15 M。结论:相比于Faster RCNN、SSD、YOLOv3、YOLOv4、YOLOv5s,试验算法识别准确率更高,模型更加轻量化,对咖啡瑕疵豆的识别效果更好。     

绿咖啡豆中总绿原酸提取工艺优化

研究了绿咖啡豆中总绿原酸的提取工艺。以未烘焙的绿咖啡豆为实验材料,采用浸提的方法提取总绿原酸。在单因素实验基础上,选择溶剂体积分数、温度、p H、料液比等4个影响因素进行响应面设计。采用Box-Behnken中心组合实验设计和响应面分析法,建立以绿咖啡豆中总绿原酸提取得率为响应值的二次回归方程。结果表明溶剂体积分数、温度、p H、料液比对多酚提取率的影响显著,最佳提取条件为乙醇体积分数75%、温度45℃、p H3、料液比1∶6,在此条件下能得到最大提取率为90.88%。     

连锁经营对国际咖啡产业的影响及趋势分析

咖啡是世界上消费量最大的两种热饮料之一,连锁经营化是近年全球咖啡消费市场的一次重要的发展机遇。2010～2015年咖啡消费市场进入高速发展期,咖啡连锁店遍布世界各大中城市的各个角落,为分析国际咖啡市场的动态提供了一种思路,即透过连锁经营的发展路径来了解咖啡消费市场的动态与趋势。     

绿咖啡豆中绿原酸的分离纯化

对未烘焙绿咖啡豆中绿原酸的分离纯化进行深入研究.采用热水重复分批浸提法,在单因素实验基础上,采用Box-Behnken中心组合实验设计响应面分析法,获得了绿咖啡豆中绿原酸的最佳提取条件:温度79.8℃,溶剂pH值2.8,料液比1∶6,提取时间3.0 h,绿原酸的最大提取得率为92.0％.比较了多种不同规格的树脂对绿原酸的分离纯化效果,最终选用XDA-8大孔树脂,在优化后的最适工艺条件下,绿原酸含量可达70.9％,回收率达85.4％.进一步采用高效液相制备色谱获得了高纯度(95.2％)的绿原酸.所建立的绿原酸制备工艺操作简便、高效环保,产品功效明确,具有良好的市场应用前景.     

咖啡发酵含乳饮料的研制

研究了卡拉胶、耐酸型CMC、琼脂、黄原胶及其复配稳定剂在咖啡发酵型含乳饮料中的应用,通过正交试验得到咖啡发酵含乳饮料的最佳配方,即15％的咖啡萃取液、50％的发酵乳、3％的复配稳定剂Ⅱ(0.1％卡拉胶+0.1％耐酸型CMC)和8％的白砂糖.结果表明,咖啡发酵型含乳饮料口感和稳定性最佳,理化指标、感官指标、微生物指标都可以达到所要求的范围,常温贮存时间2个月以上,可以应用于生产实践.