荷叶盐渍和糖渍过程中苦涩味物质含量变化研究

对盐渍和糖渍处理过程中荷叶内的苦味和涩味代表物质-单宁和槲皮素含量进行动态监测,并结合感官实验对盐渍和糖渍处理过程中荷叶的苦味和涩味进行评定,结果显示:在盐渍和糖渍过程中,单宁和槲皮素的含量均有所下降。单宁含量分别下降了72.56%和71.15%;槲皮素的含量分别降低了29.79%和34.08%。荷叶碱含量上升,在盐渍和糖渍过程中分别增加了47.50%和76.14%。感官评价结果为,在盐渍15d,糖渍9d荷叶无明显苦涩味。荷叶盐渍15d和糖渍9d达到良好可食性。     

不同脱苦涩处理刺梨果汁风味品质分析

以刺梨果汁为原料,采用感官评定方法结合电子舌技术,探讨不同苦涩味的脱除方法对刺梨果汁风味品质的影响,并确定最佳脱除条件。结果表明：刺梨汁整体味感以酸味、涩味和苦味为主。添加剂组合方法脱除刺梨汁苦涩味效果明显优于单一方法,其最佳脱苦涩味的方法为添加质量分数0.12%单宁酶和质量分数0.015%三氯蔗糖,该方法处理的刺梨汁感官评定分值最高、结果最佳、口感适宜、苦涩味最轻,经电子舌检测在苦味和涩味2 个传感器上的响应值最小。在食品风味评价中,应将电子舌技术结合传统感官评定方法进行分析,利于获得更准确、可靠的结论。     

绿竹笋苦味物质成分分析

目的:确定绿竹笋(Dendrocalamopsisoldhami)主要苦味物质成分。方法:通过感官鉴定确定绿竹笋苦味部位主要在笋尖,并对笋基和笋尖中黄酮、生物碱、金属元素、氨基酸及氰化物的成分进行差异比较,初步确定主要苦味物质。结果:绿竹笋笋基中黄酮含量为笋尖的4倍;笋尖与笋基中生物碱及金属元素含量无显著差异;笋尖中苦味氨基酸含量为笋基的2.6倍;笋尖氰化物含量高达367.77 mg/kg·FW,为笋基部的36.38倍。结论:苦味氨基酸和氰化物含量与绿竹笋苦味相关,其中氰化物可能是绿竹笋的主要苦味物质。     

麻竹笋营养成分、风味物质和功能组分的研究进展

麻竹笋是我国常见竹笋中品质优良的一种禾本科植物, 常出现于南方地区, 其含糖率高, 富含氨基酸、膳食纤维等, 是一种营养丰富的天然优质食材, 深受人们的喜爱。本文首先系统综述了麻竹笋中的主要营养成分, 包括多糖、蛋白质、氨基酸、矿物质元素等物质; 总结了麻竹笋中的主要风味物质并明确了其关键醛类风味化合物, 对麻竹笋中苦涩风味的来源进行讨论, 发现单宁是引起麻竹笋苦味的主要原因, 简要总结了降低麻竹笋苦味的措施; 重点探讨了麻竹笋中的黄酮、多酚、甾醇等生物活性物质及其功能, 同时对膳食纤维在麻竹笋中发挥的功能性进行了简要的叙述。本综述可为麻竹笋的进一步应用推广, 尤其是功能产品的开发提供理论依据, 并为提高麻竹笋的利用率提供参考意义, 进而拉动产区的经济效益。     

多酚类物质与果汁口味关系

目的：研究不同果汁中多酚类物质的含量与组成，以及多酚类组分与果汁口味之间的内在关系。方法：以14种浓缩果汁样品为对象， 通过乙醇超声提取， HPLC-MS/MS法分析了果汁样品中15种多酚类物质的含量，利用相关分析、聚类分析等方法以及果汁7种口味(甜、酸、苦、咸、鲜、涩和辣)强度值，建立果汁感官评价体系及其分类，探索了果汁中多酚类物质与口味之间的联系。结果：14种果汁从口感上分为四类，分别是甜味、酸甜味、苦味和苦涩味。果汁样品中总多酚物质、总酚酸类物质、总黄酮类物质、绿原酸类物质和游离酚酸类物质的含量均与口味中的涩味得分显著正相关。结论：不同果汁中多酚类物质组成和含量差异很大，口感为苦味和涩味果汁多酚含量较高，多酚物质尤其是游离酚酸类物质是影响果汁涩味的关键因素。     

新鲜莲子不同组织涩味成分与关键酶基因差异表达分析

为探究新鲜莲子不同组织涩味物质的差异及其合成过程中的关键酶基因,研究了莲子种皮、去种皮后莲肉和莲心中可溶性单宁、不溶性单宁和原花青素含量,同时对单宁合成途径中关键酶活性和相关基因表达量进行测定,结合感官评价和电子舌检测,并采用正交偏最小二乘判别分析和相关性分析。结果表明：引起莲子涩味的主要物质为可溶性单宁;蜡熟期莲子中的单宁对其优良风味的形成具有正向作用;花青素还原酶是影响莲子涩味强度的关键酶,SnANR9影响莲子不同组织涩味物质的合成。     

基于电子舌的氯吡脲对草莓风味影响的研究

在草莓“甜查理”盛花后一周,喷施清水及4个浓度（2.5、5.0、10、20 mg/L）的氯吡脲,检测由此产生的草莓果实可溶性固形物、总酸、游离氨基酸、单宁等风味营养品质含量,电子舌分析技术检测酸、甜、苦、鲜、咸、涩味、苦味回味、涩味回味等味觉指标,评价氯吡脲的使用及浓度水平对草莓风味营养品质和滋味的影响,并分析电子舌在检测氯吡脲对草莓滋味影响方面运用的优势。结果表明：氯吡脲能够提高草莓果实的可溶性固形物的含量,降低总酸含量,提高固酸比值,降低游离氨基酸种类和游离氨基酸总量;低浓度（2.5、5.0 mg/L）的氯吡脲处理能降低草莓单宁含量,而高浓度（10、20 mg/L）处理会使单宁含量显著升高;电子舌味觉分析结果表明低浓度氯吡脲处理可使草莓甜味增加,酸味降低,但是咸味和鲜味及与其高度相关（相关系数均为0.99）的苦味也相应降低;游离氨基酸总量与鲜味值、单宁含量与涩味回味值、总酸含量与酸味值、固酸比与甜味值均呈正相关性。低浓度氯吡脲使用对草莓的甜味、酸味等滋味和风味组成具有正面影响,而无论氯吡脲浓度使用高低对咸味和鲜味等滋味和风味组成均有负面影响。     

绿茶滋味量化及其与化学组分的相关性研究

对绿茶滋味做分属性量化分析,探讨其与化学组分的相关性。以不同鲜叶原料、不同加工工艺的绿茶为代表,以茶叶中的谷氨酸钠、葡萄糖、咖啡碱和儿茶素EGCG等呈味单体作为标准滋味化学物质,建立鲜味、甜味、苦味和涩味等滋味分属性标准曲线。基于此标准曲线对茶汤滋味分属性进行量化分析,探讨茶汤化学组分与滋味分属性的相关性。研究结果表明,茶汤滋味、香气和感官总分三者之间呈显著正相关,茶汤整体滋味品质与鲜味和苦味分别呈显著正相关和显著负相关;鲜味与甜味、苦味与涩味之间具有显著正相关,而鲜味与苦味和涩味、甜味与苦味和涩味之间都呈显著负相关;茶汤中茶多酚、咖啡碱、水浸出物、没食子酸、儿茶素(EGCG、EGC、ECG及儿茶素总量)、苯丙氨酸含量都与苦味、涩味强度呈显著正相关,而与鲜味呈显著负相关;茶汤中总糖含量与甜味强度呈显著正相关;茶汤中谷氨酸含量与鲜味强度呈显著正相关,与苦味强度呈显著负相关。本研究实现了对茶叶滋味品质的定量分析,为茶叶分等分级和茶汤滋味化学研究提供理论基础。     

橡木对黄酒陈化效果的影响

研究橡木片对黄酒陈化效果的影响。选用2012年产的黄酒原酒,分别按0、3、6、9 g/L的添加量向其中加入橡木片。4 个月后对黄酒样品中的风味物质和游离氨基酸进行检测,并进行感官分析。结果表明：添加橡木片处理后,黄酒中高级醇类风味物质的种类和含量均显著减少,醛类风味物质的含量显著增加而种类呈现减少的趋势,酯类风味物质的种类和含量均显著增加（P＜0.05）,说明橡木可促进黄酒的陈化,加快了醇成醛、醇醛成缩醛、醇酸成酯、醛成酸等反应;苦味氨基酸中的苯丙氨酸、苏氨酸、精氨酸、组氨酸和涩味氨基酸中的酪氨酸、缬氨酸的含量均减少;综合黄酒中的风味物质、游离氨基酸变化以及感官评定的结果,表明当橡木片添加量为6 g/L时,贮存4 个月后的黄酒样品已具有较好的陈化效果。     

不同品种柿果成熟过程中果胶与单宁相互作用对其脱涩的影响

本文通过电子舌评价柿果胶与柿单宁体外相互作用的涩味强度,结果显示柿果胶能显著降低柿单宁涩味。为验证柿果成熟过程中果胶与单宁的相互作用是否是导致其脱涩的原因之一,本文研究了不同品种柿果(日本甜柿上西早生、中国甜柿鄂柿一号、涩柿恭城水柿)在成熟过程中的单宁及果胶含量变化及涩味变化,结合切片染色观察单宁果胶的形态分布,讨论了不同品种柿果成熟过程中果胶与单宁互作对其脱涩的影响。切片染色结果表明3品种柿果在成熟过程中单宁和果胶有可能相互接触并结合;2种甜柿的可溶性单宁含量在其成熟过程中均能降至0.1%以下,涩柿的可溶性单宁含量降至0.4%,3种柿果的水溶性果胶含量并未完全呈上升趋势,表明可溶性单宁可能与水溶性果胶结合,二者的结合是引起柿果脱涩的因素之一,且对不同品种柿果的影响程度不一。     

Effects of phenolics in sorghum grain on its bitterness,astringency and other sensory properties

Despite the fact that condensed tannins are potentially important antioxidants, there is a general belief that tannins in sorghum confer objectionable sensory attributes. The objective of this study was to determine differences in the sensory attributes of sorghums containing different levels of total phenolic compounds. A trained sensory panel described and quantified the sensory attributes of different sorghums (condensed‐tannin containing and tannin‐free). All the sorghum cultivars were perceived as bitter and astringent. Bran infusions of tannin sorghums were perceived as darker, clearer, more bitter and more astringent than those of the tannin‐free sorghums, while those of tannin‐free sorghums were perceived as sweeter and cloudy. Sorghum whole‐grain rice from the tannin sorghums which had relatively soft endosperm texture (PAN 3860 and Ex Nola 97 GH) was perceived as dark, hard, chewy, bitter and astringent, while that from tannin‐free sorghums having relatively hard endosperm texture (Segaolane and Phofu) was perceived as soft, sweet and had a maize‐flavour. Surprisingly, the bitterness and astringency, as well as other sensory attributes of NS 5511 (tannin sorghum), were perceived as similar to PAN 8564 (tannin‐free sorghum) even though NS 5511 had more than twice the total phenol content of PAN 8564. This suggests not all condensed‐tannin containing sorghums have objectionable sensory attributes. Copyright © 2007 Society of Chemical Industry     

Bitterness and astringency of grape and wine polyphenols

Extracts containing anthocyanins (ACN), and skin tannins (SKIN) and seed tannins (SEED) were prepared from Vitis vinifera cv. Cabernet Franc grapes grown in the Loire Valley, and characterised. Phenolic fractions from Cabernet Franc wines made from three Loire Valley locations were also isolated and characterised. Bitterness and astringency of ACN, SEED and SKIN as well as the wine extracts were evaluated by time intensity procedures in citric acid solution and in a base white wine. SEED and SKIN were equally astringent when tasted at the same concentration in spite of differences in tannin composition. The lower molecular weight (MW) of SEED was equal in astringency to larger MW SKIN which had a lower percentage of galloylation. The SEED fraction was slightly more bitter than the SKIN fraction in the citric acid solution, although no difference could be detected between samples in base white wine. Astringency of ACN alone was much lower than either SKIN or SEED. Addition of ACN to either tannin fraction produced very small sensory effects in citric acid. In wine, addition of ACN to either SEED or SKIN increased astringency significantly over either fraction alone, but had no effect on bitterness. The wine fractions differed only in astringency, which was correlated with tannin units as determined by thiolysis.     

定量描述分析在茶汤滋味评定中的应用

目的研究用量化数据来判断茶叶的滋味品质,并确定茶叶感官品质特征与化学成分间的相关性。方法采用定量描述分析方法,对同一鲜叶原料加工的炒青、云尖和龙井的8种感官滋味特征分别进行定量描述,并绘制出反映滋味特征的雷达图,应用Excel和SPSS18.0软件进行相关的数据分析。结果云尖在苦度、浓度、强度和涩度这4个感官特性上要弱于炒青和龙井,在鲜度这一感官特性上要强于炒青和龙井;8种茶汤滋味特征中的浓度、鲜度、苦度、涩度与茶叶化学成分具有相关性。结论定量描述分析方法可以有效地判别茶叶滋味特征,更直观地表现茶叶的滋味差异,阐明了浓度、鲜度、苦度、涩度与不同茶叶化学物质间的相关性。     

Application of the dual attribute time‐intensity (DATI) sensory method to the temporal measurement of bitterness and astringency in sorghum

Bitterness and astringency are attributes generally cited as the cause of tannin sorghums being unpalatable. The objective here was to determine the effect of sorghums with varying tannin content on bitterness and astringency simultaneously using dual attribute time‐intensity (DATI). A trained panel assessed bitterness and astringency of bran infusions of tannin and tannin‐free sorghums. In both sorghum types, bitterness developed and reached maximum intensity faster (T_max 22.5 s; P < 0.001) than astringency (27.9 s). The duration of the astringent sensation (D_tot 69.9 s) lasted longer than bitterness (66.3 s). Overall, the temporal parameters for bitterness distinguished infusions from tannin and tannin‐free sorghums slightly more clearly than those for astringency. The research established that, for sorghum, bitterness and astringency are related. The DATI method also revealed that panellists’ perceptions of the time course of bitterness and astringency differ.     

基于电子舌技术的红茶滋味品质评价

目的研究电子舌技术在红茶滋味品质评价上的应用,探索电子舌评价结果同人工感官滋味审评结果间的关系。方法采用电子舌传感器响应值及滋味分值结合主成分分析、聚类分析等方法进行红茶滋味的评价,并同人工感官滋味结果进行比较;绘制滋味雷达图、酸鲜味等级评价图、滋味分属性间及感官滋味的相关性表。结果利用电子舌测定的数据结合主成分分析和聚类分析对茶样进行的分类结果同感官滋味分类结果一致;不同类别间的茶样滋味特点不同,滋味口感好的茶样鲜味强度值高而苦涩味值低;分属性滋味间的相关性显著。结论电子舌技术在红茶滋味的评价上有较好的应用,可以定性的区分不同滋味等级的茶样,且能定量的给出不同茶样间的酸、甜、苦、咸、鲜滋味的相对强度分值。     

Sensory assessment and chemical measurement of astringency of Greek wines: Correlations with analytical polyphenolic composition

The purpose of this study was to measure the astringency of selected Greek red wines and to assess the relationship between sensory and chemical data. Nine red wines produced by three native Greek grape varieties (agiorgitiko, xinomavro and mavrodafni) were used and their astringency and bitterness was assessed by a trained panel. In addition, their astringency was estimated chemically employing the ovalbumin precipitation method. Their polyphenolic composition was also determined by High Performance Liquid Chromatography (HPLC). The sensory data showed that mandilaria was the most astringent variety whereas agiorgitiko was the least. Statistical analysis of the results indicated that the chemical data obtained for astringency significantly correlated with the sensory determinations. In addition, significant correlations were obtained between the sensory data and the wine polyphenolic composition.     

蛋白酶处理对脱脂乳感官品质及游离氨基酸的影响

以新鲜脱脂牛乳为原料,采用分光测色仪、电子舌及氨基酸自动分析仪等分析酶解处理对脱脂牛乳感官品质、游离氨基酸含量及组成的影响。结果表明：经风味蛋白酶处理的脱脂牛乳水解度高,达到24.61%;蛋白酶处理会导致其感官性状的改变,与脱脂牛乳相比,3?种酶解产物L*值均显著（P＜0.05）下降,a*（负值）显著上升（P＜0.05）,风味蛋白酶处理对脱脂牛乳色泽影响大于碱性蛋白酶、复合蛋白酶处理;不同酶解产物滋味轮廓之间存在较大差异,与脱脂牛乳相比其甜味值下降显著,且随酶解时间延长,苦味值上升,甜味值衰退,碱性蛋白酶处理的酶解产物以涩味及涩味回味为主,风味蛋白酶的酶解产物以咸、苦味及苦味回味为主,复合蛋白酶的酶解产物以酸味为主,苦涩等味觉较低,电子舌能较好地区分不同酶解物的滋味差异;酶解处理可使脱脂牛乳中的游离氨基酸及必需氨基酸含量显著增加,苦味氨基酸为主要呈味氨基酸。酶解处理及酶解进程会使脱脂牛乳色泽、滋味及游离氨基酸产生变化,其中风味蛋白酶处理产生的影响大于碱性蛋白酶和复合蛋白酶处理。