基于主成分分析优化咖啡微水脱胶工艺

为优化微水脱胶工艺，本文分析机械脱皮脱胶+晒干（A）、机械脱皮脱胶+烘干（B）、手工脱皮+带胶烘干（C）、机械脱皮脱胶+水洗脱胶+烘干（D）及手工脱皮+水洗脱胶+烘干（E）五种不同加工工艺对咖啡生豆中香味前体物质（蛋白质、粗脂肪）、滋味呈味物质（咖啡因、绿原酸、咖啡酸）及挥发性物质相对含量的影响。结果显示，机械脱皮脱胶+烘干处理组相比于手工脱皮+带胶烘干处理组，随着果胶残留量的增加，咖啡生豆中绿原酸、咖啡酸含量显著增加（P<0.05），蛋白质含量显著减少（P<0.05）；机械脱皮脱胶+水洗脱胶+烘干处理组相比于机械脱皮脱胶+烘干处理组，咖啡生豆中粗脂肪、咖啡酸含量显著增加（P<0.05）；机械脱皮脱胶+烘干处理组相比于机械脱皮脱胶+晒干处理组，咖啡生豆中绿原酸、咖啡酸含量显著增加（P<0.05）。手工脱皮+带胶烘干、手工脱皮+水洗脱胶+烘干处理后咖啡生豆中蛋白质、粗脂肪、咖啡因含量均较低，机械脱皮脱胶+水洗脱胶+烘干处理后咖啡生豆中蛋白质含量最高，达13.71%，粗脂肪含量仅次机械脱皮脱胶+晒干，为9.84%。按照品质指标综合得分由高到低排名：D>B>...     

橡木片浸泡发酵对赤霞珠干红葡萄酒品质的影响

选用内蒙古乌海地区赤霞珠葡萄品种为原料,采用橡木片浸泡发酵法,酿制赤霞珠干红葡萄酒。通过测定比较发酵期间、发酵结束及陈酿后赤霞珠干红葡萄酒的理化指标并进行感官评定,确定最佳的橡木片添加量,进而提高赤霞珠干红葡萄酒品质。结果表明,在葡萄醪液中加入1 g/L的天然橡木片进行发酵及陈酿,最终得到的赤霞珠干红葡萄酒色度（2.35）、色调（0.84）、单宁（850.5 mg/L）、总酚（1 254.7 mg/L）均有明显改善且酒体较为稳定,明胶指数和盐酸指数最高分别为194.4 mg/L和195.0 mg/L,其感官评分为83分。因此,添加1 g/L天然橡木片浸泡发酵能改善赤霞珠干红葡萄酒品质。     

湿法加工关键环节对咖啡品质的影响

目的:优化咖啡湿法加工工艺。方法:探究果胶酶添加量、温度及咖啡干燥方式对咖啡豆风味前体物质、滋味呈味物质含量的影响,通过灰色关联度分析获得质量排序并开展挥发性物质分析。结果:不同果胶酶添加量、温度及晒干、烘干处理样品的蛋白质、粗脂肪、咖啡酸、咖啡因、绿原酸含量及挥发性物质相对含量之间有显著性差异,灰色关联度分析得到2%果胶酶+27℃+晒干处理组咖啡质量排序第一,其生豆中蛋白质含量为14.04%,粗脂肪含量为9.05%,熟豆中咖啡酸含量为1.05 mg/g,咖啡因含量为1.41%,绿原酸含量为13.89 mg/g,主要挥发性物质酯类、酸类的相对含量分别为40.87,7.62μg/g。结论:2%果胶酶+27℃+晒干处理得到的咖啡综合品质最佳。     

酶解咖啡鲜果对烘焙咖啡饮用品质和化学成分的影响研究

选用不同种类的酶对云南小粒咖啡去皮鲜果进行酶解,确定胃蛋白酶最适于制备麝香猫咖啡,随后进行了胃蛋白酶酶解咖啡鲜果的条件优化,确定最佳酶解条件为胃蛋白酶添加量1%,酶解2 h,酶解温度55℃,此时感官评分为13.5分,高出未处理咖啡鲜果的感官评价结果 1倍。同时研究酶解对咖啡鲜果中主要化学成分的影响,及其对咖啡鲜果烘焙后饮用品质的作用。     

基于模糊感官评价的大豆品种对豆浆加工品质影响分析

以黑龙江产区6?个大豆品种为原料,测定了大豆籽粒的百粒质量和粗蛋白质、粗脂肪、钙、磷水平等理化指标以及加工制成豆浆的得率、理化品质,并基于模糊感官评价方法分析了不同品种大豆的豆浆感官品质,进一步分析了大豆籽粒与豆浆理化指标和感官品质之间的相关性。结果表明：6?个大豆品种中‘中龙606’制得的豆浆综合感官品质最佳,且具有甜度高、豆香味浓郁、色泽良好、豆腥味和涩感相对较弱的特点;在现有的品种中蛋白质量分数低于40%,且脂肪质量分数较高的品种更有利于加工高品质豆浆。     

低度艾草酒研制

以全脂乳粉、脱脂乳粉、咖啡为主要原料,添加蔗糖,以安琪酵母8型菌为发酵剂,酸奶感官品质评分和酸奶黏度的综合评分为考察指标,采用正交试验方法对凝固型咖啡酸奶配方进行优化,得到最佳的发酵咖啡酸奶的工艺与配方。结果表明,在发酵温度为42 ℃条件下发酵6 h,脂肪含量3.4%,咖啡添加量1.0%,蔗糖添加量6%,8菌型发酵剂添加量0.1%,发酵后在4 ℃条件下冷藏24 h,获得的发酵酸奶的感官品质评分为89分,黏度为5 640 mPa·s,产品组织状态均匀,口感细腻,略带有咖啡香味,感官评价最佳。最佳发酵条件下的酸度为88 °T,pH值为4.24,乳酸菌活菌数为1.25×108 CFU/mL,符合GB 19302—2010对酸奶品质的规定。     

凝固型咖啡酸奶的研制

以全脂乳粉、脱脂乳粉、咖啡为主要原料,添加蔗糖,以安琪酵母8型菌为发酵剂,酸奶感官品质评分和酸奶黏度的综合评分为考察指标,采用正交试验方法对凝固型咖啡酸奶配方进行优化,得到最佳的发酵咖啡酸奶的工艺与配方。结果表明,在发酵温度为42 ℃条件下发酵6 h,脂肪含量3.4%,咖啡添加量1.0%,蔗糖添加量6%,8菌型发酵剂添加量0.1%,发酵后在4 ℃条件下冷藏24 h,获得的发酵酸奶的感官品质评分为89分,黏度为5 640 mPa·s,产品组织状态均匀,口感细腻,略带有咖啡香味,感官评价最佳。最佳发酵条件下的酸度为88 °T,pH值为4.24,乳酸菌活菌数为1.25×108 CFU/mL,符合GB 19302—2010对酸奶品质的规定。     

外源菌种和辅助碳源发酵糟辣椒条件优化与品质分析评价

为探讨菌种辅助碳源对糟辣椒发酵品质的影响,在分析不同处理条件下糟辣椒发酵pH、总酸、脆度及感官指标的基础上,采用模糊数学法结合逼近理想解排序(technique for order preference by similarity to an ideal solution,TOPSIS)法筛选最佳处理条件。研究发现:乳酸菌接种量、葡萄糖及乳糖添加量越大,发酵速度越快(P<0.05),而果胶添加量小于0.25%时,发酵速度较空白组快;发酵第30天,接种组、葡萄糖及乳糖处理组在果胶添加量小于0.75%时,脆度值大于空白组;葡萄糖及乳糖处理组在乳酸菌接种量低于3%时,感官评分高于空白组,而果胶处理组感官评分均低于空白组。通过TOPSIS法综合评价及验证实验最终得出,接种体积分数为2%的乳酸菌、添加50 g/L葡萄糖或30 g/L乳糖有利于促进发酵液中乳酸菌的生长及糟辣椒脆度的保持,发酵成品品质最优。模糊数学-TOPSIS法筛选外源物质在糟辣椒发酵中应用的工艺参数具有可靠性。     

糖醇替代对芸豆蜜豆品质特性的影响

为开发无糖芸豆蜜豆,选用赤藓糖醇、麦芽糖醇、木糖醇、山梨糖醇完全替代糖渍液中的蔗糖,通过分析不同糖醇对芸豆蜜豆色度、质构、含水量、水分活度、γ-氨基丁酸(GABA)含量、消化特性及感官品质的影响以确定最佳蔗糖替代物。结果表明,4种糖醇在保持GABA含量的基础上(P>0.05),提高了芸豆蜜豆的亮度,显著降低芸豆蜜豆的硬度、咀嚼度、水分活度及估计血糖生成指数(eGI)(P<0.05)。麦芽糖醇芸豆蜜豆的eGI最低,显著降低了30.25%(P<0.05)。4种糖醇及蔗糖芸豆蜜豆综合感官评分分别为72.60、79.50、80.60、72.70、80.70,其中麦芽糖醇、木糖醇芸豆蜜豆与蔗糖组最为接近(P>0.05)。综合考虑,麦芽糖醇是替代蔗糖开发无糖芸豆蜜豆的最佳选择。     

酿酒酵母多物混合发酵对咖啡豆风味品质的影响

中国咖啡主产于云南,云南咖啡在花果风味及甜香风味方面有所欠缺,发酵是影响咖啡风味品质的重要因素之一.利用酿酒酵母在低温厌氧条件下发酵咖啡鲜果,添加香草、肉桂、热带水果、蜂蜜等原料为基底共同发酵,最终对发酵咖啡豆进行理化、香气成分分析及主观评价,探究发酵对咖啡品质的影响.结果表明:添加香草、肉桂、苹果、甜橙、香蕉、蜂蜜发酵的咖啡与无添加的对照组咖啡相比,灰分和脂肪含量无差异(P>0.05),可溶性蛋白质含量显著提高(P<0.05),底物的添加对最终咖啡豆中多糖、还原糖、总蛋白质、多酚有不同程度的影响,无明显规律.采用气相离子迁移色谱(gas chromatography-ion mobility spectrometry,GC-IMS)对发酵咖啡生豆挥发性成分进行分析,共定性出36种化合物,9种酯、6种酮、8种醛、6种醇、5种烯萜、1种呋喃、1种酸类,其中酮、醛、醇、酯类共占挥发性成分的60％以上.结合感观评价结果,香草、肉桂、热带水果与咖啡发酵可赋予咖啡水果香气,提升咖啡花果香特质,其中香料组、甜橙组达精品咖啡标准,香蕉组香气较为突出,蜂蜜组在香气方面未有突出特点,且酸度过高对甜度提升不足.研究为进一步改善云南咖啡花果甜香特质,提升咖啡风味提供一定理论依据和数据支持.     

Improvement of coffee beverage quality by using selected yeasts strains during the fermentation in dry process

Coffee is an important commercial product to Brazil with its consumption distributed globally. The aim of this work was to evaluate the potential of yeast strains as starter cultures for dry fermentation of washed and non-washed coffee beans. Four yeast strains (Saccharomyces cerevisiae UFLA YCN727, S. cerevisiae UFLA YCN724, Candida parapsilosis UFLA YCN448 and Pichia guilliermondii UFLA YCN731) were inoculated separately in washed and non washed coffee cherries and in the control was not added any of the starter cultures. The fruits inoculated were spread on trays and placed on a terrace until the coffee beans reached 11% of moisture. Samples were collected for evaluation of the persistence of the inoculum by PCR-DGGE, and for chemical composition by HPLC and GC-FID. Sensory analysis was performed using the Temporal Dominance of Sensations (TDS) methodology. In all tests the yeasts persisted until the end of fermentation. There was no propionic and butyric acid production in concentrations that could compromise the final quality of the beverage. Forty-eight volatile compounds were identified, some were similar for green and roasted coffee. The most abundant class of compounds was alcohols (11–27%) followed by furan in roasted grains (~ 27%), and aldehydes (~ 13%) in green grains. The coffee inoculated with yeast showed sensations of flavors higher than the control coffee indicating increased sensory quality. The treatment with C. parapsilosis UFLA YCN448 showed dominance rate higher (near 1) for the sensation of caramel. In non-washed coffee those sensations were not pleasant in relation to the washed coffee, except when P. guilliermondii UFLA YCN731 was inoculated, suggesting that washing the fruit before the fermentation process positively influenced the final product quality. A coffee with special aroma of caramel, herbs and fruits could be produced using the starter cultures C. parapsilosis UFLA YCN448 and S. cerevisiae UFLA YCN727 in coffee processed by the dry method.     

Metagenomics and metabolomic profiles of Coffea canephora processed by honey/pulped natural technique

Post-harvest processing of coffee is the dominant factor affecting the metabolite composition and quality of the final brew. This study proposes a novel coffee processing method based on an established semi-dry process. Honey/pulped natural coffee (HC) process combines fermentation and drying excluding the washing stage thus conserving water, unlike wet method. Robusta coffee (Coffee canephora) mucilage was monitored for the evolution of bacterial and fungal diversity along with metabolites produced. Lactic acid bacteria (LAB) (48%) and the major fungal community of Wallemia (31%), a selective marker of Robusta coffee fermentation, were predominant throughout the processing. The process modulates volatiles without significantly affecting the total polyphenols (4.66%), chlorogenic acid (2.07%), caffeine (1.66%), trigonelline (0.53%) and theophylline (0.16%). HC contained compounds like 2-methoxy-4-vinyl phenol, 2-furancarboxaldehyde, 5-methyl-, acetic acid, pyrazine, methyl-, 2-propanone, 1-hydroxy-, and furfural that promotes sweet, caramelly, nutty, pungent and hazelnut taste to coffee.     

Influence of processing on the generation of γ-aminobutyric acid in green coffee beans

A determination of the concentrations of free amino acids in differently processed green coffees indicated the nonprotein amino acid -aminobutyric acid (GABA), a well-known plant stress metabolite, to be present in raw coffee beans (Coffea arabica L.) in significantly varying amounts. The GABA content of unwashed Arabica beans (green coffee produced by the dry processing method) was always markedly higher than that of washed Arabicas (wet processing method) as well as that of untreated seeds. This result underlined the assumption that during postharvest treatment a significant metabolism occurs within coffee seeds. A putative relation between drought stress of the coffee seeds and postharvest treatment methods is discussed. The GABA content of green coffee beans may serve as a potent tool to characterize the type of postharvest treatment applied in coffee processing.     

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。     

不同方法发酵的酸豆角品质对比分析

本文将研究不同方法发酵的酸豆角品质对比分析。选取质地嫩脆、条形均匀、无病虫害的新鲜豆角为泡制原料。采用自然干法发酵、自然湿法发酵与纯种湿法发酵的发酵方法制作酸豆角。检测发酵过程中,pH值、还原糖含量、总酸含量、总糖含量、亚硝酸盐含量以及氨基酸态氮含量,分析纯种湿法发酵与自然湿法发酵对酸豆角品质的影响。结果表明：纯种湿法发酵25 d后,其pH值和还原糖含量分别为3.92、0.03%,均高于自然湿法发酵;总酸、总糖、亚硝酸盐含量、氨基酸态氮含量分别为0.25%、0.04%、0.01 mg/kg和0.01%,均低于自然湿法发酵。另外,纯种湿法发酵酸豆角的甲氧基乙酸含量为0.37%,乙酸乙酯为0.51%,含水量为81.15%,感官评分为45.52,均高于自然干法发酵。纯种湿法发酵对酸豆角品质的效果最好,亚硝酸盐的含量在发酵后期显著降低,感官评分较高,对豆角工业化生产提供了较好的参考价值。     

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.     

响应面法优化发酵型黑米蜂蜜酒加工工艺

以黑米、蜂蜜和纯净水为主要原料,以感官评分为评价指标,考察原料比、酒曲添加量、发酵温度、发酵时间对发酵型黑米蜂蜜酒品质的影响,通过单因素和响应面试验优化黑米蜂蜜酒的最佳发酵工艺条件。结果表明,黑米蜂蜜酒的最佳发酵工艺条件为蜂蜜与黑米质量比6∶100、酒曲添加量0.6%、发酵温度33 ℃、发酵时间78 h。在此优化条件下,黑米蜂蜜酒的感官评分最高,为86分,酒精度为12.7%vol,总酸（以乙酸计）为4.5 g/L,挥发性酸（以乙酸计）为0.8 g/L,总糖为57.2 g/L。黑米蜂蜜酒颜色亮红,具有蜂蜜和黑米的独特风味,酒体协调,色泽均匀,底部无明显沉淀物,酒味浓郁,口感醇甜爽口。     

Determination of the complex permittivity of cherry,pulped, green,and roasted coffee using a planar dielectric platform and a coaxial probe between 0.3 and 6 GHz

The complex permittivity for four processing stages of coffee: coffee cherries, pulped coffee, green coffee, and roasted coffee was obtained and divided into two groups. The wet group is constituted by cherry and pulped coffee, and the dry group by green and roasted coffee. The wet group presented a dielectric constant between 64 and 43, and a loss factor between 34 and 12. The dry group has values oscillating between 1.55 and 1.1 for the dielectric constant, and 0.037 and 0.005 for the loss factor. The permittivity difference between the wet and dry groups suggests the dependence of the coffee permittivity on the water content, along with the presence of other polar compounds. A decaying response for the dielectric constant was seen, with a proportion of 30:1 from the wet to the dry group. The loss factor presents a convex response for the wet group and a constant response for the dry group with a factor of 500 to a 100:1 from the wet to the dry group. A set of 18 samples at every stage was used to estimate the moisture content by partial least squares. The Meyer and Schilz coefficient was used for these models, that resulted in prediction errors of 2.8% and 3.8% when compared to the stage mean moisture content for the wet group. The dry group resulted in errors of 21% and 89.7%. These results indicate that the complex permittivity of coffee is capable of estimating physicochemical variables as the moisture content of the beans at distinct processing stages.